JP2003051345A - Photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element having excellent photoelectric conversion characteristics. SOLUTION: This photoelectric conversion element has an electrode including at least one surface coated with a semiconductor layer carrying a dye, and a counter electrode facing to the semiconductor layer of the electrode, and a charge transport layer between the counter electrode and the semiconductor layer of the electrode. The semiconductor layer is formed from a semiconductor layer-forming solution wherein an amino compound and a substance obtained from a metal compound and a polycarboxylic acid or its salt are dissolved in an alcohol solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device using a semiconductor layer manufactured by a specific method as an electrode.

[0002]

_2. Description of the Related Art Global warming due to a large amount of CO ₂ produced by burning fossil fuels and an increase in energy demand accompanying population increase have become major problems relating to the survival of humankind. Sunlight has nurtured the global environment since ancient times and has become an energy source for all living things, including humans. Recently, the use of sunlight, which is an infinite and clean energy source that does not generate harmful substances, has been vigorously studied. Practical applications include single-crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, and cadmium telluride and indium copper selenide, which serve as power sources for residential and remote areas or portable electronic devices. Compound solar cells of.

However, the silicon used in this solar cell is required to have a very high purity, and the refining process requires a large amount of energy and a complicated process, resulting in a high manufacturing cost. As a result, the photovoltaic power generation system has a higher power generation cost than existing commercial power, and there is a problem in widespread use. There is also a problem that the user has a long energy payback time.

On the other hand, many solar cells using an organic material as a photosensitive material, which is easy to have a large area, have been proposed for the purpose of cost reduction. As an organic solar cell, a Schottky photoelectric conversion element for joining a p-type organic semiconductor and a metal having a small 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 is a heterojunction photoelectric conversion element and the like. Organic semiconductors used for these include synthetic dyes and pigments such as chlorophyll and perylene, conductive polymer materials such as polyacetylene, and composite materials thereof, which are vacuum vapor deposition methods, casting methods, dipping methods, or the like. Are formed into a thin film. However, there are problems that the conversion efficiency is as low as 1% or less and the durability is poor.

Under these circumstances, Nature (Vol. 353, P7)
37, 1991) and U.S. Pat. No. 4,927,721, and a photoelectric conversion device and a solar cell using dye-sensitized semiconductor fine particles were epoch-making. This document also discloses materials and manufacturing techniques necessary for manufacturing. The proposed battery is
It is a wet solar cell using a titanium dioxide porous thin film spectrally sensitized by a ruthenium complex called a Gretzell type as a working electrode. The advantage of this method is that it is possible to use an inexpensive oxide semiconductor such as titanium dioxide without having to purify it to a high degree of purity. Therefore, an inexpensive photoelectric conversion element can be provided, and the dye used has a wide absorption of visible light. That is, sunlight can be effectively converted into electricity over the wavelength range.

As a method for forming a thin film of titanium dioxide on the surface of glass, metal or the like, sputtering method, CVD
Method, dry method such as vapor deposition method, sol-gel method, plating method,
Wet methods such as electrolytic polymerization are known. A typical dry method, a sputtering method, can obtain a uniform and stable thin film, but the equipment is complicated and expensive, and the manufacturing cost is high.
There are also restrictions such as difficulty in increasing the area. Examples of the wet method include a method of applying a dispersion or colloidal solution of semiconductor fine particles on a conductive support, a sol-gel method, and the like. JP-A-11-86916, JP-A-11-21473
No. 0, JP-A No. 11-345991, JP-A 20
The dispersion or colloidal solution reported in JP-A-00-285980 is not suitable for industrialization because sedimentation of semiconductor fine particles is observed upon standing. JP-A-10-924
In the sol-gel method reported in Japanese Patent Publication No. 77, a device is simple and a large area can be obtained, but if a thin film forming condition is not strictly controlled, a uniform thin film cannot be obtained. Since it is poor in stability, it has a drawback that the cost becomes higher than expected in industrialization.

