JP2007123717A - Organic semiconductor material and organic semiconductor element using the same - Google Patents

Abstract

｛（Ａｒ^１は一般式（II）で表される２価の複素環基。Ａｒ^２及びＡｒ^３は２価の芳香環基。Ｒ^１及びＲ^２は炭素数１〜３０の有機基。ｍ，ｎは１〜５の整数。）

（環ＺはＡｒ^２及びＡｒ^３と結合する２価の基。環Ａは環Ｚと縮合した環。）｝
【選択図】なしAn organic semiconductor material having high carrier mobility and no orientation flow due to vibrations, and an organic semiconductor element using the organic semiconductor material are provided.
An organic semiconductor material containing a compound represented by the general formula (I).

{(Ar ¹ is a divalent heterocyclic group represented by the general formula (II). Ar ² and Ar ³ are divalent aromatic ring groups. R ¹ and R ² are organic groups having 1 to 30 carbon atoms. M , N is an integer of 1 to 5.)

(Ring Z is a divalent group bonded to Ar ² and Ar ^3. Ring A is a ring condensed with ring Z.)}
[Selection figure] None

Description

  The present invention relates to an organic semiconductor material and an organic semiconductor element using the organic semiconductor material. In particular, the organic semiconductor material has high carrier mobility and does not flow in orientation due to vibration or the like. The present invention relates to an organic semiconductor element having an organic semiconductor layer containing a semiconductor material.

  In recent years, researches for developing new organic semiconductor elements having organic semiconductor layers have been actively conducted. Organic semiconductor elements can be manufactured by a low-temperature process compared to conventional inorganic semiconductor elements having an inorganic semiconductor layer such as silicon because the organic semiconductor material has flexibility; mass production of large-area elements is possible. There are merits such as being able to manufacture flexible semiconductor elements.

  However, the organic semiconductor element has a problem that the performance as a semiconductor element is low because the carrier mobility is lower than that of the inorganic semiconductor element. Therefore, research on organic semiconductor materials having high carrier mobility has been recently conducted.

  Among organic semiconductor materials, liquid crystalline organic semiconductor materials have a feature that they are easily molecularly oriented spontaneously by self-organization. Therefore, the organic semiconductor layer formed from the liquid crystalline organic semiconductor material is efficiently filled with each other due to the orientation of the liquid crystal molecules, and the carriers are likely to smoothly hop-conduct between the molecules. Can do. Therefore, an organic semiconductor element having an organic semiconductor layer using a liquid crystalline organic semiconductor material has a feature of higher carrier mobility than an amorphous organic semiconductor element formed by vacuum deposition.

  For example, in Patent Document 1, a liquid crystalline organic semiconductor material typified by 4,4 ″ -didecaroxy-3 ″ -isopropyl-p-terphenyl or the like is formed through a smectic liquid crystal phase or a liquid crystal phase. It has been reported that it is used as an organic semiconductor layer in a crystalline phase state.

However, the organic semiconductor layer using the liquid crystal phase has a drawback that the movement of the charge is inhibited by the liquid crystal phase flowing due to vibration or the like, and the phase transition from the nematic liquid crystal phase where the degree of freedom of each molecule is high. Since the crystal phase has a low orientation order, the carrier movement is considered to be slow.
JP 2005-93955 A

  The present invention has been made in view of the current state of the organic semiconductor layer as described above, has high carrier mobility, and does not flow alignment due to vibration or the like. Therefore, charge transfer is not hindered. An object of the present invention is to provide an organic semiconductor material and an organic semiconductor element using the organic semiconductor material.

As a result of intensive studies to achieve the above object, the present inventors have found that the above problems can be solved by using a compound represented by the following general formula (I), and have reached the present invention.
That is, the gist of the present invention is as follows.

〔（一般式（Ｉ）において、Ａｒ^１は、下記一般式（II）で表される２価の複素環基を表し、Ａｒ^２及びＡｒ^３は、各々独立に、置換基を有していてもよい２価の芳香環基を表す。Ｒ^１及びＲ^２は、各々独立に、炭素数１〜３０の有機基を表し、添字ｍ，ｎは、各々独立に、１〜５の整数を表す。ｍ及び／又はｎが２以上の場合、２以上の各Ａｒ^２及び／又はＡｒ^３は互いに同一であってもよく、異なっていてもよい。）

（一般式（II）において、環ＺはＡｒ^２及びＡｒ^３と結合する２価の基であり、環Ａは、環Ｚと炭素原子を２個共有して縮合した環を表す。環Ａ及び環Ｚは各々置換基を有していてもよい。）〕 [1] An organic semiconductor material comprising a compound represented by the following general formula (I) as at least a part of constituent components.

[In the general formula (I), Ar ¹ represents a divalent heterocyclic group represented by the following general formula (II), and Ar ² and Ar ³ each independently have a substituent. R ¹ and R ² each independently represents an organic group having 1 to 30 carbon atoms, and the subscripts m and n each independently represent an integer of 1 to 5. When m and / or n is 2 or more, two or more of Ar ² and / or Ar ³ may be the same as or different from each other.

(In the general formula (II), ring Z is a divalent group bonded to Ar ² and Ar ^3, and ring A represents a ring condensed by sharing two carbon atoms with ring Z. Ring A and Each ring Z may have a substituent.

[2] In general formula (II), ring Z represents a 6-membered ring which may have a substituent, and ring A represents a 5-membered ring which may have a substituent. The organic semiconductor material according to [1].

〔一般式（IIａ）において、環Ｚは一般式（II）における環Ｚと同義の環よりなる２価の基であり、Ｙは１６族元素を表す。〕

〔一般式（IIｂ）において、環Ｚは一般式（II）における環Ｚと同義の環よりなる２価の基であり、ＸはＮ又はＳを表す。〕 [3] The organic semiconductor material according to [1] or [2], wherein the general formula (II) is represented by any one of the following general formulas (IIa) and (IIb).

