JP2000323191A - Photoelectric transfer element, photoelectrochemical battery and metal complex pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a complex pigment having excellent light absorbing capability by coordinating a unidentate or bidentate ligand to be coordinated by acyloxy group or the like in a complex pigment formed by coordinately bonding a lignand having a specific number or more of positions capable of being coordinated in a bidentate form on a metal atom by nitrogen to a bidentate ligand having non-metal atoms required for completing 5 or 6 membered ring. SOLUTION: This metal complex pigment is expressed by formula I, (M1 and M2 are each a metal atom; BL is a ligand having two or more positions capable of being coordinated in a bidentate form on a metal atom by nitrogen; X1 and X2 are each a unidentate or bidentate ligand capable of being coordinated by a dithiocarbamate group or the like; LL1 and LL2 are each a bidentate ligand expressed by formula II; m1 and m4 are each 0 or 1; m2 and m3 are each an integer of 1-4; and CI is a counter ion for neutralizing charge). In formula II, Za and Zb are each a non-metal atom group required for independently completing a 5-6 membered ring. This photoelectric transfer element containing semiconductor fine particles sensitized by the metal complex pigment shows high photoelectric transfer efficiency and is suitable for a photoelectrochemical battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal complex dye having high light absorption even in a long wavelength region, a photoelectric conversion element using semiconductor fine particles sensitized by such a metal complex dye, and a photoelectrochemical cell comprising the same. About.

[0002]

2. Description of the Related Art As a solar cell used for photovoltaic power generation, a solar cell made of single-crystal silicon, polycrystalline silicon, amorphous silicon, or a compound such as cadmium telluride or indium copper selenide has been put into practical use or has been mainly used for research and development. Although it is a target, in order to spread it widely to household power sources, there are problems such as high production cost, difficulty in securing raw materials, long energy payback time, etc. There is a need. On the other hand, many solar cells using an organic material have been proposed for the purpose of increasing the area and reducing the cost, but generally have the problems of low conversion efficiency and poor durability.

[0003] Under such circumstances, "Nature", No. 353
737-740, 1991, and U.S. Pat.
, WO 94/04497, etc., propose a wet photoelectric conversion element and a solar cell using a titanium dioxide porous thin film spectrally sensitized with a ruthenium complex dye as a working electrode, and materials and manufacturing techniques for producing the same. Was done. The first advantage of this wet photoelectric conversion element is that an inexpensive oxide semiconductor such as titanium dioxide can be used without purification to a high degree of purity, so that an inexpensive photoelectric conversion element can be provided.
The second advantage is that since the absorption of the dye used is broad, light in almost all visible wavelength regions can be converted into electricity.

[0004] However, although known ruthenium complex dyes absorb visible light, they hardly absorb infrared light having a wavelength longer than 700 nm, and thus have a problem of low photoelectric conversion ability in the infrared region. Therefore, in order to further increase the conversion efficiency, it is desired to develop a dye having an absorptivity in a wide wavelength range from visible light to an infrared region and exhibiting a high photoelectric conversion ability.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal complex which has a high light absorption capacity not only in the visible light region but also in the infrared region and which can efficiently sensitize semiconductor fine particles to a long wavelength region. An object of the present invention is to provide a dye, a photoelectric conversion element having high photoelectric conversion efficiency by using such a metal complex dye, and a photoelectrochemical cell including the same.

[0006]

Means for Solving the Problems As a result of intensive studies in view of the above-mentioned object, a ligand having two or more sites capable of bidentate coordination with nitrogen to a metal atom, and a 5- or 6-membered ring as required And a bidentate or bidentate ligand coordinated with an acyloxy group, an acylthio group, or the like, to a metal complex dye formed by coordinating a bidentate ligand having a nonmetal atom necessary to complete By coordination, a metal complex dye having excellent light absorption ability even in a long wavelength region can be obtained, and semiconductor fine particles sensitized by such a metal complex dye exhibit high photoelectric conversion efficiency suitable as a photoelectric conversion element. The present inventors have found that a good photoelectrochemical cell can be obtained, and have reached the present invention.

That is, the photoelectric conversion element of the present invention has the following general formula (I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI ·· (I) (where M ₁ and M ₂ each represent a metal atom, BL represents a ligand having two or more sites capable of bidentate coordination with nitrogen to the metal atom, X ₁ and X ₂ is each independently an acyloxy group, oxalylene group, acylthio group, thioacyloxy group, thioacylthio group, acylaminooxy group, thiocarbamate group, dithiocarbamate group, thiocarbonate group, dithiocarbonate group, trithiocarbonate group , An acyl group, a carbonyl group, a thiocyanate group, an isothiocyanate group, a cyanate group, an isocyanate group, a halogen atom, a cyano group, an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group. 1 locus or bidentate ligand coordinated in selected groups from the group, or represents a monodentate or bidentate ligand consisting of a dialkyl ketone or carboxylic amide, the following LL ₁ and LL ₂ are each independently General formula (II):

Embedded image (However, Za and Zb each independently represent a non-metallic atom group necessary for completing a 5- or 6-membered ring), and m1 and m4 each independently represent 0. or a 1, m2 and m3 each independently represents an 1-4 integer, when m2 or m3 is 2 or more, X ₁ or X ₂ may be the same or different and each also X ₁ s or X _{The two} may be linked to each other, and CI represents a counter ion when a counter ion is required to neutralize the charge. ), Characterized by containing semiconductor fine particles sensitized by the metal complex dye represented by the formula (1).

A photoelectrochemical cell according to the present invention is characterized by using the above-mentioned photoelectric conversion element.

According to the present invention, a photovoltaic cell and a photoelectrochemical cell containing semiconductor fine particles sensitized by a metal complex dye having more excellent light absorbing ability in a long wavelength region can be obtained by satisfying the following conditions.

(1) LL ₁ and L represented by the general formula (II)
In L _2, ring a pyridine ring formed by Za or Zb, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a pyrazole ring, an imidazole ring, a triazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, benzotriazole ring, benzoxazole It is preferably at least one selected from the group consisting of a ring and a benzothiazole ring.

(2) In the metal complex dye represented by the general formula (I), the ligand BL is represented by the following general formulas (III-1) to (III-3):

Embedded image (However, Zc, Zd, Ze and Zf are each independently 5 or 6
Represents a group of non-metallic atoms necessary for forming a membered ring, and n1 is 0
Or represents 1. ) Are preferred.

(3) The ring formed by Ze or Zf in the ligand BL is preferably a pyrazine ring.

(4) In the metal complex dye represented by the general formula (I), as the ligand BL, the following general formulas B-1 to B-1
0:

Embedded image R ₂₁ to R ₃₀ each independently represent a substituent group or may be substituted on a carbon atom of the B-1 to B-10 throat ring. e, f,
g, h, j, k, and q each independently represent an integer of 0 to 8, p and r each independently represent an integer of 0 to 6, and s represents an integer of 0 to 4. ) Are preferred.

(5) In the ligand BL represented by the general formulas B-1 to B-10, R _{21 to} R ₃₀ each independently represent an alkyl group,
It preferably represents an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic group, a phosphoryl group, a phosphonyl group or a halogen atom.

(6) Ligand in metal complex dye of general formula (I)
BL is preferably represented by any of B-1 to B-4.

(7) Ligand in metal complex dye of general formula (I)
LL ₁ or LL ₂ is independently of the general formula (IV-1) or (IV-2):

Embedded image (However, R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, R ₃ and R ₄ each independently represent hydrogen, an alkyl group or an aryl group, and a and b each independently represent 0. Represents an integer of ~ 4, and c and d each independently represent 0 ~
Represents an integer of 2, R ₁ and R ₂ , R ₃ and R ₄ , R ₃ and R ₅ and R ₄ and R ₆
May be connected to each other to form a ring. )
Is preferably represented by

(8) R ₁ and R in the general formula (IV-1) or (IV-2)
₂ , R ₅ and R ₆ are each independently an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group,
Amino group, alkoxycarbonyl group, carboxyl group,
It is preferably a sulfonic acid group, a phosphoryl group, a phosphonyl group or a halogen atom.

(9) In the general formula (I), X ₁ and X ₂ are
Preferably, each is independently a dithiocarbamate group, an acylaminooxy group, an acyloxy group, an oxalylene group, an isocyanate group, a cyanate group, an isothiocyanate group, a thiocyanate group, an alkylthio group or an arylthio group.

(10) The metal complex dye represented by the general formula (I) preferably has at least one acidic group.

(11) M ₁ and M ₂ in the general formula (I) each independently represent Ru, Fe, Os, Cu, W, Cr, Mo, Ni, Pd, Pt, C
It is preferably o, Ir, Rh, Re, Mn or Zn.

(12) M ₁ and M ₂ in the general formula (I) are preferably each independently Ru, Fe, Os or Cu.

(13) M ₁ and M ₂ in the general formula (I) are preferably Ru.

(14) The semiconductor fine particles are preferably titanium oxide fine particles.

The metal complex dye of the present invention has the following general formula:
(I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI (I) (where M ₁ and M ₂ are each 4 Or a metal atom capable of coordinating 6; BL represents the following general formulas B-1 to B-10:

Embedded image (However, R _{21 to} R ₃₀ each independently represent a substituent, and B-
1 to B-10 may be bonded to any ring carbon atom,
e, f, g, h, j, k and q are each independently 0 to
Represents an integer of 8, p and r each independently represent an integer of 0 to 6, and s represents an integer of 0 to 4. X ₁ and X ₂ are each independently an acyloxy group, an oxalylene group, an acylthio group, a thioacyloxy group, a thioacylthio group, an acylaminooxy group, a thiocarbamate group, a dithiocarbamate group, a thiocarbonate group , Dithiocarbonate group, trithiocarbonate group, acyl group, carbonyl group, thiocyanate group, isothiocyanate group, cyanate group, isocyanate group,
A monodentate or bidentate ligand coordinated with a group selected from the group consisting of a halogen atom, a cyano group, an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group, or a monodentate consisting of a dialkyl ketone or carbonamide Or LL ₁ and LL ₂ each independently represent the following general formula (IV-1) or (IV-2):

Embedded image (However, R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, R ₃ and R ₄ each independently represent hydrogen, an alkyl group or an aryl group, and a and b each independently represent 0. Represents an integer of ~ 4, and c and d each independently represent 0 ~
Represents an integer of 2, R ₁ and R ₂ , R ₃ and R ₄ , R ₃ and R ₅ and R ₄ and R ₆
May be connected to each other to form a ring. )
Wherein m1 and m4 are each independently 0 or 1, m2 and m3 each independently represent an integer of 1 to 4, and when m2 or m3 is 2 or more, X ₁
Or X ₂ may be the same or different, and
X _{1 and} X ₂ may be linked to each other, and CI represents a counter ion when a counter ion is required to neutralize the charge. ).