[0007]

An object of the present invention is to provide a photoelectric conversion device having high conversion efficiency.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a semiconductor layer obtained by dissolving a polycarboxylic acid or a salt thereof and a metal compound and an amino compound in an alcohol solution. This was achieved by using the semiconductor layer produced by the forming solution as an electrode.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The photoelectric conversion element of the present invention comprises a conductive support, a semiconductor layer sensitized by a dye provided on the conductive support, a charge transfer layer and a counter electrode. The photosensitive layer may have a single-layer structure or a laminated structure, and is designed according to the purpose. At the boundaries 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, one having conductivity to the support itself such as metal, or glass or plastic support having a conductive layer containing a conductive agent on the surface can be used. In the latter case, the conductive agent is platinum,
Metals such as gold, silver, copper, and aluminum, carbon, or indium-tin composite oxide (hereinafter abbreviated as “ITO”), fluorine-doped metal oxide such as tin oxide (hereinafter abbreviated as “FTO”) Etc. The conductive support preferably has a transparency that transmits 10% or more of light, and more preferably 50% or more. Among these, conductive glass in which a conductive film made of ITO or FTO is deposited on glass is particularly preferable.

For the purpose of reducing the resistance of the transparent conductive substrate, it is preferable to use a metal lead wire. The material of the metal lead wire is preferably a metal such as aluminum, copper, silver, gold, platinum or nickel. There is a method of installing a metal lead wire on a transparent substrate by vapor deposition, sputtering, etc., and providing ITO or FTO on it, or installing a metal lead wire on a transparent conductive layer.

The method for forming a semiconductor layer according to the present invention is a method for applying a semiconductor layer-forming solution prepared by dissolving a polycarboxylic acid or a salt thereof and a metal compound and an amino compound in an alcohol solution onto a conductive support. It is obtained by doing.

Specific examples of the polycarboxylic acid used in preparing the semiconductor layer forming solution include oxalic acid, tartaric acid, malic acid, citric acid, phthalic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, 1,2- Propanediamine tetraacetic acid, 1,3-Propanediamine tetraacetic acid,
N-hydroxyethylethylenediaminediacetic acid, N, N
-Bis (hydroxyethyl) ethylenediaminediacetic acid,
2-hydroxy-1,3-propanediaminetetraacetic acid, triethylenetetramine hexaacetic acid and the like can be mentioned.

Examples of the polycarboxylic acid salt include salts of the above-mentioned polycarboxylic acid and amine. Examples of amines include primary or secondary amines,
Specific examples thereof include n-propylamine, cyclohexylamine, benzylamine, aniline, 1-naphthylamine, 2-aminoquinoline, 2-aminopyrimidine,
2-amino-3-picoline, di-n-butylamine,
N, N-bis (3-chlorobenzyl) amine, diphenylamine, p, p'-ditolylamine, N-phenyl-
1-naphthylamine, 2,2'-dipyridylamine, etc. can be mentioned.

The metal compound used in the present invention includes
Metal halides such as metal chlorides and bromides, metal acid salts such as metal sulfates and metal phosphates, metal salts of organic acids such as metal p-toluenesulfonate, metal alkoxides such as metal methoxide and metal phenoxide, or metal A single substance can be mentioned. As an amino compound,
Examples thereof include ammonia gas or aqueous ammonia solution, the above-mentioned primary amine, the above-mentioned secondary amine, triethylamine, triethanolamine, and tertiary amines such as N, N-dimethylaniline.

The amount of the amino compound added is preferably 1 mol or more per 1 mol of the metal compound. There is no particular upper limit, but 10 mol or less is preferable, and 3 mol or less is more preferable.

The alcohol solution in which the polycarboxylic acid or its salt and the complex formed from the metal compound and the amino compound are dissolved may contain water. Specific examples thereof include methanol, ethanol, isopropyl alcohol, benzyl alcohol, ethylene glycol and diethylene glycol. These can be used alone or as a mixed solvent of two or more kinds.

