JP2014005461A - Copolymer, organic semiconductor material, organic electronic device, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copolymer which can be used as a semiconductor material and is highly stable when prepared as a solution.SOLUTION: The copolymer contains a repeating unit represented by formula (1A) and a repeating unit represented by formula (1B).

Description

  The present invention relates to copolymers, and organic semiconductor materials, organic electronic devices and solar cell modules containing the copolymers.

  A π-conjugated polymer is used as a semiconductor material for organic electronic devices such as organic solar cells, organic EL elements, organic thin film transistors, and organic light emitting sensors. In particular, in an organic solar cell, it is desired to improve sunlight absorption efficiency, and it is important to develop a polymer that can absorb light having a long wavelength (600 nm or more). In order to achieve a longer absorption wavelength, an example in which a copolymer of a donor monomer and an acceptor monomer (hereinafter sometimes referred to as a copolymer) is used for a photoelectric conversion element has been reported.

  Specifically, Non-Patent Document 1 describes a photoelectric conversion element using a copolymer having an imidothiophene skeleton and a dithienocyclopentadiene skeleton. Non-Patent Documents 1, 2, 3 and Patent Document 1 describe photoelectric conversion elements using a copolymer having an imidothiophene skeleton and a dithienosilole skeleton. Further, Non-Patent Document 2 describes a photoelectric conversion element using a copolymer having an imidothiophene skeleton and a dithienogermol skeleton.

International Publication No. 2011/028827

J. et al. Mater. Chem. , 2011, 21, 3895-3902 J. et al. Am. Chem. Soc. , 2011, 133, 10062-10065 Chem. Commun. , 2011, 47, 4920-4922.

  In order to fabricate an organic electronic device more easily, a solution in which an organic semiconductor material is dissolved (hereinafter sometimes referred to as ink) is produced, and the organic semiconductor material is formed by applying the ink. desirable. However, as a result of studies by the inventors of the present application, an ink containing the above-described copolymer synthesized with a higher molecular weight and an organic solvent has found a problem that it gels only by standing at room temperature for a few minutes. It was done.

  An object of the present invention is to provide a copolymer that can be used as a semiconductor material and has high stability when in solution.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found a copolymer containing a repeating unit having a dioxopyrrole condensed ring skeleton and a repeating unit having a dithieno condensed ring skeleton, wherein the dioxopyrrole condensed ring A copolymer having a linear alkyl group having 10 or more carbon atoms and a dithieno condensed ring having a branched alkyl group was found to have high stability when in solution, and the present invention was completed based on this finding.

（式（１Ａ）中、Ａは周期表第１６族から選ばれる原子を表し、Ｒ^１は直接結合又は置換基を有していてもよい２価の有機基を表し、Ｒ^２は置換基を有していてもよい炭素数１０以上の直鎖アルキル基を表す。）

（式（１Ｂ）中、Ｑは周期表第１４族元素から選ばれる原子を表し、Ｒ^３は置換基を有していてもよい分岐アルキル基を表し、Ｒ^４は置換基を有していてもよい直鎖アルキル基、置換基を有していてもよい分岐アルキル基、置換基を有していてもよいシクロアルキル基、置換基を有していてもよい芳香族炭化水素基、置換基を有していてもよい脂肪族複素環基又は置換基を有していてもよい芳香族複素環基を表す。）
［２］下記式（２）で表される繰り返し単位を含むことを特徴とする、［１］に記載のコポリマー。

（式（２）中、Ａは周期表第１６族元素から選ばれる原子を表し、Ｑは周期表第１４族元素から選ばれる原子を表し、Ｒ^１は直接結合又は置換基を有していてもよい２価の有機基を表し、Ｒ^２は置換基を有していてもよい炭素数１０以上の直鎖アルキル基を表し、Ｒ^３は置換基を有していてもよい分岐アルキル基を表し、Ｒ^４は置換基を有していてもよい直鎖アルキル基、置換基を有していてもよい分岐アルキル基、置換基を有していてもよいシクロアルキル基、置換基を有していてもよい芳香族炭化水素基、置換基を有していてもよい脂肪族複素環基又は置換基を有していてもよい芳香族複素環基を表す。）
［３］［１］又は［２］に記載のコポリマーを含むことを特徴とする、有機半導体材料。
［４］［３］に記載の有機半導体材料を含むことを特徴とする、有機電子デバイス。
［５］光電変換素子であることを特徴とする、［４］に記載の有機電子デバイス。
［６］太陽電池であることを特徴とする、［４］に記載の有機電子デバイス。
［７］［６］に記載の有機電子デバイスを備えることを特徴とする、太陽電池モジュール。 That is, the gist of the present invention is as follows.
[1] A copolymer comprising a repeating unit represented by the following formula (1A) and a repeating unit represented by the formula (1B).

(In formula (1A), A represents an atom selected from Group 16 of the periodic table, R ¹ represents a divalent organic group which may have a direct bond or a substituent, and R ² represents a substituent. Represents a linear alkyl group having 10 or more carbon atoms which may be present.)

(In formula (1B), Q represents an atom selected from Group 14 elements of the periodic table, R ³ represents a branched alkyl group which may have a substituent, and R ⁴ has a substituent. A linear alkyl group which may have a substituent, a branched alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, a substituent It represents an aliphatic heterocyclic group which may have an aromatic heterocyclic group which may have a substituent.
[2] The copolymer according to [1], comprising a repeating unit represented by the following formula (2).

(In Formula (2), A represents an atom selected from Group 16 elements of the Periodic Table, Q represents an atom selected from Group 14 Elements of the Periodic Table, and R ¹ has a direct bond or a substituent. Represents a divalent organic group, R ² represents a linear alkyl group having 10 or more carbon atoms which may have a substituent, and R ³ represents a branched alkyl group which may have a substituent. R ⁴ represents a linear alkyl group that may have a substituent, a branched alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may be substituted, an aliphatic heterocyclic group which may have a substituent, or an aromatic heterocyclic group which may have a substituent.
[3] An organic semiconductor material comprising the copolymer according to [1] or [2].
[4] An organic electronic device comprising the organic semiconductor material according to [3].
[5] The organic electronic device according to [4], which is a photoelectric conversion element.
[6] The organic electronic device according to [4], which is a solar cell.
[7] A solar cell module comprising the organic electronic device according to [6].

  A copolymer that can be used as a semiconductor material and has high stability when in solution can be provided.

It is sectional drawing which shows typically the structure of the photoelectric conversion element as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell module as one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent requirements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not specified in these contents unless it exceeds the gist.

<1. Copolymer according to the present invention>
The copolymer according to the present invention includes a repeating unit represented by the following formula (1A) and a repeating unit represented by the formula (1B). The copolymer according to the present invention is suitable for coating film formation because it is difficult to gel when dissolved. Further, the copolymer according to the present invention is preferable in that the light absorption wavelength region is at a longer wavelength, the light absorption is high, and the mobility is higher. Further, the copolymer according to the present invention is preferable in that a high molecular weight product is easily obtained.

  In formula (1A), A represents an atom selected from Group 16 of the periodic table. Specific examples of A include an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Among these, an oxygen atom, a sulfur atom or a selenium atom is preferred from the viewpoint of ease of synthesis, more preferably a sulfur atom or an oxygen atom, and particularly preferably a sulfur atom.

In formula (1B), Q represents an atom selected from Group 14 elements of the periodic table. Specific examples of atoms selected from Group 14 elements of the periodic table include carbon atoms, silicon atoms, germanium atoms, tin atoms, and lead atoms. Q is preferably a carbon atom, a silicon atom, a germanium atom and a tin atom, and more preferably a carbon atom, a silicon atom and a germanium atom. More preferably, they are a silicon atom or a germanium atom. Since silicon atoms and germanium atoms have a larger atomic radius than carbon atoms, steric hindrance due to substituents R ^{3 to} R ⁴ that inhibit π-π stacking can be reduced. This is preferable in that the intermolecular interaction between the copolymers can be maintained moderately.

In Formula (1A), R ¹ represents a divalent organic group which may have a direct bond or a substituent. The number of carbon atoms of the divalent organic group is preferably 1 or more and 20 or less. Examples of the divalent organic group include an alkylene group, an alkenylene group, an alkynylene group, an arylene group, and a heteroarylene group. Among these, R ¹ is preferably a direct bond, an alkylene group or an arylene group from the viewpoint of the stability of the copolymer according to the present invention, and particularly preferably a direct bond or an arylene group.

  Examples of the alkylene group include a linear alkylene group such as a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, or a hexylene group; a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclo A cycloalkylene group such as an octylene group, a dicyclopentylene group or a tricyclopentylene group; or a branched alkylene group such as a methylethylene group. Of these, a cycloalkylene group or a branched alkylene group is preferable in terms of improving solubility.

  Examples of the alkenylene group include vinylene group and propenylene. Of these, a vinylene group is preferable.

  Examples of the arylene group include 1,4-phenylene group, 1,3-phenylene group, 1,2-phenylene group, naphthylene group, anthrylene group, pyrenylene group, phenanthrylene group, biphenylene group, and triphenylene group. Of these, a 1,4-phenylene group, a 1,3-phenylene group, a 1,2-phenylene group, or a naphthylene group is more preferable. From the viewpoint of improving the solubility of the copolymer according to the present invention, the arylene group is particularly preferably a phenylene group.

  Examples of the heteroarylene group include a thienylene group, a furylene group, and a pyridylene group. From the viewpoint of improving the solubility of the copolymer according to the present invention, the arylene group is preferably a monocyclic heterocyclic group, and particularly preferably a thienylene group.

  In the present specification, the substituent that each group may “have” is not particularly limited as long as the effects of the present invention are not impaired, but preferably a halogen atom, a hydroxyl group, a carboxyl group, a carbamoyl group, an acyl group. Group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, boryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, amino group, substituted amino group , A silyl group, a substituted silyl group, an aliphatic heterocyclic group, an aromatic hydrocarbon group or an aromatic heterocyclic group. Among these, an alkoxy group or an alkylthio group is preferable because the intramolecular polarity of the copolymer according to the present invention can be controlled.

In Formula (1A), R ² represents a linear alkyl group having 10 or more carbon atoms which may have a substituent. The linear alkyl group has 10 or more carbon atoms, preferably 12 or more, and is usually 40 or less, preferably 25 or less, more preferably 20 or less, still more preferably 16 or less.

  Examples of linear alkyl groups include n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n -Octadecyl group, n-nonadecyl group, n-icosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n -Octacosyl group, n-nonacosyl group, n-triacontyl group, n-hentriacontyl group, n-dotriacontyl group, n-tritriacontyl group, n-tetratriacontyl group, n-pentatriacontyl group, n -A hexatriacontyl group or an n-tetracontyl group is exemplified. Among these, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group are preferable. , N-nonadecyl group, n-icosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group or n-pentacosyl group, more preferably n-decyl group, n-undecyl group Group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group or n-hexadecyl group.

Preferable examples of the substituent that R ² may have include a substituent composed of an atom selected from the group containing a hydrogen atom and a hetero atom, such as a halogen atom. It is also preferable that R ² is a linear alkyl group having no substituent.

It is preferable that R ² is a linear alkyl group having 10 or more carbon atoms in that the solubility of the copolymer according to the present invention in an organic solvent can be easily improved and the copolymer according to the present invention can be easily formed by coating. . Further, it is also preferable in that storage stability can be improved by suppressing the precipitation or gelation of the copolymer when the copolymer according to the present invention is used as a solution.

In formula (1B), R ³ represents a branched alkyl group. Since R ³ is a branched alkyl group, the solubility of the copolymer according to the present invention in an organic solvent is improved, so that a high molecular weight copolymer is easily obtained, and gelation is suppressed when the copolymer is used as a solution. It is preferable in that the storage stability can be improved.

  Examples of the branched alkyl group include a branched primary alkyl group, a branched secondary alkyl group, and a branched tertiary alkyl group. The branched primary alkyl group means a branched alkyl group having two hydrogen atoms bonded to a carbon atom having a free valence. The branched secondary alkyl group means a branched alkyl group having one hydrogen atom bonded to a carbon atom having a free valence. The branched tertiary alkyl group means a branched alkyl group having no hydrogen atom bonded to a carbon atom having a free valence. Here, the free valence refers to a substance that can form a bond with another free valence as described in the organic chemistry / biochemical nomenclature (above) (Revised 2nd edition, Nankodo, 1992).

  Examples of the branched primary alkyl group include 2-ethylhexyl group, 2-methylpropyl group, 2-ethylhexyl group, 2,2-dimethylpropyl group, 2-methylbutyl group, 2-ethylbutyl group, and 2,4-dimethylhexyl. Group, 2-methylpentyl group, 2,4,4-trimethylpentyl group, 2,3-dimethylbutyl group, 2,6-dimethylheptyl group, 2-hexyldecyl group, 2,2-dimethylbutyl group, 2 -Methylheptyl group, 2-methylhexadecyl group, 2-butyloctyl group, 2-methylnonyl group, 2-propylpentyl group, 2-methylundecyl group, 2-hexyloctyl group, 2-methyloctyl group, 2- Examples thereof include a methyldecyl group, a 2-methyldodecyl group, and a 2,5-dimethylhexyl group. Among them, 2-ethylhexyl group, 2,4-dimethylhexyl group, 2,4,4-trimethylpentyl group, 2,6-dimethylheptyl group, 2-hexyldecyl group, 2-methylheptyl group, 2-butyl Octyl group, 2-methylnonyl group, 2-propylpentyl group, 2-methylundecyl group, 2-hexyloctyl group, 2-methyloctyl group, 2-methyldecyl group, 2-methyldodecyl group or 2,5-dimethylhexyl Group is preferable, and 2-ethylhexyl group, 2-hexyldecyl group, 2-butyloctyl group or 2-hexyloctyl group is more preferable.

  Examples of the branched secondary alkyl group include isopropyl group, 1-methylpropyl group, 1-methylbutyl group, 1-methylheptyl group, 1-propylpentyl group, 1-ethylhexyl group, 1-ethylpropyl group, 1-methyl. Pentyl group, 1-ethylpentyl group, 1-butylpentyl group, 1-methyloctyl group, 1-ethylbutyl group, 1-ethyl-2-methylpropyl group, 1,5-dimethylhexyl group, 1-butylheptyl group, 1-methylundecyl group, 1,2-dimethylpropyl group, 1,3-dimethylbutyl group, 1-ethyloctyl group, 1-propylhexyl group, 1,2-dimethylpentyl group, 4-ethyl-1-methyl Octyl group, 1-ethylundecyl group, 4-methyl-1-propylhexyl group, 1-hexylheptyl group, 1,3-dimethylpen Group, 1-ethyl-2-methylpentyl group, 1,2-dimethylpentyl group, 1-butylhexyl group, 1-methyltridecyl group, 1-methylpentadecyl group, 1,3-dimethyldecyl group, 1 , 3,5-trimethylhexyl group, 3-ethyl-1,5-dimethylnonyl group, 1-propylheptyl group and the like. Among them, 1-methylpropyl group, 1-methylbutyl group, 1-methylheptyl group, 1-propylpentyl group, 1-ethylhexyl group, 1-methylpentyl group, 1-ethylpentyl group, 1-methyloctyl group, 1 -Ethylbutyl group, 1-ethyl-2-methylpropyl group, 1,5-dimethylhexyl group, 1-butylheptyl group, 1,2-dimethylpropyl group, 1,3-dimethylbutyl group, 1-ethyloctyl group, 1-propylhexyl group, 1,2-dimethylpentyl group, 4-ethyl-1-methyloctyl group, 4-methyl-1-propylhexyl group, 1,3-dimethylpentyl group, 1-ethyl-2-methylpentyl Group, 1,2-dimethylpentyl group, 1-butylhexyl group, 1,3,5-trimethylhexyl group, 3-ethyl-1,5-dimethylnonyl Group or 1-propylheptyl group, more preferably 1-propylpentyl group, 1-ethylhexyl group, 1-ethylpentyl group, 1-ethylbutyl group, 1-ethyl-2-methylpropyl group, 1-butylheptyl group. 1-ethyloctyl group, 1-propylhexyl group, 4-ethyl-1-methyloctyl group, 4-methyl-1-propylhexyl group, 1-ethyl-2-methylpentyl group, 1-butylhexyl group, 3 -Ethyl-1,5-dimethylnonyl group or 1-propylheptyl group.

  Examples of the branched tertiary alkyl group include a t-butyl group, 1- (1-methylethyl) -1-methylpentyl group, 1-ethyl-1,3,3-trimethylbutyl group, 1-ethyl-1, 3-dimethylpentyl group, 3-ethyl-1,1-dimethylpentyl group, 2-ethyl-1,1-dimethylpentyl group, 1,1,3,4-tetramethylpentyl group, 1,1,3,3 -Tetramethylpentyl group, 1,1,4-trimethylhexyl group, 1,1,3-trimethylhexyl group, 1,1,2-trimethylhexyl group, 1,1-diethyl-2-methylpropyl group, 1- Ethyl-1,2-dimethylpropyl group, 1,1-dipropylpentyl group, 1,1-dimethyldodecyl group, 1,1,5-trimethylhexyl group, 1,1-dibutyldodecyl group, 1-butyl-1 -Ethyl Xyl group, 1,1,4-trimethylpentyl group, 1- (2-methylpropyl) -1-methylpentyl group, 1,3-dimethyl-1- (2-methylpropyl) butyl group, 3-methyl-1 -(2-methylpropyl) butyl group, 2,2-dimethyltetracosyl group, 1-ethyl-1-propylpentyl group, 1,3,3,5,5-pentamethylhexyl group, 1-ethyl-1 , 2,2-trimethylpropyl group, 1,1,2,3,3-pentamethylhexyl group, 1,1-dimethylnonyl group, 1-ethyl-1,4-dimethylpentyl group, 1,1,2- Trimethylpropyl group, 1,1-dimethylheptyl group, 1-ethyl-1-methylpentyl group, 1,1-dimethyldecyl group, 1,1-dimethyloctyl group, 1,1-bis (1-methylethyl)- 2-methylpropi Group, 1- (1-methylethyl) -1,2-dimethylbutyl group, 1,1-dimethyloctadecyl group, 1- (2-methylpropyl) -1,3,3-trimethylbutyl group, 1-ethyl- 1,3-dimethylbutyl group, 1,1-dimethylundecyl group, 1,1-diethylpropyl group, 1,1-dimethylpentyl group, 1-propyl-1,2-dimethylbutyl group, 2-methyl-1 -(1-methylethyl) propyl group, 1,1-dibutylpentyl group, 1-butyl-1-propylpentyl group, 1,1-dipropylbutyl group, 1,1,3,3-tetramethylbutyl group, 1,1-dimethylhexadecyl group, 1,1-dibutyl-4-methylpentyl group, 1,4-dimethyl-1- (2-methylpropyl) pentyl group, 1-butyl-1,4-dimethylpentyl group, 1-Buchi 1-ethylpentyl group, 1-butyl-1-methylpentyl group, 1-ethyl-1-methylhexyl group, 1-methyl-1-propylpentyl group, 1-hexyl-1-methylnonyl group, 1-ethyl -1-methylpropyl group, 1- (2-ethylhexyl) -1-methyldodecyl group, 1,1-bis (2-ethylhexyl) -3-ethylheptyl group, 1,1-dioctylnonyl group or 1,1, Examples include 2,2-tetramethylpropyl group. Of these, a t-butyl group or a 1,1-dimethylpropyl group is preferable, and a t-butyl group is more preferable.

Preferable examples of the substituent that R ³ may have include a substituent made of an atom selected from the group containing a hydrogen atom and a hetero atom, such as a halogen atom. It is also preferable that R ³ is a branched alkyl group having no substituent.

In formula (1B), R ⁴ represents a linear alkyl group which may have a substituent, a branched alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, a substituted group. An aromatic hydrocarbon group which may have a group, an aliphatic heterocyclic group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. In particular, R ⁴ may have a linear alkyl group that may have a substituent, an aromatic hydrocarbon group that may have a substituent, or the point that the solubility of the copolymer according to the present invention can be improved. An aromatic heterocyclic group which may have a substituent is preferable. The substituent which may have is preferably a substituent consisting of an atom selected from the group containing a hydrogen atom and a hetero atom, such as a halogen atom. Further, as a substituent which the cycloalkyl group, aromatic hydrocarbon group, aliphatic heterocyclic group and aliphatic aromatic ring group may have, a branched alkyl group such as 2-ethylhexyl group, or n- A linear alkyl group such as an octyl group is also included.

Examples of the branched alkyl group include the same as those mentioned for R ³ . When R ⁴ is a branched alkyl group, R ⁴ may be the same as or different from R ³ .

  The linear alkyl group has, for example, 1 or more carbon atoms, preferably 3 or more, more preferably 4 or more, and 40 or less, preferably 20 or less, more preferably 16 or less, and still more preferably 12 or less. Can be mentioned. Examples of linear alkyl groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, n-triacontyl group, n-hentriacontyl group, n-dotriacontyl group, n-tritriacontyl group, n-tetratriacontyl group, n-pentato Akonchiru group, n- hex triacontyl group or n- tetracontyl group.

  Among these, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-icosyl group, n-henicosyl group, n-docosyl group, n-tricosyl group, n-tetracosyl group, n-pentacosyl group, n-hexacosyl group, n-heptacosyl group, n-octacosyl group, n-nonacosyl group, n-triacontyl group, n-hentriacontyl group Group, n-dotriacontyl group, n-tritriacontyl group, n-tetratriacontyl group, n-pentatriacontyl group, n-hexato An acontyl group or an n-tetracontyl group, more preferably n-- in that the intermolecular distance of the copolymer is not too great so as to maintain high solubility of the copolymer according to the present invention and promote charge transfer. It is a butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group or n-dodecyl group.

  Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cyclolauryl group. Of these, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group or a cyclooctyl group is preferable.

  Examples of the aromatic hydrocarbon group include those having 6 or more carbon atoms and 30 or less, preferably 20 or less, more preferably 14 or less. Examples of such an aromatic hydrocarbon group include a phenyl group, a naphthyl group, an indane group, an indene group, a fluorene group, an anthracene group, and an azulene group. Of these, a phenyl group or a naphthyl group is preferable.