[In general formula (IIa), ring Z is a divalent group consisting of a ring having the same meaning as ring Z in general formula (II), and Y represents a group 16 element. ]

[In general formula (IIb), ring Z is a divalent group consisting of a ring having the same meaning as ring Z in general formula (II), and X represents N or S. ]

[4] An organic semiconductor element comprising a first substrate and a second substrate arranged to face each other with a predetermined interval, and an organic semiconductor layer formed between the first substrate and the second substrate In this, the organic-semiconductor layer contains the organic-semiconductor material as described in [1]-[3], The organic-semiconductor element characterized by the above-mentioned.

The compound represented by the general formula (I) has high carrier mobility, and the orientation does not flow due to vibration or the like, so that charge transfer is not inhibited. That is, in the compound represented by the general formula (I), Ar ¹ is formed of a heterocyclic ring, preferably a condensed ring of a 6-membered ring and a 5-membered ring. It is thought that there is a polarization structure in the direction. It is presumed that this structure increases molecular orientation order and improves carrier mobility.
In addition, since the crystal is obtained through the crystal state, the orientation does not flow due to vibration or the like, so that charge transfer is not hindered.

  For this reason, according to the organic semiconductor material of the present invention containing such a compound, a high-performance organic semiconductor element having a low driving voltage and high carrier mobility is provided.

  Embodiments of the present invention will be specifically described below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

〔（一般式（Ｉ）において、Ａｒ^１は、下記一般式（II）で表される２価の複素環基を表し、Ａｒ^２及びＡｒ^３は、各々独立に、置換基を有していてもよい２価の芳香環基を表す。Ｒ^１及びＲ^２は、各々独立に、炭素数１〜３０の有機基を表し、添字ｍ，ｎは、各々独立に、１〜５の整数を表す。ｍ及び／又はｎが２以上の場合、２以上の各Ａｒ^２及び／又はＡｒ^３は互いに同一であってもよく、異なっていてもよい。）

（一般式（II）において、環ＺはＡｒ^２及びＡｒ^３と結合する２価の基であり、環Ａは、環Ｚと炭素原子を２個共有して縮合した環を表す。環Ａ及び環Ｚは各々置換基を有していてもよい。）〕 [Organic semiconductor materials]
The organic semiconductor material of the present invention is characterized by containing a compound represented by the following general formula (I) as at least a part of the constituent components.

[In the general formula (I), Ar ¹ represents a divalent heterocyclic group represented by the following general formula (II), and Ar ² and Ar ³ each independently have a substituent. R ¹ and R ² each independently represents an organic group having 1 to 30 carbon atoms, and the subscripts m and n each independently represent an integer of 1 to 5. When m and / or n is 2 or more, two or more of Ar ² and / or Ar ³ may be the same as or different from each other.

(In the general formula (II), ring Z is a divalent group bonded to Ar ² and Ar ^3, and ring A represents a ring condensed by sharing two carbon atoms with ring Z. Ring A and Each ring Z may have a substituent.

  Below, the compound represented by the said general formula (I) is demonstrated in detail.

{Explanation of words}
In the present invention, the “aromatic ring” means a ring having aromaticity, that is, a ring having a (4p + 2) π electron system (p is a natural number), and therefore, “aromatic hydrocarbon ring” and “aromatic heterocycle”. "Hydrocarbon ring" means both "aromatic hydrocarbon ring" and "non-aromatic hydrocarbon ring", and "heterocycle" means "aromatic heterocycle" Both “non-aromatic heterocycles” are meant.
“(Hetero) aryl” means both “aryl” and “heteroaryl”. Similarly, “(hetero) aralkyl” means both “aralkyl” and “heteroaralkyl”.
Further, “may have a substituent” means that one or more substituents may be present.

{Ar ¹ }
Ar ¹ is a structure that polarizes the compound represented by the general formula (I) in the minor axis direction, that is, a divalent heterocyclic group represented by the general formula (II).

<Skeletal structure of ring Z>
In the general formula (II), examples of the ring Z include 5- or 6-membered aromatic hydrocarbon rings or heterocyclic rings each having a single ring or 2 to 6 condensed rings, which may have a substituent. . When the ring Z is a heterocycle, the heteroatom constituting the heterocycle is not particularly limited, but usually from the viewpoint of the stability of each atom such as O, S, Se, N, P, Si, and the ring. N is particularly preferable because O, S, N, and a heterocyclic ring are easily electron withdrawing. When two or more of these heteroatoms are contained in the ring Z, the heteroatoms may be the same atom or different atoms.

  Specific examples of the ring Z include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, pyridine ring, thiophene ring, pyrrole ring, furan ring, benzothiophene ring, benzofuran ring, benzopyrrole ring, imidazole ring, quinoline A ring, an isoquinoline ring, a carbazole ring, a thiazole ring, a dibenzothiophene ring, and the like. A monocyclic ring is preferable because it easily exhibits liquid crystallinity, and a 6-membered aromatic group such as a benzene ring is particularly preferable because of easy synthesis. An aromatic heterocycle having a heteroatom such as N such as a hydrocarbon ring or a pyridine ring.

<Ring A skeleton structure>
In the general formula (II), ring A is preferably a heterocycle optionally having a substituent, which is constituted with two carbon atoms shared with ring Z, and a heteroatom constituting this heterocycle Although there is no restriction | limiting in particular, Usually, each atom, such as O, S, Se, N, P, Si, is mentioned. When two or more of these heteroatoms are contained in ring A, the heteroatoms may be the same or different. Ring A is preferably an aromatic heterocyclic ring so that the pi-conjugated system affects the electron attracting effect of heteroatoms throughout the molecule, and particularly preferably has a heteroatom such as N, S, O or the like having a high electron attracting effect. It is a membered aromatic heterocycle.

<Substituents of Ring A and Ring Z>
In the general formula (II), examples of the substituent that the ring A and the ring Z may have include the substituents described later as the substituent in the general formulas (IIa) and (IIb).

<Especially preferred form of Ar ¹ >
In particular, Ar ¹ represented by the general formula (II) is a divalent compound composed of two cyclic structures sharing two carbon atoms with each other and represented by any one of the following general formulas (IIa) and (IIb). The heterocyclic group is preferably from the viewpoint of easy synthesis, and in particular, it has an electron-withdrawing 5-membered ring, and since the steric hindrance of the ring itself is small, the following general formula ( It is preferably represented by IIa).