Further, the solution may contain a metal chalcogenide. The metal chalcogenide may be added to the above solution as a powder, or may be added as a dispersion liquid or a colloidal solution. In the case of a dispersion liquid produced by mechanical pulverization or pulverization using a mill, it is formed by dispersing at least semiconductor fine particles and a binder resin in water or an organic solvent. Examples of the binder resin used include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyesters. Resin, cellulose ester resin, cellulose ether resin, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin,
Polyamide resin, polyimide resin or the like can be used.

The preferred solvent for dispersing the metal chalcogenide is water, an alcohol solvent such as methanol, ethanol or isopropyl alcohol, acetone,
Ketone solvents such as methyl ethyl ketone or methyl isobutyl ketone, ester solvents such as ethyl formate, ethyl acetate or n-butyl acetate, ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane or dioxane, N, N
An amide solvent such as dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone, dichloromethane, chloroform, bromoform,
Methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, halogenated hydrocarbon solvents such as 1-chloronaphthalene, n-pentane, n-hexane, n- Hydrocarbon solvents such as octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene and cumene can be mentioned. These can be used alone or as a mixed solvent of two or more kinds.

As a coating method, a roller method, a dipping method, an air knife method, a blade method, a wire bar, a slide hopper method, an extrusion method, a curtain method, a spin method, or a spray method is preferable.

As the semiconductor, metal chalcogenide is preferable, and titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium,
Cerium, yttrium, lanthanum, vanadium, niobium, tantalum, aluminum, gallium, chromium, cobalt, nickel, molybdenum oxide, cadmium, zinc, lead, silver, antimony, bismuth sulfide, cadmium, lead selenide, cadmium. In the present invention, titanium dioxide is the most preferable.

The semiconductor used in the present invention may be single crystal or polycrystal. A single crystal is preferable as the conversion efficiency, but a polycrystal is preferable from the viewpoints of production cost, securing of raw materials, and the like, and a nanoparticle to micrometer-sized fine particle semiconductor is particularly preferable.

Further, the semiconductor layer need not be limited to a single layer. It is also possible to apply multiple layers of dispersions of semiconductor fine particles having different particle diameters, or to apply multiple layers of semiconductors of different types, or coating layers having different compositions of resins and additives. Further, when the film thickness is insufficient by one-time coating, multi-layer coating is an effective means.

In general, as the film thickness of the semiconductor layer increases, the amount of supported dye per unit projected area also increases, so that the light trapping rate increases, but the diffusion distance of generated electrons also increases, so that charge recombination occurs. Will also increase. Therefore, the thickness of the semiconductor layer is preferably 0.1 to 100 μm, more preferably 1 to 30 μm.

The semiconductor layer is preferably heat-treated after applying the semiconductor layer forming solution. The heat treatment temperature at that time is preferably 40 to 700 ° C, more preferably 100 to 600 ° C. The heat treatment time is preferably 5 minutes to 20 hours, more preferably 10 minutes to 10 hours. However, the heat treatment needs to be performed at a temperature below the temperature at which the support is not damaged.

The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. Therefore, the surface area of the semiconductor layer coated on the support is preferably 10 times or more, and more preferably 100 times or more, the projected area.

