JP2006002107A - Dye, photoelectric conversion material, semiconductor electrode and photoelectric conversion element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pigment for obtaining a photoelectric transducer of high performance and provide a photoelectric material, a semiconductor electrode and a photoelectric transducer of high performance by using the pigment. <P>SOLUTION: This photoelectric material is obtained by using a pigment that is represented by the chemical formula (wherein Z is an atom group needed for forming a five or six-membered nitrogen-containing heterocycle). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensitizing dye for dye-sensitized solar cells, a sensitizing dye for silver halide photographic materials, a filter dye, and a novel dye usable for dye laser dyes. The present invention relates to a photoelectric conversion element using the dye 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. Although organic materials have advantages such as low cost and easy area enlargement, 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. As sensitizing dyes used in this battery, for example, merocyanine dyes, cyanine dyes, 9-phenylxanthene dyes, coumarin dyes and the like as described in Patent Documents 1 to 3 have been reported. However, even if these dyes are used, the desired properties have not yet been obtained, and further improvements are required.
Japanese Patent Laid-Open No. 10-92477 JP 11-238905 A JP 2004-95450 A Nature, 353, 737 (1991)

  An object of the present invention is to provide a dye for obtaining a high-performance photoelectric conversion element. Another object of the present invention is to provide a high-performance photoelectric conversion material, semiconductor electrode, and photoelectric conversion element using such a dye.

  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 following chemical formula 1 as a sensitizing dye of a photoelectric conversion material.

   In Chemical Formula 1, Z represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring.

  By using the dye of Formula 1 of the present invention as a sensitizing dye of a photoelectric conversion material, a photoelectric conversion element exhibiting excellent conversion efficiency can be obtained.

  The benzopyran ring in the formula 1 may be substituted with a known substituent such as an aliphatic group, an aromatic group, a heterocyclic group, an amino group, a hydroxy group, or an alkoxy group. Specific examples thereof include alkyl groups such as methyl, ethyl and n-propyl, alkenyl groups such as allyl and butenyl, alkynyl groups such as propargyl groups (above aliphatic groups), aromatic groups such as phenyl, tolyl and naphthyl, There are heterocyclic groups such as thiazolyl, imidazolyl and morpholino, unsubstituted or amino groups such as N, N-dimethylamino and N, N-diethylamino, hydroxy groups, alkoxy groups such as methoxy, ethoxy and n-propoxy groups. . These substituents may be further substituted with known substituents if possible.

  Of those described above, preferred is a substituent that acts as an electron-donating group such as an amino group, a hydroxy group, or an alkoxy group on the benzo-fused ring side (positions 5 to 8). Of these, alkoxy groups such as methoxy and ethoxy substituted at the 7-position and N, N-dialkylamino groups such as N, N-dimethylamino and N, N-diethylamino are particularly preferable. The N, N-dialkylamino group may be linked to the 6-position and / or 8-position of the benzopyran ring to form a 5- or 6-membered cyclic structure, respectively. The pyran ring side (3, 4 position) is preferably unsubstituted or a lower aliphatic group having 3 or less carbon atoms.

  Z represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring. Examples thereof include acidic nuclei used in merocyanine dyes well known in the art. Specific examples include a pyrazolone ring, an oxazolidinone ring, an imidazolidinone ring, a thiazolidinone ring, a barbituric acid ring, and a thiobarbituric acid ring. Nitrogen atoms and carbon atoms on these rings may be substituted with known substituents. If possible, two or more of them may be linked to form a so-called complex merocyanine. Of these, a pyrazolone ring and a thiazolidinone ring are preferable, and a thiazolidinone ring is particularly preferable.

  Chemical formula 1 preferably has at least one acidic group in the molecule. Examples thereof include groups having a dissociating proton of pKa11 or less, such as a carboxy group, a sulfo group, a phosphonic acid group, a sulfonamide group, and a phenolic hydroxyl group. These may be in the form of a free acid or a salt such as an ammonium salt or a metal salt. Of these, a carboxy group is preferable, and among them, a carboxy group present as a part of the substituent on the Z ring is particularly preferable.

  Although the specific example of the pigment | dye of this invention is illustrated below, these do not limit this invention.

  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 support made of glass or plastic having a conductive layer containing a conductive agent on its surface, 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.

  Examples of a method for forming a semiconductor layer on a conductive support include a method in which a dispersion or colloidal solution of semiconductor fine particles is applied 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 need not be heat-treated after being coated on the conductive support, but from the viewpoint of improving the electronic contact between the particles and the strength of the coating film and the adhesion to the support, 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.

  As the dye in the photoelectric conversion element of the present invention, the dye represented by Chemical Formula 1 is used 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 the present invention, a steroidal compound may be used in combination when adsorbing the dye represented by Chemical Formula 1. Specific examples of the steroid compound include compounds described in JP-A No. 2004-139755. 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 bromide, pyridinium bromide 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 preferable. 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, electrolytic plating, 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 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, phenanthrenequinone and other quinones, 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.

