JP2005132914A - Photoelectric conversion material, semiconductor electrode and photoelectric converter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric converter excellent in photoelectric conversion characteristics. <P>SOLUTION: The photoelectric conversion material uses a compound represented by general formula (1). In the formula R<SB>1</SB>, R<SB>2</SB>and R<SB>3</SB>indicate each a hydrogen atom, alkyl, aralkyl, alkenyl, alkoxy, alkylthio, di-substituted amino, halogen atom, aryl or hetero ring, and R<SB>1</SB>and R<SB>2</SB>, and R<SB>2</SB>and R<SB>3</SB>, each bonded together, may form a cyclic structure. R<SB>4</SB>indicates a linking group combining a 5-membered hetero ring and A1 ring, R<SB>5</SB>indicates a hydrogen atom or alkyl, and X<SB>1</SB>indicates an oxygen atom, sulfur atom or substituted amino. X<SB>2</SB>and X<SB>3</SB>indicate each an oxygen atom, sulfur atom, nitrogen atom, alkylene, substituted amino, carbonyl, sulfonyl or thiocarbonyl. The A1 ring indicates an aliphatic condensed ring, aromatic condensed ring or hetero ring. The sign n1 indicates an integer of 0-3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photoelectric conversion element using any one of the dyes represented by the general formulas (1) to (3) as a photoelectric conversion material.

Global warming due to the increase in CO ₂ concentration caused by the use of a large amount of fossil fuel, and the increase in energy demand accompanying population increase are recognized as problems related to the existence of human beings. For this reason, in recent years, the use of sunlight that is infinite and does not generate harmful substances has been energetically studied. What is currently put into practical use as sunlight, which is a clean energy source, includes residential single crystal silicon, polycrystalline silicon, amorphous silicon, and inorganic solar cells such as cadmium telluride and indium copper selenide.

  However, these inorganic solar cells also have drawbacks. For example, a silicon system is required to have a very high purity. Naturally, the purification process is complicated, the number of processes is large, and the manufacturing cost is high. In addition, there is a demand for weight reduction and the like, and in particular, it is disadvantageous in that payback to the user is long, and there is a problem in the spread.

  On the other hand, many solar cells using organic materials have been proposed. As an organic solar cell, a Schottky photoelectric conversion element that joins a p-type organic semiconductor and a metal having a low work function, a p-type organic semiconductor and an n-type inorganic semiconductor, or a p-type organic semiconductor and an electron-accepting organic compound are joined. There are heterojunction photoelectric conversion elements and the like, and organic semiconductors used are synthetic dyes and pigments such as chlorophyll and perylene, conductive polymer materials such as polyacetylene, or composite materials thereof. These are thinned by a vacuum deposition method, a casting method, a dipping method, or the like to form a battery material. The organic material has advantages such as low cost and easy area enlargement, but there are many problems that the conversion efficiency is as low as 1% or less and the durability is poor.

  Under such circumstances, a solar cell exhibiting good characteristics has been reported by Dr. Gretzell of Switzerland (see Non-Patent Document 1). This document also discloses materials and manufacturing techniques necessary for battery fabrication. The proposed battery is called a dye-sensitized solar cell or a Gretzel solar cell, and is a wet solar cell using a titanium oxide porous thin film spectrally sensitized with a ruthenium complex as a working electrode. The advantage of this method is that it is not necessary to purify an inexpensive oxide semiconductor such as titanium oxide to high purity, and therefore, it is inexpensive and more usable light extends over a wide visible light region, and the solar light with many visible light components. It is that light can be effectively converted into electricity.

On the other hand, ruthenium complexes with limited resources are used, so when this solar cell is put to practical use, the supply of ruthenium complexes is in danger. Moreover, since this ruthenium complex is expensive, this problem can be solved if it can be changed to an inexpensive organic dye. Merocyanine dyes, cyanine dyes, and 9-phenylxanthene dyes have been reported as dyes for this battery (see, for example, Patent Documents 1 to 3). However, these dyes have low adsorption to titanium oxide and have not yet achieved a high sensitizing effect, and also have problems with stability over time.
JP 11-238905 A JP 2001-76773 A Japanese Patent Laid-Open No. 10-92477 Nature, 353,737 (1991)

  An object of the present invention is to provide a high-performance photoelectric conversion element.

  As a result of intensive studies to achieve the above object, the present inventors were able to achieve the target by using at least one of the dyes represented by the general formulas (1) to (3) as a photoelectric conversion material.