The dye in the photoelectric conversion device of the present invention is described in JP-A-7-500630 and JP-A-10-23323.
No. 8, JP 2000-26487, and JP 20
No. 00-323191, JP 2001-59062 A.
Metal complex compounds described in JP-A-11-86
No. 916, No. 11-214730, No. 2000-106224, No. 2001-767.
No. 73, Japanese Patent Application No. 2001-186599, and other cyanine dyes, JP-A Nos. 11-214731, 11-238905, and 2001-2001.
52766, JP 2001-76775 A,
Merocyanine dyes described in Japanese Patent Application No. 2001-192395, JP-A-10-92477, and JP-A-11-2.
No. 73754, JP-A No. 11-273755,
9-arylxanthene compounds described in Japanese Patent Application No. 2001-214126, JP-A-10-93118,
Triarylmethane compounds described in Japanese Patent Application No. 2001-214126 and the like, coumarin compounds and acridine compounds described in JP-A No. 10-93118, etc.
-37543, JP-A-53-95033,
JP-A-53-132347, JP-A-53-133
No. 445, No. 54-12742, No. 54-20736, No. 54-20737, No. 54-21728, No. 54-22.
834, JP-A-55-69148, JP-A-55-69654, JP-A-55-79449, JP-A-55-117151, and JP-A-56-4.
6237, JP-A-56-116039, JP-A-56-116040, and JP-A-56-1191.
34, JP-A-56-143437, JP-A-57-63537, JP-A-57-63538, JP-A-57-63541, and JP-A-57-63.
542, JP-A-57-63549, JP-A-57-66438, JP-A-57-74746, JP-A-57-78542, and JP-A-57-78.
543, JP-A-57-90056, JP-A-57-90057, JP-A-57-90632, JP-A-57-116345, and JP-A-57-2.
No. 02349, JP-A-58-4151, JP-A-58-90644, and JP-A-58-144358.
JP, JP-A-58-177955, JP-A-59.
-31962, JP-A-59-33253,
JP-A-59-71059 and JP-A-59-7244
No. 8, JP-A-59-78356, JP-A-59.
-136351, JP-A-59-201060, JP-A-60-15642, and JP-A-60-14.
0351, JP60-179746, JP61-11754, JP61-90164.
JP-A-61-90165, JP-A-61-90165
90166, Japanese Patent Laid-Open No. 61-112154,
JP-A-61-269165 and JP-A-61-281.
No. 245, No. 61-51063, No. 62-267363, No. 63-68844, No. 63-89866, and No. 63-1.
39355, JP-A-63-142063,
JP-A-63-183450, JP-A-63-282
743, JP 64-21455 A, JP 64-78259 A, JP 1-200267 A, JP 1-2202757 A, JP 1-319 A.
754, JP-A-2-72372, and JP-A-2
-254467, JP-A-3-95561,
JP-A-3-278063 and JP-A-4-96068
Japanese Patent Laid-Open No. 4-96069, Japanese Patent Laid-Open No. 4-14
7265, JP-A-5-142841, JP-A-5-303226, JP-A-6-324504, JP-A-7-168379, and Japanese Patent Application No. 2001-2001.
No. 161942, Japanese Patent Application No. 2001-175875, and other azo compounds, JP-A-9-199744, JP-A-10-233238, and JP-A-11-2048.
21, a phthalocyanine compound and a porphyrin compound described in JP-A No. 21-265738 and the like are used as a photoelectric conversion material in the form of at least one kind or a mixture of two or more kinds.

As a method for adsorbing a dye on the semiconductor layer, a working electrode containing semiconductor fine particles is dipped in a dye solution or a dye dispersion, or a dye solution or dispersion is applied to the semiconductor layer and adsorbed. Can be used. In the former case, dipping method, dipping method, roller method,
The air knife method or the like can be used. In the latter case,
The wire bar method, slide hopper method, extrusion method, curtain method, spin method, spray method and the like can be used.

The charge transfer layer of the present invention includes an electrolytic solution in which a redox couple is dissolved in an organic solvent, a gel electrolyte in which a polymer matrix is impregnated with a liquid in which an redox couple is dissolved in an organic solvent, and a melt containing the redox couple. A salt, a solid electrolyte, an organic hole transport material, etc. can be used.