〔一般式（IIａ），（IIｂ）において、環Ｚは一般式（II）における環Ｚと同義の環よりなる２価の基であり、一般式（IIａ）中、Ｙは１６族元素を表し、一般式（IIｂ）中、ＸはＮ又はＳを表す。〕

[In General Formulas (IIa) and (IIb), Ring Z is a divalent group consisting of a ring having the same meaning as Ring Z in General Formula (II). In General Formula (IIa), Y represents a Group 16 element. In general formula (IIb), X represents N or S. ]

  In particular, in the general formula (IIa), Y is preferably O or S in view of a high electron withdrawing effect.

Ar ¹ represented by the general formulas (IIa) and (IIb) may have a substituent, that is, a ring Z or a heterocyclic ring containing a Y atom in the general formula (IIa), the general formula (IIb) Examples of the substituent that the heterocyclic ring containing X atom may have include an alkyl group, an alkoxy group, a nitro group, a cyano group, an ester group, a halogen atom, and a hydroxyl group.

  More specifically, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a nitro group, a cyano group, an ester group having 1 to 6 carbon atoms, a halogen atom, and the like as exemplified below. A hydroxyl group and the like, preferably an atomic group having a molecular weight of 100 or less, such as a methyl group, a cyano group, or a halogen atom.

  Examples of the alkyl group having 1 to 9 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, hexyl group and octyl group. .

  Examples of the alkoxy group having 1 to 9 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, hexyloxy group, octyloxy group, etc. Is mentioned.

  Examples of the ester group having 1 to 6 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, and an isopropoxycarbonyl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

{Ar ² and Ar ³ }
<Ar ² and Ar ³ Skeletal Structure>
In the general formula (I), Ar ² and Ar ³ are each independently a divalent aromatic heterocyclic group or aromatic hydrocarbon ring group which may have a substituent, preferably 5 Alternatively, it represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group consisting of a 6-membered monocyclic ring or a 2-6 condensed ring, which may have a substituent. Ar ² and Ar ³ are preferably monocyclic because a liquid crystal phase is easily formed.

  Here, the aromatic hydrocarbon ring group is preferably a 6-membered monocyclic group or a group derived from 2 to 10 condensed rings. Specific examples include a phenylene group, a naphthylene group, an anthranylene group, a phenanthrylene group, and a pyrenylene group. Particularly, a naphthylene group and a phenylene group are preferable because a liquid crystal phase is easily formed. It is preferable because of having sex.

On the other hand, examples of the aromatic heterocyclic group include a group derived from a single ring or a 2-10 condensed ring, preferably a 5- or 6-membered ring, particularly preferably a 5-membered ring. Although there is no restriction | limiting in particular as a hetero atom which comprises a heterocyclic ring, Usually, each atoms, such as O, S, Se, N, P, Si, are mentioned. When two or more of these heteroatoms are contained, the heteroatoms may be the same atom or different atoms. In view of the stability of the heterocyclic ring, particularly preferred heteroatoms are O, S, and N.
Specific examples of the aromatic heterocyclic group include furan, thiophene, pyrrole, benzofuran, isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole, isoindole, indolizine, carbazole, xanthene, pyridine, quinoline, isoquinoline, Divalent aromatic heterocyclic groups derived from rings such as phenanthridine, acridine, oxazole, isoxazole, thiazole, isothiazole, furazane, imidazole, pyrazole, benzimidazole, 1,8-naphthyridine, pyrazine, pyrimidine, pyridazine Of these, aromatic heterocyclic groups derived from 5-membered rings such as thiophene, furan, and pyrrole ring are preferred because the linearity of the whole molecule is high and the liquid crystallinity is improved.

In addition, although m and n represent the integer of 1-5 each independently, Preferably it is 1-3, Most preferably, it is 1-2. When m and / or n is 2 or more, two or more Ar ² and / or Ar ³ may be the same or different from each other.

<Substituents Ar ² and Ar ³ have>
In the general formula (I), Ar ² and Ar ³ may have a substituent as an alkyl group, hydrocarbon ring group, heterocyclic group, alkoxy group, aryloxy group, heteroaryloxy group, aralkyl. Examples thereof include an oxy group, a heteroaralkyloxy group, an amino group which may have a substituent, an acyl group, a nitro group, a cyano group, an ester group, a halogen atom, a hydroxyl group, and a carboxyl group. More specifically, it is derived from an alkyl group having 1 to 9 carbon atoms, a hydrocarbon ring group having 3 to 20 carbon atoms, a 5 or 6-membered monocyclic ring or a 2 to 6 condensed ring as exemplified below. Heterocyclic group, C1-C9 alkoxy group, C2-C18 (hetero) aryloxy group, C3-C18 (hetero) aralkyloxy group, C2-C20 alkylamino group, carbon Examples thereof include a (hetero) arylamino group having 2 to 30 carbon atoms, an acyl group having 1 to 20 carbon atoms, a nitro group, a cyano group, an ester group having 1 to 6 carbon atoms, a halogen atom, a hydroxyl group, and a carboxyl group.

  Examples of the alkyl group having 1 to 9 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, hexyl group and octyl group. .

  Examples of the hydrocarbon ring group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclohexyl group, a tetradecahydroanthranyl group, a phenyl group, an anthranyl group, and a phenanthryl group.

  Examples of the heterocyclic group derived from a 5- or 6-membered monocyclic ring or a 2-6 condensed ring include 1-pyrenyl group, 1-naphthyl group, 2-naphthyl group, 1-phenanthrenyl group, 1-perylenyl group, 2-piperidinyl Group, 2-piperazinyl group, decahydroquinolinyl group, julolidin-9-yl group and the like.

  Examples of the alkoxy group having 1 to 9 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, hexyloxy group, octyloxy group, etc. Is mentioned.

  Examples of the (hetero) aryloxy group having 2 to 18 carbon atoms include a phenoxy group, a naphthyloxy group, a 2-thienyloxy group, a 2-furyloxy group, and a 2-quinolyloxy group.