In the general formula (1), R ₁ , R ₂ , and R ₃ represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group, and a heterocyclic ring, It may have a substituent. Further, R ₁ and R ₂ , R ₂ and R ₃ may be bonded to each other to form a cyclic structure. R ₄ represents a linking group that binds the hetero 5-membered ring to the A1 ring, and may have a substituent. R ₅ represents a hydrogen atom or an alkyl group, and may have a substituent. X ₁ represents an oxygen atom, a sulfur atom, or a substituted amino group. X ₂ and X _{3 each} represents an oxygen atom, a sulfur atom, a nitrogen atom, an alkylene group, a substituted amino group, a carbonyl group, a sulfonyl group or a thiocarbonyl group, which may be the same or different and have a substituent. May be. Ring A1 represents an aliphatic condensed ring, an aromatic condensed ring, or a heterocyclic ring. n1 represents an integer of 0 to 3.

In the general formula (2), R ₆ , R ₇ and R ₈ represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group, and a heterocyclic ring, It may have a substituent. R ₆ and R ₇ , R ₇ and R ₈ may be bonded to each other to form a cyclic structure. R ₉ represents a linking group that binds the hetero 5-membered ring and the B1 ring, and may have a substituent. R ₁₀ represents a hydrogen atom or an alkyl group, and may have a substituent. X ₄ represents an oxygen atom, a sulfur atom, or a substituted amino group. X ₅ represents a hydrogen atom or an aryl group, and may have a substituent. X ₆ represents a methine group or a substituted amino group. X ₇ represents an oxygen atom, a sulfur atom or a substituted amino group. Ring B1 represents a heterocycle. n2 represents an integer of 0 to 3.

In the general formula (3), R ₁₁ , R ₁₂ and R _{13 each} represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group, or a heterocyclic ring. It may have a substituent. Further, R ₁₁ and R ₁₂ , R ₁₂ and R ₁₃ may be bonded to each other to form a cyclic structure. R ₁₄ represents a linking group that binds the hetero 5-membered ring and the C1 ring, and may have a substituent. R ₁₇ represents a hydrogen atom or an alkyl group, and may have a substituent. R ₁₅ and R _{16 each} represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a heterocyclic ring or a halogen atom. X ₈ represents an oxygen atom, a sulfur atom, or a substituted amino group. X ₉ represents a substituted amino group, an oxygen atom, a sulfur atom, a carbonyl group, a dicyanomethylene group, or a bis (alkoxycarbonyl) methylene group. Ring C1 represents an aliphatic condensed ring, an aromatic condensed ring, or a heterocyclic ring. n3 represents an integer of 0 to 3.

  By using the photoelectric conversion materials of the general formulas (1) to (3) used in the present invention, a photoelectric conversion element exhibiting excellent conversion efficiency can be obtained.