The electrolytic solution used in the present invention is preferably composed of an electrolyte, a solvent, and an additive. Preferred electrolytes are metal iodide-iodine combinations such as lithium iodide, sodium iodide, potassium iodide, cesium iodide and calcium iodide, tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide and the like. Iodine salt of primary ammonium compound-combination of iodine, lithium bromide, sodium bromide, potassium bromide, cesium bromide, metal bromide such as calcium bromide-bromine combination, tetraalkylammonium bromide, quaternary such as pyridinium bromide Bromine salt-bromine combination of ammonium compound, ferrocyanate-ferricyanate, metal complex such as ferrocene-ferricinium ion, sodium polysulfide, sulfur compound such as alkylthiol-alkyldisulfide, viologen Dye, hydroquinone - quinones, and the like. The above-mentioned electrolytes may be used alone or in combination. Alternatively, a salt in a molten state at room temperature can 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 0.05 to
20M is preferable, and 0.1-15M is more preferable. As the solvent used for the electrolytic solution, a carbonate-based solvent such as ethylene carbonate and propylene carbonate, a heterocyclic compound such as 3-methyl-2-oxazolidinone, an ether-based solvent such as dioxane, diethyl ether, and ethylene glycol dialkyl ether, methanol, and ethanol. Preferred are alcohol solvents such as polypropylene glycol monoalkyl ether, nitrile solvents such as acetonitrile and benzonitrile, and aprotic polar solvents such as dimethyl sulfoxide and sulfolane.

Further, a basic compound such as t-butylpyridine, 2-picoline or 2,6-lutidine can be added.

In the present invention, the electrolyte may be gelled by a method such as addition of a polymer, addition of an oil gelling agent, polymerization containing polyfunctional monomers, and crosslinking reaction of the polymer. As a preferable polymer in the case of gelation by adding a polymer, polyacrylonitrile, polyvinylidene fluoride and the like can be mentioned. As a preferred gelling agent when gelled by adding an oil gelling agent,
Dibenzylden-D-sorbitol, cholesterol derivative, amino acid derivative, trans- (1R, 2R)-
Examples thereof include alkylamide derivatives of 1,2-cyclohexanediamine, alkylurea derivatives, N-octyl-D-gluconamide benzoate, double-headed amino acid derivatives, and quaternary ammonium derivatives.

In the case of polymerizing with a polyfunctional monomer, preferred monomers are divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate,
Examples thereof include triethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate and the like. In addition, acrylic acid such as acrylamide and methyl acrylate and α-
Esters and amides derived from alkyl acrylic acid, esters derived from maleic acid and fumaric acid such as dimethyl maleate and diethyl fumarate, dienes such as butadiene and cyclopentadiene, styrene, p-
Aromatic vinyl compounds such as chlorostyrene and sodium styrenesulfonate, vinyl esters, acrylonitrile, methacrylonitrile, vinyl compounds having a nitrogen-containing heterocyclic ring, vinyl compounds having a quaternary ammonium salt, N
-A monofunctional monomer such as vinylformamide, vinylsulfonic acid, vinylidene fluoride, vinyl alkyl ethers, and N-phenylmaleimide may be contained. The polyfunctional monomer accounts for 0.5 to 70 of the total amount of monomers.
Weight% is preferable, and 1.0 to 50 weight% is more preferable.

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 electrochemically. 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'-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 parts by mass, and more preferably 0.1 to 10 parts by mass, based on the total amount of the monomers.

When the electrolyte is gelled by the crosslinking reaction of the polymer, it is desirable to use a polymer containing a reactive group necessary for the crosslinking reaction and a crosslinking agent together. Preferred examples of the crosslinkable reactive group include nitrogen-containing heterocycles such as pyridine, imidazole, thiazole, oxazole, triazole, morpholine, piperidine and piperazine. Preferred crosslinking agents are alkyl halides and halogens. Aralkyl, sulfonic acid ester, acid anhydride, acid chloride, isocyanate, and the like, which are bifunctional or higher functional reagents capable of electrophilic reaction with a nitrogen atom.