  Examples of the (hetero) aralkyloxy group having 3 to 18 carbon atoms include benzyloxy group, phenethyloxy group, naphthylmethoxy group, 2-thienylmethoxy group, 2-furylmethoxy group, and 2-quinolylmethoxy group.

  Examples of the alkylamino group having 2 to 20 carbon atoms include a dimethylamino group, a methylethylamino group, a dibutylamino group, and a dioctylamino group.

  Examples of the (hetero) arylamino group having 2 to 30 carbon atoms include diphenylamino group, dinaphthylamino group, naphthylphenylamino group, ditolylamino group, di (2-thienyl) amino group, di (2-furyl) amino group, A phenyl (2-thienyl) amino group etc. are mentioned.

  Examples of the acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, propionyl group, isobutyryl group, valeryl group, and cyclohexylcarbonyl group.

  Examples of the ester group having 1 to 6 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, and an isopropoxycarbonyl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Among the substituents of the heterocyclic group Z represented by the general formula (II) of Ar ^{1 and} the substituents of Ar ² and Ar ³ described above, adjacent groups are bonded to form a cyclic structure. You may do it. As for what adjoins substituents couple | bond together and forms a cyclic structure, for example, the substituents which this benzene ring of the benzene ring group as Ar < ¹ > -Ar < ³ > has couple | bonded, and it shows in following structural formula And those having formed a phenoxatin ring, a phenothiazine ring, or a phenoxazine ring.

{R ¹ and R ² }
<Skeleton structure of R ¹ and R ² >
R ¹ and R ² in the general formula (I) each independently represent an organic group having 1 to 30 carbon atoms, preferably an alkyl group or an alkoxyl group, and these may further have a substituent. .

More specifically, examples of R ¹ and R ² include an alkyl group having 1 to 30 carbon atoms, an alkoxyl group having 1 to 30 carbon atoms, and the like, which are exemplified below. Since it is necessary for the metastable crystal to exist stably near room temperature, the carbon number of these groups is preferably 7 to 25, more preferably 8 to 20, particularly preferably 10 to 17, and cooling from isotropic crystals. In the process, a metastable crystal can be easily obtained regardless of cooling conditions.

  Examples of the alkyl group having 1 to 30 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, octyl group, nonyl group, decyl group, dodecyl group, propadecyl group, butadecyl group, pentadecyl group, hexadecyl group Group, heptadecyl group, octadecyl group and the like. From the viewpoint of easy formation of a smectic liquid crystal phase, a decyl group, a dodecyl group, a propadecyl group, a butadecyl group, a pentadecyl group, or a hexadecyl group is preferable.

  Examples of the alkyloxy group having 1 to 30 carbon atoms include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butyloxy group, octyloxy group, nonyloxy group, decyloxy group, dodecyloxy group, propadecyloxy group, Examples include butadecyloxy group, pentadecyloxy group, hexadecyloxy group, heptadecyloxy group, octadecyloxy group and the like. Of these, a decyloxy group, a dodecyloxy group, a propadecyloxy group, a butadecyloxy group, a pentadecyloxy group, and a hexadecyloxy group are preferable because a smectic liquid crystal phase is easily formed.

<Substituents R ¹ and R ² have>
In the general formula (I), R ¹ and R ² may further have a substituent, and specific examples of the substituent include the alkyl group having 1 to 30 carbon atoms of R ¹ and R ² described above. , An alkyloxy group and a halogen atom. Preferably, it is an alkyl group or a halogen atom, and it is considered to have high durability when such a substituent is introduced.

  Examples of the alkyl group having 1 to 30 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, octyl group, nonyl group, decyl group, dodecyl group, propadecyl group, butadecyl group, pentadecyl group, hexadecyl group Group, heptadecyl group, octadecyl group and the like. A decyl group, a dodecyl group, a propadecyl group, a butadecyl group, a pentadecyl group, and a hexadecyl group are preferable because of the ease of forming a smectic liquid crystal phase.

  Examples of the alkyloxy group having 1 to 30 carbon atoms include methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butyloxy group, octyloxy group, nonyloxy group, decyloxy group, dodecyloxy group, propadecyloxy group, Examples include butadecyloxy group, pentadecyloxy group, hexadecyloxy group, heptadecyloxy group, octadecyloxy group and the like. Of these, a decyloxy group, a dodecyloxy group, a propadecyloxy group, a butadecyloxy group, a pentadecyloxy group, and a hexadecyloxy group are preferable because a smectic liquid crystal phase is easily formed.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

{Substitution position of ring Z with Ar ² and Ar ³ }
The substitution position between ring Z and Ar ² or Ar ³ is 6-membered, para-position (4-position), 5-membered ring is 3-position or 4-position, and 7-membered ring is 4-position or If the 5-position is a condensed ring, the position where each substituent is on a straight line is preferable because liquid crystallinity is improved by increasing the linearity of the compound.

{Molecular weight}
In order to maintain the solubility of the organic semiconductor material of the present invention, the molecular weight of the compound represented by the general formula (I) is usually 2000 or less, particularly 1000 or less, particularly 750 or less.

{Specific examples of compounds represented by formula (I)}
Specific examples of the compound represented by the general formula (I) are listed in the following (A-1) to (A-31), but the organic semiconductor material of the present invention is not limited to these (hereinafter, Me). Represents a methyl group, and Et represents an ethyl group.

{Synthesis method}
The compound represented by the general formula (I) Mater. Chem. , 2004, 1901-1904, etc., for example, can be synthesized as follows.