In the metal complex dye according to a preferred embodiment of the present invention, M ₁ and M ₂ are each Ru, and X ₁ and X ₂ are each independently a dithiocarbamate group, an acylaminooxy group, an acyloxy group, an oxalylene group. , Isocyanate group, cyanate group, isothiocyanate group,
BL represents a monodentate or bidentate ligand coordinated by a group selected from the group consisting of a thiocyanate group, an alkylthio group and an arylthio group, and BL represents the following general formulas B-1 to B-4:

Embedded image (However, R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ each independently represent an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, a phosphoryl group, Represents a phosphonyl group or a halogen atom, and may be bonded to any ring carbon atom of B-1 to B-4, and e, f, g and h each independently represent an integer of 0 to 8.) It is a ligand represented by any of them.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION [1] Metal Complex Dye The metal complex dye used in the photoelectric conversion device of the present invention has the following general formula (I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI (I) Hereinafter, each component will be described in detail.

(A) Metal atoms M ₁ , M ₂ M ₁ and M ₂ each represent a metal atom, and M ₁ and M ₂ may be the same or different. M ₁ and M ₂ are preferably a metal capable of 4 or 6 coordination, more preferably R
u, Fe, Os, Cu, W, Cr, Mo, Ni, Pd, Pt, Co, Ir, R
h, Re, Mn or Zn, particularly preferably Ru, Fe, Os
Or, it is Cu, most preferably Ru.

(B) Ligands X ₁ and X _{2 In the} general formula (I), X ₁ and X ₂ each represent a monodentate or bidentate ligand, and each independently represents an acyloxy group (preferably having no carbon atom). 1-20, for example, acetyloxy, benzoyloxy, etc.), oxalylene (-OC (O) C (O) O-) group, acylthio group (preferably having 1-20 carbon atoms, for example, acetylthio, benzoylthio, etc.), thiol An acyloxy group (preferably having 1 to 20 carbon atoms such as thioacetyloxy (CH
₃ C (S) O-) thio benzoyloxy), Chioashiruchio group (preferably having 1 to 20 carbon atoms, for example, thio-acetyl thio (CH ₃ C (S) S-), thio benzoyl thio (PhC (S) CS-)
Etc.), an acylaminooxy group (preferably having 1 carbon atom)
-20, for example, N-methylbenzoylaminooxy (PhC (O)
N (CH ₃ ) O-), acetylaminooxy (CH ₃ C (O) NHO-), p
-Toluoylaminooxy, etc.), thiocarbamate groups (preferably having 1 to 20 carbon atoms, such as N, N-diethylthiocarbamate, N, N-dimethylthiocarbamate, etc.),
Dithiocarbamate group (preferably having 1 to 20 carbon atoms,
For example, N, N-dibenzyldithiocarbamate ((PhCH ₂ ) ₂ N
C (S) S -), N, N- dimethyldithiocarbamate ((CH _{3) 2} NC
(S) S-) etc.), a thiocarbonate group (preferably having 1 to 20 carbon atoms, for example, ethylthiocarbonate, methylthiocarbonate and the like), a dithiocarbonate group (preferably having 1 to 20 carbon atoms, for example, ethyl dithiocarbonate _{(C 2 H 5 OC (S} ) S-)), trithiocarbonate group (preferably having 1 to 20 carbon atoms, for example ethyl trithiocarbonate _{(C 2 H 5 SC (S} ) S- )), An acyl group (preferably having 1 to 20 carbon atoms such as acetyl and benzoyl), a carbonyl group (—CO), a dialkyl ketone (preferably having 3 to 20 carbon atoms such as acetone ((CH ₃ ) ₂ ) CO ···), CH ₃ C
_{(O ···) CH 2 C (} O ···) CH 3 , etc. (... represents a coordinate bond), acetylacetone), carboxylic amide (preferably having 1 to 20 carbon atoms, for example CH ₃ NHC (CH ₃ ) O ・ ・ ・ ・ ・ ・ ・ ・ ・ OC (NH ₂ ) -C
(NH ₂ ) O, etc.), thiocyanate group, isothiocyanate group, cyanate group, isocyanate group, halogen atom (preferably chlorine, bromine, iodine), cyano group, alkylthio group (preferably having 1 to 20 carbon atoms) For example, methanethio, ethylenedithio, propylenedithio, etc.), an arylthio group (preferably having 6 to 20 carbon atoms, such as benzenethio, 1,2-phenylenedithio, etc.), an alkoxy group (preferably having 1 to 20 carbon atoms, such as methoxy And a ligand selected from the group consisting of aryloxy groups (preferably having 6 to 20 carbon atoms, for example, phenoxy, 1,2-phenylenedioxy and the like).

In the general formula (I), m2 and m3 representing the numbers of the ligands X ₁ and X ₂ each independently represent an integer of 1 to 4,
Preferably it is 1 or 2. When m2 or m3 is 2 or more, to X ₁ or X ₂ may be the same or different, respectively, also may be connected is X ₁ or between X ₂ together.

When m2 and m3 are each 1, X ₁ or
X ₂ is preferably a bidentate ligand, specifically, an acyloxy group, an oxalylene group, an acylthio group, a thioacyloxy group, a thioacylthio group, an acylaminooxy group, a thiocarbamate group, a dithiocarbamate group,
A ligand coordinated with a thiocarbonate group, a dithiocarbonate group, a trithiocarbonate group, an alkylthio group or an arylthio group, or a ligand composed of a dialkyl ketone or a carbonamide is preferred.

When m2 and m3 are each 2 or more,
X ₁ or X ₂ is preferably a monodentate ligand, specifically, an acyl group, a carbonyl group, a thiocyanate group, an isothiocyanate group, a cyanate group, an isocyanate group,
A ligand coordinated with a halogen atom, a cyano group, an alkylthio group, an arylthio group, an alkoxy group or an aryloxy group, or a ligand composed of a dialkyl ketone or a carbonamide is preferred. At this time, X ₁ and X ₂ may be the same or different, but are preferably the same.

Specific examples of X ₁ and X ₂ are shown below, but the present invention is not limited to these. It should be noted that the structural formula shown here is only one limit structure among a number of resonance structures that can be taken, and a covalent bond (represented by-) and a coordination bond (...)
Is also a formal distinction, not an absolute distinction.

[0033]

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[0034]

Embedded image

[0035]

Embedded image

[0036] (C) 2 bidentate ligand LL _1, LL _{2 2} bidentate ligand LL ₁ and LL ₂ are each independently the general formula
(II). LL ₁ and LL ₂ may be the same or different, but are preferably the same. In the general formula (II),
Za and Zb each independently represent a nonmetallic atomic group capable of forming a 5- or 6-membered ring. Za and Zb are preferably constituted by an element selected from the group consisting of carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus and halogen atoms, and preferably form an aromatic ring.

The aromatic ring independently formed by Za and Zb is preferably a pyridine ring, a pyrimidine ring, a pyrazine ring or a pyridazine ring in the case of a 6-membered ring.
In the case of a 5-membered ring, a pyrazole ring, an imidazole ring, a triazole ring, a thiazole ring, an oxazole ring, a benzimidazole ring, a benzotriazole ring, a benzoxazole ring or a benzothiazole ring is preferable. Among them, a pyridine ring, an imidazole ring and a benzimidazole ring are more preferred.

More preferably, LL ₁ and LL ₂ are each independently represented by the following formula (IV-1) or (IV-2).

Embedded image In each of the general formulas (IV-1) and (IV-2),
R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, preferably an alkyl group (preferably having 1 to 20 carbon atoms, for example, methyl, ethyl, i-propyl, t-butyl, benzyl, 4 -Carboxymethyl, etc.), alkenyl groups (preferably having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), aryl groups (preferably having 6 to 26 carbon atoms, for example, phenyl, 2-naphthyl, 4-carboxylphenyl) Etc.), hydroxyl group, alkoxy group (preferably having 1 to 20 carbon atoms such as methoxy, 2-carboxyethoxy and the like), amino group (preferably having 0 to 20 carbon atoms such as amino, N, N-dimethylamino, Anilino), an alkoxycarbonyl group (preferably having 2 to 20 carbon atoms, such as ethoxycarbonyl), a carboxyl group, a sulfonic acid group (—SO ₃ H), a phosphoryl group (preferably Preferably 0 carbon atoms
20, for example, _{-OP (O) (OH) 2} , -OP (O) (OC 2 H 5) 2), a phosphonyl group (preferably 0 to 20 carbon atoms, such as -P (O) (O
H) ₂ , —P (O) (OC ₂ H ₅ ) _2, etc.) or a halogen atom (eg, fluorine, chlorine, bromine, iodine, etc.), more preferably an alkyl group, an alkenyl group, a hydroxyl group, an alkoxy group Represents a group, a carboxyl group, a sulfonic acid group, a phosphoryl group or a phosphonyl group.

A and b each independently represent an integer of 0-4, preferably an integer of 0-2, more preferably 0 or 1.

R ₃ and R ₄ each independently represent hydrogen, an alkyl group or an aryl group, more preferably an alkyl group. Preferred examples of R ₃ and R ₄ are the same as R ₁ .
Further, c and d each independently represent an integer of 0 to 2.
Further, R ₁ and R ₂ , R ₃ and R ₄ , R ₃ and R _5, and R ₄ and R ₆ may be connected to each other to form a ring.

[0041] While specific examples of LL ₁ and LL ₂₂ of the metal complex dye of the present invention represented by the general formula (I) shown below, the present invention is not limited thereto.

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

(D) Ligand BL In the general formula (I), BL represents a ligand having two or more sites capable of bidentate coordination with nitrogen to a metal atom. When there are three or more sites capable of bidentate coordination, M ₁ and M ₂ of the formula (I)
And a coordinating metal. BL is preferably represented by the above general formula (III-1), (III-2) or (III-3). In the general formulas (III-1) to (III-3), Zc, Zd, Ze and Zf each independently represent a non-metal atom group capable of forming a 5- or 6-membered ring, and include carbon, oxygen, hydrogen, nitrogen, It is preferably composed of an element selected from the group consisting of sulfur, phosphorus and halogen atoms, and more preferably forms an aromatic ring. Two or more of these rings may be bonded to each other to form a condensed ring.