  Examples of the aliphatic heterocyclic group include those having 2 or more carbon atoms, 20 or less, preferably 14 or less, more preferably 12 or less, still more preferably 10 or less, and particularly preferably 6 or less. . Examples of such an aliphatic heterocyclic group include an oxetanyl group, a pyrrolidinyl group, a tetrahydrofuryl group, a tetrahydrothienyl group, a piperidinyl group, a tetrahydropyranyl group, and a tetrahydrothiopyranyl group.

  Examples of the aromatic heterocyclic group include those having 2 or more carbon atoms and 30 or less, preferably 20 or less, more preferably 14 or less. Examples of such aromatic heterocyclic groups include thienyl, furanyl, pyridyl, pyrimidyl, thiazolyl, oxazolyl, triazolyl, benzothiophenyl, benzofuranyl, benzothiazolyl, and benzoxazolyl groups. Or a benzotriazolyl group etc. are mentioned. Of these, a thienyl group, a pyridyl group, a pyrimidyl group, a thiazolyl group, or an oxazolyl group is preferable.

When the substituents (R ¹ and R ² ) on the dioxopyrrole fused ring have a linear alkyl group having 10 or more carbon atoms, the degree of freedom of the substituents (R ¹ and R ² ) is further increased, The distance can be moderately separated. Further, when the dithieno condensed ring has a branched alkyl group as a substituent, an appropriate steric hindrance is introduced around the dithieno condensed ring. Since the substituent on the dioxopyrrole condensed ring has a linear alkyl group having 10 or more carbon atoms and the dithieno condensed ring has a branched alkyl group as a substituent, a dithieno condensed ring is formed between a plurality of copolymer chains. The intermolecular interaction between the dioxopyrrole fused rings and / or between the dithieno fused rings is appropriately adjusted. Therefore, even if the copolymer according to the present invention has a high molecular weight, the solubility is improved and the aggregation, crystallization, or gelation of the copolymer is suppressed, so that the stability of the ink containing the copolymer is improved. sell.

  The copolymer according to the present invention may contain two or more of each one or more of the repeating unit represented by the formula (1A) and the repeating unit represented by the formula (1B).

  The copolymer according to the present invention may contain a repeating unit other than the repeating unit represented by the formula (1A) or (1B) as long as the effects of the present invention are not impaired. The ratio of the total of the repeating units represented by the formula (1A) and the repeating units represented by the formula (1B) to the repeating units constituting the copolymer according to the present invention is not particularly limited, but is usually 2 mol. % Or more, preferably 10 mol% or more, more preferably 25 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, and even more preferably 90% or more. Particularly preferably, the copolymer according to the present invention comprises a repeating unit represented by the formula (1A) and a repeating unit represented by the formula (1B) and is composed only of these repeating units, or these repeating units. A polymer chain containing units and composed only of these repeating units is included.

  The ratio of the repeating unit represented by the formula (1A) in the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 2 mol% or more, more preferably It is 10 mol% or more, more preferably 30 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.

  The ratio of the repeating unit represented by the formula (1B) to the repeating units constituting the copolymer according to the present invention is not particularly limited, but is usually 1 mol% or more, preferably 10 mol% or more, more preferably It is 30 mol% or more. On the other hand, it is usually 99 mol% or less, preferably 90 mol% or less, more preferably 70 mol% or less.

  The number ratio of repeating units represented by the formula (1B) to the number of repeating units represented by the formula (1A) in the copolymer according to the present invention (1B / 1A) is not particularly limited. Usually, it is 0.01 or more, preferably 0.1 or more, more preferably 0.5 or more. On the other hand, it is usually 100 or less, preferably 10 or less, more preferably 2 or less.

  In the copolymer according to the present invention, the arrangement state of the repeating units represented by the formula (1A) and the formula (1B) may be alternating, block, or random. That is, the copolymer according to the present invention may be an alternating copolymer, a block copolymer, or a random copolymer. In addition, a copolymer having an intermediate structure among these copolymers, for example, a random copolymer having a block property may be used. Also included are copolymers and dendrimers that are branched in the main chain and have three or more terminal portions.

  Especially, it is preferable that the copolymer which concerns on this invention has a repeating unit represented by following formula (2). A copolymer having a repeating unit represented by the following formula (2) is preferable in that the charge separation state can be more easily maintained.

In formula (2), A represents an atom selected from Group 16 elements of the periodic table. A is the same as A in Formula (1A). Q represents an atom selected from Group 14 elements of the Periodic Table. Q is the same as Q in Formula (1B). R ¹ represents a divalent organic group which may have a direct bond or a substituent. R ² represents a linear alkyl group having 10 or more carbon atoms which may have a substituent. R ³ represents a branched alkyl group which may have a substituent. R ⁴ has a linear alkyl group which may have a substituent, a branched alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may be substituted, an aliphatic heterocyclic group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. R ¹ to R ⁴ are the same as ^R 1 to R ⁴ in formula (1A) and (1B).

  The copolymer according to the present invention may contain two or more repeating units represented by the formula (2). Moreover, the copolymer which concerns on this invention may contain repeating units other than the repeating unit represented by Formula (2) in the range which does not impair the effect of this invention. The ratio of the repeating unit represented by the formula (2) to the repeating unit constituting the copolymer according to the present invention is not particularly limited, but is usually 2 mol% or more, preferably 10 mol% or more, more preferably It is 25 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more, and still more preferably 90% or more. Particularly preferably, the copolymer according to the present invention comprises only a repeating unit represented by the formula (2) or contains a polymer chain composed only of this repeating unit.

  Preferred specific examples of the copolymer according to the present invention are shown below. However, the copolymer according to the present invention is not limited to the following examples.

The polystyrene-converted weight average molecular weight (Mw) of the copolymer according to the present invention is usually 2.0 × 10 ⁴ or more, preferably 3.0 × 10 ⁴ or more, more preferably 4.0 × 10 ⁴ or more, and still more preferably. It is 5.0 × 10 ⁴ or more, more preferably 7.0 × 10 ⁴ or more, and particularly preferably 1.0 × 10 ⁵ or more. On the other hand, it is preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, and particularly preferably 5.0 × 10 ⁵ or less. The weight average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

The polystyrene-reduced number average molecular weight (Mn) of the copolymer according to the present invention is usually 5.0 × 10 ³ or more, preferably 1.0 × 10 ⁴ or more, more preferably 2.0 × 10 ⁴ or more, and still more preferably. It is 2.5 × 10 ⁴ or more, particularly preferably 3.0 × 10 ⁴ or more. On the other hand, it is preferably 1.0 × 10 ⁷ or less, more preferably 1.0 × 10 ⁶ or less, further preferably 5.0 × 10 ⁵ or less, even more preferably 2.0 × 10 ⁵ or less, and particularly preferably 1 0.0 × 10 ⁵ or less. The number average molecular weight is preferably in this range from the viewpoint of increasing the light absorption wavelength, from the viewpoint of realizing high absorbance, from the viewpoint of realizing high carrier movement, and from the viewpoint of solubility in an organic solvent.

  The molecular weight distribution (PDI, (weight average molecular weight / number average molecular weight (Mw / Mn))) of the copolymer according to the present invention is usually 1.0 or more, preferably 1.1 or more, more preferably 1.2 or more, Preferably it is 1.3 or more. On the other hand, it is preferably 20.0 or less, more preferably 15.0 or less, and still more preferably 10.0 or less. The molecular weight distribution is preferably in this range in that the solubility of the copolymer can be in a range suitable for coating.

  The polystyrene-reduced weight average molecular weight, number average molecular weight, and molecular weight distribution of the copolymer according to the present invention can be determined by gel permeation chromatography (GPC). Specifically, two Polymer Laboratories GPC columns (PLgel MIXED-B 10 μm inner diameter 7.5 mm, length 30 cm) are connected in series as a column, LC-10AT (manufactured by Shimadzu Corporation) as a pump, and an oven It can be measured by using CTO-10A (manufactured by Shimadzu Corp.), a differential refractive index detector (manufactured by Shimadzu Corp .: RID-10A), and a UV-vis detector (manufactured by Shimadzu Corp .: SPD-10A). As a measuring method, a copolymer (1 mg) to be measured is dissolved in chloroform (200 mg), and 1 μL of the obtained solution is injected into a column. Measurement is performed at a flow rate of 1.0 mL / min using chloroform as the mobile phase. For the analysis, LC-Solution (manufactured by Shimadzu Corporation) is used.

The copolymer according to the present invention preferably has a light absorption maximum wavelength (λ _max ) of usually 470 nm or more, preferably 480 nm or more, while usually 1200 nm or less, preferably 1000 nm or less, more preferably 900 nm or less. Further, the full width at half maximum of the absorption maximum wavelength on the longest wavelength side in the range of 350 nm to 850 nm is usually 10 nm or more, preferably 20 nm or more, and usually 300 nm or less. Moreover, when using the copolymer which concerns on this invention for a solar cell use, it is so desirable that the absorption wavelength range of a copolymer is near the wavelength range of sunlight.

  The solubility of the copolymer according to the present invention is not particularly limited, but preferably the solubility in chlorobenzene at 25 ° C. is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more. On the other hand, it is usually 30% by mass or less, preferably 20% by mass. High solubility is preferable because a thicker film can be formed by coating.

  The copolymer according to the present invention preferably has an appropriate interaction between molecules. In the present specification, the interaction between molecules means that the distance between polymer chains is shortened by an interaction such as π-π stacking between molecules. The stronger the interaction, the higher the mobility and / or crystallinity, and the more suitable the semiconductor material is. That is, in a copolymer that interacts between molecules, electron transfer between molecules is likely to occur. For example, when the copolymer according to the present invention is used in an active layer in a photoelectric conversion element, a p-type semiconductor compound in the active layer is used. It is considered that holes generated at the interface between the n-type semiconductor compound and the n-type semiconductor compound can be efficiently transported to the electrode (anode).

  An example of a crystallinity measuring method is an X-ray diffraction method (XRD). In this specification, having crystallinity means that an X-ray diffraction spectrum obtained by XRD measurement has a diffraction peak. Having crystallinity is considered to mean that it has a laminated structure in which molecules are arranged, and is preferable in that the active layer described later tends to be thickened. XRD measurement can be performed based on a method described in a known document (X-ray crystal analysis guide (applied physics selection book 4)).

The hole mobility of the copolymer according to the present invention (sometimes referred to as hole mobility) is usually 1.0 × 10 ⁻⁷ cm ² / Vs or more, preferably 1.0 × 10 ⁻⁶ cm ² / Vs or more. More preferably, it is 1.0 × 10 ⁻⁵ cm ² / Vs or more, and particularly preferably 1.0 × 10 ⁻⁴ cm ² / Vs or more. On the other hand, the hole mobility of the copolymer according to the present invention is usually 1.0 × 10 ⁴ cm ² / Vs or less, preferably 1.0 × 10 ³ cm ² / Vs or less, and more preferably 1.0 × 10 6. ² cm ² / Vs or less, particularly preferably 1.0 × 10 cm ² / Vs or less. When the hole mobility is in this range, the copolymer according to the present invention is suitably used as a semiconductor material. Further, in order to obtain high conversion efficiency in the photoelectric conversion element, it is important to balance the mobility of the n-type semiconductor compound and the mobility of the p-type semiconductor compound. When the copolymer according to the present invention is used as a p-type semiconductor compound in a photoelectric conversion element, from the viewpoint of bringing the hole mobility of the copolymer according to the present invention close to the electron mobility of the n-type semiconductor compound, the copolymer according to the present invention is positive. The hole mobility is preferably within this range. As a method for measuring the hole mobility, there is an FET method. The FET method can be performed by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

  On the other hand, the copolymer according to the present invention preferably has high storage stability in a solution state. High storage stability means that it is difficult to aggregate when made into a solution. More specifically, 2 mg of the copolymer according to the present invention was placed in a 2 mL screw vial, dissolved in o-xylene to a concentration of 1.5% by mass, and then cooled to room temperature. Then, it is preferable not to gel for 5 minutes or more, and it is more preferable not to gel for 1 hour or more.

  The impurities in the copolymer according to the present invention are preferably as few as possible. In particular, when a transition metal catalyst such as palladium or copper remains, exciton trapping occurs due to the heavy atom effect of the transition metal, which inhibits charge transfer. As a result, the copolymer according to the present invention was used in a photoelectric conversion element. In some cases, the photoelectric conversion efficiency may be reduced. The concentration of the transition metal catalyst is usually 1000 ppm or less, preferably 500 pm or less, more preferably 100 ppm or less, per 1 g of the copolymer. On the other hand, it is usually larger than 0 ppm and may be 1 ppm or more, or 3 ppm or more.

  The residual amount of atoms constituting the terminal residue (for example, X and Y in the formulas (3A) and (3B) described later) in the copolymer according to the present invention is not particularly limited, It is 6000 ppm or less, preferably 4000 ppm or less, more preferably 3000 ppm or less, further preferably 2000 ppm or less, still more preferably 1000 ppm or less, particularly preferably 500 ppm or less, and most preferably 200 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more.

  In particular, the residual amount of Sn atoms in the copolymer according to the present invention is usually 5000 ppm or less, preferably 4000 ppm or less, more preferably 2500 ppm or less, further preferably 1000 ppm or less, even more preferably 750 ppm or less, especially per 1 g of the copolymer. Preferably it is 500 ppm or less, and most preferably 100 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more. The remaining amount of Sn atoms of 5000 ppm or less is preferable because it means that there are few alkylstannyl groups and the like that are easily thermally decomposed, and high performance can be obtained in terms of stability.

  Further, the residual amount of halogen atoms in the copolymer according to the present invention is usually 5000 ppm or less, preferably 4000 ppm or less, more preferably 2500 ppm or less, further preferably 1000 ppm or less, even more preferably 750 ppm or less, and particularly preferably, per 1 g of the copolymer. Is 500 ppm or less, most preferably 100 ppm or less. On the other hand, it is usually greater than 0 ppm, preferably 1 ppm or more, more preferably 3 ppm or more. It is preferable to set the residual amount of halogen atoms to 5000 ppm or less because performances such as the photoelectric conversion characteristics and durability of the copolymer tend to be improved.

The residual amount of atoms constituting the terminal residue (for example, X and Y in the formulas (3A) and (3B) described later) in the copolymer can be determined by measuring the element amount. The elemental analysis of the copolymer can be carried out by ICP mass spectrometry for Pd and Sn, for example, and can also be carried out by ICP mass spectrometry for bromine ions (Br ⁻ ) and iodine ions (I ⁻ ).

ICP mass spectrometry can be carried out by a method described in a known document (“Plasma ion source mass spectrometry” (Academic Publishing Center)). Specifically, for Pd and Sn, after wet decomposition of the sample, Pd and Sn in the decomposition solution are quantified by a calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies). be able to. For Br ⁻ and I ⁻ , the sample was burned with a sample combustion device (sample combustion device QF-02 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and the combustion gas was absorbed into an alkaline absorbent containing a reducing agent. Br ⁻ and I ⁻ in the absorbing solution can be quantified by a calibration curve method using an ICP mass spectrometer (ICP mass spectrometer 7500ce type manufactured by Agilent Technologies).

<2. Method for producing copolymer according to the present invention>
The method for producing the copolymer according to the present invention is not particularly limited. For example, the copolymer can be produced by a known method using a compound having a dioxopyrrole condensed ring and a compound having a dithieno condensed ring. Preferable methods include a method of polymerizing a compound represented by the following general formula (3A) and a compound represented by the following general formula (3B) in the presence of an appropriate catalyst if necessary. .

In formula (3A), R ¹ , R ² and A have the same meaning as in formula (1A). In formula (3B), R ³ , R ⁴ and Q have the same meaning as in formula (1B).

In the formulas (3A) and (3B), X and Y can be appropriately selected depending on the type of polymerization reaction. For example, the copolymer according to the present invention can be produced by a polymerization reaction using a coupling reaction. Usable reactions include a Suzuki-Miyaura cross-coupling reaction method, a Stille coupling reaction method, a Yamamoto coupling reaction method, a Grignard reaction method, a Heck reaction method, a Sonogashira reaction method, and a reaction using an oxidizing agent such as FeCl _3. And a method using an electrochemical oxidation reaction, a reaction method by decomposition of an intermediate compound having an appropriate leaving group, and the like. Among these, the Suzuki-Miyaura coupling reaction method, the Stille coupling reaction method, the Yamamoto coupling reaction method, and the Grignard reaction method are preferable in terms of easy structure control. In particular, the Suzuki-Miyaura cross-coupling reaction method, the Stille coupling reaction method, and the Grignard reaction method are preferable from the viewpoint of easy availability of materials and easy reaction operation. These reactions are described in "Cross Coupling-Fundamentals and Industrial Applications (CMC Publishing)", "Transition Metal Catalyzed Reactions for Organic Synthesis (edited by Jiro Jiro: edited by Organic Synthetic Chemistry Association)", "For Organic Synthesis" The reaction can be carried out according to a method described in known literature such as “catalytic reaction 103 (Teijiro Hatakeyama: Tokyo Kagaku Dojin)”.

Examples of X and Y are each independently a halogen atom, alkylstannyl group, alkylsulfo group, arylsulfo group, arylalkylsulfo group, boric acid ester residue, sulfoniummethyl group, phosphoniummethyl group, phosphonatemethyl Group, monohalogenated methyl group, boric acid residue (-B (OH) ₂ ), formyl group, silyl group, alkenyl group or alkynyl group.

  As the halogen atom, a bromine atom or an iodine atom is preferable. Examples of the alkenyl group include alkenyl groups having 2 to 12 carbon atoms.

Examples of the boric acid ester residue include those represented by the following formula. In the following formulae, Me represents a methyl group, and Et represents an ethyl group.

Examples of the alkylstannyl group include those represented by the following formula. In the following formulae, Me represents a methyl group, and Bu represents an n-butyl group.

From the viewpoint of the synthesis of the compounds represented by formulas (3A) and (3B) and the ease of reaction, one of X and Y is a halogen atom, and the other is an alkylstannyl group or borate ester. It is preferably a residue or a boric acid residue (—B (OH) ₂ ).

  The polymerization reaction can be performed according to a known method. For example, when X or Y is an alkylstannyl group, the reaction may be performed in accordance with known Stille coupling reaction conditions. In addition, when X or Y is a boric acid ester residue or a boric acid residue, the reaction may be performed according to the conditions of a known Suzuki-Miyaura coupling reaction. Furthermore, when X or Y is a silyl group, the reaction may be carried out in accordance with known Hiyama coupling reaction conditions. As a catalyst for the coupling reaction, for example, a combination of a transition metal such as palladium and a ligand (for example, a phosphine ligand such as triphenylphosphine) can be used.

  Hereinafter, a method for producing the copolymer according to the present invention using the Stille coupling reaction method will be described. When the Stille coupling reaction method is used, in the formulas (3A) and (3B), X is a halogen atom and Y is an alkylstannyl group, or X is an alkylstannyl group and Y is a halogen atom. Preferably there is.

  The ratio (3B / 3A) of the amount of the compound represented by the formula (3B) to the amount of the compound represented by the formula (3A) used in the polymerization reaction is usually 0.90 or more in terms of molar ratio. , Preferably 0.95 or more, and usually 1.3 or less, preferably 1.2 or less. It is preferable that the ratio is in such a range in that a high molecular weight product can be obtained with a higher yield.

  When it is desirable that the copolymer according to the present invention has a high purity, it is preferable to carry out the polymerization reaction after purifying the monomer before polymerization (compounds represented by formulas (3A) and (3B)). Examples of the purification method include distillation, sublimation purification, column chromatography, recrystallization, and the like.

  For example, when the copolymer according to the present invention is used as a material for an organic photoelectric conversion device, it is desirable that the copolymer has a high purity since the device characteristics can be improved due to its high purity. When the copolymer according to the present invention is used as a material for an organic photoelectric conversion element, the purity of each of the compounds represented by formulas (3A) and (3B) is usually 90% or more, preferably 95% or more.

  Examples of the catalyst used for the promotion of polymerization in the polymerization reaction include transition metal catalysts. What is necessary is just to select a transition metal catalyst according to the kind of superposition | polymerization. Examples of transition metal catalysts include homogeneous transition metal catalysts and heterogeneous transition metal catalysts.

The homogeneous transition metal catalyst is preferably one that is sufficiently soluble in the solvent used for the polymerization reaction. Preferred examples include late transition metal complex catalysts containing palladium, nickel, iron, or copper, among others. Specific examples include zero-valent palladium catalysts such as tetrakis (triphenylphosphine) palladium (Pd (PPh ₃ ) ₄ ) or tris (dibenzylideneacetone) dipalladium (Pd ₂ (dba) ₃ ); bis (tri Palladium (Pd) catalysts such as phenylphosphine) palladium chloride (PdCl ₂ ((PPh ₃ )) ₂ ) or divalent palladium catalysts such as palladium acetate; nickel such as Ni (dppp) Cl ₂ or Ni (dppe) Cl ₂ Catalysts: iron catalysts such as iron chloride; copper catalysts such as copper iodide. Here, dba represents dibenzylideneacetone, dppp represents 1,2-bis (diphenylphosphino) propane, and dppe represents 1,2-bis (diphenylphosphino) ethane.

Specific examples of the zero-valent Pd catalyst include Pd (PPh ₃ ) ₄ , Pd (P (o-tolyl) ₃ ) ₄ , Pd (PCy ₃ ) ₂ , Pd ₂ (dba) _3, PdCl ₂ (PPh ₃ ) ) ₂ etc. are mentioned. When a divalent Pd catalyst such as PdCl ₂ ((PPh ₃ )) ₂ or palladium acetate is used, it is preferably used in combination with an organic ligand such as PPh ₃ or P (o-tolyl) ₃ . Here, Ph represents a phenyl group, Cy represents a cyclohexyl group, and o-tolyl represents a 2-tolyl group.