<In the case of the compound of Ar ² = Ar ³ , m, n = 1, R ¹ = R ^{2 in} the general formula (I)>
In a hydrocarbon solvent such as benzene, toluene or xylene or an ether solvent such as tetrahydrofuran, dioxane or ethylene glycol dimethyl ether, the compounds represented by the following general formulas A1 and A2 are mixed with sodium carbonate and cesium carbonate. A basic aqueous solution such as potassium tertiary butoxide or sodium tertiary butoxide is added, and the mixture is stirred under an inert gas such as argon or nitrogen, and phosphine represented by tetrakistriphenylphosphine palladium (0). A palladium catalyst having a ligand is added, and the mixture is stirred at 60 to 150 ° C. for 1 to 72 hours until the raw material disappears, and the resulting mixture is purified by a purification method such as column chromatography, recrystallization, reprecipitation, or crystallization. To obtain the target compound represented by the general formula (I) Kill.
^X-Ar 1 -X (A1)
R ¹ —Ar ² —B (OH) ₂ (A2)
(In the above formula, X is a halogen atom, particularly Br or I.)

Further, using sodium nitrite as a catalyst, the compound represented by the following general formula A3 is stirred in the range of room temperature to 60 ° C. using concentrated nitric acid and acetic acid as solvents, and the resulting mixture is subjected to column chromatography, recrystallization, reprecipitation. The intermediate represented by the following general formula A4 is synthesized by purification using a purification method such as crystallization, and then the compound represented by the general formula A4 is dissolved in a solution of acetic acid and acetic anhydride to obtain equimolar zinc. Is added and stirred, and the resulting mixture is purified by a purification method such as column chromatography, recrystallization, reprecipitation, or crystallization to synthesize an intermediate represented by the following general formula A5.
Thereafter, an intermediate represented by the following general formula A5, hydrazine, phosphorous pentasulfide, methylamines and the like, hydrocarbon solvents such as benzene, toluene, xylene, etc. or ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, etc. In a solvent such as a system solvent or ethanol, butanol, ethylene glycol monomethyl ether, the mixture is stirred at 60 to 150 ° C. for 1 to 72 hours until the raw material disappears, and the resulting mixture is subjected to column chromatography, recrystallization, reprecipitation, crystal The target compound of the general formula (I) can be obtained by purification by a purification method such as analysis.

{Physical properties}
Preferred organic semiconductor materials of the present invention containing the compound represented by the general formula (I) as at least a part of the constituents have the following physical properties.

When used for a general-purpose organic semiconductor element, it is preferable from the viewpoint of stability that the transition from a metastable crystal to a stable crystal does not easily occur. In other words, in order to avoid the loss of properties of the metastable crystal obtained from the isotropic crystal by the heat source, the metastable crystal to the stable crystal observed when switching from the cooling process to the heating process is observed. The lower limit of the transition temperature is usually 40 ° C. or higher, preferably 60 ° C. or higher, particularly preferably 80 ° C. or higher.
However, when used as a switching element or the like, the transition temperature from the metastable crystal to the stable crystal is not necessarily in this range, and the transition temperature may be used for switching.

{Other ingredients}
In addition, the organic-semiconductor material of this invention may contain individually 1 type of the compound represented by the said general formula (I), and may contain 2 or more types.
For example, the content of the compound represented by the general formula (I) in the organic semiconductor material of the present invention is particularly suitable as long as it satisfies the above-mentioned preferred physical properties and exhibits sufficient characteristics as an organic semiconductor material. Although there is no limitation, usually, the content of the compound represented by the general formula (I) in the organic semiconductor material of the present invention is 50% by weight or more, particularly 75% by weight or more, preferably 90% by weight or more, Particularly preferred is 95% by weight or more, and most preferred is 99% or more, from the viewpoint of easy expression of liquid crystallinity.

[Organic semiconductor devices]
The organic semiconductor element of the present invention has an organic semiconductor layer including the above-described organic semiconductor element of the present invention and has two or more electrodes, and a current flowing between the electrodes and a generated voltage other than light, for example, It is a device controlled by electricity, magnetism, or chemical substances. For example, there are a device that controls current and voltage by applying voltage and current, a device that controls voltage and current by applying a magnetic field, and a device that controls voltage and current by applying a chemical substance. Examples of this control include rectification, switching, amplification, and oscillation. In addition, even in a device controlled by light or controlling light emission, the organic semiconductor material of the present invention can be used for applications other than operating by directly absorbing light or emitting light, such as wiring, the above voltage, and current. Devices used for control are also included.

  Currently, the corresponding devices realized by inorganic semiconductors such as silicon include resistors, rectifiers (diodes), switching elements (transistors, thyristors), amplification elements (transistors), memory elements, chemical sensors, etc. Examples include combinations of elements and integrated devices. More specific examples of these include S.I. M.M. Examples include those described in Sze, Physics of Semiconductor Devices, 2nd Edition (Wiley-Interscience 1981).

  The organic semiconductor element of the present invention can be substituted for any of these inorganic semiconductor devices.

  Specifically, the organic semiconductor element of the present invention is arranged such that two substrates provided with an electrode and an alignment film are opposed to each other with the surface provided with the electrode or the like facing inside, and between the two substrates. Are provided with an organic semiconductor layer. That is, for example, an organic semiconductor layer formed by causing a phase transition from a liquid crystal phase (smectic A phase) to a metastable crystal phase is provided in a cell formed of a substrate including an electrode and an alignment film. Organic semiconductor elements.

  Hereinafter, an organic semiconductor device and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing an example of an embodiment of an organic semiconductor element of the present invention.
The organic semiconductor element 1 of FIG. 1 is arranged with a predetermined interval so that two substrates 2 and 2 provided with an electrode 3 and an alignment film 4 face each other with the surface provided with the electrode 3 and the like inside. The organic semiconductor layer 5 is provided between the two substrates 2 and 2. 6 shows a liquid crystal molecule. The electrode 3 is connected to a wiring (not shown). The organic semiconductor material of the present invention preferably has a protective film (not shown) in the outermost layer in order to minimize the influence of outside air.

<substrate>
As the substrate, among the substrates of conventional wireless semiconductor devices, the same substrate as that used particularly in the field effect transistor can be used, and the thickness is preferably in the range of 0.01 to 10 mm, A range of 0.05 to 2 mm is particularly preferable. Further, the substrate may be a laminated body composed of a plurality of layers.