A preferred aromatic ring independently formed by Zc and Zd is the same as Za, more preferably a pyridine ring or an imidazole ring, and further preferably a pyridine ring. The ring independently formed by Ze and Zf is preferably a pyrazine ring, a pyridazine ring or a tetrazine ring, and more preferably a pyrazine ring.

Specific examples of the ligands represented by the general formulas (III-1) to (III-3) include those represented by the following general formulas B-1 to B-10.

Embedded image In the general formulas B-1 to B-10, R _{21 to} R ₃₀ each independently represent a substituent, and may be substituted on any ring carbon atom of B-1 to B-10. R _{21 to} R ₃₀ preferably represent an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, a phosphoryl group, a phosphonyl group or a halogen atom, and are more preferable. examples are the same as those exemplified R _1.

E, f, g, h, j, k and q each independently represent an integer of 0-8, p and r each independently represent an integer of 0-6, and s represents 0-4. Represents an integer. Each is preferably an integer of 0 to 2.

The ligand BL is preferably represented by any of B-1 to B-4, B-7 and B-10, and is preferably represented by B-1 to B-4 or
It is more preferably represented by B-10, and even more preferably by B-1 to B-4.

Specific examples of the bridging ligand BL are shown below, but the present invention is not limited thereto.

[0051]

Embedded image

[0052]

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(E) Counter ion CI In the general formula (I), CI represents a counter ion when a counter ion is required to neutralize the charge. Whether a dye is a cation or anion, or has a net ionic charge, depends on the metal, ligand, and substituents in the dye. When the substituent has a dissociable group, it may dissociate and have a negative charge, and in this case also, the charge of the entire molecule is neutralized by CI. Typical cations are inorganic or organic ammonium ions (eg, tetraalkylammonium ions, pyridinium ions, etc.) and alkali metal ions. On the other hand, the anion may be either an inorganic or organic anion, such as a halogen anion (eg, a fluoride ion, a chloride ion, a bromide ion, an iodide ion), or a substituted aryl sulfonate ion (eg,
p-toluenesulfonate ion, p-chlorobenzenesulfonate ion, etc., aryldisulfonate ion (for example,
1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonic acid ion, 2,6-naphthalenedisulfonic acid ion, etc.), alkyl sulfate ion (eg, methyl sulfate ion), sulfate ion, thiocyanate ion, perchloric acid Ion, tetrafluoroborate ion, hexafluorophosphate ion, picrate ion, acetate ion, trifluoromethanesulfonate ion and the like. Further, as the charge-balancing counterion, an ionic polymer or another dye having a charge opposite to that of the dye may be used,
Metal complex ions (eg, bisbenzene-1,2-dithiolatonickel (III)) can also be used.

(F) Bonding Group The dye represented by the general formula (I) preferably has at least one suitable interlocking group for the surface of the semiconductor fine particles. Preferred linking groups include carboxyl (COOH) groups, sulfonic acids (SO
₃ H) group, phosphonic acid (-P (O) (OH) ₂ ) group, phosphoric acid (-OP (O)
An acidic group (substituent having a dissociable proton) such as an (OH) ₂ ) group or a hydroxyl group, or a π-conductive chelating group such as oxime, dioxime, hydroxyquinoline, salicylate and α-ketoenolate. Is mentioned. Among them, a carboxyl group, a phosphate group, and a phosphonate group are particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an intramolecular salt.

[0055] These linking groups BL, is preferably included in the LL ₁ or LL _2, what is included in any of the R ₁ to R ₆ and R ₂₁ to R ₃₀ are more preferred. The number of these bonding groups in the metal complex dye represented by the general formula (I) is 1 to 8
Is preferable, 2-6 are more preferable, and 2-4 are especially preferable.

(G) Specific Examples of Metal Complex Dyes Among the above metal complex dyes, particularly preferred are the following formulas (I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI (I) (where M ₁ and M ₂ each represent a metal atom capable of coordinating 4 or 6 and BL is the above-mentioned general formula B-1 to B-10 ( Where R
_{21 to} R ₃₀ each independently represent a substituent, which may be bonded to any ring carbon atom of B-1 to B-10, e, f, g,
h, j, k and q each independently represent an integer of 0 to 8, p and r each independently represent an integer of 0 to 6,
s represents an integer of 0 to 4. ),
X ₁ and X ₂ are each independently an acyloxy group, an oxalylene group, an acylthio group, a thioacyloxy group, a thioacylthio group, an acylaminooxy group, a thiocarbamate group, a dithiocarbamate group, a thiocarbonate group, a dithiocarbonate group, a trithiol group. A group selected from the group consisting of carbonate groups, acyl groups, carbonyl groups, thiocyanate groups, isothiocyanate groups, cyanate groups, isocyanate groups, halogen atoms, cyano groups, alkylthio groups, arylthio groups, alkoxy groups and aryloxy groups. Represents a monodentate or bidentate ligand to be coordinated, or a monodentate or bidentate ligand composed of a dialkyl ketone or carbonamide, and LL ₁ and LL ₂ each independently represent the above-mentioned general formula (IV-1) Or (IV-2) (where R ₁ , R ₂ , R ₅ and R ₆ are each independently substituted A and b each independently represent an integer of 0 to 4, c and d each independently represent an integer of 0 to 2, R ₁₁ and R ₁₂ , R ₃ and R ₄ , R ₃ and R
₁₅ and R ₄ and R ₁₆ may be connected to each other to form a ring. ) Represents a bidentate ligand represented by m1
And m4 are each independently 0 or 1, m2 and
m3 each independently represents an 1-4 integer, when m2 or m3 is 2 or more, X ₁ or X ₂ may be the same or different and each also be linked is X ₁ or between X ₂ together Alternatively, CI represents a counter ion where a counter ion is required to neutralize the charge. ).

Particularly preferred metal complex dyes are represented by the following general formula:
_{(V): (LL 1)} m1 (X 1) is _{m2 Ru (BL) Ru (X} 2) m3 (LL 2) ruthenium complex dye represented by _{m4 · CI ··· (V),} X 1 and X ₂
Is independently coordinated with a group selected from the group consisting of a dithiocarbamate group, an acylaminooxy group, an acyloxy group, an oxalylene group, an isocyanate group, a cyanate group, an isothiocyanate group, a thiocyanate group, an alkylthio group and an arylthio group. Represents a bidentate or bidentate ligand, and BL represents the above general formulas B-1 to B-4 (provided that R ₂₁ , R _21
22 , R ₂₃ and R ₂₄ are each independently an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group,
Amino group, alkoxycarbonyl group, carboxyl group,
Represents a sulfonic acid group, a phosphoryl group, a phosphonyl group or a halogen atom, and may be bonded to any ring carbon atom of B-1 to B-4, and e, f, g and h are each independently 0
Represents an integer of ８8. ), And LL ₁ and LL ₂ are each independently the above-mentioned general formula (IV-
1) or (IV-2) (where R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, and a and b each independently represent 0
Represents an integer of 4 to 4, and c and d each independently represent 0 to 2
R ₁₁ and R ₁₂ , R ₃ and R ₄ , R ₃ and R ₁₅ and R ₄ and R
₁₆ may be mutually connected to form a ring. ) Represents a bidentate ligand represented by

Specific examples of such a metal complex dye are shown below, but the present invention is not limited thereto. In the following specific examples, the ligands with “′” such as L-5 ′ are dissociated from protons from the carboxyl group of the ligand such as L-5, and the carboxylate anion It shows what became. However, L-5 ', etc. may be in equilibrium with L-5, respectively, and the corresponding counter ion CI
May also change.

[0059]

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[0064]

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The synthesis of the metal complex dye represented by formula (I) used in the present invention is described in Inorg. Chem. Acta., 206 , 69.
(1993), Inorg. Chem., 29 , 1888 (1990), J. Am. Chem.
Soc., 109 , 2691 (1987), Inorg.Chem., 29 , 4750 (199
0), Inorg. Chem., 28 , 1520 (1989), Inorg. Chem., 2
9 , 167 (1990) and the like.

The metal complex dye of the present invention has an alkyl group,
When it contains an alkenyl group, an alkynyl group, an alkylene group, etc., they may be linear or branched, and may be substituted or unsubstituted. When the metal complex dye of the present invention contains an aryl group, a heterocyclic group, a cycloalkyl group, etc., they may be substituted or unsubstituted, and may be monocyclic or condensed.

[2] Photoelectric conversion element The photoelectric conversion element of the present invention has a photosensitive layer having semiconductor fine particles sensitized by the metal complex dye. Preferably, as shown in FIG. 1, a conductive support 10, a photosensitive layer
20, the charge transfer layer 30 and the counter electrode 40 are laminated in this order, the conductive support layer 10 is composed of the base material 11 and the conductive layer 12, and the photosensitive layer 20 is sensitized by the metal complex dye 22 of the present invention. Semiconductor fine particles 21 and an electrolyte 30 filled in voids between the semiconductor fine particles 21. A photoelectrochemical cell in which the photoelectric conversion element is connected to an external circuit to perform a work is provided.

The light incident on the photosensitive layer 20 containing the semiconductor fine particles 21 sensitized by the metal complex dye 22 of the present invention excites the dyes 22 and the like, and the high-energy electrons in the excited dyes 22 and the like are used as the semiconductor fine particles. It is passed to the conduction band 21 and reaches the conductive support 10 by diffusion. At this time, molecules such as the dye 22 are oxidized. In the photoelectrochemical cell, the electrons in the conductive support 10 return to an oxidized form such as the dye 22 through the counter electrode 40 and the charge transfer layer 30 while working in an external circuit, and the dye
22 plays. The semiconductor layer 20 functions as a negative electrode. Each layer boundary (for example, the conductive layer 12 and the photosensitive layer of the conductive support 10)
At the boundary with 20, the boundary between the photosensitive layer 20 and the charge transfer layer 30, the boundary between the charge transfer layer 30 and the counter electrode 40, etc.), the constituent components of each layer may be mutually diffused and mixed. Hereinafter, each layer will be described in detail.

[A] Conductive Support The conductive support may be a conductive support such as a metal or a conductive layer 12 containing a conductive agent on the photosensitive layer side as shown in FIG. A glass or plastic substrate 11 can be used. In the latter case, preferred conductive agents include metals (eg, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or conductive metal oxides (indium-tin composite oxide, tin oxide doped with fluorine). And the like). Conductive layer
The thickness of 12 is preferably about 0.02 to 10 μm.