Here, specific examples of R ₁ , R ₂ , R ₃ , R ₆ , R ₇ , R ₈ , R ₁₁ , R ₁₂ , R ₁₃ are alkyl groups such as hydrogen atom, methyl group, ethyl group, isopropyl group, etc. Aralkyl groups such as benzyl group and 1-naphthylmethyl group, alkenyl groups such as vinyl group, diphenylvinyl group and cyclohexenyl group, alkoxy groups such as methoxy group, ethoxy group and n-hexyloxy group, methylthio group, n- Alkylthio groups such as hexylthio group, disubstituted amino groups such as dimethylamino group and N-methyl-N-phenylamino group, halogen atoms such as chlorine atom and bromine atom, aryl groups such as phenyl group and 1-naphthyl group, furyl And heterocycles such as a group, thienyl group and indolyl group. R ₁ , R ₂ , R ₃ , R ₆ , R ₇ , R ₈ , R ₁₁ , R ₁₂ , R ₁₃ may have a substituent. Specific examples of the substituent include those described above. An alkyl group, the above alkoxy group, the above alkylthio group, an phenoxy group, an aryloxy group such as a 4-tolyloxy group, an arylthio group such as a phenylthio group, the above halogen atom, the above disubstituted amino group, the above aryl group, Heterocycle described above, carboxyalkyl group such as carboxymethyl group, sulfonylalkyl group such as sulfonylpropyl group, acidic group such as carboxyl group, sulfonic acid group, phosphoric acid group, hydroxamic acid group, cyano group, nitro group, trifluoro Mention may be made of electron-withdrawing groups such as methyl groups. The acidic group may be in the form of a quaternary ammonium salt, metal salt, ester or amide. R ₁ and R ₂ , R ₂ and R ₃ , R ₆ and R ₇ , R ₇ and R ₈ , R ₁₁ and R ₁₂ , R ₁₂ and R ₁₃ may be bonded together to form a cyclic structure. More specifically, the structures shown in (A-01) to (A-22) can be given. Specific examples of R ₅ , R ₁₀ and R ₁₇ include a hydrogen atom and the above-described alkyl group, which may have a substituent. Specific examples of the substituent include the above alkyl group, the above alkoxy group, the above alkylthio group, the above aryloxy group, the above arylthio group, the above halogen atom, the above disubstituted amino group, and the above aryl. A group, the above-mentioned heterocycle, the above-mentioned carboxyalkyl group, the above-mentioned sulfonylalkyl group, the above-mentioned acidic group, and the above-mentioned electron-withdrawing group. The acidic group may be in the form of a quaternary ammonium salt, metal salt, ester or amide. Specific examples of R ₄ , R ₉ and R ₁₄ include those shown in (E-01) to (E-37). Specific examples of X ₁ , X ₄ and X ₈ include an oxygen atom, a sulfur atom and a substituted amino group. Specific examples of X ₂ and X ₃ include oxygen atom, sulfur atom, nitrogen atom, methylene group, 1,2-ethylene group, 1,1-vinylidene group and other alkylene groups, the above substituted amino group, carbonyl group, A sulfonyl group and a thiocarbonyl group can be shown, and may be the same or different, and may have a substituent. Specific examples of the substituent include the above alkyl group, the above alkoxy group, the above alkylthio group, the above aryloxy group, the above arylthio group, the above halogen atom, the above disubstituted amino group, and the above aryl. A group, the above-mentioned heterocycle, the above-mentioned carboxyalkyl group, the above-mentioned sulfonylalkyl group, the above-mentioned acidic group, and the above-mentioned electron-withdrawing group. The acidic group may be in the form of a quaternary ammonium salt, metal salt, ester or amide. Specific examples of the A1 ring include the structures shown in (B-01) to (B-63). Specific examples of X ₅ include a hydrogen atom and the above-described aryl group, which may have a substituent. Specific examples of the substituent include the above alkyl group, the above alkoxy group, the above alkylthio group, the above aryloxy group, the above arylthio group, the above halogen atom, the above disubstituted amino group, and the above aryl. A group, the above-mentioned heterocycle, the above-mentioned carboxyalkyl group, the above-mentioned sulfonylalkyl group, the above-mentioned acidic group, and the above-mentioned electron-withdrawing group. The acidic group may be in the form of a quaternary ammonium salt, metal salt, ester or amide. X ₆ can include a methine group, a nitrogen atom, and the above-described substituted amino group. X ₇ can include an oxygen atom, a sulfur atom, and the above-described substituted amino group. Specific examples of the ring B1 include the structures shown in (C-01) to (C-15). Specific examples of R ₁₅ and R ₁₆ include a hydrogen atom, the above alkyl group, the above alkoxy group, the above aryl group, the above heterocycle, and the above halogen atom. Specific examples of X ₈ include an oxygen atom, a sulfur atom, and the above-described alkyl group. Specific examples of X ₉ include the above-mentioned substituted amino group, oxygen atom, sulfur atom, carbonyl group, dicyanomethylene group, and the above-mentioned bis (alkoxycarbonyl) methylene group. Specific examples of the ring C1 include the structures shown in (D-01) to (D-18).

  Next, specific examples of the photoelectric conversion material of the present invention represented by the general formula (1) are shown in (F-01) to (F-24), and the photoelectric conversion material of the present invention represented by the general formula (2). (G-01) to (G-08)) and specific examples of the photoelectric conversion material of the present invention represented by the general formula (3) are shown in (H-01) to (H-13). However, it is not limited to these.

  The photoelectric conversion element of the present invention comprises a conductive support, a semiconductor layer sensitized by a dye placed on the conductive support, a charge transfer layer, and a counter electrode. The photosensitive layer may be a single layer structure or a stacked structure, and is designed according to the purpose. In addition, at the boundary of this element such as the boundary between the conductive layer and the photosensitive layer of the conductive support, the boundary between the photosensitive layer and the moving layer, the constituent components of each layer may be diffused or mixed with each other.

  As the conductive support, there can be used a glass or plastic support having a conductive layer containing a conductive agent on the surface thereof, such as a metal having a conductive property in itself. In the latter case, the conductive agent is a metal oxide such as platinum, gold, silver, copper, aluminum or the like, carbon or indium-tin composite oxide (hereinafter abbreviated as “ITO”), fluorine-doped tin oxide or the like. (Hereinafter abbreviated as “FTO”) and the like. The conductive support preferably has a transparency that transmits light of 10% or more, and more preferably transmits 50% or more. Among these, conductive glass in which a conductive layer made of ITO or FTO is deposited on glass is particularly preferable.