  That is, examples of the substrate include those made of inorganic materials such as glass, silicon oxide, and metals such as silicon, and organic materials such as various organic polymers. Two or more types can be used in combination, including the case where an inorganic material and an organic material are used together, such as a substrate having an insulating layer formed on the surface by coating a polymer or the like. Examples of the organic polymer include polyester, polycarbonate, polyimide, polyamide, polyether sulfone, epoxy resin, polybenzoxazole, polybenzothiazole, polyparabanic acid, polysilsesquioxane, polyvinylphenol, and polyolefin. Moreover, these organic polymers may contain a filler, an additive, etc. as needed.

  Further, the surface of these substrates may be subjected to a surface treatment for changing the characteristics of the layer formed thereon, for example, by adjusting the balance between hydrophilicity and hydrophobicity. For example, the characteristics of the semiconductor layer vary greatly depending on the state of molecular orientation and the like. Therefore, the molecular orientation at the interface between the substrate and the semiconductor layer is controlled by the surface treatment of the substrate, and the characteristics can be improved. Examples of such substrate surface treatment means include hydrophobization treatment with hexamethyldisilazane, cyclohexene, octadecyltrichlorosilane, etc., acid treatment with hydrochloric acid, sulfuric acid, acetic acid, etc., sodium hydroxide, potassium hydroxide, calcium hydroxide. , Alkaline treatment with ammonia, ozone treatment, fluorination treatment, plasma treatment with oxygen, argon, etc., formation treatment of Langmuir / Blodgett film, other thin film formation treatment such as insulators and semiconductors, corona discharge, etc. Processing, mechanical processing, and the like.

<Electrodes and wiring>
As an electrode, among the substrates of conventional wireless semiconductor devices, the same conductive material as that used particularly in a field effect transistor can be used. In particular, the thickness of the electrode is preferably 1 to 100 nm. 10 to 50 nm is particularly preferable.

That is, as the conductive material constituting the electrodes and wiring, for example, metals such as platinum, gold, aluminum, chromium, nickel, copper, titanium, magnesium, calcium, barium, sodium, InO ₂ , SnO ₂ , ITO Conductive oxides such as polyaniline, polypyrrole, polythiophene, polyacetylene, polydiacetylene, etc., and acids such as hydrochloric acid, sulfuric acid, sulfonic acid, Lewis acids such as PF ₆ , AsF ₅ , FeCl _3, etc. Semiconductor materials such as silicon, germanium, gallium arsenide and the like, carbon materials such as fullerenes, carbon nanotubes and graphite , As well as carbon black, graphay Powder, composite material of the conductive dispersed metal fine particles and the like.

  In addition, these electrodes and wirings are formed by patterning a film formed by, for example, a vacuum deposition method, a sputtering method, a coating method, a printing method, a sol-gel method or the like into a desired shape as necessary. . As the patterning method, for example, a photolithographic method combining photoresist patterning and etching such as wet etching with an etchant or dry etching with reactive plasma, ink jet printing, screen printing, offset printing, letterpress printing, etc. Soft lithography techniques such as the printing method and micro contact printing method, and a combination of these techniques. It is also possible to directly form a pattern by irradiating an energy beam such as a laser or an electron beam to remove the material or changing the conductivity of the material.

<Alignment film>
The alignment film is provided adjacent to one side or both sides of the organic semiconductor layer. The alignment film in the present invention is obtained by aligning a film formed of a conductive material, and has a role of orderly aligning liquid crystal molecules of the organic semiconductor layer and a role of easily injecting carriers into the organic semiconductor layer.

  The conductive material is an organic or inorganic material having a conductivity that does not prevent carriers from being injected into the organic semiconductor layer, and the organic semiconductor layer is formed when an orientation treatment is performed on a film made of this material. Any liquid crystal molecule may be used as long as it can align the liquid crystal molecules that constitute the structure. Examples of such conductive materials include polyethylene dioxythiophene, polyaniline, polypyrrole, or polyphenylene vinylene doped with iodine, polyacetylene. The alignment film formed from such a conductive material not only aligns the liquid crystal molecules of the organic semiconductor layer but also allows carriers to be easily injected into the organic semiconductor layer.

  This conductive material preferably contains a dopant for the purpose of improving conductivity, and an electron acceptor material such as polystyrene sulfonate (PSS) can be used as such a dopant.

  The alignment film is formed by performing an alignment process on a film made of such a conductive material. By performing such treatment, not only the carrier mobility of the adjacent organic semiconductor layer can be improved, but also carriers can be easily injected into the organic semiconductor layer.

  The alignment film is formed by forming a film on the substrate on which the electrode is formed by vapor deposition or coating with the conductive material, and performing an alignment process on the thin film. Note that the book film before the orientation treatment can be fired as necessary.

  The alignment treatment is preferably performed so that the liquid crystal molecules constituting the organic semiconductor layer are aligned in the in-plane direction of the electrode, and such treatment includes rubbing treatment. Further, as another alignment treatment, energy beam irradiation to a film formed of a conductive material can be used. For example, ion irradiation or ultraviolet irradiation can be used.

  Note that alignment means other than the alignment means using the alignment film (for example, alignment means using spacer edges, temperature gradient, mechanical shear, magnetic field, etc.) can be used in combination with the alignment means using the alignment film.

The alignment film may be provided on one side or both sides of the organic semiconductor layer, but is preferably provided on both sides because the effect of alignment is higher.
The film thickness of the alignment film only needs to be such that the liquid crystal molecules of the organic semiconductor layer can be aligned, and is usually 0.01 to 2 μm.

<Organic semiconductor layer>
The organic semiconductor layer is a layer that is located between two opposing electrodes and transports carriers supplied from one electrode to the other electrode.
The organic semiconductor layer in the present invention is a layer formed from an organic semiconductor material containing a compound represented by the general formula (I) crystallized from a liquid crystal phase (smectic A phase) to a metastable crystal phase.

  In the organic semiconductor element of the present invention, the thickness of the organic semiconductor layer is usually 0.01 to 1000 μm, preferably 0.1 to 500 μm, and particularly preferably 1 to 100 μm. If the thickness of the organic semiconductor layer is thinner than the above range, it is difficult in terms of production, and if it is thick, the carrier conductivity is lowered.