The lower the surface resistance of the conductive support, the better. A preferred range of the surface resistance is 100 Ω / □ or less, more preferably 40 Ω / □ or less. The lower limit of the surface resistance is not particularly limited, but is usually about 0.1Ω / □.

When light is irradiated from the conductive support side, it is preferable that the conductive support is substantially transparent electrochemically. Substantially transparent means that light transmittance is 10
% Or more, preferably 50% or more, particularly preferably 70% or more. As the transparent conductive support, it is preferable that a transparent conductive layer made of a conductive metal oxide is formed on the surface of a transparent substrate such as glass or plastic by coating or vapor deposition. Of these, conductive glass in which a conductive layer made of tin dioxide doped with fluorine is deposited on a transparent substrate made of low-cost soda-lime float glass is preferable. For a low-cost and flexible photoelectric conversion element or solar cell, a transparent polymer film provided with a conductive layer is preferably used. For the transparent polymer film, tetraacetyl cellulose (TA
C), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndioctatic polysterene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy, and the like. In order to ensure sufficient transparency, the amount of the conductive metal oxide applied is preferably 0.01 to 100 g per 1 m ² of a glass or plastic support.

It is preferable to use a metal lead for the purpose of lowering the resistance of the transparent conductive support. The material of the metal lead is preferably a metal such as aluminum, copper, silver, gold, platinum, and nickel, and particularly preferably aluminum and silver. The metal lead is preferably provided on a transparent substrate by vapor deposition, sputtering, or the like, and a transparent conductive layer made of tin oxide doped with fluorine or an ITO film is preferably provided thereon. It is also preferable to provide a metal lead on the transparent conductive layer after providing the transparent conductive layer on the transparent substrate. The decrease in the amount of incident light due to the installation of the metal leads is within 10%, more preferably 1 to 5%.

[B] Photosensitive Layer In the photosensitive layer containing semiconductor fine particles sensitized by the metal complex dye of the present invention, the semiconductor fine particles act as a so-called photoreceptor, absorb light to separate electric charges, and form electrons and positive electrons. Creates a hole. In the dye-sensitized semiconductor fine particles, light absorption and the resulting generation of electrons and holes mainly occur in the dye, and the semiconductor fine particles have a role of receiving and transmitting the electrons.

(1) Semiconductor Fine Particles Semiconductor fine particles include a simple semiconductor such as silicon or germanium, a III-V compound semiconductor, a metal chalcogenide (eg, oxide, sulfide, selenide, etc.), or a perovskite structure. Compounds (for example, strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, etc.) can be used.

Preferred metal chalcogenides are titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc, lead and silver. , Antimony, bismuth sulfide, cadmium, lead selenide,
And cadmium telluride. Other compound semiconductors include phosphides such as zinc, gallium, indium and cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide and the like.

Preferred specific examples of the semiconductor used in the present invention
Is Si, TiO_Two, SnO_Two, Fe_TwoO_Three, WO_Three, ZnO, Nb_TwoO_Five, CdS, Z
nS, PbS, Bi_TwoS_Three, CdSe, CdTe, GaP, InP, GaAs, CuIn
S_Two, CuInSe_TwoAnd more preferably TiO_Two, ZnO, Sn
O_Two, Fe_TwoO_Three, WO_Three, Nb_TwoO_Five, CdS, PbS, CdSe, InP, GaA
s, CuInS_Two, CuInSe_TwoAnd particularly preferably, TiO_TwoAlso
Is Nb _TwoO_FiveAnd most preferably TiO_TwoIt is.

The semiconductor used in the present invention may be single crystal or polycrystal. From the viewpoint of conversion efficiency, a single crystal is preferable,
Polycrystal is preferred from the viewpoints of production cost, securing of raw materials, energy payback time and the like.

The particle size of the semiconductor fine particles is generally on the order of nm to μm, but the average particle size of the primary particles obtained from the diameter when the projected area is converted into a circle is preferably from 5 to 200 nm, and from 8 to 200 nm. 100 nm is more preferred. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is preferably 0.01 to 100 μm.

Two or more types of fine particles having different particle size distributions may be mixed. In this case, the average size of the small particles is 5 nm.
It is preferred that: For the purpose of improving the light capture rate by scattering incident light, semiconductor particles having a large particle size, for example, about 300 nm may be mixed.

As methods for producing semiconductor fine particles, Sakuhana Shizuo's "Sol-Gel Method Science" Agne Shofusha (1998), Technical Information Association "Sol-Gel Method for Thin Film Coating" (1995 ), Tadao Sugimoto, "Synthesis of Monodisperse Particles and Size Morphology Control by New Synthetic Gel-Sol Method", "Materia", Vol. 35, No. 9, 1012-
The gel-sol method described on page 1018 (1996) is preferred. Further, a method of producing an oxide by high-temperature hydrolysis of a chloride in an oxyhydrogen salt developed by Degussa is also preferable.

When the semiconductor fine particles are titanium oxide, any of the above-mentioned sol-gel method, gel-sol method, and high-temperature hydrolysis method in chloride oxyhydrogen salt are preferable. Applied Technology "Gihodo Publishing (1997)
The sulfuric acid method and the chlorine method described in (1) can also be used. Furthermore, as a sol-gel method, Barb et al., Journal of American Ceramic Society, No. 80
Vol. 12, No. 3, pp. 3157-3171 (1997),
"Chemical Materials", Burnside, 10th
Vol. 9, No. 9, pages 2419 to 2425 are also preferable.

(2) Semiconductor fine particle layer In order to coat the semiconductor fine particles on the conductive support, in addition to the method of applying a dispersion or colloid solution of the semiconductor fine particles on the conductive support, the above-mentioned sol-gel is used. A method can also be used. In consideration of mass production of photoelectric conversion elements, physical properties of semiconductor fine particle liquid, flexibility of a conductive support, and the like, a wet film forming method is relatively advantageous. As a wet film forming method, a coating method and a printing method are typical.

As a method for preparing a dispersion of semiconductor fine particles, in addition to the above-described sol-gel method, a method of grinding in a mortar, a method of dispersing while pulverizing using a mill, or a method of preparing a solvent when synthesizing a semiconductor. A method of precipitating fine particles in the solution and using it as it is, may be mentioned.

Examples of the dispersion medium include water and various organic solvents (eg, methanol, ethanol, isopropyl alcohol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). At the time of dispersion, a polymer, a surfactant, an acid, a chelating agent, or the like may be used as a dispersing aid, if necessary.

The application method includes a roller method and a dip method as an application system, an air knife method and a blade method as a metering system, and a method in which application and metering can be performed in the same part.
No. 589, the wire bar method disclosed in U.S. Pat.
The slide hopper method, extrusion method, curtain method and the like described in JP-A Nos. 94, 2761419 and 2761791 are preferable. As a general-purpose machine, a spin method or a spray method is also preferable. As the wet printing method, intaglio printing, rubber printing, screen printing and the like are preferable, including three major printing methods of letterpress, offset and gravure. From these, a preferable film forming method is selected according to the liquid viscosity and the wet thickness.

The viscosity of the dispersion of semiconductor fine particles greatly depends on the type and dispersibility of the semiconductor fine particles, the type of solvent used, and additives such as a surfactant and a binder. For a high viscosity liquid (for example, 0.01 to 500 Poise), an extrusion method, a casting method, a screen printing method, or the like is preferable. For a low-viscosity liquid (for example, 0.1 Poise or less), a slide hopper method, a wire bar method, or a spin method is preferable, and a uniform film can be formed. If a certain amount of coating is used, application by the extrusion method is possible even in the case of a low-viscosity liquid. Thus, the viscosity of the coating solution, the amount of coating, the support,
A wet film forming method may be appropriately selected according to the coating speed and the like.

The layer of semiconductor fine particles is not limited to a single layer, but a multi-layer coating of a dispersion of semiconductor fine particles having different particle diameters, or a coating layer containing semiconductor fine particles of different types (or different binders and additives) may be formed in multiple layers. It can also be applied. Multilayer coating is effective even when the film thickness is insufficient by one coating. The extrusion method or slide hopper method is suitable for multi-layer coating. In the case of multi-layer coating, multi-layer coating may be performed at the same time, or several to dozens of times may be sequentially applied. Furthermore, a screen printing method can also be preferably used in the case of successive coating.

In general, as the thickness of the semiconductor fine particle layer (same as the thickness of the photosensitive layer) becomes larger, the amount of the dye carried per unit projected area increases, so that the light capture rate increases, but the diffusion distance of generated electrons increases. Therefore, the loss due to charge recombination also increases. Therefore, the preferred thickness of the semiconductor fine particle layer is
It is 0.1-100 μm. When used in a photoelectrochemical cell, the thickness of the semiconductor fine particle layer is preferably 1 to 30 μm, and 2 to 25 μm.
Is more preferred. The coating amount per support 1 m ² of the semiconductor fine particles is preferably 0.5~400g, 5~100g is more preferable.

After applying the semiconductor fine particles on the conductive support, the semiconductor fine particles are brought into electronic contact with each other,
Heat treatment is preferably performed to improve the strength of the coating film and the adhesion to the support. A preferred heating temperature range is from 40 ° C to less than 700 ° C, more preferably from 100 ° C to 600 ° C. The heating time is about 10 minutes to 10 hours. When a support having a low melting point or softening point such as a polymer film is used, high-temperature treatment is not preferable because it causes deterioration of the support. It is preferable that the temperature be as low as possible from the viewpoint of cost. The lowering of the temperature can be attained by the above-mentioned combined use of semiconductor fine particles having a size of 5 nm or less, heat treatment in the presence of a mineral acid, and the like.

For the purpose of increasing the surface area of the semiconductor fine particles after the heat treatment, increasing the purity in the vicinity of the semiconductor fine particles, and increasing the efficiency of injecting electrons from the dye into the semiconductor particles, for example, chemical plating using an aqueous solution of titanium tetrachloride or trichloride. Electrochemical plating using an aqueous titanium solution may be performed.

The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. Therefore, the surface area in a state where the layer of semiconductor fine particles is coated on the support is preferably 10 times or more the projected area,
Further, it is preferably 100 times or more. The upper limit is not particularly limited, but is usually about 1000 times.