  A metal lead wire may be used for the purpose of reducing the resistance of the transparent conductive substrate. Examples of the material of the metal lead wire include metals such as aluminum, copper, silver, gold, platinum, and nickel. A metal lead wire is installed on a transparent substrate by vapor deposition, sputtering, pressure bonding, or the like, and a method of providing ITO or FTO thereon or a metal lead wire on a transparent conductive layer.

  As the semiconductor, a single semiconductor such as silicon or germanium, a compound semiconductor typified by a metal chalcogenide, a compound having a perovskite structure, or the like can be used. Metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, or tantalum oxide, cadmium, zinc, lead, silver, antimony, bismuth. Sulfide, cadmium, lead selenide, cadmium telluride and the like. Other compound semiconductors are preferably phosphides such as zinc, gallium, indium, cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like. As the compound having a perovskite structure, strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate and the like are preferable.

  The semiconductor used in the present invention may be single crystal or polycrystalline. As the conversion efficiency, a single crystal is preferable, but a polycrystal is preferable in terms of manufacturing cost, securing raw materials, and the like, and the particle size of the semiconductor is preferably 2 nm or more and 1 μm or less.

  As a method of forming a semiconductor layer on a conductive support, there are a method of applying a dispersion or colloidal solution of semiconductor fine particles on a conductive support, a sol-gel method, and the like. The dispersion can be prepared by the above-mentioned sol-gel method, a method of mechanically pulverizing with a mortar, etc., a method of dispersing while pulverizing using a mill, or a fine particle in a solvent when synthesizing a semiconductor. And a method of using it as it is.

  In the case of a dispersion prepared by mechanical pulverization or pulverization using a mill, it is formed by dispersing at least semiconductor fine particles alone or a mixture of semiconductor fine particles and a resin in water or an organic solvent. Resins used include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins. , Cellulose ester resin, cellulose ether resin, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin, polyamide resin, polyimide resin and the like.

  Solvents for dispersing the semiconductor fine particles include alcohol solvents such as water, methanol, ethanol, and isopropyl alcohol, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethyl formate, ethyl acetate, and n-butyl acetate. Ester solvents, diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or ether solvents such as dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, or amide solvents such as N-methyl-2-pyrrolidone , Dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodine Halogenated hydrocarbon solvents such as debenzene or 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, Examples thereof include hydrocarbon solvents such as m-xylene, p-xylene, ethylbenzene, and cumene. These can be used alone or as a mixed solvent of two or more.

  Examples of a method for applying the obtained dispersion include a roller method, a dip method, an air knife method, a blade method, a wire bar, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method.

  Furthermore, the semiconductor layer may be a single layer or multiple layers. In the case of multiple layers, a dispersion of semiconductor fine particles having different particle diameters can be applied in multiple layers, or different types of semiconductors, and application layers having different compositions of resins and additives can be applied in multiple layers. In addition, when the film thickness is insufficient with a single coating, the multilayer coating is an effective means.

  In general, as the thickness of the semiconductor layer increases, the amount of supported dye increases per unit projected area and the light capture rate increases. However, the diffusion distance of the generated electrons also increases, and the recombination of charges also increases. End up. Therefore, the film thickness of the semiconductor layer is preferably 0.1 to 100 μm, and more preferably 1 to 30 μm.

The semiconductor fine particles may or may not be heat-treated after being coated on the conductive support. However, from the viewpoint of improving the electronic contact between the particles and the strength of the coating film and the adhesion to the support, the heat treatment is performed. Is preferable. Furthermore, microwave irradiation, press treatment, or electron beam irradiation may be performed, and these treatments may be performed alone or in combination of two or more. In the heat treatment, the heating temperature is preferably 40 to 700 ° C, more preferably 80 to 600 ° C. The heating time is preferably 5 minutes to 50 hours, and more preferably 10 minutes to 20 hours. The microwave irradiation may be performed from the semiconductor layer forming side of the semiconductor electrode or from the back side. Although there is no restriction | limiting in particular in irradiation time, It is preferable to carry out within 1 hour. The press treatment is preferably 100 kg / cm ² or more, more preferably 1000 kg / cm ² . There is no particular limitation on the pressing time, but it is preferably performed within 1 hour.