<Protective layer>
Examples of the protective layer include polymer films such as epoxy resin, acrylic resin, polyurethane, polyimide, and polyvinyl alcohol, inorganic oxide films such as silicon oxide, aluminum oxide, and silicon nitride, and nitride films. The polymer film is formed by a method in which a solution is applied and dried, a method in which a monomer is applied or vapor-deposited and polymerized, and a crosslinking treatment or a multilayer film can also be formed. For the formation of the inorganic film, a formation method using a vacuum process such as a sputtering method or a vapor deposition method, or a formation method using a solution process typified by a sol-gel method can be used.

<Method for manufacturing organic semiconductor element>
The manufacturing method of the organic-semiconductor element of this invention is shown as an example.
Through the following steps, an organic semiconductor element made of an organic semiconductor material that has become a metastable crystal phase via a smectic liquid crystal phase can be produced.

  First, a step of forming an electrode on the substrate, a step of applying a conductive polymer material to the surface of the substrate on which the electrode is formed, a step of rubbing a film made of the conductive polymer material, and thus The obtained substrate is subjected to a process of bonding the image on which the electrode and the alignment film are formed to face each other, excluding the injection hole, thereby producing a cell.

  Next, a liquid crystalline organic semiconductor material exhibiting an isotropic phase is injected from the injection hole of this cell, and this material is cooled to exhibit a desired phase via a smectic liquid crystal phase to form an organic semiconductor layer. Thus, an organic semiconductor element is manufactured.

  The organic semiconductor layer is formed by heating a liquid crystalline organic semiconductor material to a temperature exhibiting an isotropic phase and injecting it into the cell, and then cooling to a temperature exhibiting a crystalline phase via a smectic liquid crystal phase.

  The cooling rate of the liquid crystalline organic semiconductor material injected into the cell is 0.1 to 200 ° C./min. From the viewpoint of forming a metastable crystal and forming an organic semiconductor layer with higher orientation order, It is preferable that it is 200 degreeC / min, More preferably, it is 100-200 degreeC / min.

  In the organic semiconductor element of the present invention, carriers are easily injected into the organic semiconductor layer by the action of the alignment film, so that the voltage at which current starts to flow through the organic semiconductor element is low, and has practical current driving characteristics. Since the alignment order of liquid crystal molecules in the organic semiconductor layer is high, it has high carrier mobility. Furthermore, since the organic semiconductor element of the present invention can easily inject carriers into the organic semiconductor layer, a sufficient amount of carriers for carrier movement can be easily supplied to the organic semiconductor layer, and a large voltage can be obtained at a low voltage. The current can be controlled.

  Here, the voltage at which current starts to flow through the organic semiconductor element is low. In the evaluation of current-voltage characteristics performed by applying a voltage between the electrodes, the voltage at which the current starts to flow is usually 20 V or less, preferably 10 V or less, particularly Preferably it says that it is 7V or less.

The carrier mobility is high when the carrier mobility (in-plane direction of the electrode) evaluated by the Time of Flight method is 10 ¹ to 10 ⁻² cm ² / V · s, preferably 10 ⁰ to 10 ^−2. cm ² / V · s, particularly 10 ^{0 to} 5 × 10 ⁻² , particularly preferably 10 ⁰ to 10 ⁻¹ cm ² / V · s.

  Such an organic semiconductor element of the present invention can be used as, for example, a field effect transistor, a static induction transistor, or a diode.

  Hereinafter, the present invention will be described more specifically with reference to synthesis examples and examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

[Synthesis example]
Synthesis Example 1: Synthesis of compound (A-2) 4,7-dibromo-2,1,3-benzothiadiazole (294 mg, 1.0 mmol), tetrakistriphenylphosphine palladium (0) (46 mg, 0.04 mmol), To a mixture of benzene (32 mL) and 2M aqueous sodium carbonate solution (16 mL) was added a degassed ethanol solution (8 mL) of 4-decyloxyphenylboronic acid (834 mg, 3.0 mmol) at room temperature under a stream of argon. Reflux for hours. The reaction mixture was poured into water and extracted with chloroform. The organic layer was washed with saturated brine, dried over magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was subjected to silica gel column chromatography to obtain the exemplified compound (A-2) (414 mg, yield 69%).
Yellow needles
EI-MS m / z 600 (M ⁺ )
Elemental analysis calculated C: 75.92, H: 8.69, N: 4.64
Measurement C: 75.95, H: 8.72, N: 4.66

Synthesis Example 2: Synthesis of Compound (A-3) In the same manner as in the synthesis method of Compound (A-2), except that 4-decyloxyphenylboronic acid was changed to 4-dodecyloxyphenylboronic acid, Compound (A-3) was obtained with a yield of 87%.
Yellow needles
IR (KBr, cm ^-1 ): 2919,2851,2360,1606,1516,1473,1252,1182,1022
H-NMR (CDCL ₃ ): 0.89 (t, 6H, J = 6.3Hz), 1.28-1.49 (m, 36H), 1.78-1.88 (m, 4H), 4.05 (t, 6H, J = 6.6Hz), 7.06 (d, 4H, J = 8.6Hz), 7.72 (s, 2H), 7.91 (d, 4H, J = 8.6Hz)

Synthesis Example 3: Synthesis of Compound (A-4) In the synthesis method of Compound (A-2), except that 4-decyloxyphenylboronic acid was changed to 4-tetradecyloxyphenylboronic acid, The exemplary compound (A-4) was obtained with a yield of 92%.
Yellow needles
IR (KBr, cm ^-1 ): 2918,2851,1605,1515,1474,1252,1182,1012
H-NMR (CDCL ₃ ): 0.88 (t, 6H, J = 6.5Hz), 1.27-1.51 (m, 44H), 1.78-1.88 (m, 4H), 4.05 (t, 6H, J = 6.6Hz), 7.07 (d, 4H, J = 8.8Hz), 7.72 (s, 2H), 7.91 (d, 4H, J = 8.6Hz)