  Examples of the heterogeneous transition metal catalyst include a catalyst obtained by supporting a homogeneous transition metal catalyst as described above on a carrier. Preferable examples of the transition metal included in the heterogeneous transition metal catalyst include late transition metals including palladium, nickel, iron, or copper. As an organic ligand which a heterogeneous transition metal complex catalyst has, the same thing as what was mentioned about the homogeneous transition metal complex catalyst can be used. In addition, organic ligands described in known literature (Strem, “Heterogeneous Catalysts” (2011)) can also be used. Examples of the carrier include metals, nanocolloids, nanoparticles, magnetic compounds, metal oxides, porous materials, clays, polymers such as urea resins, and dendrimers. Specific examples of the porous material include microporous material, mesoporous material, activated carbon, silica gel, alumina, and zeolite. In particular, it is preferable to use a heterogeneous transition metal complex catalyst supported on a polymer because the heterogeneous transition metal complex catalyst can be easily recovered. Moreover, it is more preferable that the polymer is porous in terms of promoting the reaction.

  In the polymerization reaction, it is preferable to use two or more transition metal complex catalysts in that a high molecular weight copolymer can be obtained. For example, two or more kinds of homogeneous transition metal complexes may be used, two or more kinds of heterogeneous transition metal complexes may be used, or a combination of a homogeneous transition metal complex and a heterogeneous transition metal complex may be used. May be used. Of these two or more transition metal complex catalysts, at least one of them is preferably a heterogeneous metal complex catalyst in that a monomer can be quickly converted into an oligomer under coupling reaction conditions. In addition, since oligomerization tends to decrease the polymerization reaction rate due to the heterogeneous metal catalyst, it is preferable to induce the oligomer to the polymer with the homogeneous metal catalyst in order to obtain a high molecular weight product. From this viewpoint, it is more preferable that at least one of the two or more transition metal complex catalysts is a heterogeneous metal complex catalyst and at least one is a homogeneous metal complex catalyst.

The amount of the transition metal complex used relative to the total amount of the compounds represented by formulas (3A) and (3B) is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, more preferably and a 1 × ¹⁰ -2 mol% or more, whereas, usually 1 × ¹⁰ 2 mol%, more preferably at most 5 mol%. It is preferable that the amount of the catalyst used be in this range because a higher molecular weight copolymer tends to be obtained at a lower cost and a higher yield.

  When a transition metal catalyst is used, an alkali, a cocatalyst, or a phase transfer catalyst may be used in combination.

  Examples of the alkali include inorganic bases such as potassium carbonate, sodium carbonate and cesium carbonate; organic bases such as triethylamine.

Examples of the cocatalyst include inorganic salts such as cesium fluoride, copper oxide, and copper halide. The amount of the cocatalyst used is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, based on the total amount of the compounds represented by formulas (3A) and (3B). Preferably, it is 1 × 10 ⁻² mol% or more, and is usually 1 × 10 ⁴ mol% or less, preferably 1 × 10 ³ mol% or less, more preferably 1.5 × 10 ² mol% or less. It is preferable that the amount of the cocatalyst used be in this range because the copolymer tends to be obtained at a lower cost and with a higher yield.

Examples of the phase transfer catalyst include tetraethylammonium hydroxide or quaternary ammonium salts such as Aliquat 336 (manufactured by Aldrich). The amount of the phase transfer catalyst used is usually 1 × 10 ⁻⁴ mol% or more, preferably 1 × 10 ⁻³ mol% or more, based on the total amount of the compounds represented by the formulas (3A) and (3B). More preferably, it is 1 × 10 ⁻² mol% or more, while it is usually 5 mol% or less, more preferably 3 mol% or less. It is preferable that the amount of the phase transfer catalyst used is in this range because the copolymer tends to be obtained at a lower cost and in a higher yield.

  Examples of the solvent used in the polymerization reaction include saturated hydrocarbons such as pentane, hexane, heptane, octane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene; halogens such as chlorobenzene, dichlorobenzene, and trichlorobenzene. Aromatic hydrocarbons; alcohols such as methanol, ethanol, propanol, isopropanol, butanol or t-butyl alcohol; water; ethers such as dimethyl ether, diethyl ether, methyl t-butyl ether, tetrahydrofuran, tetrahydropyran or dioxane; DMF And aprotic polar organic solvents such as These solvents may be used alone or in combination of two or more.

The amount of the solvent used is usually 1 × 10 ⁻² mL or more, preferably 1 × 10 ⁻¹ mL or more, more preferably ¹ mL with respect to a total of 1 g of the compounds represented by formulas (3A) and (3B). On the other hand, it is usually 1 × 10 ⁵ mL or less, preferably 1 × 10 ³ mL or less, more preferably 2 × 10 ² mL or less. It is preferable that the amount of the solvent used is in this range in that the reaction can be easily controlled.

The reaction temperature of the polymerization reaction is usually 0 ° C. or higher, preferably 20 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 60 ° C. or higher. On the other hand, it is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, further preferably 180 ° C. or lower, and particularly preferably 160 ° C. or lower. The heating method is not particularly limited, but examples include oil bath heating, thermocouple heating, infrared heating, microwave heating, heating by contact using an IH heater, and the like. The time for the polymerization reaction is usually 1 minute or more, preferably 10 minutes or more, while it is usually 160 hours or less, preferably 120 hours or less, more preferably 100 hours or less. The polymerization reaction is preferably performed in a nitrogen (N ₂ ) or argon (Ar) atmosphere. By carrying out the reaction under these reaction conditions, the copolymer can be obtained in a shorter time and with a higher yield.

  It is preferable to further end-treat the copolymer obtained by the polymerization reaction. By performing the terminal treatment of the copolymer, the residual amount of the terminal residues (X and Y described above) can be reduced. For example, when a copolymer is polymerized by a Stille coupling reaction, halogen atoms such as bromine (Br) and iodine (I) and alkylstannyl groups present at the terminal of the copolymer can be reduced by terminal treatment. This terminal treatment is preferable because a copolymer having better performance in terms of efficiency and durability can be obtained.

  The terminal treatment method of the copolymer after the polymerization reaction is not particularly limited, and examples thereof include a method of substituting the terminal residue with another substituent such as an aromatic group.

  For example, as a terminal treatment method when a copolymer is polymerized by a Stille coupling reaction, the following method may be mentioned. The method for terminal treatment of the halogen atom of the copolymer can be carried out by adding aryltrialkyltin as a terminal treatment agent in the reaction system after the polymerization reaction and before purification, followed by heating and stirring. Examples of aryltrialkyltin include phenyltrimethyltin or thienyltrimethyltin. Substitution of a halogen atom at the terminal of the copolymer with an aromatic group is preferable because the copolymer becomes more stable due to the conjugate stability effect.

The addition amount of the end treatment agent is not particularly limited, but is usually 1.0 × 10 ⁻² molar equivalent or more with respect to the amount of the monomer having a halogen atom at the terminal (3A or 3B) used in the polymerization reaction. , Preferably 0.1 molar equivalents or more, more preferably 1 molar equivalents or more, and usually 50 molar equivalents or less, preferably 20 molar equivalents or less, more preferably 10 molar equivalents or less. The reaction temperature of the halogen atom terminal treatment is usually 0 ° C. or higher, preferably 20 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 60 ° C. or higher. On the other hand, it is usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, further preferably 180 ° C. or lower, and particularly preferably 160 ° C. or lower. The heating method is not particularly limited, and examples thereof include oil bath heating, thermocouple heating, infrared heating, microwave heating, heating by contact using an IH heater, and the like. The reaction time of the terminal treatment of the halogen atom of the copolymer is not particularly limited, but is usually 30 minutes or longer, preferably 1 hour or longer, and is usually 50 hours or shorter, preferably 20 hours or shorter. By performing the reaction under these reaction conditions, the terminal treatment can be performed in a shorter time and with a higher conversion rate.

  Further, the terminal treatment method of the alkylstannyl group of the copolymer can be carried out by adding an aryl halide as a terminal treating agent in the reaction system after the polymerization reaction and before purification, followed by heating and stirring. Examples of aryl halides include iodothiophene, iodobenzene, bromothiophene or bromobenzene. By substituting the alkylstannyl group at the terminal of the copolymer with another substituent, the Sn atom in the alkylstannyl group which is easily thermally decomposed does not exist in the copolymer, and deterioration of the copolymer over time can be suppressed. Further, substitution of the alkylstannyl group at the terminal of the copolymer with an aryl group is also preferable in that the copolymer can be more stable due to the conjugate stability effect.

The addition amount of the end treatment agent is not particularly limited, but is usually 1.0 × 10 ⁻² molar equivalent to the amount of the monomer (3B or 3A) having an alkylstannyl group at the terminal used for polymerization. As mentioned above, Preferably it is 0.1 molar equivalent or more, More preferably, it is 1 molar equivalent or more, On the other hand, Usually, it is 50 molar equivalent or less, Preferably it is 20 molar equivalent or less, More preferably, it is 10 molar equivalent or less. As the reaction temperature and reaction conditions for the terminal treatment of the alkylstannyl group, those similar to the terminal treatment of the halogen atom of the copolymer can be used. By performing the reaction under these reaction conditions, the terminal treatment can be performed in a shorter time and with a higher conversion rate.

  Moreover, the following method is mentioned as a method of terminal treatment at the time of polymerizing a copolymer by Suzuki-Miyaura cross-coupling reaction. Examples of the method for terminal treatment of the halogen atom of the copolymer include a method in which arylboronic acid is added and then heated and stirred. Examples of the terminal treatment method of the boron atom-containing group of the copolymer include a method in which an aryl halide is added as a terminal treatment agent and then heated and stirred.

  There are no particular restrictions on the terminal treatment method for terminal residue X and the terminal treatment method for terminal residue Y, but it is preferable to carry out each independently. In addition, there is no special restriction | limiting in the order of each terminal process, It can select suitably.

  Further, the terminal treatment may be performed before the purification of the copolymer, but may be performed after the purification of the copolymer. When the end treatment is performed after the copolymer purification, the copolymer and one of the end treatment agents (for example, aryl halide or aryltrialkyltin) are dissolved in an organic solvent, and then a reaction is performed by adding a transition metal catalyst such as a palladium catalyst. Further, the other end treatment agent (aryltrialkyltin or aryl halide) may be added to carry out the reaction. From the viewpoint of accelerating the reaction, it is preferable to perform heating and stirring during the terminal treatment, as in the case where the terminal treatment is performed before the purification of the copolymer. Moreover, it is also preferable to perform reaction under nitrogen conditions from a viewpoint of improving a yield. The reaction time is not particularly limited, but is usually 30 minutes or longer, preferably 1 hour or longer, and is usually 25 hours or shorter, preferably 10 hours or shorter.

The addition amount of the transition metal catalyst is not particularly limited, but is usually 5.0 × 10 ⁻³ molar equivalent or more, preferably the total amount of the compound represented by the formula (3A) or (3B), Is 1.0 × 10 ⁻² molar equivalent or more, and is usually 1.0 × 10 ⁻¹ molar equivalent or less, preferably 5.0 × 10 ⁻² molar equivalent or less. When the addition amount of the catalyst is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

There is no particular limitation on the amount of the alkylstannyl end-treating agent added at the end treatment after refining the copolymer, but the amount of the monomer (3B or 3A) having an alkylstannyl group used for polymerization is not limited. Is usually 1.0 × 10 ⁻² molar equivalents or more, preferably 1.0 × 10 ⁻¹ molar equivalents or more, more preferably 1 molar equivalents or more, and usually 50 molar equivalents or less, preferably 20 The molar equivalent or less, more preferably 10 molar equivalent or less. When the added amount of the end treatment agent is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

The addition amount of the halogen atom end treatment agent at the end treatment after the copolymer formation is not particularly limited, but with respect to the amount of the monomer having a halogen atom at the terminal (3A or 3B) used for polymerization, Usually 1.0 × 10 ⁻² molar equivalent or more, preferably 1.0 × 10 ⁻¹ molar equivalent or more, more preferably 1 molar equivalent or more, while usually 50 molar equivalent or less, preferably 20 molar equivalent or less, More preferably, it is 10 molar equivalents or less. When the added amount of the end treatment agent is within this range, the end treatment can be performed at a lower cost and at a higher conversion rate.

  Although there is no limitation in particular as a process performed after a polymerization reaction, Usually, the process of isolate | separating a copolymer is performed. When the terminal treatment of the copolymer is performed, it is preferable to perform a step of separating the copolymer after the terminal treatment. If necessary, further copolymer separation and purification may be performed prior to copolymer termination. From the viewpoint of obtaining the copolymer in a shorter processing step, it is preferable to carry out the terminal treatment of the copolymer, separation of the copolymer and purification of the copolymer in this order after the polymerization reaction.

  As a method for separating the copolymer, for example, the reaction solution and a poor solvent are mixed to precipitate the copolymer, or the active species in the reaction solution is quenched with water or hydrochloric acid, and then the copolymer is extracted with an organic solvent. Examples include a method of distilling off the organic solvent.

  Examples of the purification method of the copolymer include known methods such as reprecipitation purification, extraction using a Soxhlet extractor, gel permeation chromatography, or metal removal using a scavenger.

[2-1. Method for producing compounds represented by formulas (3A) and (3B)]
The compound represented by the formula (3A) used as a raw material for the polymerization reaction is described in J. Am. Am. Chem. Soc. 2010, 132 (22), 7595-7597. In addition, the compound represented by the formula (3B) is described in J. Org. Mater. Chem. , 2011, 21, 3895, and J.A. Am. Chem. Soc. 2008, 130, 16144-16145.

  A particularly preferable production method of the compound represented by the formula (3B) includes a method using the compound represented by the following formula (4B) as a raw material. More specifically, the compound represented by the formula (3B) can be obtained by reacting a non-nucleophilic base with the compound represented by the formula (4B) and then reacting the electrophile. . According to this method, it is possible to reduce the amount of by-products generated when producing the compound represented by the formula (3B), for example, having only one substituent Y. A small amount of by-products is preferable in that the copolymer according to the present invention obtained by the polymerization reaction can have a higher molecular weight.

In the formula (4B), Q and R ^{3 to} R ⁴ are the same as in the formula (3B).

  Examples of non-nucleophilic bases include metal hydrides, metal alkoxides with bulky substituents, amines, phosphazene bases, metal magnesium reagents with bulky substituents (Grignard reagents), metal amides, and the like. . The use of a non-nucleophilic base is preferable in that it can effectively suppress nucleophilic attack on the condensed ring of the compound represented by formula (4B) and can suppress the formation of by-products. . From the viewpoint of high basicity and low nucleophilicity, the non-nucleophilic base is preferably a metal amide, and particularly preferably a metal amide having a bulky substituent.

  The compound represented by the general formula (3B) is obtained by deprotonating the compound represented by the general formula (4B) using a non-nucleophilic base and then reacting the generated anion species with an electrophile. Can be obtained.

  In the case where the substituent Y is an alkylstannyl group, the electrophile is not particularly limited, and examples thereof include a trialkyltin halide compound. When the substituent Y is a boric acid residue or a boric acid ester residue, the electrophile is not particularly limited, but a boric acid triester is preferably used. A compound having a boric acid ester residue obtained by a reaction with a boric acid triester can be isolated as it is, or after the boric acid ester residue is hydrolyzed and led to a boric acid residue, the compound is simply used. May be separated.

  The method for purifying the compound represented by formula (3B) after the reaction is not particularly limited, and a known method can be used. A particularly preferred method is a method using zeolite. More specifically, the obtained compound may be contacted with zeolite. This method is preferable because the compound can be purified more easily while preventing the compound represented by the formula (3B) from being decomposed. As the zeolite, aluminosilicate zeolite such as aluminosilicate, metallosilicate or silicalite; or phosphate zeolite such as aluminophosphate, gallophosphate or berylphosphate is preferable.

  As a method of bringing the obtained compound represented by the formula (3B) into contact with zeolite, (1) preparing a layer containing zeolite and allowing the compound to pass therethrough, (2) charging the zeolite into the composition, Thereafter, a method of removing the zeolite, and the like can be mentioned.

  There is no particular limitation on the amount of the non-nucleophilic base added to the compound represented by the formula (4B), and usually 2 molar equivalents or more of the non-nucleophilic group based on the compound represented by the formula (4B). A base is used. On the other hand, in order to reduce the amount of reagent used, the amount of non-nucleophilic base is usually 20 molar equivalents or less, preferably 10 molar equivalents or less, more preferably 5 molar equivalents or less. There is no particular limitation on the amount of the electrophile added to the compound represented by the formula (4B), and usually 2 mole equivalent or more of the electrophile is used relative to the compound represented by the formula (4B). . On the other hand, in order to reduce the amount of the reagent used, the amount of the electrophilic reagent is usually 20 mole equivalents or less, preferably 10 mole equivalents or less, more preferably 5 mole equivalents or less.

  Although the compound represented by Formula (4B) can be manufactured using a well-known method, it is especially preferable to manufacture using the method shown below. That is, the compound represented by the formula (4B) can be obtained by removing the silyl group from the compound obtained by adding a silyl group to the compound represented by the formula (4B). This method is preferable in that the compound represented by the formula (4B) can be obtained with higher yield.

For example, the compound represented by the formula (4B) can be produced by a desilylation reaction using an acid of the compound represented by the following formula (5B).

In the formula (5B), Q and R ^{3 to} R ⁴ are the same as in the formula (3B). In the formula (5B), R ⁷ represents a silyl group which may have a substituent. The two substituents R ⁷ may be different from each other. Examples of the silyl group that may have a substituent include a trialkylsilyl group, a dialkylarylsilyl group, an alkyldiarylsilyl group, and a triarylsilyl group. The acid used in the desilylation reaction is not particularly limited, and an inorganic acid or an organic acid can be used. There are no particular limitations on the type of inorganic acid, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, or the like can be used. There are no particular limitations on the type of organic acid, and acetic acid, trifluoroacetic acid, oxalic acid, citric acid, benzoic acid, chlorobenzoic acid, p-toluenesulfonic acid, and the like can be used.

When Q is a silicon atom or a germanium atom, the compound represented by the formula (5B) can be obtained, for example, by treating a bithiophene compound with a base and reacting with a silyl halide or a germyl halide. As a more specific example, 5,5′-bis (trimethylsilyl) -3,3′-dibromo-2,2′-bithiophene is treated with n-butyllithium, and R ³ R ⁴ SiCl ₂ , R ³ R By reacting ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr ₂ , the compound represented by the formula (5B) can be obtained. A compound represented by the formula (3B) or (4B) is also synthesized using R ³ R ⁴ SiCl ₂ , R ³ R ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr _2. sell. In this case, R ³ R ⁴ SiCl ₂ , R ³ R ⁴ SiBr ₂ , R ³ R ⁴ GeCl ₂ , or R ³ R ⁴ GeBr ₂ is preferably purified by distillation under reduced pressure. In order to carry out vacuum distillation at a vacuum degree that can be easily achieved and at a lower temperature, the number of carbon atoms of R ³ and R ⁴ is preferably 15 or less, and more preferably 8 or less.

<3. Organic Semiconductor Material Containing Copolymer According to the Present Invention>
The copolymer according to the present invention has solubility in a solvent and light absorption in a long wavelength region, and is suitable as an organic semiconductor material.

  The organic semiconductor material according to the present invention includes at least the copolymer according to the present invention. The organic semiconductor material according to the present invention may contain one of the copolymers according to the present invention, or may contain two or more kinds in any combination. Further, the organic semiconductor material according to the present invention may be composed only of the copolymer according to the present invention, but contains other components (for example, other polymers, monomers, various additives, etc.). May be.

  The organic semiconductor material according to the present invention is suitable as a material for an organic semiconductor layer or an organic active layer of an organic electronic device described later. In this case, an organic semiconductor material is preferably used after being formed into a film. In this case, physical properties such as the solubility of the copolymer according to the present invention in an organic solvent and its excellent processability are preferably used. A method of using the organic semiconductor according to the present invention in an organic electronic device will be described later.

The organic semiconductor material according to the present invention exhibits semiconductor characteristics. For example, in the field effect mobility measurement, the hole mobility (sometimes referred to as hole mobility) is usually 1.0 × 10 ⁻⁷ cm ² / Vs or more. , Preferably 1.0 × 10 ⁻⁶ cm ² / Vs or more, more preferably 1.0 × 10 ⁻⁵ cm ² / Vs or more, particularly preferably 1.0 × 10 ⁻⁴ cm ² / Vs or more, On the other hand, the hole mobility is usually 1.0 × 10 ⁴ cm ² / Vs or less, preferably 1.0 × 10 ³ cm ² / Vs or less, more preferably 1.0 × 10 ² cm ² / Vs or less, particularly Preferably, it is 1.0 × 10 cm ² / Vs or less. As a method for measuring the hole mobility, there is an FET method. The FET method can be carried out by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

The organic semiconductor material according to the present invention can be used alone or as a material of an organic semiconductor layer of an organic electronic device, but can also be mixed and / or laminated with other organic semiconductor materials. Other organic semiconductor materials that can be used in combination with the organic semiconductor material according to the present invention include poly (3-hexylthiophene) (P3HT), poly [2,6- (4,4-bis [2-ethylhexyl] -4H- Cyclopenta [2,1-b: 3,4-b ′] dithiophene) -alt-4,7- (2,1,3-benzothiadiazole)] (PCPDTBT), benzoporphyrin (BP), pentacene, etc. organic semiconductor materials and the like, further, perylene known as n-type semiconductor compound - bisimide, [6,6] - phenyl _{-C 61} - butyric acid methyl ester ([60] PCBM) or larger fullerenes _{C 70,} etc. PCBM with, [6,6] - phenyl _{-C 61} - butyric acid n- butyl ester ([60] PCBNB) or larger fullerenes _{C 70,} etc. Examples thereof include fullerene derivatives such as PCBNB, but are not particularly limited thereto.