  The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For this reason, it is preferable that the surface area in the state which coated the semiconductor layer on the support body is 10 times or more with respect to a projection area, and it is more preferable that it is 100 times or more.

  The pigment | dye in the photoelectric conversion element of this invention uses the pigment | dye shown by General formula (1)-(3) as a photoelectric conversion material.

  As a method of adsorbing the dye to the semiconductor layer, a method of immersing a working electrode containing semiconductor fine particles in a dye solution or a dye dispersion, or a method of applying a dye solution or a dispersion to the semiconductor layer and adsorbing it is used. Can do. In the former case, dipping method, dipping method, roller method, air knife method, etc. can be used, and in the latter case, wire bar method, slide hopper method, extrusion method, curtain method, spin method, spray method, etc. Can be used.

  When adsorbing the dye, a condensing agent may be used in combination. The condensing agent may be either one that has a catalytic action that is supposed to physically or chemically bind the dye to the inorganic surface, or one that acts stoichiometrically to favorably shift the chemical equilibrium. Furthermore, a thiol or a hydroxy compound may be added as a condensation aid.

  Solvents for dissolving or dispersing the dye are water, methanol, ethanol, alcohol solvents such as isopropyl alcohol, ketone solvents such as acetone, methyl ethyl ketone, or methyl isobutyl ketone, ethyl formate, ethyl acetate, or n-butyl acetate. Ester solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, nitrile solvents such as acetonitrile, propionitrile, N, N-dimethylformamide, N, N-dimethylacetamide, or Amide solvents such as N-methyl-2-pyrrolidone, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-di Halogenated hydrocarbon solvents such as lolobenzene, fluorobenzene, bromobenzene, iodobenzene, or 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene , Hydrocarbon solvents such as benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, or cumene, and these can be used alone or as a mixture of two or more.

  The temperature at which these are used and the dye is adsorbed is preferably -50 ° C or higher and 200 ° C or lower. Further, this adsorption may be performed while stirring. Examples of the stirring method include, but are not limited to, a stirrer, a ball mill, a paint conditioner, a sand mill, an attritor, a disperser, and ultrasonic dispersion. The time required for adsorption is preferably 5 seconds or more and 1000 hours or less, more preferably 10 seconds or more and 500 hours or less, and further preferably 1 minute or more and 150 hours.

  In this invention, when adsorb | sucking the pigment | dye shown by General formula (1)-(3), you may use a steroid type compound together. Specific examples of the steroid compound include those shown in (I-01) to (I-10). 0.01-1000 mass parts is preferable with respect to 1 mass part of pigment | dyes, and, as for the quantity of a steroid type compound, 0.1-100 mass parts is more preferable.

  After adsorbing the dye or adsorbing the dye and the co-adsorbent, a basic compound such as t-butylpyridine, 2-picoline, 2,6-lutidine, or phosphoric acid, phosphate ester, alkyl phosphoric acid, You may immerse in the organic solvent containing acidic compounds, such as an acetic acid and propionic acid.

  As the charge transfer layer of the present invention, an electrolytic solution in which a redox couple is dissolved in an organic solvent, a gel electrolyte in which a liquid in which the redox couple is dissolved in an organic solvent is impregnated in a polymer matrix, a molten salt containing the redox couple, a solid An electrolyte, an organic hole transport material, or the like can be used.

  The electrolytic solution used in the present invention is preferably composed of an electrolyte, a solvent, and an additive. Preferred electrolytes include metal iodide-iodine combinations such as lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, and the like. Iodine salts of quaternary ammonium compounds-iodine combinations, metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, calcium bromide-bromine combinations, quaternary compounds such as tetraalkylammonium bromides, pyridinium bromides Bromine-bromine combinations of ammonium compounds, metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion, sulfur compounds such as sodium polysulfide, alkylthiol-alkyldisulfide, viologen Dye, hydroquinone - quinones, and the like. The above-mentioned electrolytes may be a single combination or a mixture. Further, a molten salt in a molten state at room temperature can also be used as the electrolyte. When this molten salt is used, it is not necessary to use a solvent.

  The electrolyte concentration in the electrolytic solution is preferably 0.05 to 20M, and more preferably 0.1 to 15M. Solvents used for the electrolyte include carbonate solvents such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether solvents such as dioxane, diethyl ether and ethylene glycol dialkyl ether, methanol, ethanol Alcohol solvents such as polypropylene glycol monoalkyl ether, nitrile solvents such as acetonitrile and benzonitrile, aprotic polar solvents such as dimethyl sulfoxide and sulfolane are preferred. Further, basic compounds such as t-butylpyridine, 2-picoline, and 2,6-lutidine may be used in combination.