Synthesis Example 4: Synthesis of Compound (A-5) In the synthesis method of Compound (A-2), except that 4-decyloxyphenylboronic acid was changed to 4-pentadecyloxyphenylboronic acid, The exemplary compound (A-5) was obtained with a yield of 91%.
Yellow needles
IR (KBr, cm ^-1 ): 2918,2850,1606,1474,1252
H-NMR (CDCL ₃ ): 0.88 (t, 6H, J = 6.6Hz), 1.27-1.51 (m, 48H), 1.78-1.86 (m, 4H), 4.05 (t, 6H, J = 6.6Hz), 7.07 (d, 4H, J = 8.8Hz), 7.71 (s, 2H), 7.91 (d, 4H, J = 8.8Hz)

Synthesis Example 5: Synthesis of Compound (A-6) In the synthesis method of Compound (A-2), except that 4-decyloxyphenylboronic acid was changed to 4-hexadecyloxyphenylboronic acid, The exemplary compound (A-6) was obtained with a yield of 61%.
Yellow needles
IR (KBr, cm ^-1 ): 2918,2850,1606,1474,1252
H-NMR (CDCL ₃ ): 0.88 (t, 6H, J = 6.6Hz), 1.26-1.52 (m, 52H), 1.59-1.86 (m, 4H), 4.05 (t, 6H, J = 6.6Hz), 7.07 (d, 4H, J = 8.9Hz), 7.72 (s, 2H), 7.91 (d, 4H, J = 8.9Hz)

[Example]
Examples 1-5
Regarding the compounds shown in Table 1 in which R is a group shown in Table 1 below, the carrier mobility was measured by the following measuring method, and the results are shown in Table 1. Moreover, the phase transition behavior was measured by DSC, and the results are shown in FIGS.

[Method for measuring carrier mobility]
Equipment used: Digital storage scope, nitrogen laser (excitation light source)
Measurement conditions: Under reduced pressure or normal pressure, temperature ranges from room temperature to 200 ° C. Sample preparation method for measurement: Each compound is melted and poured into a sandwich-type cell made of an ITO substrate.
The sample for measurement was created by putting in.
Measurement method (Time of flight): A voltage is applied to the ITO electrode of the measurement sample, and a nitrogen laser is applied.
And analyze the transient photocurrent waveform obtained at that time.
To determine the carrier travel time and determine the mobility.
Set.

[DSC measurement conditions]
Device model: “DSC 822e” manufactured by METTLER TOLEDO
Sample amount: 1 mg to 2 mg
Sample container (material): Aluminum (Al)
Gas flow conditions: Nitrogen (N ₂ ), 40 ml / min
Temperature program
Heating speed: 5 ° C / min. (Upper limit temperature: Transition temperature (SmA → Iso) + (40-50 ° C))
Cooling speed: 5 ℃ / min (slow) (minimum temperature: 25 ℃)
100 ° C / min (rapid) (minimum temperature: 25 ° C (however, compound (A-2)
Only -30 ℃))
keep 2 min (maintain isothermal at lower temperature limit)
Temperature calibration conditions: Measure the melting temperature of the following high-purity metals and calibrate the value to the following value.
A similar formula was derived.
Indium Pills 99.999%
Lit mp. (= Melting temperature) 156.6 ℃
Temperature range 110 ° C-180 ° C, 10 ° C / min.
Zinc Pills 99.998%
Lit mp.419.6 ℃
Temperature range 370 ℃ -450 ℃, 10 ℃ / min.
(All reading temperatures are peak top temperatures)

Table 1 shows that the organic semiconductor material of the present invention has high carrier mobility.
2 to 6, the organic semiconductor material of the present invention can stably obtain a metastable crystal by rapid cooling from an isotropic crystal state; in particular, compounds (A-4) and (A-5) ) And (A-6), it can be seen that metastable crystals can be obtained stably even under slow cooling conditions; and that the obtained metastable crystals exist stably at room temperature.

It is sectional drawing which shows embodiment of the organic-semiconductor element of this invention. 2 is a schematic diagram showing a phase transition behavior of the compound (A-2) of Example 1. FIG. 3 is a schematic diagram showing a phase transition behavior of the compound (A-3) of Example 2. FIG. 4 is a schematic diagram showing a phase transition behavior of the compound (A-4) of Example 3. FIG. 4 is a schematic diagram showing a phase transition behavior of the compound (A-5) of Example 4. FIG. 6 is a schematic diagram showing a phase transition behavior of the compound (A-6) of Example 5. FIG.

Explanation of symbols

1 Organic Semiconductor Element 2 Substrate 3 Electrode 4 Alignment Film 5 Organic Semiconductor Layer

Claims (4)

An organic semiconductor material comprising a compound represented by the following general formula (I) as at least a part of a constituent component.

[In the general formula (I), Ar ¹ represents a divalent heterocyclic group represented by the following general formula (II), and Ar ² and Ar ³ each independently have a substituent. R ¹ and R ² each independently represents an organic group having 1 to 30 carbon atoms, and the subscripts m and n each independently represent an integer of 1 to 5. When m and / or n is 2 or more, two or more of Ar ² and / or Ar ³ may be the same as or different from each other.

(In the general formula (II), ring Z is a divalent group bonded to Ar ² and Ar ^3, and ring A represents a ring condensed by sharing two carbon atoms with ring Z. Ring A and Each ring Z may have a substituent.   In the general formula (II), the ring Z represents a 6-membered ring which may have a substituent, and the ring A represents a 5-membered ring which may have a substituent. The organic semiconductor material described in 1. The organic semiconductor material according to claim 1 or 2, wherein the general formula (II) is represented by any one of the following general formulas (IIa) and (IIb).

[In general formula (IIa), ring Z is a divalent group consisting of a ring having the same meaning as ring Z in general formula (II), and Y represents a group 16 element. ]

[In general formula (IIb), ring Z is a divalent group consisting of a ring having the same meaning as ring Z in general formula (II), and X represents N or S. ]   In an organic semiconductor element comprising: a first substrate and a second substrate arranged to face each other at a predetermined interval; and an organic semiconductor layer formed between the first substrate and the second substrate, An organic semiconductor element, wherein the organic semiconductor layer contains the organic semiconductor material according to claim 1.

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