  The organic semiconductor material according to the present invention may be used in the form of a solution. Since the copolymer according to the present invention has high stability when made into a solution, the solution containing the organic semiconductor material according to the present invention and the solvent, that is, the solution containing the copolymer according to the present invention and the solvent is applied by a coating method. Can be preferably used for forming an organic semiconductor layer. In this case, it is preferable that the semiconductor layer obtained by applying the solution exhibits the semiconductor characteristics described above.

  The solvent is not particularly limited as long as it can uniformly dissolve or disperse the copolymer according to the present invention. For example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; toluene, xylene, Aromatic hydrocarbons such as chlorobenzene or orthodichlorobenzene; lower alcohols such as methanol, ethanol or propanol; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; esters such as ethyl acetate, butyl acetate or methyl lactate Halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene; ethers such as ethyl ether, tetrahydrofuran or dioxane; dimethylformamide or dimethylacetate Amides such as bromide, and the like. Among them, preferred are aromatic hydrocarbons such as toluene, xylene, chlorobenzene or orthodichlorobenzene, and halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene.

<4. Electronic Device Containing Organic Semiconductor Material According to the Present Invention>
Next, the organic electronic device according to the present invention will be described. The organic electronic device according to the present invention is manufactured using the organic semiconductor material according to the present invention. That is, the organic electronic device according to the present invention includes the organic semiconductor material according to the present invention. As long as the organic semiconductor material according to the present invention can be applied, the type of the organic electronic device according to the present invention is not particularly limited. Examples include a light emitting element, a switching element, a photoelectric conversion element, an optical sensor using photoelectric conductivity, and the like.

  Examples of the light emitting element include various light emitting elements used for display devices. Specific examples include a liquid crystal display element, a polymer dispersion type liquid crystal display element, an electrophoretic display element, an electroluminescent element, an electrochromic element, and the like.

  Specific examples of the switching element include a diode (pn junction diode, Schottky diode, MOS diode, etc.), a transistor (bipolar transistor, field effect transistor (FET), etc.), a thyristor, and a composite element thereof (for example, TTL). Etc.).

  Specific examples of the photoelectric conversion element include a thin film solar cell, a charge coupled device (CCD), a photomultiplier tube, and a photocoupler. Moreover, what utilized these photoelectric conversion elements is mentioned as an optical sensor using photoelectric conductivity.

  In which part of the organic electronic device the organic semiconductor material according to the present invention is used is not particularly limited, and can be used in any part. In order to utilize the semiconductor characteristics of the organic semiconductor material according to the present invention, it is preferable to use the organic semiconductor material according to the present invention in the semiconductor layer of the organic electronic device. Particularly in the case of a photoelectric conversion element, the organic semiconductor layer containing the organic semiconductor material according to the present invention is usually used as an organic active layer.

<5. Photoelectric conversion element>
The photoelectric conversion element according to the present invention is a photoelectric conversion element including a pair of electrodes and an active layer disposed between the electrodes, and the active layer contains the copolymer according to the present invention.

[5-1. Configuration of photoelectric conversion element]
FIG. 1 shows an embodiment of a photoelectric conversion element according to the present invention. The photoelectric conversion element shown in FIG. 1 is a photoelectric conversion element used in a general organic thin film solar cell, but the photoelectric conversion element according to the present invention is not limited to that shown in FIG. A photoelectric conversion element 107 according to an embodiment of the present invention includes a base material 106, an anode 101, a hole extraction layer 102, an active layer 103 (a mixed layer of a p-type semiconductor material and an n-type semiconductor material), and an electron extraction layer 104. , And a layer structure including the cathode 105. Another layer may be inserted between each layer to such an extent that the function of each layer described later is not affected.

[5-2. Active layer (103)]
The active layer 103 refers to a layer in which photoelectric conversion is performed, and includes a p-type semiconductor material and an n-type semiconductor material. The active layer 103 includes the organic semiconductor material according to the present invention. That is, the active layer 103 includes the copolymer according to the present invention. The copolymer according to the present invention is usually used as a p-type semiconductor material. When the photoelectric conversion element 107 receives light, the light is absorbed by the active layer 103, electricity is generated at the interface between the p-type semiconductor material and the n-type semiconductor material, and the generated electricity is extracted from the electrodes 101 and 105.

As the material of the active layer 103, either an inorganic compound or an organic compound may be used, but a layer that can be formed by a simple coating process is preferable. More preferably, the active layer 103 is an organic active layer made of an organic compound. In the following description, it is assumed that the active layer 103 is an organic active layer.
[5-2-1. Layer structure of active layer]

  Examples of the layer structure of the active layer 103 include a thin film stacked type in which a p-type semiconductor material and an n-type semiconductor material are stacked, or a bulk heterojunction type having a layer in which a p-type semiconductor material and an n-type semiconductor material are mixed. . The bulk heterojunction active layer includes a p-type semiconductor material containing a p-type semiconductor material, an n-type semiconductor layer containing an n-type semiconductor material, a layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, You may have at least one of these. In terms of photoelectric conversion efficiency, the active layer 103 is preferably a bulk heterojunction type.

(Thin film type active layer)
The thin film stacked active layer has a structure in which a p-type semiconductor layer containing a p-type semiconductor material and an n-type semiconductor layer containing an n-type semiconductor material are stacked. The thin film stacked active layer can be formed by forming a p-type semiconductor layer and an n-type semiconductor layer, respectively. The p-type semiconductor layer and the n-type semiconductor layer may be formed by different methods.

(P-type semiconductor layer)
The p-type semiconductor layer is a layer containing the copolymer according to the present invention. The p-type semiconductor layer may further contain a p-type semiconductor material described later. There is no limitation on the film thickness of the p-type semiconductor layer. However, it is usually 5 nm or more, preferably 10 nm or more, and usually 500 nm or less, preferably 200 nm or less. It is preferable that the thickness of the p-type semiconductor layer is 500 nm or less from the viewpoint of reducing the series resistance. The film thickness of the p-type semiconductor layer is preferably 5 nm or more from the viewpoint that more light can be absorbed.

  The p-type semiconductor layer can be formed by any method including a coating method and a vapor deposition method. However, it is preferable to use a coating method, preferably a wet coating method, because the p-type semiconductor layer can be formed more easily. . The copolymer according to the present invention is preferable in that it has solubility in a solvent and is excellent in coating film formation.

  When a p-type semiconductor layer is produced by a coating method, a coating liquid containing a p-type semiconductor material may be prepared and applied. As an application method, any method can be used. For example, spin coating method, inkjet method, doctor blade method, drop casting method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method , Air knife coating method, wire barber coating method, pipe doctor method, impregnation / coating method or curtain coating method. You may perform the drying process by heating etc. after application | coating of a coating liquid.

  Of the p-type semiconductor material contained in the p-type semiconductor layer, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more is the copolymer according to the present invention. Since the copolymer according to the present invention has suitable properties as a p-type semiconductor material, it is particularly preferable that the p-type semiconductor layer contains only the copolymer according to the present invention as a p-type semiconductor material.

(N-type semiconductor layer)
The n-type semiconductor layer is a layer containing an n-type semiconductor material described later. Although there is no special restriction | limiting in the film thickness of an n-type semiconductor layer, Usually, 5 nm or more, Preferably it is 10 nm or more, On the other hand, it is 500 nm or less normally, Preferably it is 200 nm or less. The film thickness of the n-type semiconductor layer is preferably 500 nm or less from the viewpoint of reducing the series resistance. The film thickness of the n-type semiconductor layer is preferably 5 nm or more from the viewpoint that more light can be absorbed.

  The n-type semiconductor layer can be formed by any method including a coating method and a vapor deposition method, but it is preferable to use the coating method because the n-type semiconductor layer can be more easily formed. When an n-type semiconductor layer is manufactured by a coating method, a coating solution containing an n-type semiconductor material may be prepared and this coating solution may be applied. As a coating method, any method can be used, and for example, the methods mentioned as the method for forming the p-type semiconductor layer can be used. You may perform the drying process by heating etc. after application | coating of a coating liquid.

(Bulk heterojunction active layer)
The bulk heterojunction active layer includes a layer (i layer) in which a p-type semiconductor material and an n-type semiconductor material are mixed. The i layer has a structure in which a p-type semiconductor material and an n-type semiconductor material are phase-separated, carrier separation occurs at the phase interface, and the generated carriers (holes and electrons) are transported to the electrode.

  Of the p-type semiconductor material contained in the i layer, the copolymer according to the present invention is usually 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more. Since the copolymer according to the present invention has suitable properties as a p-type semiconductor material, it is particularly preferable that the i layer contains only the copolymer according to the present invention as a p-type semiconductor material.

  There is no restriction | limiting in the film thickness of i layer. However, it is usually 5 nm or more, preferably 10 nm or more, and usually 500 nm or less, preferably 200 nm or less. The film thickness of the i layer is preferably 500 nm or less from the viewpoint of reducing the series resistance. The film thickness of the i layer is preferably 5 nm or more from the viewpoint that more light can be absorbed.

  The i layer can be formed by any method including a coating method and a vapor deposition method (for example, a co-evaporation method), but it is preferable to use the coating method because the i layer can be formed more easily. Since the copolymer according to the present invention has solubility in a solvent, it is preferable from the viewpoint of excellent coating film-forming properties. When the i layer is formed by a coating method, a coating solution containing a p-type semiconductor material and an n-type semiconductor material is prepared, and this coating solution may be applied. The coating solution containing the p-type semiconductor material and the n-type semiconductor material may be prepared by preparing and mixing a solution containing the p-type semiconductor material and a solution containing the n-type semiconductor material, respectively. The material and the n-type semiconductor material may be dissolved. Further, as described later, an i layer may be formed by preparing a coating liquid containing a semiconductor material precursor, applying the coating liquid, and then converting the semiconductor material precursor into a semiconductor material. As the coating method, the methods mentioned as the method for forming the p-type semiconductor layer can be used. You may perform the drying process by heating etc. after application | coating of a coating liquid.

  When a bulk heterojunction active layer is formed by a coating method, an additive may be further added to a coating solution containing a p-type semiconductor material and an n-type semiconductor material. The phase separation structure of the p-type semiconductor material and the n-type semiconductor material in the bulk heterojunction type active layer has an influence on the light absorption process, exciton diffusion process, exciton separation (carrier separation) process, carrier transport process, etc. is there. Therefore, it is considered that good photoelectric conversion efficiency can be realized by optimizing the phase separation structure. When the coating liquid contains an additive having volatility different from that of the solvent, an active layer having a preferable phase separation structure can be obtained, and the photoelectric conversion efficiency can be improved.

  As an example of an additive, the compound etc. which are described in the international publication 2008/066933 are mentioned, for example. More specific examples of the additive include an aliphatic compound having a substituent or an aromatic compound such as naphthalene having a substituent. Substituents include aldehyde groups, oxo groups, hydroxy groups, alkoxy groups, thiol groups, thioalkyl groups, carboxyl groups, ester groups, amine groups, amide groups, halogen atoms, nitrile groups, epoxy groups, aromatic groups or arylalkyls. Groups and the like. There may be one or more, for example two, substituents. The substituent that the alkane has is preferably a thiol group or an iodine atom. Moreover, as a substituent which an aromatic compound like naphthalene has, Preferably they are a bromine atom or a chlorine atom.

  Since the additive preferably has a high boiling point, the aliphatic hydrocarbon used as the additive preferably has 6 or more carbon atoms, and more preferably 8 or more carbon atoms. Moreover, since it is preferable that an additive is liquid at normal temperature, carbon number of an aliphatic hydrocarbon has preferable 14 or less, and 12 or less is more preferable. For the same reason, the aromatic hydrocarbon used as an additive usually has 6 or more carbon atoms, preferably 8 or more, more preferably 10 or more, and usually 50 or less, preferably 30 or less, more preferably 20 or less. Similarly, the aromatic heterocyclic compound used as an additive generally has 2 or more carbon atoms, preferably 3 or more, more preferably 6 or more, and usually 50 or less, preferably 30 or less, more preferably 20 carbon atoms. It is as follows. The boiling point of the additive is usually 100 ° C. or higher, preferably 200 ° C. or higher at normal pressure (1 atm), and is usually 600 ° C. or lower, preferably 500 ° C. or lower.

  The amount of the additive contained in the coating solution containing the p-type semiconductor material and the n-type semiconductor material is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more with respect to the entire coating solution. Moreover, 10 mass% or less is preferable with respect to the whole coating liquid, and 3 mass% or less is further more preferable. When the amount of the additive is within this range, a preferable phase separation structure can be obtained while reducing the additive remaining in the active layer. As described above, a bulk heterojunction active layer can be formed by applying a coating liquid (ink) containing a p-type semiconductor material, an n-type semiconductor material, and, if necessary, an additive.

(Solvent for coating solution)
Examples of the solvent for the coating liquid containing the p-type semiconductor material, the coating liquid containing the n-type semiconductor material, and the coating liquid containing the p-type semiconductor material and the n-type semiconductor material include p-type semiconductor material and / or n-type. Although it will not specifically limit if a semiconductor material can be melt | dissolved uniformly, For example, aliphatic hydrocarbons, such as hexane, heptane, octane, isooctane, nonane, or decane; Toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene, or orthodi Aromatic hydrocarbons such as chlorobenzene; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; lower alcohols such as methanol, ethanol or propanol; acetone, methyl ethyl ketone, Cyclo Aliphatic ketones such as ntanone or cyclohexanone; aromatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene And ethers such as ethyl ether, tetrahydrofuran and dioxane; or amides such as dimethylformamide and dimethylacetamide.

  Among them, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; cycloaliphatic carbonization such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin Hydrogens; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene; or ethers such as ethyl ether, tetrahydrofuran or dioxane. More preferably, non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene; non-halogen ketones such as cyclopentanone or cyclohexanone; aromatic ketones such as acetophenone or propiophenone; tetrahydrofuran, cyclohexane Alicyclic hydrocarbons such as pentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; or non-halogens such as 1,4-dioxane Aliphatic ethers. Particularly preferred are non-halogen aromatic hydrocarbons such as toluene, xylene, mesitylene or cyclohexylbenzene.

  As the solvent, one kind of solvent may be used alone, or any two or more kinds of solvents may be used in any ratio. When two or more kinds of solvents are used in combination, it is preferable to combine a low boiling point solvent having a boiling point of 60 ° C. or higher and 150 ° C. or lower and a high boiling point solvent having a boiling point of 180 ° C. or higher and 250 ° C. or lower. Examples of combinations of low and high boiling solvents include non-halogen aromatic hydrocarbons and alicyclic hydrocarbons, non-halogen aromatic hydrocarbons and aromatic ketones, ethers and alicyclic carbonization. Examples thereof include hydrogens, ethers and aromatic ketones, aliphatic ketones and alicyclic hydrocarbons, or aliphatic ketones and aromatic ketones. Specific examples of preferred combinations include toluene and tetralin, xylene and tetralin, toluene and acetophenone, xylene and acetophenone, tetrahydrofuran and tetralin, tetrahydrofuran and acetophenone, methyl ethyl ketone and tetralin, methyl ethyl ketone and acetophenone, and the like.

[5-2-2. p-type semiconductor material]
The active layer 103 contains at least the copolymer according to the present invention as a p-type semiconductor material. However, other organic semiconductor materials can be used in combination with and / or laminated with the copolymer according to the present invention. Hereinafter, organic semiconductor materials that can be used in combination, for example, high-molecular organic semiconductor materials and low-molecular organic semiconductor materials will be described.

(Polymer organic semiconductor materials)
The polymer organic semiconductor material that can be used in combination as the p-type semiconductor material is not particularly limited, and is a conjugated copolymer semiconductor material such as polythiophene, polyfluorene, polyphenylene vinylene, polythienylene vinylene, polyacetylene, or polyaniline; an alkyl group or other substitution Examples thereof include copolymer semiconductor materials such as oligothiophene having a substituted group. Moreover, the copolymer semiconductor material which copolymerized 2 or more types of monomer units is also mentioned. Conjugated copolymers are described in, for example, Handbook of Conducting Polymers, 3 ^rd Ed. (2 volumes), 2007, Materials Science and Engineering, 2001, 32, 1-40, Pure Appl. Chem. Use a copolymer described in known literature such as 2002, 74, 2031-3044, Handbook of THIOPHENE-BASED MATERIALS (2 volumes), 2009, or a derivative thereof, and a copolymer that can be synthesized by a combination of the described monomers. Can do. The polymer organic semiconductor material used in combination as the p-type semiconductor material may be a single compound or a mixture of a plurality of compounds.

  Specific examples of the polymer organic semiconductor material that can be used in combination as the p-type semiconductor material include the following, but are not limited to the following.

(Low molecular organic semiconductor materials)
The low-molecular organic semiconductor material that can be used in combination as the p-type semiconductor material is not particularly limited. Specifically, a condensed aromatic hydrocarbon such as naphthacene, pentacene, or pyrene; a thiophene ring such as α-sexithiophene; Oligothiophenes containing 4 or more; those containing at least one of thiophene ring, benzene ring, fluorene ring, naphthalene ring, anthracene ring, thiazole ring, thiadiazole ring and benzothiazole ring, and a total of 4 or more linked; Examples thereof include macrocyclic compounds such as phthalocyanine compounds and metal complexes thereof, or porphyrin compounds such as tetrabenzoporphyrin and metal complexes thereof. Preferably, they are a phthalocyanine compound and its metal complex, or a porphyrin compound and its metal complex.

Examples of the porphyrin compound and its metal complex (Z ¹ in the figure is CH), and the phthalocyanine compound and its metal complex (Z ¹ in the figure is N) include compounds having the following structures.

Here, M represents a metal or two hydrogen atoms. As the metal, in addition to a divalent metal such as Cu, Zn, Pb, Mg, Co or Ni, a trivalent or higher metal having an axial ligand. Examples thereof include TiO, VO, SnCl ₂ , AlCl, InCl, and Si.

R ^{11 to} R ¹⁴ are each independently a hydrogen atom or an alkyl group having 1 to 24 carbon atoms. The alkyl group having 1 to 24 carbon atoms is a saturated or unsaturated chain hydrocarbon group having 1 to 24 carbon atoms or a saturated or unsaturated cyclic hydrocarbon group having 3 to 24 carbon atoms. Among these, a saturated or unsaturated chain hydrocarbon group having 1 to 12 carbon atoms or a saturated or unsaturated cyclic hydrocarbon group having 3 to 12 carbon atoms is preferable.

  Among phthalocyanine compounds and metal complexes thereof, preferably 29H, 31H-phthalocyanine, copper phthalocyanine complex, zinc phthalocyanine complex, magnesium phthalocyanine complex, lead phthalocyanine complex, titanium phthalocyanine oxide complex, vanadium phthalocyanine oxide complex, indium phthalocyanine halogen complex, gallium A phthalocyanine halogen complex, an aluminum phthalocyanine halogen complex, a tin phthalocyanine halogen complex, a silicon phthalocyanine halogen complex, or a copper 4,4 ′, 4 ″, 4 ′ ″-tetraaza-29H, 31H-phthalocyanine complex, more preferably Titanium phthalocyanine oxide complex, vanadium phthalocyanine oxide complex, indium phthalocyanine chloro complex, aluminum fluoride Russia is a Nin chloro complexes. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  Among the porphyrin compounds and metal complexes thereof, 5,10,15,20-tetraphenyl-21H, 23H-porphine, 5,10,15,20-tetraphenyl-21H, 23H-porphine cobalt (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine copper (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20- Tetraphenyl-21H, 23H-porphine nickel (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine vanadium (IV) oxide, 5,10,15,20-tetra (4-pyridyl)- 21H, 23H-porphine, 29H, 31H-tetrabenzo [b, g, l, q] porphine, 2 H, 31H-tetrabenzo [b, g, l, q] porphine cobalt (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine copper (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine zinc (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine nickel (II) or 29H, 31H-tetrabenzo [b, g, l, q] porphine vanadium (IV) oxide And preferably 5,10,15,20-tetraphenyl-21H, 23H-porphine or 29H, 31H-tetrabenzo [b, g, l, q] porphine. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  Examples of the method for forming the low molecular organic semiconductor material include a vapor deposition method and a coating method. The latter is preferred because of the process advantage that coating can be formed. When the coating method is used, a method of converting a low molecular organic semiconductor material precursor into a low molecular organic semiconductor material after coating is preferable from the viewpoint of excellent film formability. Specifically, there is no particular limitation, but specific examples include the methods described in JP2007-324587A and JP2011-119648A.

  As a p-type semiconductor material that can be used in combination with the copolymer according to the present invention, among them, a polymer organic semiconductor material is preferably a conjugated copolymer semiconductor material such as polythiophene, and a low molecular organic semiconductor material may be naphthacene, pentacene, pyrene, or the like. A condensed aromatic hydrocarbon, a phthalocyanine compound and a metal complex thereof, or a porphyrin compound such as tetrabenzoporphyrin (BP) and a metal complex thereof. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  The p-type semiconductor material may have some self-organized structure in the deposited state or may be in an amorphous state.

  The HOMO (highest occupied molecular orbital) energy level of the p-type semiconductor material is not particularly limited, and can be selected according to the type of the n-type semiconductor material described later. In particular, when a fullerene compound is used as an n-type semiconductor material, the HOMO energy level of the p-type semiconductor material is usually −5.7 eV or more, more preferably −5.5 eV or more, while usually −4.6 eV or less. Preferably it is -4.8 eV or less. When the HOMO energy level of the p-type semiconductor material is −5.7 eV or more, the characteristics as a p-type semiconductor are improved, and when the HOMO energy level of the p-type semiconductor material is −4.6 eV or less, Stability is improved and the open circuit voltage (Voc) is also improved.

  The LUMO (lowest unoccupied molecular orbital) energy level of the p-type semiconductor material is not particularly limited, but can be selected according to the type of the n-type semiconductor material described later. In particular, when a fullerene compound is used as an n-type semiconductor material, the LUMO energy level of the p-type semiconductor material is usually −3.7 eV or more, preferably −3.6 eV or more. On the other hand, it is usually −2.5 eV or less, preferably −2.7 eV or less. When the LUMO energy level of the p-type semiconductor is −2.5 eV or less, the band gap is adjusted, light energy having a long wavelength can be effectively absorbed, and the short-circuit current density is improved. When the LUMO energy level of the p-type semiconductor material is −3.7 eV or more, electron transfer to the n-type semiconductor material easily occurs and the short-circuit current density is improved.