  In the present invention, the electrolyte can be gelled by a technique such as addition of a polymer, addition of an oil gelling agent, polymerization including polyfunctional monomers, or a crosslinking reaction of the polymer. Preferable polymers in the case of gelation by polymer addition include polyacrylonitrile, polyvinylidene fluoride and the like. Preferred gelling agents for gelation by adding an oil gelling agent include dibenzylden-D-sorbitol, cholesterol derivatives, amino acid derivatives, alkylamide derivatives of trans- (1R, 2R) -1,2-cyclohexanediamine, alkylureas Derivatives, N-octyl-D-gluconamide benzoate, double-headed amino acid derivatives, quaternary ammonium derivatives and the like can be mentioned.

  Preferred monomers for polymerization with a polyfunctional monomer include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and the like. be able to. Furthermore, esters and amides derived from acrylic acid such as acrylamide and methyl acrylate and α-alkyl acrylic acid, esters derived from maleic acid and fumaric acid such as dimethyl maleate and diethyl fumarate, butadiene, cyclohexane and the like. Dienes such as pentadiene, aromatic vinyl compounds such as styrene, p-chlorostyrene and sodium styrene sulfonate, vinyl esters, acrylonitrile, methacrylonitrile, vinyl compounds having a nitrogen-containing heterocyclic ring, vinyl having a quaternary ammonium salt A monofunctional monomer such as a compound, N-vinylformamide, vinylsulfonic acid, vinylidene fluoride, vinyl alkyl ethers, N-phenylmaleimide may be contained. 0.5-70 mass% is preferable and the polyfunctional monomer which occupies for the monomer whole quantity has more preferable 1.0-50 mass%.

  The above-mentioned monomers can be polymerized by radical polymerization. The monomer for gel electrolyte that can be used in the present invention can be radically polymerized by heating, light, electron beam or electrochemical. The polymerization initiator used when the crosslinked polymer is formed by heating is 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2. Azo initiators such as 2,2′-azobis (2-methylpropionate) and peroxide initiators such as benzoyl peroxide are preferred. The addition amount of these polymerization initiators is preferably 0.01 to 20% by mass and more preferably 0.1 to 10% by mass with respect to the total amount of monomers.

  When the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a reactive group necessary for the crosslinking reaction and a crosslinking agent in combination. Preferable examples of the crosslinkable reactive group include nitrogen-containing heterocycles such as pyridine, imidazole, thiazole, oxazole, triazole, morpholine, piperidine, piperazine, etc. Preferred crosslinking agents include alkyl halides, halogens Bifunctional or higher functional reagents capable of electrophilic reaction with nitrogen atoms such as aralkyl fluoride, sulfonic acid ester, acid anhydride, acid chloride, and isocyanate can be exemplified.

  When an inorganic solid compound is used instead of the electrolyte, copper iodide, copper thiocyanide, or the like can be introduced into the electrode by a casting method, a coating method, a spin coating method, a dipping method, an electrolytic plating method, or the like.

  In the present invention, an organic charge transport material can be used instead of the electrolyte. Charge transport materials include hole transport materials and electron transport materials. Examples of the former include, for example, oxadiazoles disclosed in Japanese Patent Publication No. 34-5466, triphenylmethanes disclosed in Japanese Patent Publication No. 45-555, and Japanese Patent Publication No. 52-4188. Pyrazolines shown in the above, hydrazones shown in JP-B-55-42380, oxadiazoles shown in JP-A-56-123544, etc., JP-A-54-58445 And tetrasylbenzidines disclosed in JP-A No. 58-65440, and stilbenes disclosed in JP-A No. 60-98437. Among them, examples of the charge transport material used in the present invention are shown in JP-A-60-24553, JP-A-2-96767, JP-A-2-183260, and JP-A-2-226160. Particularly preferred are the hydrazones described, and the stilbenes shown in JP-A-2-51162 and JP-A-3-75660. Moreover, these can be used individually or in mixture of 2 or more types.

  On the other hand, examples of the electron transport material include chloranil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 1,3,7-trinitrodibenzothiophene, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, etc. . These electron transport materials can be used alone or as a mixture of two or more.