(3) Adsorption of Metal Complex Dye on Semiconductor Fine Particles The metal complex dye is adsorbed on the semiconductor fine particles by immersing a conductive support having a well-dried semiconductor fine particle layer in a solution of the metal complex dye. Alternatively, a method of applying a solution of the metal complex dye to the semiconductor fine particle layer can be used. In the former case, a dipping method, a dipping method, a roller method, an air knife method, or the like can be used. In the case of the immersion method, the adsorption of the metal complex dye may be performed at room temperature, or may be performed by heating and refluxing as described in JP-A-7-249790. The latter coating method includes a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, a spray method, and the like, and a printing method includes letterpress, offset, gravure, screen printing, and the like. The solvent can be appropriately selected according to the solubility of the metal complex dye. For example, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.), nitromethane, halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene) ), Ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N, N-
Dimethylformamide, N, N-dimethylacetamide, etc.),
N-methylpyrrolidone, 1,3-dimethylimidazolidinone,
3-methyloxazolidinone, esters (ethyl acetate,
Butyl acetate, etc.), carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone,
2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.) and mixed solvents thereof.

Regarding the viscosity of the solution of the metal complex dye, a high-viscosity liquid (eg, 0.01
~ 500 Poise), various printing methods other than the extrusion method are suitable, and low viscosity liquids (for example, 0.1 Poise or less)
In this case, a slide hopper method, a wire bar method or a spin method is suitable, and any of them can form a uniform film.

Thus, the viscosity of the coating solution of the metal complex dye was
The dye adsorption method may be appropriately selected according to the amount of application, the conductive support, the application speed, and the like. The time required for dye adsorption after coating should be as short as possible in consideration of mass production.

Since the presence of unadsorbed metal complex dye causes disturbance of device performance, it is preferable to remove the metal complex dye by washing immediately after adsorption. It is preferable to perform washing with a polar solvent such as acetonitrile and an organic solvent such as an alcohol solvent using a wet washing tank. In order to increase the amount of dye adsorbed,
It is preferable to perform a heat treatment before the adsorption. After the heat treatment, it is preferable that the dye be quickly adsorbed at a temperature of 40 to 80 ° C. without returning to room temperature in order to avoid the adsorption of water on the surface of the semiconductor fine particles.

The total amount of the metal complex dye used is preferably 0.01 to 100 mmol per unit surface area (1 m ² ) of the conductive support. The amount of the dye adsorbed on the semiconductor fine particles is preferably 0.01 to 1 mmol per 1 g of the semiconductor fine particles.
By setting the adsorption amount of the metal complex dye as described above, a sufficient sensitizing effect in the semiconductor can be obtained. In contrast,
If the amount of the dye is too small, the sensitizing effect becomes insufficient, and if the amount of the dye is too large, the dye not attached to the semiconductor floats,
This causes the sensitizing effect to be reduced.

In order to widen the wavelength range of photoelectric conversion as much as possible and to increase the conversion efficiency, two or more dyes can be mixed. In this case, it is preferable to select the dyes to be mixed and the ratio thereof so as to match the wavelength range and the intensity distribution of the light source. Specifically, the metal complex dye of the present invention is
It is possible to use more than one kind in combination, or to use the metal complex dye of the present invention in combination with a conventional metal complex dye and / or polymethine dye.

For the purpose of reducing the interaction between metal complex dyes such as association, a colorless compound may be co-adsorbed on the semiconductor fine particles. Examples of the hydrophobic compound to be co-adsorbed include a steroid compound having a carboxyl group (for example, chenodeoxycholic acid). Further, an ultraviolet absorber can be used in combination.

For the purpose of promoting the removal of excess metal complex dye, the surface of the semiconductor fine particles may be treated with amines after adsorbing the metal complex dye. Preferred amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine and the like. When these are liquids, they may be used as they are, or may be used after being dissolved in an organic solvent.

[C] Charge Transfer Layer The charge transfer layer is a layer having a function of replenishing the oxidized metal complex dye with electrons. Typical materials that can be used for the charge transfer layer include a liquid (electrolytic solution) in which a redox couple is dissolved in an organic solvent, a so-called gel electrolyte in which a liquid in which a redox couple is dissolved in an organic solvent is impregnated in a polymer matrix,
Molten salts containing a redox couple may be mentioned. Further, a solid electrolyte or a hole transporting material can be used.

The electrolyte used in the present invention preferably comprises an electrolyte, a solvent and an additive. As the electrolyte,
(a) I ₂ and an iodide (a metal iodide such as LiI, NaI, KI, CsI, CaI ₂ or an iodine salt of a quaternary ammonium compound such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc.) ), And (b) Br ₂ and bromide (LiBr, NaBr, KBr, CsBr, Ca
A metal bromide such as Br ₂ or a bromide salt of a quaternary ammonium compound such as tetraalkylammonium bromide or pyridinium bromide), and (c) ferrocyanate-ferricyanate or ferrocene-ferricinium ion. Metal complex, (d) sodium polysulfide,
Sulfur compounds such as alkylthiol-alkyldisulfide, (e) viologen dyes, hydroquinone-quinone and the like can be used. Among them, I ₂ and LiI or pyridinium iodide, electrolyte obtained by combining the iodine salt of imidazolium iodide quaternary ammonium compounds such as id are preferred. The above electrolytes may be used as a mixture. The electrolyte is EP718288, WO95 / 18456, J. Electrochem. Soc., Vo
l. 143, No. 10, 3099 (1996), Inorg. Chem., 35, 1168-
Salt in the molten state at room temperature (molten salt) described in 1178 (1996)
Can also be used. When a molten salt is used as an electrolyte, a solvent need not be used.

The preferred electrolyte concentration is 0.1 to 15M, more preferably 0.2 to 10M. Further, when adding iodine to the electrolyte, a preferable concentration of added iodine is 0.01 to 0.
5M.

As the solvent for the electrolyte, a compound which can exhibit excellent ionic conductivity because it has low viscosity and high ion mobility, or high dielectric constant and high effective carrier concentration, or both is used. It is desirable. Examples of such solvents include, for example, the following.

(A) Carbonates Esters such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dipropyl carbonate and the like are preferable.

(B) Lactones For example, γ-butyrolactone, γ-valerolactone, γ-
Caprylolactone, crotlactone, γ-caprolactone, δ-valerolactone and the like are preferred.

(C) Ethers For example, ethyl ether, 1,2-dimethoxyethane, diethoxyethane, trimethoxymethane, ethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, 1,3-dioxolan, 1,4-dioxane and the like are preferable.

(D) Alcohols Preferred are, for example, methanol, ethanol, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, polyethylene glycol monoalkyl ether, and polypropylene glycol monoalkyl ether.

(E) Glycols For example, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin and the like are preferable.

(F) Glycol ethers Preferred are, for example, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether and the like.

(G) Tetrahydrofurans For example, tetrahydrofuran, 2-methyltetrahydrofuran and the like are preferable.

(H) Nitriles Preferred are, for example, acetonitrile, glutarodinitrile, propionitrile, methoxyacetonitrile, benzonitrile and the like.

(I) Carboxylic esters Esters such as methyl formate, methyl acetate, ethyl acetate and methyl propionate are preferred.

(J) Phosphoric acid triesters Preferred are, for example, trimethyl phosphate, triethyl phosphate and the like.

(K) Heterocyclic compounds For example, N-methylpyrrolidone, 4-methyl-1,3-dioxane, 2-methyl-1,3-dioxolan, 3-methyl-2-oxazolidinone, 1,3-propanesal Ton, sulfolane and the like are preferred.

(L) Other aprotic organic solvents such as dimethyl sulfoxide, formamide, N, N-dimethylformamide, nitromethane, etc.
Water and the like are preferred.

Of these, carbonate-based, nitrile-based and heterocyclic compound-based solvents are preferred. These solvents may be used as a mixture of two or more as necessary.

In the present invention, J. Am. Ceram. Soc., 8
0 (12), 3157-3171 (1997).
Basic compounds such as butylpyridine, 2-picoline and 2,6-lutidine can also be added. A preferred concentration range when adding a basic compound is 0.05 to 2M.

The electrolyte may be gelled (solidified) by a method such as addition of a polymer or an oil gelling agent, polymerization of coexisting polyfunctional monomers, and crosslinking reaction with the polymer. In the case of gelation by adding a polymer, use {Polymer Electrolyte Reviews-1,2} (JR Mac
ELSEIVER APPLIED SCIE co-edited by CaLLum and CA Vincent
Although the compounds described in (NCE) can be used, it is particularly preferable to use polyacrylonitrile and polyvinylidene fluoride. When gelation is performed by adding an oil gelling agent, use J. Chem. Soc. Japan, Ind. Chem. Se.
c., 46, 779 (1943), J. Am. Chem. Soc., 111, 5542 (198
9), J. Chem. Soc., Chem. Commun., 1993, 390, Ange
w. Chem. Int. Ed. Engl., 35, 1949 (1996), Chem. Let.
t., 1996, 885, J. Chem. Soc., Chem. Commun., 545 (1
The compounds described in 997) can be used.
Among these, preferred are compounds having an amide structure in the molecular structure.

When a gel electrolyte is formed by polymerization of polyfunctional monomers coexisting in the electrolyte, a solution is prepared from the polyfunctional monomers, polymerization initiator, electrolyte and solvent,
Coating is performed on the dye-sensitized semiconductor fine particle layer (photosensitive layer 20) by a method such as a casting method, a coating method, a dipping method, and an impregnation method. FIG.
As shown in (2), it is preferable to fill the voids between the dye-sensitized semiconductor fine particles 21 with a sol-like electrolyte, form a sol-like electrolyte layer on the photosensitive layer 20, and then gel it by radical polymerization.

The polyfunctional monomer has an ethylenically unsaturated group.
It is preferably a compound having two or more, for example, divinylbenzene, ethylene glycol dimethacrylate,
Preferred are ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and the like.

The gel electrolyte may contain a monofunctional monomer in addition to the above polyfunctional monomer. Examples of the monofunctional monomer include esters or amides derived from acrylic acid or α-alkylacrylic acid (eg, methacrylic acid) (eg, N-iso-propylacrylamide, acrylamide, 2-acrylamido-2-methylpropanesulfone) Acid, acrylamidopropyltrimethylammonium chloride, methyl acrylate, hydroxyethyl acrylate, N-propyl acrylate, N-butyl acrylate, 2-methoxyethyl acrylate, cyclohexyl acrylate, etc.), vinyl esters (for example, vinyl acetate), maleic acid or fumaric acid (E.g., dimethyl maleate, dibutyl maleate, diethyl fumarate, etc.) and organic acid salts (e.g., maleic acid, fumaric acid, sodium salt of p-styrenesulfonic acid, etc.) Nitriles (acrylonitrile, methacrylonitrile, etc.), dienes (eg, butadiene, cyclopentadiene, isoprene, etc.), aromatic vinyl compounds (eg, styrene, p-chlorostyrene, sodium styrenesulfonate, etc.), and nitrogen-containing heterocycles Vinyl compounds having, quaternary ammonium salt-containing vinyl compounds, N-vinylformamide, N-vinyl-N-methylformamide, vinylsulfonic acid, sodium vinylsulfonate, vinylidene fluoride, vinylidene chloride,
Preferred are vinyl alkyl ethers (eg, methyl vinyl ether), olefins (ethylene, propylene, 1-butene, isobutene, etc.), N-phenylmaleimide, and the like. The ratio of polyfunctional monomer to total monomer is
It is preferably 0.5 to 70% by weight, more preferably 1.
0 to 50% by weight.