[5-2-3. n-type semiconductor material]
The n-type semiconductor material is not particularly limited, but specifically, a fullerene compound; a quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum; a condensed ring such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide Tetracarboxylic acid diimides; perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzthiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazoles Derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives, Pyridine derivatives, borane derivatives; anthracene, pyrene, total fluoride condensed polycyclic aromatic hydrocarbons such as naphthacene or pentacene; single-walled carbon nanotubes, n-type polymer (n-type polymer semiconductor material), and the like.

  Among them, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl-substituted naphthalenetetracarboxylic acid diimides, N-alkyl-substituted perylene diimide derivatives or n-type polymer semiconductor materials are preferable. More preferred are fullerene compounds, N-alkyl-substituted perylene diimide derivatives, N-alkyl-substituted naphthalene tetracarboxylic acid diimides or n-type polymer semiconductor materials. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  The LUMO energy level of the n-type semiconductor material is not particularly limited. For example, the value with respect to the vacuum level calculated by a cyclic voltammogram measurement method is usually −3.85 eV or higher, preferably −3.80 eV or higher. . In order to efficiently transfer electrons from a p-type semiconductor material to an n-type semiconductor material, the relative relationship of LUMO energy levels between the p-type semiconductor material and the n-type semiconductor material is important. Specifically, the LUMO energy level of the p-type semiconductor material is higher than the LUMO energy level of the n-type semiconductor material by a predetermined value, in other words, the electron affinity of the n-type semiconductor material is p-type semiconductor material. It is preferable that a predetermined energy is larger than the electron affinity. Since the open circuit voltage (Voc) depends on the difference between the HOMO energy level of the p-type semiconductor material and the LUMO energy level of the n-type semiconductor material, increasing the LUMO of the n-type semiconductor material tends to increase Voc. On the other hand, the LUMO value is usually −1.0 eV or less, preferably −2.0 eV or less, more preferably −3.0 eV or less, and still more preferably −3.3 eV or less. By lowering the LUMO energy level of the n-type semiconductor material, electrons tend to move and the short circuit current (Jsc) tends to increase.

  As a method for calculating the LUMO energy level of the n-type semiconductor material, there are a theoretically calculated method and a method of actually measuring. The theoretically calculated values include semi-empirical molecular orbital methods and non-empirical molecular orbital methods. Examples of the actual measurement method include an ultraviolet-visible absorption spectrum measurement method and a cyclic voltammogram measurement method. Among them, the cyclic voltammogram measurement method is preferable, and the cyclic voltammogram measurement method is used in this specification. Specifically, it can measure by the method as described in well-known literature (International Publication 2011/016430), for example.

  The HOMO energy level of the n-type semiconductor material is not particularly limited, but is usually −5.0 eV or less, preferably −5.5 eV or less. On the other hand, it is usually −7.0 eV or more, preferably −6.6 eV or more. It is preferable that the HOMO energy level of the n-type semiconductor material is −7.0 eV or more because light absorption of the n-type semiconductor material can also be used for power generation. It is preferable that the HOMO energy level of the n-type semiconductor material is −5.0 eV or less in terms of preventing reverse movement of holes.

The electron mobility of the n-type semiconductor material is not particularly limited, but is usually 1.0 × 10 ⁻⁶ cm ² / Vs or more, preferably 1.0 × 10 ⁻⁵ cm ² / Vs or more. 0 × 10 ⁻⁵ cm ² / Vs or more is more preferable, and 1.0 × 10 ⁻⁴ cm ² / Vs or more is more preferable. On the other hand, it is usually 1.0 × 10 ³ cm ² / Vs or less, preferably 1.0 × 10 ² cm ² / Vs or less, and more preferably 5.0 × 10 ¹ cm ² / Vs or less. The fact that the electron mobility of the n-type semiconductor material is 1.0 × 10 ⁻⁶ cm ² / Vs or more can provide effects such as improvement of the electron diffusion rate, improvement of short-circuit current, and improvement of conversion efficiency of the photoelectric conversion element. Is preferable. As a method for measuring the electron mobility, an FET method can be mentioned, which can be performed by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

  The solubility of n-type semiconductor material in toluene at 25 ° C. is usually 0.5% by mass or more, preferably 0.6% by mass or more, and more preferably 0.7% by mass or more. On the other hand, 90 mass% or less is preferable normally, 80 mass% or less is more preferable, and 70 mass% or less is further more preferable. When the solubility of n-type semiconductor material in toluene at 25 ° C. is 0.5 mass or more, the dispersion stability of the n-type semiconductor material in the solution is improved, and aggregation, sedimentation, separation, and the like are less likely to occur. It is preferable.

  Hereinafter, examples of preferable n-type semiconductor materials will be described.

(Fullerene compound)
As a fullerene compound, what has the partial structure represented by general formula (n1), (n2), (n3), and (n4) is mentioned as a preferable example.

In the above formula, FLN represents fullerene, which is a carbon cluster having a closed shell structure. The carbon number of fullerene is not particularly limited as long as it is an even number of usually 60 or more and 130 or less. Examples of fullerenes include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ and higher carbon clusters having more carbon than these. . Among these, _C60 or _C70 is preferable. As fullerenes, carbon-carbon bonds on some fullerene rings may be broken. Moreover, some of the carbon atoms constituting the fullerene may be replaced with other atoms. Further, the fullerene may include a metal atom, a non-metal atom, or an atomic group composed of these in a fullerene cage.

a, b, c and d are integers, and the sum of a, b, c and d is usually 1 or more, and usually 5 or less, preferably 3 or less. The partial structures in (n1), (n2), (n3) and (n4) are bonded to the same 5-membered ring or 6-membered ring in the fullerene skeleton. In the general formula (n1), —R ²¹ and — (CH ₂ ) _L are bonded to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. . In the general formula (n2), -C (R ²⁵ ) (R ²⁶ ) -N (R ²⁷ ) -C with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. (R ²⁸ ) (R ²⁹ ) — are added to form a 5-membered ring. In the general formula (n3), —C (R ³⁰ ) (R ³¹ ) —C—C—C (R) with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. ³² ) (R ³³ ) — are added to form a 6-membered ring. In the general formula (n4), —C (R ³⁴ ) (R ³⁵ ) — is added to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton to form a 3-membered ring. Forming. L is an integer of 1 to 8. L is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.

R ²¹ in the general formula (n1) is an alkyl group having 1 to 14 carbon atoms which may have a substituent, an alkoxy group having 1 to 14 carbon atoms which may have a substituent, or a substituent. An aromatic group which may have a group.

  The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group, and even more preferably a methyl group or an ethyl group. . The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably a methoxy group or an ethoxy group. The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group. More preferred are groups or thienyl groups.

  Although it does not specifically limit as a substituent which said alkyl group, an alkoxy group, and an aromatic group may have, A halogen atom or a silyl group is preferable. As the halogen atom, a fluorine atom is preferable. The silyl group is preferably a diarylalkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group or a trialkylsilyl group, more preferably a dialkylarylsilyl group, and even more preferably a dimethylarylsilyl group.

R ^{22 to} R ²⁴ in the general formula (n1) may each independently have a hydrogen atom, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. It is an aromatic group.

  As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, or an n-hexyl group is preferable. . The substituent that the alkyl group may have is preferably a halogen atom. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group.

  The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group. More preferred are groups or thienyl groups. The substituent that the aromatic group may have is not particularly limited, but is a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or a carbon atom having 1 to 14 carbon atoms. An alkoxy group or an aromatic group having 3 to 10 carbon atoms is preferred, a fluorine atom or an alkoxy group having 1 to 14 carbon atoms is more preferred, and a methoxy group, n-butoxy group or 2-ethylhexyloxy group is still more preferred. When the aromatic group has a substituent, the number is not limited, but is preferably 1 or more and 3 or less, and more preferably 1. When the aromatic group has a plurality of substituents, the types of the substituents may be different, but are preferably the same.

R ^{25 to} R ²⁹ in the general formula (n2) may each independently have a hydrogen atom, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. It is an aromatic group.

  The alkyl group is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group or octyl group, and more preferably a methyl group. The substituent that the alkyl group may have is not particularly limited, but a halogen atom is preferable. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group.

  As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, a phenyl group or a pyridyl group is more preferable, and a phenyl group is further preferable. Although it does not specifically limit as a substituent which an aromatic group may have, Preferably they are a fluorine atom, a C1-C14 alkyl group, or a C1-C14 alkoxy group. The alkyl group may be substituted with a fluorine atom. More preferably, it is an alkoxy group having 1 to 14 carbon atoms, and more preferably a methoxy group. When it has a substituent, the number is not limited, but it is preferably 1 or more and 3 or less, more preferably 1. The types of substituents may be different, but are preferably the same.

Ar ¹ in the general formula (n3) is an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, preferably A phenyl group, a naphthyl group, a biphenyl group, a thienyl group, a furyl group, a pyridyl group, a pyrimidyl group, a quinolyl group or a quinoxalyl group, more preferably a phenyl group, a thienyl group or a furyl group.

  Although there is no limitation as a substituent which may have, an amino group which may be substituted with a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, a silyl group, a boryl group or an alkyl group, having 1 to 14 carbon atoms An alkyl group, an alkoxy group having 1 to 14 carbon atoms, an alkylcarbonyl group having 2 to 14 carbon atoms, an alkylthio group having 1 to 14 carbon atoms, an alkenyl group having 2 to 14 carbon atoms, and 2 to 14 carbon atoms An alkynyl group, an ester group having 2 to 14 carbon atoms, an arylcarbonyl group having 3 to 20 carbon atoms, an arylthio group having 2 to 20 carbon atoms, an aryloxy group having 2 to 20 carbon atoms, and 6 or more carbon atoms An aromatic hydrocarbon group having 20 or less or a heterocyclic group having 2 to 20 carbon atoms is preferable, a fluorine atom, an alkyl group having 1 to 14 carbon atoms, 1 or less carbon atoms 1 An alkoxy group, having 2 to 14 ester groups carbons, an alkyl group or having 3 to 20 arylcarbonyl group carbons of 2 to 14 carbon atoms and more preferable. The alkyl group having 1 to 14 carbon atoms may be substituted with 1 or 2 or more fluorine atoms.

  The alkyl group having 1 to 14 carbon atoms is preferably a methyl group, an ethyl group or a propyl group. The alkoxy group having 1 to 14 carbon atoms is preferably a methoxy group, an ethoxy group, or a propoxy group. The alkylcarbonyl group having 1 to 14 carbon atoms is preferably an acetyl group. The ester group having 2 to 14 carbon atoms is preferably a methyl ester group or an n-butyl ester group. The arylcarbonyl group having 3 to 20 carbon atoms is preferably a benzoyl group.

  When it has a substituent, the number is not limited, but it is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less. When there are a plurality of substituents, the types may be different, but are preferably the same.

R ^{30 to} R ³³ in the general formula (n3) each independently have a hydrogen atom, an alkyl group which may have a substituent, an amino group which may have a substituent, or a substituent. It is an optionally substituted alkoxy group or an optionally substituted alkylthio group. R ³⁰ or R ³¹ may be bonded to any one of R ³² and R ³³ to form a ring. As a structure in the case of forming a ring, the structure shown to the general formula (n5) which is a bicyclo structure which the aromatic group condensed is mentioned, for example.

F In the general formula (n5) has the same meaning as c, Z ⁴ is an oxygen atom, a sulfur atom, an amino group, an alkylene group or an arylene group. The alkylene group preferably has 1 to 2 carbon atoms. The arylene group preferably has 5 to 12 carbon atoms, and examples thereof include a phenylene group. The amino group may be substituted with an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group. The alkylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or 2 to 20 carbon atoms. The aromatic heterocyclic group may be substituted. The arylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or 2 to 20 carbon atoms. The aromatic heterocyclic group may be substituted.

  The structure represented by the formula (n5) is particularly preferably a structure represented by the following formula (n6) or formula (n7).

R ^{34 to} R ³⁵ in the general formula (n4) each independently have a hydrogen atom, an alkoxycarbonyl group, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. An aromatic group that may be present.

  The alkoxy group constituting the alkoxycarbonyl group is preferably an alkoxy group having 1 to 12 carbon atoms or a fluorinated alkoxy group having 1 to 12 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and a methoxy group. Ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group A methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group or an n-hexoxy group is particularly preferable.

  As the alkyl group, a linear alkyl group having 1 to 8 carbon atoms is preferable, and an n-propyl group is more preferable. The substituent that the alkyl group may have is not particularly limited, but is preferably an alkoxycarbonyl group. The alkoxy group constituting the alkoxycarbonyl group is preferably an alkoxy group having 1 to 14 carbon atoms or a fluorinated alkoxy group, more preferably a hydrocarbon group having 1 to 14 carbon atoms, a methoxy group, an ethoxy group, n- Propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group are more preferable, methoxy group or n A butoxy group is particularly preferred.

  As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, and a phenyl group, a biphenyl group, a thienyl group, a furyl group, or a pyridyl group is preferable. More preferred are a phenyl group and a thienyl group. The substituent that the aromatic group may have is preferably an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms. An alkoxy group having a number of 1 or more and 14 or less is more preferable, and a methoxy group or 2-ethylhexyloxy group is particularly preferable. When it has a substituent, the number is not limited, but it is preferably 1 or more and 3 or less, more preferably 1. The types of substituents may be different or the same, preferably the same.

As the structure of the general formula (n4), preferably R ³⁴ and R ³⁵ are both alkoxycarbonyl groups, R ³⁴ and R ³⁵ are both aromatic groups, or R ³⁴ is an aromatic group and R ^{And those in which 35} is a 3- (alkoxycarbonyl) propyl group.

  As the fullerene compound, one kind of the above compounds may be used, or a mixture of plural kinds of compounds may be used.

  In order to form a fullerene compound by a coating method, it is preferable that the fullerene compound itself can be applied in a liquid state, or that the fullerene compound is highly soluble in some solvent and can be applied as a solution. When the preferable range of solubility is raised, the solubility in toluene at 25 ° C. is usually 0.1% by mass or more, preferably 0.4% by mass or more, more preferably 0.7% by mass or more. A solubility of the fullerene compound of 0.1% by mass or more is preferable because the dispersion stability of the fullerene compound in the solution increases and aggregation, sedimentation, separation, and the like hardly occur.

  The solvent for dissolving the fullerene compound is not particularly limited as long as it is a nonpolar organic solvent, but a non-halogen solvent is preferable. Although it is possible to use a halogen-based solvent such as dichlorobenzene, an alternative is demanded from the viewpoint of environmental load. Examples of non-halogen solvents include non-halogen aromatic hydrocarbons. Of these, toluene, xylene, cyclohexylbenzene, and the like are preferable.

(Method for producing fullerene compound)
Although there is no restriction | limiting in particular as a manufacturing method of a fullerene compound, For example, the synthesis | combination of the fullerene compound which has a partial structure (n1) is international publication 2008/059771 or J.N. Am. Chem. Soc. , 2008, 130 (46), 15429-15436.

  Synthesis of fullerene compounds having a partial structure (n2) is described in J. Org. Am. Chem. Soc. 1993, 115, 9798-9799, Chem. Mater. 2007, 19, 5363-5372 and Chem. Mater. It can be carried out according to the description of known documents such as 2007, 19, 5194-5199.

  Synthesis of a fullerene compound having a partial structure (n3) is described in Angew. Chem. Int. Ed. Engl. 1993, 32, 78-80, Tetrahedron Lett. It can be carried out according to the description of known documents such as 1997, 38, 285-288, WO 2008/018931 and WO 2009/086212.

  Synthesis of fullerene compounds having a partial structure (n4) is described in J. Org. Chem. Soc. Perkin Trans. 1, 1997 1595, Thin Solid Films 489 (2005) 251-256, Adv. Funct. Mater. 2005, 15, 1979-1987 and J. Org. Org. Chem. It can be carried out according to the description of known documents such as 1995, 60, 532-538.

  Moreover, as a fullerene compound marketed, PCBM (made by a frontier carbon company), PCBNB (frontier carbon company) etc. can be used conveniently, for example.

(N-alkyl substituted perylene diimide derivatives)
N-alkyl-substituted perylene diimide derivatives are not particularly limited, and specifically, International Publication No. 2008/063609, International Publication No. 2009/115513, International Publication No. 2009/098250, International Publication No. Examples thereof include compounds described in 2009/000756 and International Publication No. 2009/091670. These compounds are preferable in that they have high electron mobility and can absorb light in the visible range, and thus can contribute to both charge transport and power generation.

(Naphthalene tetracarboxylic acid diimide)
The naphthalenetetracarboxylic acid diimide is not particularly limited, and specific examples thereof include compounds described in International Publication No. 2008/063609, International Publication No. 2007/146250 and International Publication No. 2009/000756. It is done. These compounds are preferable because they have high electron mobility, high solubility, and excellent coating properties.

(N-type polymer semiconductor material)
The n-type polymer semiconductor material is not particularly limited, but condensed ring tetracarboxylic acid diimides such as naphthalene tetracarboxylic acid diimide and perylene tetracarboxylic acid diimide, perylene diimide derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazoles N-type polymer semiconductor comprising at least one of a derivative, a benzothiazole derivative, a benzothiadiazole derivative, an oxadiazole derivative, a thiadiazole derivative, a triazole derivative, a pyrazine derivative, a phenanthroline derivative, a quinoxaline derivative, a bipyridine derivative and a borane derivative Materials and the like.

  Among them, a polymer having at least one of a borane derivative, a thiazole derivative, a benzothiazole derivative, a benzothiadiazole derivative, an N-alkyl-substituted naphthalenetetracarboxylic acid diimide and an N-alkyl-substituted perylene diimide derivative as a constituent unit is provided. Preferably, an n-type polymer semiconductor material having at least one of a N-alkyl-substituted perylene diimide derivative and an N-alkyl-substituted naphthalenetetracarboxylic acid diimide as a constituent unit is more preferable. One of the above compounds may be used as the n-type polymer semiconductor material, or a mixture of a plurality of compounds may be used.

  Specific examples of the n-type polymer semiconductor material include compounds described in International Publication No. 2009/098253, International Publication No. 2009/098250, International Publication No. 2010/012710, and International Publication No. 2009/098250. Can be mentioned. Since these compounds can absorb light in the visible range, they can contribute to power generation, are preferred because of their high viscosity and excellent coating properties.

[5-3. Buffer layer (102, 104)]
The photoelectric conversion element 107 includes buffer layers 102 and 104 between the active layer 103 and the electrodes 101 and 105. The buffer layer can be classified into an electron extraction layer 104 and a hole extraction layer 102. By providing the buffer layer, movement of electrons or holes between the active layer 103 and the electrodes 101 and 105 can be facilitated, and a short circuit between the electrodes can be prevented. However, in the present invention, the buffer layers 102 and 104 may not exist.

  The electron extraction layer 104 and the hole extraction layer 102 are disposed so as to sandwich the active layer 103 between a pair of electrodes 101 and 105. That is, when the photoelectric conversion element 107 according to the present invention includes both the electron extraction layer 104 and the hole extraction layer 102, the electrode 101, the hole extraction layer 102, the active layer 103, the electron extraction layer 104, and the electrode 105 Arranged in order. When the photoelectric conversion element 107 according to the present invention includes the electron extraction layer 104 and does not include the hole extraction layer 102, the electrode 101, the active layer 103, the electron extraction layer 104, and the electrode 105 are arranged in this order. The stacking order of the electron extraction layer 104 and the hole extraction layer 102 may be reversed, or at least one of the electron extraction layer 104 and the hole extraction layer 102 may be composed of a plurality of different films. .

[5-3-1. Electron extraction layer (104)]
The material of the electron extraction layer 104 is not particularly limited as long as it is a material that improves the efficiency of extracting electrons from the active layer 103 to the electrode 101, and examples thereof include inorganic compounds and organic compounds.

  Examples of inorganic compound materials that are preferably used in combination with the copolymer according to the present invention include alkali metal salts such as Li, Na, K or Cs; such as titanium oxide (TiOx) and zinc oxide (ZnO). Examples thereof include n-type semiconductor oxides. Among them, the alkali metal salt is preferably a fluoride salt such as LiF, NaF, KF or CsF, and the n-type semiconductor oxide is preferably zinc oxide (ZnO). Although the operation mechanism of such a material is unknown, it is possible to reduce the work function of the cathode 105 when combined with the cathode 105 made of Al or the like and increase the voltage applied to the inside of the solar cell element. It is done.

  Examples of the material of the organic compound that is preferably used in combination with the copolymer according to the present invention include, for example, a phosphine compound having a double bond between a phosphorus atom and a group 16 element such as a triarylphosphine oxide compound; bathocuproin A phenanthrene compound such as (BCP) or bathophenanthrene (Bphen), which may have a substituent and optionally substituted at the 1-position and the 10-position with a heteroatom; a boron compound such as triarylboron; Organic metal oxides such as 8-hydroxyquinolinato) aluminum (Alq3); compounds having one or two ring structures which may have a substituent such as oxadiazole compounds or benzimidazole compounds; naphthalene Tetracarboxylic anhydride (NTCDA) or perylene tetraca Such as carbon anhydride (PTCDA), aromatic compounds having a condensed dicarboxylic acid structure, such as dicarboxylic acid anhydride.

  The LUMO energy level of the material of the electron extraction layer 104 is not particularly limited, but is usually −4.0 eV or more, preferably −3.9 eV or more. On the other hand, it is usually −1.9 eV or less, preferably −2.0 eV or less. It is preferable that the LUMO energy level of the material of the electron extraction layer 104 is −1.9 eV or less because charge transfer can be promoted. It is preferable that the LUMO energy level of the material of the electron extraction layer 104 is −4.0 eV or more because reverse electron transfer to the n-type semiconductor material can be prevented.