Synthesis of D3 10.2-g 7-ethoxy-4-methylcoumarin, 12.1 g Lawesson's reagent and 100 ml benzene were mixed and heated to reflux for 8 hours. Subsequently, the solvent was distilled off under reduced pressure, and 150 ml of methanol was added to the residue, followed by heating under reflux for 30 minutes. After cooling, the precipitated crystals were collected by filtration, washed with methanol and dried to obtain 8.5 g of thiocoumarin derivative (intermediate A).

Intermediate A 2.2 g and rhodanine-3-acetic acid 1.9 g were mixed and heated at a bath temperature of 165 ° C. for 15 hours. After allowing to cool, 40 ml of methanol was added, and the mixture was stirred at room temperature for 1 hour, and then the precipitate was collected by filtration. The crystals were washed with methanol and chloroform in this order to obtain 1.1 g of D3. Melting point: 215 ° C. (decomposition). ¹ H-NMR (TMS / DMSO-d6): 1.36 ppm (3H, t), 2.40 ppm (3H, s), 4.14 ppm (2H, q), 4.65 ppm (2H, s), 6. 91-7.00 ppm (2H, m), 7.60-7.65 ppm (2H, m), 12-14 ppm (1 H, broadcast).

Synthesis of D10 9.2 g of 7-diethylamino-4-methylcoumarin, 10.6 g of Lawson reagent, and 100 ml of benzene were mixed and heated under reflux for 5 hours. Subsequently, 100 ml of methanol was added, and the mixture was refluxed for 1 hour. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (developing solvent chloroform) to obtain 9.2 g of a thiocoumarin derivative (intermediate B).

Intermediate B 4.7 g and rhodanine-3-acetic acid 3.7 g were mixed and heated at a bath temperature of 165 ° C. for 7 hours. After allowing to cool, 80 ml of methanol was added, and the mixture was stirred at room temperature for 1 hour, and then the precipitate was collected by filtration. The crystals were washed with methanol and acetone in this order to obtain 1.9 g of D10. Melting point: 280 ° C or higher. ¹ H-NMR (TMS / DMSO-d6): 1.15 ppm (6H, t), 2.38 ppm (3H, s), 3.46 ppm (4H, q), 4.65 ppm (2H, s), 6. 59-6.79 ppm (2H, m), 7.47-7.53 ppm (2H, m), 12-14 ppm (1 H, broadcast). Absorption maximum (methanol solution): 536 nm.

D13 synthetic intermediate B (2.3 g) and 3-ethyl-5- (3-carboxymethyl-4-oxo-1,3-thiazolidine-2-ylidene) rhodanine (1.5 g) were mixed, and the bath temperature was 165 ° C. Heating was performed for hours. After allowing to cool, 60 ml of acetonitrile was added, and the mixture was stirred at room temperature for 1 hour, and then the precipitate was collected by filtration. The crystals were washed with acetonitrile and acetone in this order to obtain 0.5 g of D13. Melting point: 280 ° C or higher. ¹ H-NMR (TMS / DMSO-d6): 1.10-1.24 ppm (9H, m), 2.38 ppm (3H, s), 3.46 ppm (4H, q), 4.04 ppm (2H, q) ), 4.68 ppm (2H, s), 6.60-6.78 ppm (2H, m), 7.47-7.53 ppm (2H, m), 12-14 ppm (1H, broadcast). Absorption maximum (methanol solution): 575 nm.

  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 Example Compound D10 was dissolved in N, N-dimethylformamide to prepare a dye solution having a concentration of 0.3 mM. The semiconductor electrode prepared previously was immersed in this dye solution at room temperature for 20 hours to perform an 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, an open circuit voltage of 0.53 V, a short circuit current density of 10.3 mA / cm ² , a form factor of 0.63, and a conversion efficiency of 3.6% were shown.

  A device was prepared and evaluated in the same manner as in Example 4 except that the exemplified compound D10 was changed to the compound shown in (Result 1). As a comparative compound, a dye represented by the following chemical formula 6 was used. The evaluation results are shown in (Result 1).

(Result 1)
─────────────────────────────────
Compound Open-circuit voltage Short-circuit current density Form factor Conversion efficiency
(V) (mA / cm ² ) (%)
─────────────────────────────────
D3 0.50 8.7 0.60 2.9
D9 0.52 9.9 0.61 3.4
D13 0.54 9.8 0.60 3.2
C1 0.48 5.6 0.60 2.2
C2 0.43 3.7 0.58 2.1
──────────────────────────────────

  (Result 1) also shows that the photoelectric conversion element of the present invention has high characteristics.

  Examples of the use of the dye of the present invention include sensitizing dyes and filter dyes of silver halide photographic materials, dye dyes for dye lasers, and the like in addition to the sensitizing dyes of the photoelectric conversion materials described in the above examples.

Claims (5)

A dye represented by the following chemical formula 1.

In Chemical Formula 1, Z represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocyclic ring.   A photoelectric conversion material using the dye represented by Chemical Formula 1 above.   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, containing at least one compound represented by Chemical Formula 1 as a dye A semiconductor electrode.   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, 4. The semiconductor electrode according to claim 3, comprising at least one metal chalcogenide selected from gallium, chromium, cobalt, and nickel.   A photoelectric conversion element using the semiconductor electrode according to claim 3.