The above-mentioned monomers for gel electrolytes are described in Takatsu Otsu,
Masayoshi Kinoshita, "Experimental Methods for Polymer Synthesis" (Chemical Doujin)
Alternatively, it can be polymerized by a radical polymerization method, which is a general polymer synthesis method described in "Lecture Polymerization Theory 1 Radical Polymerization (I)" by Takatsu Otsu (Chemical Doujinshi).
The radical polymerization of the monomer for the gel electrolyte can be carried out by heating, light, ultraviolet rays, an electron beam or electrochemically, but it is particularly preferable to carry out the radical polymerization by heating.

When a crosslinked polymer is formed by heating, preferred polymerization initiators are, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2 Azo initiators such as 2,2'-azobis (2-methylpropionate) (dimethyl 2,2'-azobisisobutyrate), and peroxide initiators such as benzoyl peroxide. The preferable addition amount of the polymerization initiator is 0.01 to 20% by weight, more preferably 0.1 to 10% by weight, based on the total amount of the monomers.

The weight composition range of the monomers in the gel electrolyte is preferably from 0.5 to 70% by weight, more preferably from 1.0 to 50% by weight.

When the electrolyte is gelled by the crosslinking reaction of the polymer, it is desirable to use a polymer having a crosslinking reactive group and a crosslinking agent together. Preferred crosslinkable reactive groups are
It is a nitrogen-containing heterocyclic ring (for example, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a triazole ring, a morpholine ring, a piperidine ring, a piperazine ring, etc.), and a preferable crosslinking agent is capable of electrophilic reaction with a nitrogen atom. Reagents having two or more functionalities (eg, alkyl halides, aralkyl halides, sulfonic acid esters, acid anhydrides, acid chlorides, isocyanates, etc.).

Organic and / or inorganic hole transport materials can be used in place of the electrolyte. Preferred organic hole transporting materials for the present invention include the following.

(A) Aromatic amines N, N'-diphenyl-N, N'-bis (4-methoxyphenyl)-
(1,1′-biphenyl) -4,4′-diamine (J. Hagen et al.,
Synthetic Metal 89, 2153-220 (1997)), 2,2 ', 7,7'-
Tetrakis (N, N-di-p-methoxyphenylamine) 9,9'-
Spirobifluorene (Nature, Vol.395, 8 Oct. 1998,
pp. 583-585 and WO97 / 10617), 1,1-bis {4- (di-p
Aromatic diamine compound linked to a tertiary aromatic amine unit of (-tolylamino) phenyl} cyclohexane (JP-A-59-194393), 4,4'-bis [(N-1-naphthyl) -N-phenylamino] An aromatic amine containing two or more tertiary amines, such as biphenyl, in which two or more condensed aromatic rings are bonded to a nitrogen atom (JP-A-5-234681); (US Pat. No. 4,923,774, JP-A-4-30868)
No. 8), N, N'-diphenyl-N, N'-bis (3-methylphenyl)
Aromatic diamines such as-(1,1′-biphenyl) -4,4′-diamine (US Pat. No. 4,764,625), α, α, α ′, α′-tetramethyl-α, α′-bis (4 -Di-p-tolylaminophenyl) -p-
Xylene (JP-A-3-269084), p-phenylenediamine derivative, triphenylamine derivative whose whole molecule is sterically asymmetric (JP-A-4-129271), Compound in which pyrenyl group is substituted with a plurality of aromatic diamino groups (JP-A-4-175395
), Aromatic diamines having a tertiary aromatic amine unit linked by an ethylene group (Japanese Patent Laid-Open No. 4-264189), aromatic diamines having a styryl structure (Japanese Patent Laid-Open No. 4-290851), and benzylphenyl compounds (Japanese Patent Laid-Open No. -364153), 3 with fluorene group
Tertiary amine compound (JP-A-5-239455), pisdipyridylaminobiphenyl (JP-A-5-320634), N, N, N-triphenylamine derivative ( JP-A-6-1972), aromatic diamine having a phenoxazine structure (Japanese Patent Application No. 5-90728), diaminophenylphenanthridine derivative (Japanese Patent Application No. 6-45669)
No.) etc.

(B) Oligothiophene compounds α-octylthiophene and α, ω-dihexyl-α-octylthiophene (Adv. Mater., Vol. 9, No. 7, 5578 (19
97)), hexadodecyldodecithiophene (Angew. Chem.
Int. Ed. Engl., 34, No. 3, 303-307 (1995)), 2,8-dihexyl anthra [2,3-b: 6,7-b '] dithiophene (JACS, Vo
l.120, N0.4,664-672 (1998)).

(C) Conducting Polymer Polypyrrole (K. Murakoshi et al., Chem. Lett. 199
7, p.471), and polyacetylene and its derivatives,
Poly (p-phenylene) and its derivatives, poly (p-phenylenevinylene) and its derivatives, polythienylenevinylene and its derivatives, polythiophene and its derivatives, polyaniline and its derivatives, and polytoluidine and its derivatives (each a “Handbook” of Orga
nic Conductive Molecules and Polymers ", Vol. 1-4
(Written by NALWA, published by WILEY)).

Organic, hole-transporting materials include Nature,
Vol. 395, 8 Oct. 583-585 (1998).
To add a compound containing a cation radical such as (4-bromophenyl) aminium hexachloroantimonate, or to control the potential of the oxide semiconductor surface (compensate for the space charge layer), use Li [(CF ₃ SO ₂ ) ₂ N].

The organic hole transporting material can be introduced into the inside of the electrode by a method such as a vacuum evaporation method, a casting method, a coating method, a spin coating method, an immersion method, an electrolytic polymerization method, and a photoelectrolytic polymerization method. When a hole transport material is used in place of the electrolyte, use Electorochim. Acta 40, 643-65 to prevent short circuits.
2 (1995), it is preferable to apply a thin layer of titanium dioxide as an undercoat layer using a technique such as spray pyrolysis.

When an inorganic solid compound is used in place of the electrolyte, copper iodide (p-CuI) (J. Phys. D: Appl. Phys. 31, 1
492-1496 (1998)), copper thiocyanate (Thin Solid Film)
s 261 (1995), 307-310, J. Appl. Phys. 80 (8), 15 Oct.
ober 1996, 4749-4754, Chem. Mater. 1998, 10, 1501.
11509, SemiCond. Sci. Technol. 10, 1689-1693) and the like can be introduced into the electrode by a method such as a casting method, a coating method, a spin coating method, an immersion method, and an electrolytic plating method.

To form the charge transfer layer, the following two methods can be used. One is to attach a counter electrode via a spacer on the dye-sensitized semiconductor fine particle layer,
This is a method in which the open ends of both are immersed in an electrolyte solution to allow the electrolyte solution to penetrate into the semiconductor fine particle layer and the gap between the semiconductor fine particle layer and the counter electrode. The other is a method in which an electrolyte solution is applied to the semiconductor fine particle layer so that the electrolyte solution penetrates into the semiconductor fine particle layer, a charge transfer layer is formed on the semiconductor fine particle layer, and finally a counter electrode is provided.

In the former case, as a method for infiltrating the electrolyte solution into the gap between the semiconductor fine particle layer and the counter electrode, a normal pressure method utilizing capillary action, and an upper open end of the semiconductor fine particle layer and the counter electrode (dipping into the electrolyte solution). There is a decompression method that sucks from the open end that does not exist.

In the latter case, in the case of a wet type charge transfer layer, a counter electrode is provided in an undried state to take measures to prevent liquid leakage at the edge portion. In the case of a gel electrolyte, a counter electrode may be provided after being wet-coated and solidified by a method such as polymerization, or a solid may be provided after the counter electrode is provided. As a method of forming a layer of a wet organic hole transport material or a gel electrolyte in addition to the electrolytic solution, as in the case of forming a semiconductor fine particle layer and dye adsorption, a dipping method, a roller method, a dipping method, an air knife method, The extrusion method, slide hopper method, wire bar method, spin method, spray method, casting method, various printing methods and the like can be used. In the case of a solid electrolyte or a solid hole (hole) transport material, the charge transfer layer may be formed by a dry film forming process such as a vacuum evaporation method or a CVD method, and then a counter electrode may be provided.

In the case of an electrolyte which cannot be solidified or a wet hole transporting material, it is preferable to seal the edge portion immediately after application, and in the case of a solidifying hole transporting material, it is preferable to wet the hole transporting material by applying a wet type. After forming the hole transport layer, it is preferable to solidify the film by a method such as photopolymerization or thermal radical polymerization. As described above, the film application method may be appropriately selected depending on the physical properties of the electrolyte and the process conditions.

The amount of water in the charge transfer layer was 10,000 ppm.
The following is preferred, more preferably 2,000 ppm or less, and particularly preferably 100 ppm or less.

[D] Counter electrode The counter electrode functions as a positive electrode of a photoelectrochemical cell when the photoelectric conversion element is a photoelectrochemical cell. As the counter electrode, a substrate having a conductive layer can be used as in the case of the conductive support. However, the substrate is not necessarily required if a metal plate having sufficient strength and sealing property is used. As the conductive material used for the counter electrode, a metal (for example, platinum,
Gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or conductive metal oxide (indium-tin composite oxide, tin oxide doped with fluorine, etc.)
Is mentioned. An example of a preferred counter electrode is a metal or conductive metal oxide thin film applied or deposited on glass or plastic. The thickness of the counter electrode is not particularly limited,
3 nm to 10 μm is preferred. When the conductive layer is made of metal, its thickness is preferably 5 μm or less, more preferably in the range of 5 nm to 3 μm.

Since light may be irradiated from one or both of the conductive support and the counter electrode, at least one of the conductive support and the counter electrode must be substantially transparent in order for the light to reach the photosensitive layer. I just want it. From the viewpoint of improving power generation efficiency,
It is preferable that the conductive support is made transparent and light is incident from the conductive support side. In this case, the counter electrode preferably has a property of reflecting light. As such a counter electrode, glass or plastic on which a metal or a conductive oxide is deposited, or a metal thin film can be used.