  The HOMO energy level of the material of the electron extraction layer 104 is not particularly limited, but is usually −9.0 eV or more, preferably −8.0 eV or more. On the other hand, it is usually −5.0 eV or less, preferably −5.5 eV or less. The HOMO energy level of the material of the electron extraction layer 104 is preferably −5.0 eV or less from the viewpoint of preventing movement of holes.

  As a method for calculating the LUMO energy level and the HOMO energy level of the material of the electron extraction layer 104, a cyclic voltammogram measurement method can be given. For example, it can implement with reference to the method as described in well-known literature (International Publication 2011/016430).

  When the material of the electron extraction layer 104 is an organic compound, the glass transition temperature (hereinafter sometimes referred to as Tg) of this compound when measured by the DSC method is not particularly limited, but is not observed, Or it is preferable that it is 55 degreeC or more. That the glass transition temperature is not observed by the DSC method means that there is no glass transition temperature. Specifically, the determination is made based on the presence or absence of a glass transition temperature of 400 ° C. or lower. A material in which the glass transition temperature by the DSC method is not observed is preferable in that it has high thermal stability.

  Among the compounds having a glass transition temperature of 55 ° C. or higher as measured by the DSC method, the glass transition temperature is preferably 65 ° C. or higher, more preferably 80 ° C. or higher, more preferably 110 ° C. or higher, particularly preferably. Compounds that are 120 ° C. or higher are desirable. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but is usually 400 ° C. or lower, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. The material of the electron extraction layer 104 is preferably a material whose glass transition temperature by DSC method is not observed to be 30 ° C. or higher and lower than 55 ° C.

  The glass transition temperature in the present specification is defined as a point at which specific heat changes in an amorphous solid, which is a temperature at which local molecular motion is started by thermal energy. When the temperature rises further than Tg, the solid structure changes and crystallization occurs (the temperature at this time is defined as the crystallization temperature (Tc)). When the temperature rises further, it generally melts at the melting point (Tm) and changes to a liquid state. However, these phase transitions may not be observed due to molecular decomposition or sublimation at high temperatures.

  The DSC method is a thermophysical property measurement method (differential scanning calorimetry method) defined in JIS K-0129 “General Rules for Thermal Analysis”. In order to determine the glass transition temperature more clearly, it is desirable to measure after rapidly cooling a sample once heated to a temperature higher than the glass transition temperature. For example, the measurement can be carried out by a method described in a known document (International Publication No. 2011/016430).

  When the glass transition temperature of the compound used for the electron extraction layer is 55 ° C. or higher, the structure of this compound is difficult to change against external stress such as applied electric field, flowing current, stress due to bending or temperature change. It is preferable in terms of durability. Furthermore, since there is a tendency that the crystallization of the thin film of the compound does not proceed easily, the stability of the electron extraction layer is improved by making it difficult for the compound to change between the amorphous state and the crystalline state in the operating temperature range. Therefore, it is preferable in terms of durability. This effect becomes more prominent as the glass transition temperature of the material is higher.

  The thickness of the electron extraction layer 104 is not particularly limited, but is usually 0.01 nm or more, preferably 0.1 nm or more, more preferably 0.5 nm or more. On the other hand, it is usually 40 nm or less, preferably 20 nm or less. When the film thickness of the electron extraction layer 104 is 0.01 nm or more, it functions as a buffer material. When the film thickness of the electron extraction layer 104 is 40 nm or less, electrons are easily extracted, and photoelectric conversion is performed. Efficiency can be improved.

[5-3-2. Hole extraction layer (102)]
The material of the hole extraction layer 102 is not particularly limited as long as it is a material capable of improving the efficiency of extracting holes from the active layer 103 to the anode 101. Specifically, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like, a conductive polymer doped with sulfonic acid and / or iodine, a polythiophene derivative having a sulfonyl group as a substituent, or a conductive organic such as arylamine Examples thereof include compounds and the above-described p-type semiconductor materials. Among them, a conductive polymer doped with sulfonic acid is preferable, and poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. A thin film of metal such as gold, indium, silver or palladium can also be used. A thin film of metal or the like may be formed alone or in combination with the above organic material.

  The thickness of the hole extraction layer 102 is not particularly limited, but is usually 2 nm or more. On the other hand, it is usually 40 nm or less, preferably 20 nm or less. When the film thickness of the hole extraction layer 102 is 2 nm or more, it functions as a buffer material. When the film thickness of the hole extraction layer 102 is 40 nm or less, holes are easily extracted, Conversion efficiency can be improved.

  There are no limitations on the method for forming the electron extraction layer 104 and the hole extraction layer 102. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or inkjet. In the case where a semiconductor material is used for the hole extraction layer 102, the precursor may be converted into a semiconductor material after a layer including a semiconductor material precursor is formed as in the active layer 103.

[5-4. Electrode (101, 105)]
The electrodes 101 and 105 have a function of collecting holes and electrons generated by light absorption. Therefore, the pair of electrodes includes an electrode 101 suitable for collecting holes (hereinafter also referred to as an anode) and an electrode 105 suitable for collecting electrons (hereinafter referred to as a cathode). ) Are preferably used. Any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Moreover, it is preferable that the sunlight transmittance of the transparent electrode is 70% or more in order to allow light to reach the active layer 103 through the transparent electrode. The light transmittance can be measured with a normal spectrophotometer.

  The anode 101 is an electrode generally made of a conductive material having a work function higher than that of the cathode and having a function of smoothly extracting holes generated in the active layer 103.

  Examples of the material of the anode 101 include conductive metal oxides such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide, and zinc oxide. A metal such as gold, platinum, silver, chromium or cobalt, or an alloy thereof; Since these substances have a high work function, they are preferable, and further, a conductive polymer material typified by PEDOT / PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid can be laminated. When laminating such a conductive polymer, the work function of this conductive polymer material is high, so even if it is not a material with a high work function as described above, it is suitable for cathodes such as Al and Mg. Metals can also be widely used.

  A PEDOT / PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid, or a conductive polymer material in which polypyrrole or polyaniline is doped with iodine or the like can also be used as the anode material.

  When the anode 101 is a transparent electrode, it is preferable to use a light-transmitting conductive metal oxide such as ITO, zinc oxide, or tin oxide, and ITO is particularly preferable.

  The film thickness of the anode 101 is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, and more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the film thickness of the anode 101 is 10 nm or more, the sheet resistance is suppressed, and when the film thickness of the anode 101 is 10 μm or less, light can be efficiently converted into electricity without reducing the light transmittance. it can. When the anode 101 is a transparent electrode, it is necessary to select a film thickness that can achieve both light transmittance and sheet resistance.

  The sheet resistance of the anode 101 is not particularly limited, but is usually 1Ω / □ or more, on the other hand, 1000Ω / □ or less, preferably 500Ω / □ or less, more preferably 100Ω / □ or less.

  Examples of a method for forming the anode 101 include a vacuum film forming method such as an evaporation method or a sputtering method, or a wet coating method in which an ink containing nanoparticles and a precursor is applied to form a film.

  The cathode 105 is generally an electrode made of a conductive material having a work function higher than that of the anode and having a function of smoothly extracting electrons generated in the active layer 103.

  Examples of the material of the cathode 105 include metals such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, and magnesium, and alloys thereof; Examples include inorganic salts such as lithium and cesium fluoride; metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. These materials are preferable because they are materials having a low work function. Similarly to the anode 101, a material having a high work function suitable for the anode 101 can also be used for the cathode 105 by using an n-type semiconductor such as titania having conductivity as the electron extraction layer 104. From the viewpoint of electrode protection, the material of the anode 101 is preferably a metal such as platinum, gold, silver, copper, iron, tin, aluminum, calcium or indium and an alloy using these metals.

  The film thickness of the cathode 105 is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the film thickness of the cathode 105 is 10 nm or more, sheet resistance is suppressed, and when the film thickness of the cathode 105 is 10 μm or less, light can be efficiently converted into electricity without reducing light transmittance. it can. When the cathode 105 is used as a transparent electrode, it is necessary to select a film thickness that achieves both light transmittance and sheet resistance.

  The sheet resistance of the cathode 105 is not particularly limited, but is usually 1000Ω / □ or less, preferably 500Ω / □ or less, and more preferably 100Ω / □ or less. Although there is no restriction on the lower limit, it is usually 1Ω / □ or more.

  As a method for forming the cathode 105, there are a vacuum film formation method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film.

  Furthermore, the anode 101 and the cathode 105 may have a stacked structure of two or more layers. In addition, characteristics (electric characteristics, wetting characteristics, etc.) may be improved by performing surface treatment on the anode 101 and the cathode 105.

  After laminating anode 101 and cathode 105, the photoelectric conversion element is heated in a temperature range of usually 50 ° C. or higher, preferably 80 ° C. or higher, usually 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 250 ° C. or lower. It is preferable to do this (this step may be referred to as an annealing treatment step). By performing the annealing process at a temperature of 50 ° C. or higher, the adhesion between the layers of the photoelectric conversion element, for example, the adhesion between the electron extraction layer 104 and the electrode 101 and / or the electron extraction layer 104 and the active layer 103 is improved. Is preferable. By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. Further, the self-organization of the active layer can be promoted by the annealing process. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the possibility that the organic compound in the active layer 103 is thermally decomposed is reduced. In the annealing treatment step, stepwise heating may be performed within the above temperature range.

  The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment step is preferably terminated when the open-circuit voltage, the short-circuit current, and the fill factor, which are parameters of the solar cell performance, reach a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere.

  As a heating method, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be placed in a heating atmosphere such as an oven. The heating may be performed batchwise or continuously.

[5-5. Substrate (106)]
The photoelectric conversion element 107 has a base material 106 that usually serves as a support. That is, the electrodes 101 and 105 and the active layer 103 are formed on the substrate. But the photoelectric conversion element which concerns on this invention does not need to have the base material 106. FIG.

  The material of the substrate 106 is not particularly limited as long as the effects of the present invention are not significantly impaired. Preferable examples of the material of the substrate 106 include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer Organic materials such as coalescence, fluororesin film, polyolefin such as vinyl chloride or polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene or epoxy resin; paper material such as paper or synthetic paper And composite materials such as those obtained by coating or laminating a surface of a metal such as stainless steel, titanium or aluminum in order to impart insulation.

  Examples of the glass include soda glass, blue plate glass, and non-alkali glass. Among these, alkali-free glass is preferable in that there are few eluted ions from the glass.

  There is no restriction | limiting in the shape of the base material 106, For example, things, such as plate shape, a film form, or a sheet form, can be used. Moreover, although there is no restriction | limiting in the film thickness of the base material 106, Usually, it is 5 micrometers or more, Preferably it is 20 micrometers or more, On the other hand, it is 20 mm or less normally, Preferably it is 10 mm or less. It is preferable that the thickness of the substrate is 5 μm or more because the possibility that the strength of the photoelectric conversion element is insufficient is reduced. It is preferable that the thickness of the substrate is 20 mm or less because the cost is suppressed and the weight does not increase. When the material of the substrate 106 is glass, the film thickness is usually 0.01 mm or more, preferably 0.1 mm or more, and is usually 1 cm or less, preferably 0.5 cm or less. It is preferable that the glass substrate 106 has a film thickness of 0.01 mm or more because mechanical strength increases and it is difficult to break. Moreover, it is preferable that the film thickness of the glass substrate 106 is 0.5 cm or less because the weight does not increase.

[5-6. Photoelectric conversion characteristics]
The photoelectric conversion characteristics of the photoelectric conversion element 107 can be obtained as follows. The photoelectric conversion element 107 is irradiated with light having an AM1.5G condition at an irradiation intensity of 100 mW / cm ^{2 using a} solar simulator, and current-voltage characteristics are measured. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.

  The photoelectric conversion efficiency of the photoelectric conversion element according to the present invention is not particularly limited, but is usually 1% or more, preferably 1.5% or more, more preferably 2% or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better.

Moreover, as a method for measuring the durability of the photoelectric conversion element, a method for obtaining a maintenance ratio of the photoelectric conversion efficiency before and after exposing the photoelectric conversion element to the atmosphere can be mentioned.
(Maintenance rate) = (Photoelectric conversion efficiency after N hours of atmospheric exposure) / (Photoelectric conversion efficiency immediately before atmospheric exposure)

  In order to put a photoelectric conversion element into practical use, it is important to have high photoelectric conversion efficiency and high durability in addition to simple and inexpensive manufacture. From this viewpoint, the maintenance rate of photoelectric conversion efficiency before and after exposure to the atmosphere for one week is preferably 60% or more, more preferably 80% or more, and the higher the better.

<6. Solar Cell According to the Present Invention>
The photoelectric conversion element 107 according to the present invention is preferably used as a solar cell, particularly a solar cell element of a thin film solar cell.

  FIG. 2 is a cross-sectional view schematically showing the configuration of a thin film solar cell as one embodiment of the present invention. As shown in FIG. 2, the thin film solar cell 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and a solar cell element. 6, a sealing material 7, a getter material film 8, a gas barrier film 9, and a back sheet 10 are provided in this order. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 is formed, and the solar cell element 6 generates power. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

[6.1 Weatherproof Protective Film (1)]
The weather-resistant protective film 1 is a film that protects the solar cell element 6 from weather changes. By covering the solar cell element 6 with the weather-resistant protective film 1, the solar cell element 6 and the like are protected from weather changes and the power generation capacity is kept high. Since the weather resistant protective film 1 is located on the outermost layer of the thin film solar cell 14, the surface covering material of the thin film solar cell 14 such as weather resistance, heat resistance, transparency, water repellency, stain resistance and / or mechanical strength is provided. It is preferable to have a property suitable for the above and to maintain it for a long period of time in outdoor exposure.

  Moreover, the weather-resistant protective film 1 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited. Furthermore, since the thin-film solar cell 14 is often heated by receiving light, it is preferable that the weather-resistant protective film 1 also has heat resistance. From this viewpoint, the melting point of the constituent material of the weather-resistant protective film 1 is usually 100 ° C. or higher and 350 ° C. or lower.

  The material which comprises the weather-resistant protective film 1 is arbitrary as long as it can protect the solar cell element 6 from a weather change. Examples of the material include polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene Examples thereof include polyester resins such as naphthalate, phenol resins, polyacrylic resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicon resins, and polycarbonate resins.

  In addition, the weather-resistant protective film 1 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the weather-resistant protective film 1 may be formed with the single layer film, the laminated | multilayer film provided with the film of two or more layers may be sufficient as it.

  The thickness of the weather-resistant protective film 1 is not particularly defined, but is usually 10 μm or more and 200 μm or less.

  Moreover, you may perform surface treatment, such as a corona treatment and / or a plasma treatment, for the weather-resistant protective film 1 in order to improve the adhesiveness with another film.

  The weatherproof protective film 1 is preferably provided on the outer side as much as possible in the thin-film solar cell 14. This is because more of the constituent members of the thin-film solar cell 14 can be protected.

[6.2 UV cut film (2)]
The ultraviolet cut film 2 is a film that prevents the transmission of ultraviolet rays. The ultraviolet cut film 2 is provided in the light receiving portion of the thin-film solar cell 14, and the ultraviolet cut film 2 covers the light receiving surface 6a of the solar cell element 6, so that the solar cell element 6 and, if necessary, the gas barrier films 3 and 9 are exposed to ultraviolet rays. The power generation capacity can be maintained at a high level.

  The degree of the ability to suppress the transmission of ultraviolet rays required for the ultraviolet cut film 2 is preferably such that the transmittance of ultraviolet rays (for example, wavelength of 300 nm) is 50% or less, and there is no limit on the lower limit. Moreover, it is preferable that the ultraviolet cut film 2 transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, the ultraviolet cut film 2 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the ultraviolet cut film 2 is usually 100 ° C. or higher and 350 ° C. or lower.

  Moreover, the ultraviolet cut film 2 has a high softness | flexibility, its adhesiveness with an adjacent film is favorable, and what can cut water vapor | steam and oxygen is preferable.

  The material which comprises the ultraviolet cut film 2 is arbitrary if the intensity | strength of an ultraviolet-ray can be weakened. Examples of the material include films formed by blending an ultraviolet absorber with an epoxy, acrylic, urethane, or ester resin. Further, a film in which a layer of an ultraviolet absorbent dispersed or dissolved in a resin (hereinafter referred to as “ultraviolet absorbing layer” as appropriate) is formed on a base film may be used.

  Examples of the ultraviolet absorber that can be used include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ones. In addition, a ultraviolet absorber may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio. As described above, a film in which an ultraviolet absorbing layer is formed on a base film can also be used as the ultraviolet absorbing film. Such a film can be produced, for example, by applying a coating solution containing an ultraviolet absorber on a substrate film and drying it.

  Although the material of a base film is not specifically limited, For example, polyester is mentioned at the point from which the balance of heat resistance and a softness | flexibility is obtained.

  Examples of specific products of the ultraviolet cut film 2 include cut ace (MKV Plastic Co., Ltd.). In addition, the ultraviolet cut film 2 may be formed with 1 type of material, and may be formed with 2 or more types of materials.

  Further, the ultraviolet cut film 2 may be formed of a single layer film, but may be a laminated film including two or more layers. The thickness of the ultraviolet cut film 2 is not particularly limited, but is usually 5 μm or more and 200 μm or less.

  Although the ultraviolet cut film 2 should just be provided in the position which covers at least one part of the light-receiving surface 6a of the solar cell element 6, Preferably it is provided in the position which covers all the light-receiving surfaces 6a of the solar cell element 6. FIG. However, the ultraviolet cut film 2 may be provided at a position other than the position covering the light receiving surface 6 a of the solar cell element 6.

[6.3 Gas barrier film (3)]
The gas barrier film 3 is a film that prevents permeation of water and oxygen. By covering the solar cell element 6 with the gas barrier film 3, the solar cell element 6 can be protected from water and oxygen, and the power generation capacity can be kept high.

Although the degree of moisture-proof capability required for the gas barrier film 3 varies depending on the type of the solar cell element 6 and the like, the water vapor transmission rate per unit area (1 m ² ) per day is usually 1 × 10 ^−1. It is preferable that it is below g / m < ² > / day, and there is no restriction | limiting in a minimum.

Although the degree of oxygen permeability required for the gas barrier film 3 varies depending on the type of the solar cell element 6 and the like, the oxygen permeability per unit area (1 m ² ) per day is usually 1 × 10 ^−. It is preferably ¹ cc / m ² / day / atm or less, and the lower limit is not limited.

  Further, the gas barrier film 3 is preferably one that transmits visible light from the viewpoint of not preventing the light absorption of the solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the gas barrier film 3 also has heat resistance. From this viewpoint, the melting point of the constituent material of the gas barrier film 3 is usually 100 ° C. or higher and 350 ° C. or lower.

  The specific configuration of the gas barrier film 3 is arbitrary as long as the solar cell element 6 can be protected from water. However, since the manufacturing cost increases as the amount of water vapor or oxygen that can permeate the gas barrier film 3 increases, it is preferable to use an appropriate film considering these points comprehensively.

Particularly suitable gas barrier film 3 includes, for example, a film obtained by vacuum-depositing SiO _x on a base film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

  In addition, the gas barrier film 3 may be formed with 1 type of material, and may be formed with 2 or more types of materials. The gas barrier film 3 may be formed of a single layer film, but may be a laminated film including two or more layers.

  The thickness of the gas barrier film 3 is not particularly defined, but is usually 5 μm or more and 200 μm or less.

  As long as the gas barrier film 3 covers the solar cell element 6 and can be protected from moisture and oxygen, the formation position is not limited. However, the front surface of the solar cell element 6 (surface on the light receiving surface side, lower surface in FIG. 2) and It is preferable to cover the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2). This is because the front and back surfaces of the thin film solar cell 14 are often formed in a larger area than the other surfaces. In this embodiment, the gas barrier film 3 covers the front surface of the solar cell element 6, and a gas barrier film 9 described later covers the back surface of the solar cell element 6. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

[6.4 Getter material film (4)]
The getter material film 4 is a film that absorbs moisture and / or oxygen. By covering the solar cell element 6 with the getter material film 4, the solar cell element 6 and the like are protected from moisture and / or oxygen, and the power generation capacity is kept high. Here, unlike the gas barrier film 3 as described above, the getter material film 4 does not prevent moisture permeation but absorbs moisture. By using a film that absorbs moisture, the getter material film 4 captures moisture that slightly enters the space formed by the gas barrier films 3 and 9 when the solar cell element 6 is covered with the gas barrier film 3 or the like. The influence of moisture on the solar cell element 6 can be eliminated.

The degree of moisture absorption capacity of the getter material film 4 is usually 0.1 mg / cm ² or more, and although there is no upper limit, it is usually 10 mg / cm ² or less. Further, when the solar cell element 6 is covered with the gas barrier films 3 and 9 or the like by the getter material film 4 absorbing oxygen, the oxygen that slightly enters the space formed by the gas barrier films 3 and 9 is obtained as the getter material. The film 4 can capture and eliminate the influence of oxygen on the solar cell element 6.

  Furthermore, the getter material film 4 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, the getter material film 4 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the getter material film 4 is usually 100 ° C. or higher and 350 ° C. or lower.

  The material constituting the getter material film 4 is arbitrary as long as it can absorb moisture and / or oxygen. Examples of the material include alkali metal, alkaline earth metal or alkaline earth metal oxides; alkali metal or alkaline earth metal hydroxides; silica gel, zeolitic compounds, magnesium sulfate. And sulfates such as sodium sulfate and nickel sulfate; and organometallic compounds such as aluminum metal complexes and aluminum oxide octylates. Specifically, examples of the alkaline earth metal include Ca, Sr, and Ba. Examples of the alkaline earth metal oxide include CaO, SrO, and BaO. In addition, Zr-Al-BaO and aluminum metal complexes are also included. Specific product names include, for example, OleDry (Futaba Electronics).

  Examples of the substance that absorbs oxygen include activated carbon, silica gel, activated alumina, molecular sieve, magnesium oxide, and iron oxide. In addition, Fe, Mn, Zn, and inorganic salts such as sulfates, chlorides, and nitrates of these metals are also included.