  Further, as a sensitizer that further increases the sensitizing effect, a certain kind of electron-withdrawing compound can be added. Examples of the electron-withdrawing compound include quinones such as 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone, 4-nitro Aldehydes such as benzaldehyde, ketones such as 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, or 3,3 ', 5,5'-tetranitrobenzophenone, phthalic anhydride, 4-chloronaphthalic anhydride Acid anhydrides such as terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, or cyano compounds such as 4- (p-nitrobenzoyloxy) benzalmalononitrile, 3-benzalphthalide , 3- (α-cyano- - Nitorobenzaru) phthalide, or 3- (alpha-cyano -p- Nitorobenzaru) -4,5,6,7 can be mentioned phthalides such as tetrachloro phthalide like.

  When forming a charge transfer layer using these charge transport materials, a resin may be used in combination. When resin is used in combination, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, polyester resin, polyphenylene oxide resin, polyarylate resin, acrylic resin, methacrylic resin, phenoxy resin and the like can be mentioned. Among these, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, and polyarylate resin are preferable. These resins may be used alone or as a copolymer in combination of two or more.

  There are two main methods for forming the charge transfer layer. One is a method in which a counter electrode is first pasted on a semiconductor fine particle-containing layer carrying a sensitizing dye, and a liquid charge transfer layer is sandwiched between the opposite electrodes, and the other is a method in which a charge is directly applied on the semiconductor fine particle-containing layer. This is a method of providing a moving layer. In the latter case, the counter electrode is newly added thereafter.

  In the former case, examples of the method for sandwiching the charge transfer layer include a normal pressure process using a capillary phenomenon due to immersion and a vacuum process in which the gas phase is replaced with a liquid phase at a pressure lower than normal pressure. In the latter case, in the wet charge transfer layer, it is necessary to provide a counter electrode without being dried to prevent liquid leakage at the edge portion. In the case of a gel electrolyte, there is a method in which it is applied in a wet manner and solidified by a method such as polymerization. In that case, you may provide a counter electrode after drying and fixing. In addition to the electrolyte solution, the organic charge transport material solution and the gel electrolyte can be applied in the same manner as the semiconductor fine particle-containing layer and the dye, as in the immersion method, roller method, dipping method, air knife method, and extrusion method. , Slide hopper method, wire bar method, spin method, spray method, casting method, various printing methods, and the like.

  As the counter electrode, a support having a conductive layer can be used in the same manner as the conductive support described above, but the support is not necessarily required in a configuration in which the strength and the sealing performance are sufficiently maintained. Specific examples of the material used for the counter electrode include metals such as platinum, gold, silver, copper, aluminum, rhodium and indium, carbon compounds, and conductive metal oxides such as ITO and FTO. There is no particular limitation on the thickness of the counter electrode.

  In order for light to reach the photosensitive layer, at least one of the conductive support and the counter electrode must be substantially transparent. In the photoelectric conversion element of this invention, the electroconductive support body is transparent and the method of making sunlight inject from a support body side is preferable. In this case, a material that reflects light is preferably used for the counter electrode, and a metal, glass, plastic, or metal thin film on which a conductive oxide is deposited is preferable.

  As described above, there are two types of coating of the counter electrode: when applied on the charge transfer layer and when applied on the semiconductor fine particle layer. In any case, the counter electrode material can be appropriately formed on the charge transfer layer or the semiconductor fine particle-containing layer by a technique such as coating, laminating, vapor deposition, or bonding depending on the type of the counter electrode material or the type of the charge transfer layer. When the charge transfer layer is solid, the counter electrode can be formed directly on the charge transfer layer by a technique such as coating, vapor deposition, or CVD.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to these at all.

  6 hours of paint conditioner (manufactured by Red Devil) with 2 g of titanium oxide (P-25 manufactured by Nippon Aerosil Co., Ltd.), 0.2 g of acetylacetone, and 0.3 g of surfactant (Triton X-100 manufactured by Aldrich) together with 6.5 g of water. Dispersion treatment was performed. Further, 0.2 g of concentrated nitric acid, 0.4 ml of ethanol, and 1.2 g of polyethylene glycol (# 20,000) were added to 4.0 g of this dispersion to prepare a paste. This paste was applied onto an FTO glass substrate so as to have a film thickness of 12 μm, dried at room temperature, and then fired at 100 ° C. for 1 hour and further at 550 ° C. for 1 hour.

  The dye represented by the exemplary compound (F-02) was dissolved in a mixed solution of t-butanol / acetonitrile (1/1) to prepare a dye solution having a concentration of 0.3 mM. In this dye solution, the previously produced semiconductor electrode was immersed at room temperature for 15 hours for adsorption treatment. The electrolyte is a lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M 3-methoxyacetonitrile solution, and the counter electrode is sputtered with platinum on a titanium plate. We used what we did.