The procedure for providing the counter electrode is as follows: (a) when the charge transfer layer is formed and then formed thereon; and (b) when the counter electrode is disposed on the layer of the dye-sensitized semiconductor fine particles via a spacer. Then, the space is filled with an electrolyte solution and crosslinked. In the case of (a), a conductive material is applied directly on the charge transfer layer, plated or deposited (PVD, CVD), or
The conductive layer side of a substrate having a conductive layer is attached. Also (b)
In the case of, a counter electrode is assembled and fixed via a spacer on the dye-sensitized semiconductor fine particle layer, the open end of the obtained assembly is immersed in an electrolyte solution, and the dye-sensitized semiconductor The electrolyte solution is permeated into the space between the fine particle layer and the counter electrode, and then crosslinked by heating.

[E] Other Layers A functional layer such as a protective layer or an antireflection film may be provided on one or both of the conductive support serving as an electrode and the counter electrode. When such a functional layer is formed in multiple layers, a simultaneous multilayer coating method or a sequential coating method can be used, but from the viewpoint of productivity, the simultaneous multilayer coating method is preferable. In the simultaneous multi-layer coating method, a slide hopper method or an extrusion method is suitable in consideration of productivity and uniformity of a coating film. In forming these functional layers, an evaporation method, a sticking method, or the like can be used depending on the material.

Further, a layer having other necessary functions such as a protective layer and an antireflection film can be provided on the conductive support or the counter electrode of the working electrode. When such layers are multi-layered to separate functions, simultaneous multi-layer coating or sequential coating can be performed, but simultaneous multi-layer coating is more preferable in terms of productivity. In the simultaneous multi-layer coating, the slide hopper method and the extrusion method are suitable in consideration of productivity and uniformity of film formation. Further, these functional layers can be provided by a technique such as vapor deposition or pasting depending on the material.

[3] Photoelectrochemical Battery The photoelectrochemical battery of the present invention is one in which the photoelectric conversion element is made to work in an external circuit. It is preferable that the side surface of the photoelectrochemical cell is sealed with a polymer, an adhesive, or the like in order to prevent deterioration of components and volatilization of the contents. The external circuit itself connected to the conductive support and the counter electrode via a lead may be a known one.

[0150]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 Synthesis of Metal Complex Dyes D-1, D-8, D-2, D-9, D-3, D-10, D-42 and D-48 Metal Complex Dyes D-1, D The production methods and structural formulas of -8, D-2, D-9, D-3, D-10, D-42 and D-48 are as follows.
However, the carboxylate ions in the metal complex dyes D-8, D-9, D-10, and D-48 are in equilibrium with the state in which the proton is not dissociated (carboxyl group), and the corresponding counter ion The structure of CI also changes.

[0152]

Embedded image

[0153]

Embedded image

[0154]

Embedded image

[0155]

Embedded image

1. Synthesis of D-1 and D-8 10.44 g (40 mmol) of ruthenium (III) chloride trihydrate was dissolved in 50 ml of dimethyl sulfoxide (DMSO) and refluxed for 5 minutes. After concentration to 25 ml, 200 ml of acetone was added, and after cooling to room temperature, the crystals were separated by filtration, washed with acetone and ether,
13.9 g (yield: 72%) of yellow crystals of Ru complex 1 were obtained.

0.87 g (1.8 mmol) of Ru complex 1 and 0.54
g (1.8 mmol) of diethyl bipyridinedicarboxylate L-14
Was dissolved in 5 ml of chloroform and refluxed in a nitrogen atmosphere for 4 hours. After concentration, a small amount of acetone was added to dissolve, and then ether was added to precipitate crystals. After filtration and washing with ether, 0.85 g (yield 75%) of yellow crystals of Ru complex 3 was obtained.

0.166 g (0.264 mol) of Ru complex 2 and 0.0
50 g (0.29 mmol) of sodium hydroxamate 3 is dissolved in a mixed solvent consisting of 10 ml of ethanol and 10 ml of water,
Refluxed in a nitrogen atmosphere for 2 hours. 0.028g (0.12m
mol) of dipyridylpyrazine BL-1 and refluxed for 20 hours. 0.20 g of NH ₄ PF ₆ was added and concentrated, and the precipitated crystals were separated by filtration and washed with water. Sephadex column LH-20
(Developing solvent: methanol) to give 0.18 g (yield 92%) of black crystals of D-1. The structure of the black crystal D-1 is M
Confirmed by S spectrum and elemental analysis.

A mixture of 0.081 g (0.05 mmol) of D-1, 6 ml of triethylamine, 18 ml of dimethylformamide and 3 ml of water was refluxed for 12 hours. After concentration, the crystals were dissolved in acetonitrile and separated by filtration to obtain 0.06 g (yield: 85%) of black crystals D-8. The structure of the black crystal D-8 was confirmed by MS spectrum and elemental analysis.

2. Synthesis of D-2, D-9 In the synthesis of D-1 and D-8 in Step 1 above, potassium oxalate 4 was used in equimolar amount instead of sodium hydroxamate 3 and NH ₄ PF ₆ was not added. Synthesized D-2 and D-9 in exactly the same manner. The structure of D-2 and D-9 is M
Confirmed by S spectrum and elemental analysis.

[0161] 3. Synthesis of D-3 and D-10 D-3 and D-8 were synthesized in exactly the same manner as in the synthesis of D-1 and D-8 in Step 1 except that sodium dithiocarbamate 5 was used in equimolar amount instead of sodium hydroxamate 3. D
-10 was synthesized. The structures of D-3 and D-10 were confirmed by MS spectrum and elemental analysis.

4. Synthesis of D-42 and D-48 In place of dipyridylpyrazine BL-1 in the synthesis of 2,
D-42 and D-48 were synthesized in exactly the same manner except that BL-11 synthesized according to the method described in J. Am. Chem. Soc., 109 , 2691 (1987) was used in an equimolar amount. The structures of D-42 and D-48 were confirmed by MS spectrum and elemental analysis.

5. Synthesis of Other Metal Complex Dyes In the same manner as described above, other metal complex dyes are represented by X ₁ and X ₂ (X-
1 to X-48), BL (BL- _{1 to} BL-34) and LL ₁ and LL
₂ It was synthesized by appropriately combining the specific examples of (L-1 to L-50). The compounds of the ligands X ₁ and X ₂ can be easily obtained from commercial products, or Inorg. Chim. Acta., 206 , 69 (1993),
Inorg. Chem., 29 , 1888 (1990), J. Am. Chem. Soc., 1
09 , 2691 (1987), Inorg.Chem., 29 , 4750 (1990), Inor
g. Chem., 28 , 1520 (1989), Inorg. Chem., 29 , 167 (199
0), Inorg. Chem., 28 , 2465 (1989), or the literature cited therein. The introduction of a substituent such as a carboxyl group into these ligands can be achieved by a general organic synthesis method.

6. Measurement of absorption spectra Measure absorption spectra in methanol for D-8, D-9, D-10, D-11, D-47, D-48, D-49 and D-50 and comparative dyes 1 and 2. did. Table 1 shows the absorption maximum wavelength.

[0165]

[Table 1]

As is clear from Table 1, the maximum absorption wavelength of the metal complex dye of the present invention was longer than those of Comparative Dyes 1 and 2. Therefore, it is very preferable to use the metal complex dye of the present invention in a photoelectrochemical cell because it can spectrally sensitize even longer wavelength light and convert it into a photocurrent.

Embodiment 2 1. Preparation of Titanium Dioxide Dispersion 15 g of titanium dioxide fine particles (Degussa P-25, manufactured by Nippon Aerosil Co., Ltd.), 45 g of water and a dispersant (Aldrich, Triron X- 100) 1 g and 30 g of zirconia beads (manufactured by Nikkato) having a diameter of 0.5 mm are put in, and 1500 rpm using a sand grinder mill (manufactured by Imex).
For 2 hours. The zirconia beads were separated by filtration from the obtained dispersion. The average particle size of the titanium dioxide fine particles in the obtained dispersion was 2.5 μm. The particle size is MALVERN
It was measured by a master sizer manufactured by the company.

[0168] 2. Preparation of Electrode Layer Consisting of Titanium Dioxide Fine Particles Adsorbing Dye A conductive glass plate (manufactured by Nippon Sheet Glass Co., Ltd., surface resistance: about 10 Ω / cm ² ) coated with fluorine-doped tin oxide is prepared, and the conductive layer is prepared. Using a doctor blade on top, apply the titanium dioxide dispersion to a thickness of 140 μm (wet thickness),
Dry at 25 ° C. for 30 minutes. Next, this semiconductor-coated glass plate was placed in an electric furnace (muffle furnace FP-32, manufactured by Yamato Scientific Co., Ltd.) and baked at 450 ° C. for 30 minutes. The thickness of the titanium dioxide fine particle layer is 10 μm, and the coating amount of the titanium dioxide fine particles is 15 μm.
g / m ² .

After taking out the semiconductor-coated glass plate and cooling it, a methanol solution of the dye shown in Table 1 (concentration: 3 × 10 ^-4)
mol / L) for 3 hours. The semiconductor-coated glass plate on which the dye was adsorbed was immersed in 4-tert-butylpyridine for 15 minutes, washed with methanol, and air-dried. The adsorption amount of the metal complex dye in the dye-sensitized titanium dioxide fine particle layer thus obtained is 0.1 to 10 mmol / m ² depending on the type thereof.
Was within the range.

[0170] 3. Preparation of photoelectrochemical cell An electrode (2 cm × 2 cm) made of the dye-sensitized TiO ₂ fine particles prepared as described above is superimposed on the platinum-deposited layer side of a platinum-deposited glass plate of the same size via a spacer. (See FIG. 2). The open end of the assembly comprising the obtained conductive glass plate / dye-sensitized semiconductor fine particle layer / platinum-deposited glass plate was placed in an electrolyte (N-methyl-2-oxazolidinone) with a supporting electrolyte (1-butyl-3-methylimidazolium). Iodide) 0.65mol
/ L, 0.05 mol / L of iodine), and the electrolyte was impregnated into the gaps between the two glass plates by utilizing the capillary phenomenon and introduced into the dye-sensitized TiO ₂ layer. In this manner, a laminated structure of the conductive glass plate 10 / the photosensitive layer 20 in which the electrolyte is impregnated in the voids of the dye-sensitized TiO ₂ fine particle layer / the charge transfer layer 30 / the platinum-deposited glass plate 40 (see FIG. 1) Was obtained. This process was repeated using the other dyes shown in Table 2.