  In addition, the getter material film 4 may be formed of one type of material or may be formed of two or more types of materials. The getter material film 4 may be formed of a single layer film, but may be a laminated film including two or more layers.

  The thickness of the getter material film 4 is not particularly specified, but is usually 5 μm or more and 200 μm or less.

  The formation position of the getter material film 4 is not limited as long as it is in the space formed by the gas barrier films 3 and 9, but the front surface of the solar cell element 6 (the surface on the light receiving surface side, the lower surface in FIG. 2). And it is preferable to cover the back surface (surface opposite to the light receiving surface; upper surface in FIG. 2). This is because, in the thin film solar cell 14, the front and back surfaces are often formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, the getter material film 4 is preferably provided between the gas barrier film 3 and the solar cell element 6. In this embodiment, the getter material film 4 covers the front surface of the solar cell element 6, a getter material film 8 described later covers the back surface of the solar cell element 6, and the getter material films 4 and 8 are respectively the solar cell element 6 and the gas barrier film 3. , 9 are located between them. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

[6.5 Sealant (5)]
The sealing material 5 is a film that reinforces the solar cell element 6. Since the solar cell element 6 is thin, the strength is usually weak, and thus the strength of the thin film solar cell tends to be weak. However, the strength can be maintained high by the sealing material 5.

  Moreover, it is preferable that the sealing material 5 has high strength from the viewpoint of maintaining the strength of the thin-film solar cell 14. The specific strength is related to the strength of the weatherproof protective film 1 other than the sealing material 5 and the strength of the back sheet 10 and is generally difficult to define, but the thin film solar cell 14 as a whole has good bending workability. However, it is desirable to have a strength that does not cause peeling of the bent portion.

  Moreover, it is preferable that the sealing material 5 permeate | transmits visible light from a viewpoint which does not prevent the light absorption of the solar cell element 6. FIG. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  The thickness of the sealing material 5 is not particularly specified, but is usually 2 μm or more and 700 μm or less.

  The T-type peel adhesion strength of the sealing material 5 to the substrate is usually 1 N / inch or more and usually 2000 N / inch or less. It is preferable that the T-type peel adhesive strength is 1 N / inch or more in terms of ensuring the long-term durability of the module. It is preferable that the T-type peel adhesive strength is 2000 N / inch or less in that the base material, the barrier film, and the adhesive can be separated and discarded when the solar cell is discarded. The T-type peel adhesion strength is measured by a method according to JIS K6854.

  The constituent material of the sealing material 5 is not particularly limited as long as it has the above characteristics, but sealing of organic / inorganic solar cells, sealing of organic / inorganic LED elements, sealing of electronic circuit boards, etc. In general, a sealing material generally used can be used.

  Specifically, a thermosetting resin composition or a thermoplastic resin composition and an active energy ray curable resin composition can be mentioned. The active energy ray-curable resin composition is, for example, a resin that is cured by ultraviolet rays, visible light, electron beams, or the like. More specifically, an ethylene-vinyl acetate copolymer (EVA) resin composition, a hydrocarbon resin composition, an epoxy resin composition, a polyester resin composition, an acrylic resin composition, and a urethane resin composition. Or a silicon-based resin composition, etc., depending on the main chain, branched chain, terminal chemical modification of each polymer, adjustment of molecular weight, additives, etc., thermosetting, thermoplastic and active energy ray curable, etc. The characteristics are expressed.

  Moreover, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the sealing material 5 also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material 5 is usually 100 ° C. or higher and 350 ° C. or lower.

The density of the constituent material for sealing material in the sealing material 5 is preferably 0.80 g / cm ³ or more, and there is no upper limit. The measurement and evaluation of density can be performed by a method based on JIS K7112.

  Although there is no restriction | limiting in the position which provides the sealing material 5, Usually, it provides so that the solar cell element 6 may be inserted | pinched. This is for reliably protecting the solar cell element 6. In this embodiment, the sealing material 5 and the sealing material 7 are provided on the front surface and the back surface of the solar cell element 6, respectively.

[6.6 Solar cell element (6)]
The solar cell element 6 is the same as the photoelectric conversion element 107 described above.

  Although only one solar cell element 6 may be provided for each thin film solar cell 14, usually two or more solar cell elements 6 are provided. The specific number of solar cell elements 6 may be set arbitrarily. When a plurality of solar cell elements 6 are provided, the solar cell elements 6 are often arranged in an array.

  When a plurality of solar cell elements 6 are provided, the solar cell elements 6 are usually electrically connected to each other, and electricity generated from the connected group of solar cell elements 6 is taken out from a terminal (not shown). At this time, the solar cell elements are usually connected in series in order to increase the voltage.

  Thus, when connecting the solar cell elements 6, it is preferable that the distance between the solar cell elements 6 is small, and by extension, the gap between the solar cell element 6 and the solar cell element 6 is preferably narrow. This is because the light receiving area of the solar cell element 6 is widened to increase the amount of received light, and the amount of power generated by the thin film solar cell 14 is increased.

[6.7 Sealant (7)]
The sealing material 7 is a film similar to the sealing material 5 described above, and the same material as the sealing material 7 can be used in the same manner except that the arrangement position is different. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[6.8 Getter material film (8)]
The getter material film 8 is the same film as the getter material film 4 described above, and the same material as the getter material film 4 can be used as necessary, except for the arrangement position. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[6.9 Gas barrier film (9)]
The gas barrier film 9 is the same film as the gas barrier film 3 described above, and the same material as the gas barrier film 9 can be used as necessary except that the arrangement position is different. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[6.10 Back sheet (10)]
The back sheet 10 is the same film as the weather-resistant protective film 1 described above, and the same material as the weather-resistant protective film 1 can be used in the same manner except that the arrangement position is different. In addition, if the back sheet 10 is difficult to permeate water and oxygen, the back sheet 10 can also function as a gas barrier layer. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[6.11 Dimensions, etc.]
The thin film solar cell 14 of the present embodiment is usually a thin film member. Thus, by forming the thin film solar cell 14 as a film-like member, the thin film solar cell 14 can be easily installed in a building material, an automobile, an interior, or the like. The thin-film solar cell 14 is light and difficult to break, and thus a highly safe solar cell can be obtained and can be applied to a curved surface, so that it can be used for more applications. Since it is thin and light, it is preferable in terms of distribution such as transportation and storage. Furthermore, since it is in the form of a film, it can be manufactured in a roll-to-roll manner, and the cost can be greatly reduced.

  Although there is no restriction | limiting in the specific dimension of the thin film solar cell 14, The thickness is usually 300 micrometers or more and 3000 micrometers or less.

[6.12 Manufacturing method]
Although there is no restriction | limiting in the manufacturing method of the thin film solar cell 14 of this embodiment, For example, as a solar cell manufacturing method of the form of FIG. 2, after producing the laminated body shown by FIG. Is mentioned. Since the solar cell element of this embodiment is excellent in heat resistance, it is preferable in that deterioration due to the laminate sealing step is reduced.

  The laminate production shown in FIG. 2 can be performed using a known technique. The method of the laminate sealing step is not particularly limited as long as the effects of the present invention are not impaired, but for example, wet lamination, dry lamination, hot melt lamination, extrusion lamination, coextrusion molding lamination, extrusion coating, photocuring adhesive Laminate, thermal laminate, etc. are mentioned. Among them, a laminating method using a photo-curing adhesive having a proven record in organic EL device sealing, a hot melt laminate or a thermal laminate having a proven record in solar cells is preferable, and a hot melt laminate or a thermal laminate is a sheet-like sealing material. It is more preferable at the point which can be used.

  The heating temperature in the laminate sealing step is usually 130 ° C or higher, preferably 140 ° C or higher, and is usually 180 ° C or lower, preferably 170 ° C or lower. The heating time in the laminate sealing step is usually 10 minutes or longer, preferably 20 minutes or longer, and is usually 100 minutes or shorter, preferably 90 minutes or shorter. The pressure in the laminate sealing step is usually 0.001 MPa or more, preferably 0.01 MPa or more, and usually 0.2 MPa or less, preferably 0.1 MPa or less. By setting the pressure within this range, sealing can be performed reliably, and the reduction of the film thickness due to the protrusion of the sealing materials 5 and 7 from the end portion and overpressurization can be suppressed, thereby ensuring dimensional stability. In addition, what connected two or more solar cell elements 6 in series or in parallel can be manufactured similarly to the above.

[6.13 Applications]
There is no restriction | limiting in the use of the solar cell which concerns on this invention, especially the thin film solar cell 14 mentioned above, It can use for arbitrary uses. Examples of the field to which the thin-film solar cell according to the present invention is applied include building material solar cells, automobile solar cells, interior solar cells, railway solar cells, marine solar cells, airplane solar cells, and spacecrafts. Solar cells, solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like.

  The solar cell according to the present invention, in particular, a thin film solar cell may be used as it is, or a solar cell may be installed on a substrate and used as a solar cell module. For example, as schematically shown in FIG. 3, a solar cell module 13 including a thin film solar cell 14 on a base material 12 is prepared and used at a place of use. As a specific example, when a building material plate is used as the base material 12, a solar cell panel can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of the plate material.

  The substrate 12 is a support member that supports the thin film solar cell 14. Examples of the material for forming the substrate 12 include inorganic materials such as glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine. Organic materials such as resin, vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate and polynorbornene; paper materials such as paper and synthetic paper; metals such as stainless steel, titanium and aluminum; Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as stainless steel, titanium, and aluminum to impart insulation.

  In addition, 1 type may be used for the material of a base material, and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, carbon fiber may be included in these organic materials or paper materials to reinforce the mechanical strength. When the example of the base material 12 is given, Alpolic (registered trademark; manufactured by Mitsubishi Plastics) and the like may be mentioned.

  Although there is no restriction | limiting in the shape of the base material 12, Usually, a board | plate material is used. Moreover, what is necessary is just to set the material of the base material 12, a dimension, etc. arbitrarily according to the use environment. This solar cell panel can be installed on the outer wall of a building.

  Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded. The items described in the examples were measured by the following methods.

[Method for measuring weight average molecular weight and number average molecular weight]
The weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC). The molecular weight distribution (PDI) represents Mw / Mn.

Gel permeation chromatography (GPC) measurement was performed under the following conditions.
Column: PolymerLaboratories GPC column (PLgel MIXED-B 10 μm inner diameter 7.5 mm, length 30 cm) used in series connected Pump: LC-10AT (manufactured by Shimadzu Corporation)
Oven: CTO-10A (manufactured by Shimadzu Corporation)
Detector: differential refractive index detector (manufactured by Shimadzu Corporation, RID-10A) and UV-vis detector (manufactured by Shimadzu Corporation, SPD-10A)
Sample: 1 μL of 1 mg sample dissolved in chloroform (200 mg)
Mobile phase: Chloroform
Flow rate: 1.0 mL / min
Analysis: LC-Solution (manufactured by Shimadzu Corporation)

[Absorption spectrum measurement]
Absorption spectrum measurement was carried out using a spectrophotometer (Hitachi, U-3500). Specifically, the chloroform solution of the copolymer (adjusted so that the absorbance maximum value was 0.8 or less) was measured in the range of 350 nm to 850 nm using a 1 cm square quartz cell.

[Storage stability test of copolymer-containing ink]
The storage stability test of the copolymer-containing ink was carried out by the following method. 2 mg of the copolymer was placed in a 2 mL screw vial, and o-xylene was added thereto to a concentration of 1.5% by mass. The vessel was sealed with a lid and heated until the copolymer dissolved. The resulting copolymer-containing ink was cooled to room temperature and the time until gelation was measured. As a method for determining gelation, the gel was gelled when no fluidity was observed after standing for 1 minute with the screw vial turned upside down after a predetermined time. Specifically, the container was removed from the heat source and gelled after 5 minutes from the time of standing at room temperature, and whether gelled after 1 hour was determined.

[Evaluation method of photoelectric conversion element]
A 6 mm square metal mask is attached to the photoelectric conversion element, a solar simulator with an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm ² is used as an irradiation light source, and an ITO electrode and a source meter (type 2400 manufactured by Keithley) The current-voltage characteristic between the aluminum electrode was measured. From this measurement result, open circuit voltage Voc (V), short circuit current density Jsc (mA / cm ² ), form factor FF, and photoelectric conversion efficiency PCE (%) were calculated.

Here, the open circuit voltage Voc is a voltage value when the current value = 0 (mA / cm ² ), and the short circuit current density Jsc is a current density when the voltage value = 0 (V). The form factor FF is a factor representing the internal resistance, and is represented by the following expression when the maximum output is Pmax.
FF = Pmax / (Voc × Jsc)
Further, the photoelectric conversion efficiency PCE is given by the following equation when the incident energy is Pin.
PCE = (Pmax / Pin) × 100
= (Voc x Jsc x FF / Pin) x 100

<Synthesis Example 1: Synthesis of Compound E2>

  In a 200 mL four-necked eggplant flask under a nitrogen atmosphere, 4,4-bis (2-ethylhexyl) -2,6-bis (trimethylsilyl) -dithieno [3,2-b: 2 ′, 3′-d] silole ( Compound E1, Non-Patent Document J. Am. Chem. Soc. 2008, 130, 16144-16145, synthesized, 1.03 g, 1.786 mmol) was added and dissolved in chloroform (50 mL). Further, trifluoroacetic acid (0.265 mL, 3.573 mmol) was added dropwise, followed by stirring for about 3.5 hours. Water was added to the reaction solution, the lower layer was washed with water, dried over sodium sulfate, and concentrated under reduced pressure. By dissolving in hexane and subjecting to silica gel column chromatography (solvent: hexane), 4,4-bis (2-ethylhexyl) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E2 ) Was obtained as a pale yellow oil (702 mg, 94% yield).

Compound E2: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.18 (d, 2H, J = 4.8 Hz), 7.08 (d, 2H, J = 4.8 Hz), 1.43- 1.35 (m, 2H), 1.28-1.09 (m, 16H), 0.98-0.80 (m, 10H), 0.75 (d, 6H, J = 7.3 Hz).

<Synthesis Example 2: Synthesis of Compound E3>

  Under a nitrogen atmosphere, the compound E2 (100 mg, 0.239 mmol) obtained in Synthesis Example 1 was placed in a 20 mL Schlenk tube, dissolved in tetrahydrofuran (THF, 2.5 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.287 mL, 1.2 eq) was added dropwise, and the temperature was gradually raised to room temperature. After cooling again to −78 ° C., a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.287 mL, 1.2 eq) was added dropwise, and the temperature was gradually raised to room temperature. After cooling to −78 ° C. again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 0.258 mL, 1.2 eq) was added dropwise and stirred for about 1 hour. Further, a tetrahydrofuran solution of trimethyltin chloride (manufactured by Aldrich, 1.0 M, 0.310 mL, 1.3 eq) was added dropwise, and the temperature was gradually raised to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate, filtered, concentrated under reduced pressure, and then dried under vacuum, whereby 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3, 2-b: 2 ′, 3′-d] silole (compound E3) was quantitatively obtained as a yellow-green oil.

Compound E3: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.07 (s, 2H), 1.45-1.37 (m, 2H), 1.32-1.08 (m, 16H) 0.99-0.80 (m, 10H), 0.77 (t, 6H, J = 7.3 Hz), 0.36 (s, 18H).

<Synthesis Example 3: Synthesis of Compound E5>

  3,3′-Dibromo-5,5′-bis (trimethylsilyl) -2,2′-bithiophene (Compound E4, synthesized according to WO 2010/136353, 1.60 g in a 50 mL Schlenk tube under nitrogen atmosphere ) And dissolved in tetrahydrofuran (32 mL). The solution was cooled to −78 ° C., and a hexane solution of n-butyllithium (manufactured by Kanto Chemical Co., Ltd., 1.63 M, 4.40 mL) was added dropwise. After stirring for about 15 minutes, dichlorodi-n-octylsilane (Alfa Aeser, 1.6 mL) was added dropwise. After gradually warming to room temperature over about 2 hours, water was added and the product was extracted with hexane. The organic layer was washed with water, dried over sodium sulfate, filtered and concentrated. The obtained yellow-orange oily substance was dissolved in chloroform (32 mL), trifluoroacetic acid (0.53 mL) was further added, and the mixture was stirred at room temperature for about 2 hours. Heptane (32 mL) was added to the reaction mixture, and the mixture was concentrated under reduced pressure. The obtained yellow-green oily substance was dissolved in hexane and subjected to silica gel column chromatography (solvent: hexane), whereby the desired 4,4-di-n-octyl-dithieno [3,2-b: 2 ', 3'-d] silole (Compound E5, 956 mg, yield 67%) was obtained.

Compound E5: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.05 (d, 2H, J = 4.8 Hz), 7.19 (d, 2H, J = 4.8 Hz), 1.42- 1.33 (m, 4H), 1.31-1.18 (m, 20H), 0.91-0.85 (m, 10H).

<Synthesis Example 4: Synthesis of Compound E6>

  The reaction was conducted in the same manner as in Synthesis Example 2 except that Compound E5 (1.00 mg, 2.39 mmol) obtained in Synthesis Example 3 was used instead of Compound E2, and other reagents were used in the same ratio. , 4-Di-n-octyl-2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ′, 3′-d] silole (compound E6) was quantitatively obtained.

Compound E6: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.08 (s, 2H), 1.45-1.38 (m, 4H), 1.33-1.19 (m, 20H) 0.90-0.85 (m, 10H), 0.38 (s, 18H).

<Synthesis Example 5: Synthesis of Compound E7>

  Under a nitrogen atmosphere, trichloro (2-ethylhexyl) silane (synthesized according to J. Am. Chem. Soc. 2008, 130, 16144-16145, 24.8 g) was placed in a 300 mL four-necked flask and dissolved in tetrahydrofuran (100 mL). I let you. The resulting solution was cooled to 0 ° C., and a diethyl ether solution of n-octylmagnesium bromide (Aldrich, 2.00 M, 50.0 mL) was added dropwise. The reaction solution was stirred at 7 ° C. for about 30 minutes, and then stirred at room temperature for about 3 hours. Thereafter, the solvent was distilled off using an evaporator. Hexane was added to the obtained crude product, and after filtration, the solvent was distilled off again. Finally, distillation purification (111 ° C., 0.61 torr) was performed to obtain the desired dichloro (2-ethylhexyl) n-octylsilane (Compound E7, 15.9 g, yield 49%).

Compound E7: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 1.72 (m, 1H), 1.49-1.55 (m, 2H), 1.24-1.50 (m, 18H) 1.07-1.13 (m, 4H), 0.85-0.92 (m, 9H).

<Synthesis Example 6: Synthesis of Compound E8>

  3. 3,3′-dibromo-5,5′-bis (trimethylsilyl) -2,2′-bithiophene (Compound E4, synthesized according to WO 2010/136353) in a 200 mL four-necked flask under nitrogen atmosphere. 0 g) was dissolved in tetrahydrofuran (68 mL). The obtained solution was cooled to −78 ° C., and a hexane solution of n-butyllithium (manufactured by Kanto Chemical Co., Inc., 1.65 M, 11.2 mL) was added dropwise. After stirring for about 15 minutes, Compound E7 (3.6 mL, 10.3 mmol) obtained in Synthesis Example 5 was added dropwise. After gradually warming to room temperature over about 2 hours, water was added and the product was extracted with hexane. The organic layer was washed with water, dried over sodium sulfate, filtered and concentrated. The obtained yellow-orange oily substance was dissolved in chloroform (20 mL), trifluoroacetic acid (1.31 mL) was added, and the mixture was stirred at room temperature for about 2 hours. After adding heptane (40 mL), the mixture was concentrated under reduced pressure. The obtained yellow-green oily substance was dissolved in hexane and subjected to silica gel column chromatography (solvent: hexane), whereby the desired 4-n-octyl-4- (2-ethylhexyl) dithieno [3,2- b: 2 ′, 3′-d] silole (compound E8, 2.3 g, yield 64%) was obtained.

Compound E8: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.05 (d, 2H, J = 4.8 Hz), 7.19 (d, 2H, J = 4.8 Hz), 1.42- 1.33 (m, 4H), 1.31-1.18 (m, 20H), 0.96-0.75 (m, 10H).

<Synthesis Example 7: Synthesis of Compound E9>

  The reaction was conducted in the same manner as in Synthesis Example 2 except that Compound E8 (1.00 g, 2.39 mmol) obtained in Synthesis Example 6 was used instead of Compound E2, and other reagents were used in the same ratio. -N-octyl-4- (2-ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3,2-b: 2 ', 3'-d] silole (compound E9) was obtained quantitatively. .

<Synthesis Example 8: Synthesis of Compound E11>

  In a 300 mL four-necked eggplant flask under a nitrogen atmosphere, 4,4-bis (2-ethylhexyl) -dithieno [3,2-b: 2 ′, 3′-d] germole (Compound E10, J. Am. Chem. Soc., 2011, 133, 10062-10065, 7.43 g, 16.0 mmol) was added, dissolved in anhydrous tetrahydrofuran (THF, 150 mL), and cooled to -78 ° C. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Subsequently, a solution of trimethyltin chloride in tetrahydrofuran (Aldrich, 1.0M, 19.2 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Further, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise, stirred for 30 minutes, and a tetrahydrofuran solution of trimethyltin chloride (Aldrich). Manufactured, 1.0M, 19.2 mL, 1.2 eq) was added dropwise and stirred for 30 minutes. Again, a tetrahydrofuran / hexane solution of lithium diisopropylamide (LDA) (manufactured by Kanto Chemical Co., Inc., concentration 1.11 M, 17.3 mL, 1.2 eq) was added dropwise, stirred for 30 minutes, and a tetrahydrofuran solution of trimethyltin chloride (Aldrich). Manufactured, 1.0M, 20.8 mL, 1.3 eq) was added dropwise, and the mixture was stirred for 30 minutes and warmed to room temperature. Water was added to the reaction solution, followed by extraction with hexane, and the organic layer was washed with water. The organic layer was dried over sodium sulfate and filtered through zeolite. The organic layer was concentrated under reduced pressure, washed with methanol, and then dried under vacuum, whereby 4,4-bis (2-ethylhexyl) -2,6-bis (trimethyltin) -dithieno [3,2- b: 2 ′, 3′-d] germol (compound E11) was quantitatively obtained as a yellow-green oil.