An electrolytic solution was immersed between both electrodes to produce a photoelectric conversion element. Here, pseudo-sunlight generated from a solar simulator (AM1.5G, irradiation intensity 100 mW / cm ² ) was irradiated as a light source from the working electrode side. As a result, the open circuit voltage was 0.50 V, the short-circuit current density was 6.2 mA / cm ² , the shape factor was 0.58, and the conversion efficiency was 1.8%.

(Examples 2-9)
A device was prepared and evaluated in the same manner as in Example 1 except that the exemplary compound (F-02) was changed to the exemplary compound shown in Table 1. The results are shown in Table 1.

(Comparative Example 1)
A device was prepared and evaluated in the same manner as in Example 1 except that the exemplified compound (F-02) was changed to the compound shown in (J-01). As a result, the open-circuit voltage was 0.50 V, the short-circuit current density was 2.2 mA / cm ² , the shape factor was 0.60, and the conversion efficiency was 0.66%, which were low values compared to the dye of the present invention.

  Examples of utilization of the present invention include photosensors that are sensitive to light of a specific wavelength, in addition to photoelectric conversion elements such as solar cells.

Claims (6)

A photoelectric conversion material characterized by using a compound represented by the general formula (1).

(In the general formula (1), R ₁ , R ₂ and R ₃ represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group, and a heterocyclic ring. R ₁ and R ₂ , R ₂ and R ₃ may be bonded to each other to form a cyclic structure, and R ₄ connects a hetero 5-membered ring to an A1 ring. R ₅ represents a hydrogen atom or an alkyl group, and may have a substituent, X ₁ represents an oxygen atom, a sulfur atom, or a substituted amino group. X ₂ and X _{3 each} represents an oxygen atom, a sulfur atom, a nitrogen atom, an alkylene group, a substituted amino group, a carbonyl group, a sulfonyl group, or a thiocarbonyl group, which may be the same or different and has a substituent. A1 ring is an aliphatic condensed ring, an aromatic condensed ring, Represents a heterocycle, and n1 represents an integer of 0 to 3.) A photoelectric conversion material characterized by using a compound represented by the general formula (2).

(In the general formula (2), R ₆ , R ₇ and R ₈ represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group, and a heterocyclic ring. R ₆ and R ₇ , R ₇ and R ₈ may be bonded to each other to form a cyclic structure, and R ₉ is a bond between a hetero 5-membered ring and a B1 ring. R ₁₀ represents a hydrogen atom or an alkyl group, and may have a substituent, and X ₄ represents an oxygen atom, a sulfur atom, or a substituted amino group. X ₅ represents a hydrogen atom or an aryl group, which may have a substituent, X ₆ represents a methine group or a substituted amino group, and X ₇ represents an oxygen atom, a sulfur atom or a substituted amino group. Ring B1 represents a heterocycle, and n2 represents an integer of 0 to 3.) A photoelectric conversion material characterized by using a compound represented by the general formula (3).

(In the general formula (3), R ₁₁ , R ₁₂ and R ₁₃ represent a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an alkylthio group, a disubstituted amino group, a halogen atom, an aryl group or a heterocyclic ring. R ₁₁ and R ₁₂ , R ₁₂ and R ₁₃ may be bonded to each other to form a cyclic structure, and R ₁₄ is a bond between a hetero 5-membered ring and a C1 ring. R ₁₇ may be a hydrogen atom or an alkyl group, and may have a substituent, R ₁₅ and R ₁₆ may be a hydrogen atom, an alkyl group or an alkoxy group. X ₈ represents an oxygen atom, a sulfur atom or a substituted amino group, and X ₉ represents a substituted amino group, an oxygen atom, a sulfur atom, a carbonyl group, a dicyanomethylene group or a bis ( Alkoxycarbonyl) represents a methylene group .C1 ring is .n3 shown aliphatic condensed aromatic condensed ring, a hetero ring represents an integer of 0 to 3.) In a semiconductor electrode comprising a substrate having conductivity on the surface, a semiconductor layer coated on the conductive surface, and a dye adsorbed on the surface of the semiconductor layer, the dye is represented by the general formulas (1) to (3). A semiconductor electrode comprising at least one of the compounds shown. The semiconductor is titanium, tin, zinc, iron, copper, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, cadmium, lead, silver, antimony, bismuth, molybdenum, aluminum, 5. The semiconductor electrode according to claim 4, comprising at least one metal chalcogenide selected from gallium, chromium, cobalt, and nickel. A photoelectric conversion element using the semiconductor electrode according to claim 4.