[0171] 4. Measurement of Photoelectric Conversion Efficiency The photoelectric conversion efficiency at 800 nm of the obtained photoelectrochemical cell was measured using an IPCE (Incident Photon to Current C) manufactured by Optel.
onversion Efficiency). Table 2
Table 1 summarizes the photoelectric conversion efficiency of each metal complex dye.

[0172]

[Table 2]

From Table 2, it can be seen that the comparative dye does not exhibit photoelectric conversion ability for light having a wavelength of 800 nm because it has no absorption ability, whereas the metal complex dye of the present invention exhibits good photoelectric conversion ability. It turns out that it shows. Thus, all of the dyes of the present invention have high photoelectric conversion ability not only in visible light but also in infrared region.

[0174]

As described in detail above, the metal complex dye of the present invention has good light absorption in a wide wavelength range from visible light to infrared light, and therefore contains semiconductor fine particles adsorbing such a metal complex dye. The photoelectric conversion element has high photoelectric conversion characteristics over a range from visible light to infrared light. A photoelectrochemical cell comprising such a photoelectric conversion element is extremely effective as a solar cell.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a structure of a photoelectric conversion device according to a preferred embodiment of the present invention.

FIG. 2 is a partial cross-sectional view illustrating a structure of a photoelectrochemical cell according to another preferred embodiment of the present invention.

[Explanation of symbols]

 10: conductive support 11: substrate 12: conductive layer 20: photosensitive layer 21: semiconductor fine particles 22: metal complex dye 30: gel electrolyte layer 40: counter electrode 41 ・ ・ ・ Substrate 42 ・ ・ ・ Conductive layer

Claims (18)

[Claims] [Claim 1] The following general formula (I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI (I) M ₁ and M ₂ each represent a metal atom; BL represents a ligand having two or more sites capable of bidentate nitrogen with respect to the metal atom; X ₁ and X ₂ each independently represent an acyloxy group Oxalylene group, acylthio group, thioacyloxy group, thioacylthio group, acylaminooxy group, thiocarbamate group, dithiocarbamate group, thiocarbonate group, dithiocarbonate group, trithiocarbonate group, acyl group, carbonyl group, thiocyanate A monodentate coordinated with a group selected from the group consisting of a group, an isothiocyanate group, a cyanate group, an isocyanate group, a halogen atom, a cyano group, an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group. Or LL1 and LL2 independently represent a bidentate ligand or a bidentate or bidentate ligand composed of a dialkyl ketone or a carbonamide, wherein LL ₁ and LL ₂ each independently represent the following general formula (II): (However, Za and Zb each independently represent a non-metallic atom group necessary for completing a 5- or 6-membered ring), and m1 and m4 each independently represent 0. or a 1, m2 and m3 each independently represents an 1-4 integer, when m2 or m3 is 2 or more, X ₁ or X ₂ may be the same or different and each also X ₁ s or X _{The two} may be linked to each other, and CI represents a counter ion when a counter ion is required to neutralize the charge. A photoelectric conversion element comprising semiconductor fine particles sensitized by a metal complex dye represented by the formula (1). 2. The photoelectric conversion device according to claim 1, wherein M ₁ and M ₂ in the general formula (I) are each independently Ru, F
e, Os, Cu, W, Cr, Mo, Ni, Pd, Pt, Co, Ir, Rh, R
e, Mn or Zn. 3. The photoelectric conversion device according to claim 2, wherein M ₁ and M ₂ in the general formula (I) are each independently Ru, F
A photoelectric conversion element characterized by being e, Os or Cu. 4. The photoelectric conversion device according to claim 3, wherein M ₁ and M ₂ in the general formula (I) are Ru. 5. The photoelectric conversion device according to claim 1, wherein, in the general formula (II) of LL ₁ and LL ₂ , the ring formed by Za or Zb is a pyridine ring, a pyrimidine ring, Pyrazine ring, pyridazine ring, pyrazole ring, imidazole ring, triazole ring, thiazole ring, oxazole ring, benzimidazole ring, benzotriazole ring,
A photoelectric conversion element, which is at least one selected from the group consisting of a benzoxazole ring and a benzothiazole ring. 6. The photoelectric conversion device according to claim 1, wherein the ligand BL is represented by the following general formula (III-1):
(III-3): (However, Zc, Zd, Ze and Zf each independently represent a group of nonmetallic atoms required to complete a 5- or 6-membered ring, and n1
Represents 0 or 1. A photoelectric conversion element represented by any one of the above. 7. The photoelectric conversion device according to claim 6, wherein Ze or Zf forms a pyrazine ring. 8. The photoelectric conversion device according to claim 1, wherein the ligand BL has the following general formula B-1 to B-1
0: embedded image (However, R _{21 to} R ₃₀ each independently represent a substituent, and B-
1 to B-10 may be bonded to any ring carbon atom,
e, f, g, h, j, k and q are each independently 0 to
Represents an integer of 8, p and r each independently represent an integer of 0 to 6, and s represents an integer of 0 to 4. A photoelectric conversion element represented by any one of the above. 9. The photoelectric conversion device according to claim 8, wherein R in the ligand BL represented by the general formulas B-1 to B-10.
_{21 to} R ₃₀ are each independently an alkyl group, an alkenyl group,
A photoelectric conversion element, which represents an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, a phosphoryl group, a phosphonyl group, or a halogen atom. 10. The photoelectric conversion device according to claim 8, wherein the ligand BL is represented by the following general formulas B-1 to B-4: (However, R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ each independently represent an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, a phosphoryl group, Represents a phosphonyl group or a halogen atom, and may be bonded to any ring carbon atom of B-1 to B-4, and e, f, g and h each independently represent an integer of 0 to 8.) A photoelectric conversion element, which is a ligand represented by any of the above. 11. The photoelectric conversion device according to claim 1, wherein LL ₁ and LL _{2 in} the metal complex dye of the general formula (I) are each independently the following general formula (IV-1) or (IV-
2): embedded image (However, R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, R ₃ and R ₄ each independently represent hydrogen, an alkyl group or an aryl group, and a and b each independently represent 0. Represents an integer of ~ 4, and c and d each independently represent 0 ~
Represents an integer of 2, R ₁ and R ₂ , R ₃ and R ₄ , R ₃ and R ₅ and R ₄ and R ₆
May be connected to each other to form a ring. )
A photoelectric conversion element represented by: 12. The photoelectric conversion device according to claim 11,
R ₁ , R ₂ , R ₅ and R _{6 in the} general formula (IV-1) or (IV-2) each independently represent an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl A photoelectric conversion element, which represents a group, a carboxyl group, a sulfonic group, a phosphoryl group, a phosphonyl group or a halogen atom. 13. The photoelectric conversion device according to claim 1, wherein X ₁ and X ₂ in the general formula (I) are each independently a dithiocarbamate group, an acylaminooxy group,
Acyloxy group, oxalylene group, isocyanate group,
A photoelectric conversion element, which is a cyanate group, an isothiocyanate group, a thiocyanate group, an alkylthio group, or an arylthio group. 14. The photoelectric conversion device according to claim 1, wherein the metal complex dye represented by the general formula (I) has at least one acidic group. 15. The photoelectric conversion device according to claim 1, wherein the semiconductor fine particles are titanium oxide fine particles. A photoelectrochemical cell using the photoelectric conversion element according to any one of claims 1 to 15. 17. The following general formula (I): (LL ₁ ) _m1 (X ₁ ) _m2 M ₁ (BL) M ₂ (X ₂ ) _m3 (LL ₂ ) _m4 · CI (I) M ₁ and M ₂ each represent a metal atom capable of 4 or 6 coordination, and BL represents the following general formulas B-1 to B-10: (However, R _{21 to} R ₃₀ each independently represent a substituent, and B-
1 to B-10 may be bonded to any ring carbon atom,
e, f, g, h, j, k and q are each independently 0 to
Represents an integer of 8, p and r each independently represent an integer of 0 to 6, and s represents an integer of 0 to 4. X ₁ and X ₂ are each independently an acyloxy group, an oxalylene group, an acylthio group, a thioacyloxy group, a thioacylthio group, an acylaminooxy group, a thiocarbamate group, a dithiocarbamate group, a thiocarbonate group From a dithiocarbonate group, a trithiocarbonate group, an acyl group, a carbonyl group, a thiocyanate group, an isothiocyanate group, a cyanate group, an isocyanate group, a halogen atom, a cyano group, an alkylthio group, an arylthio group, an alkoxy group and an aryloxy group A monodentate or bidentate ligand coordinated by a group selected from the group consisting of, or a monodentate or bidentate ligand composed of dialkyl ketone or carbonamide, and LL ₁ and LL ₂ are each independently The following general formula (IV-1) or
(IV-2): (However, R ₁ , R ₂ , R ₅ and R ₆ each independently represent a substituent, R ₃ and R ₄ each independently represent hydrogen, an alkyl group or an aryl group, and a and b each independently represent 0. Represents an integer of ~ 4, and c and d each independently represent 0 ~
Represents an integer of 2, R ₁ and R ₂ , R ₃ and R ₄ , R ₃ and R ₅ and R ₄ and R ₆
May be connected to each other to form a ring. )
Wherein m1 and m4 are each independently 0 or 1, m2 and m3 each independently represent an integer of 1 to 4, and when m2 or m3 is 2 or more, X ₁ or X ₂ may be the same or different, and X ₁ or X ₂ may be linked to each other, and CI represents a counter ion when a counter ion is required to neutralize the charge . A metal complex dye represented by the formula: 18. The metal complex dye according to claim 17, wherein M ₁ and M ₂ are each Ru, and X ₁ and X ₂ are each independently a dithiocarbamate group, an acylaminooxy group, an acyloxy group, an oxalylene group. Represents a monodentate or bidentate ligand coordinated by a group selected from the group consisting of isocyanate group, cyanate group, isothiocyanate group, thiocyanate group, alkylthio group and arylthio group, and BL represents the following general formula B- 1 to B-4: (However, R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ each independently represent an alkyl group, an alkenyl group, an aryl group, a hydroxyl group, an alkoxy group, an amino group, an alkoxycarbonyl group, a carboxyl group, a sulfonic acid group, a phosphoryl group, Represents a phosphonyl group or a halogen atom, and may be bonded to any ring carbon atom of B-1 to B-4, and e, f, g and h each independently represent an integer of 0 to 8.) A metal complex dye, which is a ligand represented by any of the above.