Compound E5: ¹ H-NMR (400 MHz, solvent: deuterated chloroform): δ 7.07 (s, 2H), 1.48 (m, 2H), 1.35-1.12 (m, 20H), 0.85 -0.75 (m, 12H), 0.37 (s, 18H).

Example 1: Synthesis of Copolymer 1

Under a nitrogen atmosphere, 1,3-dibromo-5-hexadecyl-4H- obtained as a monomer in a 50 mL two-necked eggplant flask was obtained as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F1 (Imidothiophene dibromide), 211 mg, 0.394 mmol) and Compound E9 obtained in Synthesis Example 7 (319 mg,. 429 mmol), tetrakis (triphenylphosphine) palladium (0) (12.8 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 16.6 mg, 3 mol%) , Toluene (6.6 mL), and N, N-dimethyl Put Le formamide (1.7 mL), 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. The reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.39 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.56 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 1 (255 mg). The resulting copolymer 1 had a weight average molecular weight Mw of 2.98 × 10 ⁵ and a PDI of 6.6.

<Example 2: Synthesis of copolymer 2>

Under a nitrogen atmosphere, 1,3-dibromo-5-dodecyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F2 (imidothiophene dibromide), 184 mg, 0.383 mmol) and Compound E3 obtained in Synthesis Example 2 (300 mg, 0. 403 mmol), tetrakis (triphenylphosphine) palladium (0) (14 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 30 mg, 3 mol%), toluene (6 .3 mL), and N, N-dimethylformua Put de a (1.5 mL), 1 hour at 90 ° C., followed by stirring for 7 hours at 100 ° C.. After diluting the reaction solution 4 times with toluene and further heating and stirring at 100 ° C. for 0.5 hour, as a terminal treatment, trimethyl (phenyl) tin (0.08 mL) was added and heating and stirring at 100 ° C. for 8 hours. Bromobenzene (3 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the desired copolymer 2 (224 mg). The weight average molecular weight Mw of the obtained copolymer 2 was 1.48 * 10 < ⁵ >, and PDI was 2.7.

<Example 3: Synthesis of copolymer 3>

Under a nitrogen atmosphere, 1,3-dibromo-5-octyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384) was used. Thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F3 (imidothiophene dibromide), 53 mg, 0.125 mmol), published in known literature (Organic Letters 2004, 6, 3381-3384) 1,3-Dibromo-5-dodecyl-4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F2 (imidothiophene dibromide) obtained with reference to the method described , 60.3 mg, 0.125 mmol) and the compound E11 obtained in Synthesis Example 8 (213 mg, 0.271 m In addition, tetrakis (triphenylphosphine) palladium (0) (10 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 20 mg, 3 mol%), toluene (4 0.5 mL) and N, N-dimethylformamide (1.1 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 10 hours. The reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.3 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.5 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 3 (179 mg). The resulting copolymer 3 had a weight average molecular weight Mw of 2.49 × 10 ⁵ and a PDI of 5.2.

<Example 4: Synthesis of copolymer 4>

Under a nitrogen atmosphere, 1,3-dibromo-5-hexadecyl-4H- obtained as a monomer in a 50 mL two-necked eggplant flask was obtained as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F1 (imidothiophene dibromide), 202 mg, 0.377 mmol) and Compound E3 obtained in Synthesis Example 2 (296 mg, 0. 397 mmol), tetrakis (triphenylphosphine) palladium (0) (13.8 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 18.0 mg, 3 mol%) , Toluene (6.2 mL) and N, N-dimethyl Put formamide (1.5 mL), 1 hour at 90 ° C., followed by stirring for 9 hours at 100 ° C.. The reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.36 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.44 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 4 (219 mg). The resulting copolymer 4 had a weight average molecular weight Mw of 9.5 × 10 ⁴ and a PDI of 2.6.

Example 5 Synthesis of Copolymer 5

Under a nitrogen atmosphere, 1,3-dibromo-5-octyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384) was used. Thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F3 (imidothiophene dibromide), 156 mg, 0.370 mmol), published in known literature (Organic Letters 2004, 6, 3381-3384) 1,3-dibromo-5-hexadecyl-4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F1 (imidothiophene dibromide) obtained with reference to the method described , 22 mg, 0.0412 mmol) and the compound E3 obtained in Synthesis Example 2 (323 mg, 0.433) mmol), tetrakis (triphenylphosphine) palladium (0) (14.9 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 19.4 mg, 3 mol%) , Toluene (6.8 mL), and N, N-dimethylformamide (1.7 mL) were added, and the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 8 hours. The reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, then, as a terminal treatment, trimethyl (phenyl) tin (0.39 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (1.56 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 5 (260 mg). The resulting copolymer 5 had a weight average molecular weight Mw of 1.62 × 10 ⁵ and a PDI of 3.9.

Example 6 Synthesis of Copolymer 6

Under a nitrogen atmosphere, 1,3-dibromo-5- (4-dodecyl) obtained in a 50 mL two-necked eggplant flask as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Phenyl) -4H-thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F4 (imidothiophene dibromide), 223 mg, 0.40 mmol) and compound E3 obtained in Synthesis Example 2 (315 mg, 0.42 mmol), tetrakis (triphenylphosphine) palladium (0) (15.6 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 33. 7 mg, 3 mol%), toluene (7.0 mL) and N, N Put dimethylformamide (1.7 mL), 1 hour at 90 ° C., followed by stirring for 9 hours at 100 ° C.. The reaction solution was diluted 4 times with toluene and further heated and stirred at 100 ° C. for 0.5 hour, and as a terminal treatment, trimethyl (phenyl) tin (0.4 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (3.5 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 6 (80 mg). The resulting copolymer 6 had a weight average molecular weight Mw of 1.26 × 10 ⁵ and a PDI of 2.2.

<Comparative Example 1: Synthesis of Copolymer 7>

Under a nitrogen atmosphere, 1,3-dibromo-5-octyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384) was used. Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F3 (imidothiophene dibromide), 168 mg, 0.398 mmol) and Compound E3 obtained in Synthesis Example 2 (312 mg, 0. 419 mmol), tetrakis (triphenylphosphine) palladium (0) (22.9 mg, 5 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 29.7 mg, 3 mol%) , Toluene (6.5 mL), and N, N-dimethyl Put formamide (1.6 mL), 1 hour at 90 ° C., followed by stirring for 11 hours at 100 ° C.. After the reaction solution was diluted 4-fold with toluene and heated and stirred at 100 ° C. for another 0.5 hours, as a terminal treatment, trimethyl (phenyl) tin (0.036 mL) was added and heated and stirred at 100 ° C. for 8 hours. Further, bromobenzene (0.083 mL) was added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 7 (180 mg). The resulting copolymer 7 had a weight average molecular weight Mw of 1.35 × 10 ⁵ and a PDI of 2.9.

<Comparative Example 2: Synthesis of Copolymer 8>

1,3-dibromo-5- (2-ethylhexyl) -4H obtained by referring to a method described in known literature (J. Am. Chem. Soc. 2010, 132, 7595-7597) instead of compound F3 -Similar to Comparative Example 1 except that thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F5 (imidothiophene dibromide), 162 mg, 0.383 mmol) was used. Synthesis was performed to obtain the target copolymer 8 (170 mg). The resulting copolymer 8 had a weight average molecular weight Mw of 2.00 × 10 ⁵ and a PDI of 3.2.

<Comparative Example 3: Synthesis of Copolymer 9>

  1,3-dibromo-5-dodecyl-4H-thieno [3 obtained by referring to a method described in a known document (J. Am. Chem. Soc. 2010, 132, 7595-7597) instead of compound F3 , 4-c] pyrrole-4,6- (5H) -dione (compound F2 (imidothiophene dibromide), 183 mg, 0.383 mmol), and instead of compound E3, compound E6 obtained in Synthesis Example 4 ( The reaction was performed in the same manner as in Comparative Example 1 except that 300 mg, 0.403 mmol) was used. When the mixture was stirred at 90 ° C. for 1 hour and then at 100 ° C. for 2 hours, the product was precipitated in the reaction solution. This precipitate was not dissolved in chloroform.

<Comparative Example 4: Synthesis of Copolymer 10>

Under a nitrogen atmosphere, 1,3-dibromo-5-octyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384) was used. Thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F3 (imidothiophene dibromide), 224 mg, 0.53 mmol) and compound E11 (453 mg, 0. 3) obtained in Synthesis Example 8. 57 mmol), tetrakis (triphenylphosphine) palladium (0) (20 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 44 mg, 3 mol%), toluene (9 .6 mL), and N, N-dimethylformami (2.2 mL) were charged, 1 hour at 90 ° C., followed by stirring for 10 hours at 100 ° C.. After the reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, trimethyl (phenyl) tin (0.6 mL) was added as a terminal treatment, and the mixture was heated and stirred at 100 ° C. for 8 hours. Bromobenzene (3 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 10 (392 mg). The resulting copolymer 10 had a weight average molecular weight Mw of 1.87 × 10 ⁵ and a PDI of 5.7.

Example 7 Synthesis of Copolymer 11

Under a nitrogen atmosphere, 1,3-dibromo-5-decyl-4H- obtained as a monomer in a 50 mL two-necked eggplant flask was obtained as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F6 (imidothiophene dibromide), 197.8 mg, 0.438 mmol), Compound E3 obtained in Synthesis Example 2 (171. 5 mg, 0.23 mmol) and the compound E6 (172.0 mg, 0.23 mmol) obtained in Synthesis Example 4 were added, and tetrakis (triphenylphosphine) palladium (0) (16 mg, 3 mol%) containing triphenylphosphine Heterogeneous Palladium Complex Catalyst Pd-EnCatTPP30 (Aldrich, 21m , 3 mol%), toluene (12 mL), and N, placed N- dimethylformamide (2.5 mL), 1 hour at 90 ° C., followed by stirring for 2.5 hours at 100 ° C.. After the reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, as a terminal treatment, trimethyl (phenyl) tin (0.080 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (8 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, reprecipitated using chloroform / ethyl acetate as a solvent, and the precipitated precipitate was filtered off to obtain the target copolymer 11 (215 mg). The resulting copolymer 11 had a weight average molecular weight Mw of 1.67 × 10 ⁵ and a PDI of 4.4.

<Example 8: Synthesis of copolymer 12>

Under a nitrogen atmosphere, 1,3-dibromo-5-dodecyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (Compound F2 (imidothiophene dibromide), 197.8 mg, 0.438 mmol), Compound E3 obtained in Synthesis Example 2 (171. 5 mg, 0.23 mmol) and the compound E6 (172.0 mg, 0.23 mmol) obtained in Synthesis Example 4 were added, and tetrakis (triphenylphosphine) palladium (0) (16 mg, 3 mol%) containing triphenylphosphine Heterogeneous palladium complex catalyst Pd-EnCatTPP30 (manufactured by Aldrich, 21 g, 3mol%), toluene (12 mL), and N, placed N- dimethylformamide (2.5 mL), 1 hour at 90 ° C., followed by stirring for 2.5 hours at 100 ° C.. After the reaction solution was diluted 4-fold with toluene and further heated and stirred at 100 ° C. for 0.5 hour, as a terminal treatment, trimethyl (phenyl) tin (0.080 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (8 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, reprecipitated using chloroform / ethyl acetate as a solvent, and the precipitated precipitate was filtered off to obtain the target copolymer 12 (209 mg). The resulting copolymer 12 had a weight average molecular weight Mw of 1.70 × 10 ⁵ and a PDI of 4.1.

<Example 9: Synthesis of copolymer 13>

Under a nitrogen atmosphere, 1,3-dibromo-5-decyl-4H- obtained as a monomer in a 50 mL two-necked eggplant flask was obtained as a monomer by referring to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F6 (imidothiophene dibromide), 172 mg, 0.380 mmol) and compound E9 obtained in Synthesis Example 7 (298 mg, .0. 400 mmol), tetrakis (triphenylphosphine) palladium (0) (13.9 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 18.0 mg, 3 mol%) , Toluene (10.8 mL), and N, N-dimethyl Put formamide (2.1 mL), 1 hour at 90 ° C., followed by stirring for 11 hours at 100 ° C.. The reaction solution was diluted 4 times with toluene and heated and stirred at 100 ° C. for another 0.5 hours, then, as a terminal treatment, trimethyl (phenyl) tin (0.5 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (5.0 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 13 (177 mg). The resulting copolymer 13 had a weight average molecular weight Mw of 3.81 × 10 ⁵ and a PDI of 6.2.

<Example 10: Synthesis of copolymer 14>

Under a nitrogen atmosphere, 1,3-dibromo-5-dodecyl-4H- obtained in a 50 mL two-necked eggplant flask as a monomer with reference to a method described in a known document (Organic Letters 2004, 6, 3381-3384). Thieno [3,4-c] pyrrole-4,6- (5H) -dione (compound F2 (imidothiophene dibromide), 182 mg, 0.380 mmol) and compound E9 (298 mg, 0. 400 mmol), tetrakis (triphenylphosphine) palladium (0) (13.9 mg, 3 mol%), triphenylphosphine-containing heterogeneous palladium complex catalyst Pd-EnCatTPP30 (Aldrich, 18.0 mg, 3 mol%) , Toluene (10.8 mL), and N, N-dimethyl Put formamide (2.1 mL), 1 hour at 90 ° C., followed by stirring for 11 hours at 100 ° C.. The reaction solution was diluted 4 times with toluene and heated and stirred at 100 ° C. for another 0.5 hours, then, as a terminal treatment, trimethyl (phenyl) tin (0.5 mL) was added and heated and stirred at 100 ° C. for 8 hours. Bromobenzene (5.0 mL) was further added, and the mixture was heated and stirred at 100 ° C. for 8 hours. The reaction solution was poured into methanol, and the deposited precipitate was collected by filtration. The obtained solid was dissolved in chloroform, diamine silica gel (Fuji Silysia Chemical) was added, and the mixture was stirred for 1 hour at room temperature and passed through a short column of acidic silica gel. The solution was concentrated, recrystallized using chloroform / ethyl acetate as a solvent, and the deposited precipitate was separated by filtration to obtain the target copolymer 14 (176 mg). The resulting copolymer 14 had a weight average molecular weight Mw of 3.40 × 10 ⁵ and a PDI of 5.8.

  Each of the copolymers obtained in Examples 1 to 10 and Comparative Examples 1 to 4 was subjected to a storage stability test of the copolymer-containing ink by the above method. The results are listed in Table 1 below. In Table 1, x indicates that gelation was confirmed within 5 minutes from the time when the container was removed from the heat source and allowed to stand at room temperature, and ○ indicates that gelation was not confirmed after 5 minutes, but 1 hour. Gelation was confirmed at a later time point, and ◎ represents that gelation was not confirmed even at a time point after 1 hour. Moreover, in Table 1, molar ratio (%) represents the molar ratio of the repeating unit represented by Formula (2) among the repeating units which comprise each copolymer.

  As described above, the copolymers of Comparative Examples 1, 2, and 4 have a relatively high molecular weight, but it is understood that the storage stability of the ink containing these polymers is not good. In addition, the copolymer of Comparative Example 3 was precipitated during the polymerization reaction, and the precipitate was not dissolved in chloroform, which indicates that the solubility is low.

  On the other hand, it can be seen that all of the copolymers of Examples 1 to 10, which are copolymers according to the present invention, have a high molecular weight and good storage stability of the ink containing the copolymer. Also, the storage stability of the ink containing the copolymer was good regardless of whether the nitrogen atom of the imidothiophene ring was a 2-ethylhexyl group or a linear octyl group. Thus, the storage stability of the ink containing the repeating unit represented by the formula (1A) and the copolymer containing the repeating unit represented by the formula (1B) is high, and coating film formation is performed using this ink. Therefore, it can be seen that the copolymer according to the present invention is suitable for use as a photoelectric conversion element material.

<Example 11: Production of photoelectric conversion element 1>
Copolymer 1 obtained in Example 1 as a p-type semiconductor compound, and a mixture of fullerene compounds PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester) as an n-type semiconductor compound (manufactured by Frontier Carbon Co., Ltd.) , Nanom spectra E123) was dissolved in a mixed solvent of o-xylene and tetralin (volume ratio 9: 1) in a nitrogen atmosphere to a concentration of 1.8% by mass. This solution was stirred and mixed on a hot stirrer at a temperature of 80 ° C. for 1 hour. The solution after stirring and mixing was filtered through a 1 μm polytetrafluoroethylene (PTFE) filter to obtain an ink for coating an active layer.

  A glass substrate (manufactured by Geomatic Co., Ltd.) on which an indium tin oxide (ITO) transparent conductive film is patterned is subjected to ultrasonic cleaning with acetone, followed by ultrasonic cleaning with isopropanol, followed by drying with nitrogen blowing and UV-ozone treatment. went. Next, a mixed solvent (volume) of 2-methoxyethanol (manufactured by Aldrich) and ethanolamine (manufactured by Aldrich) so that the concentration of zinc acetate (II) dihydrate (manufactured by Wako Pure Chemical Industries, Ltd.) becomes 105 mg / mL. (100: 3) and the obtained solution (about 0.1 mL) is spin-coated on a glass substrate at a speed of 3000 rpm, UV-ozone treated, and then heated in an oven at 200 ° C. for 15 minutes. Thus, an electron extraction layer was formed.

  By bringing the substrate on which the electron extraction layer is formed into a glove box, heat-treating at 150 ° C. for 3 minutes in a nitrogen atmosphere, and spin-coating the active layer coating ink (0.12 mL) prepared as described above after cooling. An active layer was formed.

Further, a molybdenum trioxide (MoO ₃ ) film as a hole extraction layer and a silver film with a thickness of 100 nm as an electrode layer are sequentially formed on the active layer by resistance heating vacuum deposition, and a 5 mm square photoelectric film is formed. A conversion element was produced.

About the photoelectric conversion element produced in this way, the current-voltage characteristic was measured as described above. The results are shown in Table 2 together with the weight ratio (p / n ratio) between the p-type semiconductor compound and the n-type semiconductor compound, the thickness of the active layer, and the thickness of the molybdenum trioxide (MoO ₃ ) film.

<Example 12: Production of photoelectric conversion element 2>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 11 except that the copolymer 2 obtained in Example 2 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 13: Production of photoelectric conversion element 3>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 11 except that the copolymer 3 obtained in Example 3 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 14: Production of photoelectric conversion element 4>
A photoelectric conversion element was produced and evaluated in the same manner as in Example 11 except that the copolymer 5 obtained in Example 5 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 15: Production of photoelectric conversion element 5>
A photoelectric conversion element was produced and evaluated in the same manner as in Example 11 except that the copolymer 11 obtained in Example 7 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 16: Production of photoelectric conversion element 6>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 11 except that the copolymer 12 obtained in Example 8 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 17: Production of photoelectric conversion element 7>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 11 except that the copolymer 13 obtained in Example 9 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Example 18: Production of photoelectric conversion element 8>
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 11 except that the copolymer 14 obtained in Example 10 was used as the p-type semiconductor compound. The results are shown in Table 2.

<Comparative Example 5: Production of photoelectric conversion element 9>
A photoelectric conversion element was produced and evaluated in the same manner as in Example 11 except that the copolymer 7 obtained in Comparative Example 1 was used as the p-type semiconductor compound. The results are shown in Table 2.

  The photoelectric conversion elements obtained in Examples 11 to 18 all showed higher conversion efficiency than the photoelectric conversion element obtained in Comparative Example 5. Thus, it turns out that the photoelectric conversion element for solar cells excellent in conversion efficiency is obtained by using the copolymer which concerns on this invention.

DESCRIPTION OF SYMBOLS 101 Anode 102 Hole taking-out layer 103 Active layer 104 Electron taking-out layer 105 Cathode 106 Base material 107 Photoelectric conversion element 1 Weatherproofing protective film 2 Ultraviolet cut film 3, 9 Gas barrier film 4, 8 Getter material film 5, 7 Sealing material 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell unit 14 Thin film solar cell

Claims (7)

A copolymer comprising a repeating unit represented by the following formula (1A) and a repeating unit represented by the formula (1B).

(In formula (1A), A represents an atom selected from Group 16 of the periodic table, R ¹ represents a divalent organic group which may have a direct bond or a substituent, and R ² represents a substituent. Represents a linear alkyl group having 10 or more carbon atoms which may be present.)

(In formula (1B), Q represents an atom selected from Group 14 elements of the periodic table, R ³ represents a branched alkyl group which may have a substituent, and R ⁴ has a substituent. A linear alkyl group which may have a substituent, a branched alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, a substituent It represents an aliphatic heterocyclic group which may have an aromatic heterocyclic group which may have a substituent. The copolymer according to claim 1, comprising a repeating unit represented by the following formula (2).

(In Formula (2), A represents an atom selected from Group 16 elements of the Periodic Table, Q represents an atom selected from Group 14 Elements of the Periodic Table, and R ¹ has a direct bond or a substituent. Represents a divalent organic group, R ² represents a linear alkyl group having 10 or more carbon atoms which may have a substituent, and R ³ represents a branched alkyl group which may have a substituent. R ⁴ represents a linear alkyl group that may have a substituent, a branched alkyl group that may have a substituent, a cycloalkyl group that may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may be substituted, an aliphatic heterocyclic group which may have a substituent, or an aromatic heterocyclic group which may have a substituent.   An organic semiconductor material comprising the copolymer according to claim 1.   An organic electronic device comprising the organic semiconductor material according to claim 3.   The organic electronic device according to claim 4, wherein the organic electronic device is a photoelectric conversion element.   The organic electronic device according to claim 4, wherein the organic electronic device is a solar cell.   A solar cell module comprising the organic electronic device according to claim 6.

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