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

In the present invention, an organic charge transport material can be used instead of the electrolyte. The charge transport material includes a hole transport material and an electron transport material. As an example of the former,
For example, oxadiazoles disclosed in JP-B-34-5466 and the like, triphenylmethanes disclosed in JP-B-45-555, and JP-B-52-4188.
Disclosed in Japanese Patent Publication No. 55-4
2380 and the like, hydrazones shown in JP-A-56-123544 and the like, tetraarylbenzidines shown in JP-A-54-58445, and Kaisho 58-6544
No. 0 or stilbenes disclosed in JP-A-60-98437 can be used. Among them, examples of the charge transporting material used in the present invention include JP-A-60-24553, JP-A-2-96767, JP-A-2-183260, and JP-A-2.
-226160, hydrazones, JP-A-2-51162, and JP-A-3-7566.
The stilbenes disclosed in JP-A-0 are particularly preferable.
Moreover, these can be used individually or as a 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, or 1,3,7-trinitrodibenzothiophene-5,5-dioxide. These electron transport materials can be used alone or as a mixture of two or more kinds.

Further, as a sensitizer for further enhancing 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, phenanthrenequinone, and 4-nitro. Aldehydes such as benzaldehyde, 9
-Benzoylanthracene, indandione, 3,5-
Dinitrobenzophenone or 3,3 ', 5,5'
-Ketones such as tetranitrobenzophenone, phthalic anhydride, acid anhydrides such as 4-chloronaphthalic anhydride, terephthalalmalononitrile, 9-anthrylmethylidene malononitrile, 4-nitrobenzalmalononitrile, or 4- Cyano compounds such as (p-nitrobenzoyloxy) benzalmalononitrile, 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, or 3- (α-cyano-p-nitrobenzal)
Examples thereof include phthalides such as −4,5,6,7-tetrachlorophthalide.

When forming a charge transfer layer using these charge transfer materials, it is preferable to use a resin in combination, such as 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. Among these, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, and polyarylate resin are excellent. Further, these resins can be used alone or as a copolymer by mixing two or more kinds.

Some of these resins include pulling, bending,
Some have weak mechanical strength such as compression. To improve this property, plasticizing agents can be added. Specifically, phthalate ester (for example, DOP, D
BP, etc., phosphoric acid ester (eg TCP, TOP
Etc.), sebacic acid ester, adipic acid ester, nitrile rubber, chlorinated hydrocarbon and the like. If these substances are added more than necessary, the properties are adversely affected, so the ratio is preferably 20% or less with respect to the binder resin. In addition, an antioxidant, an anti-curl agent and the like can be added if necessary.

The amount of resin used is preferably 0.001 to 20 parts by weight, and 0.0 to 1 part by weight of the charge transport material.
It is more preferably 1 to 5 parts by mass or less. If the ratio of the resin is too high, the sensitivity is lowered, and if the ratio of the resin is too low, the repeating characteristics may be deteriorated or the coating film may be damaged.

There are roughly two methods for forming the charge transfer layer. One is a method in which a counter electrode is first attached to a semiconductor fine particle-containing layer supporting a sensitizing dye, and a liquid charge transfer layer is sandwiched in the gap. The other is a method of directly providing the charge transfer layer on the semiconductor fine particle-containing layer. In this case, the counter electrode will be newly added thereafter.

In the former case, examples of the method for sandwiching the charge transfer layer include an atmospheric pressure process utilizing a capillary phenomenon due to dipping and the like, and a vacuum process in which the gas phase is replaced with a liquid phase at a pressure lower than atmospheric pressure. In the latter case, in the wet charge transfer layer, it is necessary to apply a counter electrode in an undried state to prevent liquid leakage at the edge portion. Further, in the case of a gel electrolyte, there is also a method of applying it by a wet method and solidifying it by a method such as polymerization. In that case, a counter electrode may be provided after drying and fixing. As a method of applying a solution of an organic charge transporting material or a gel electrolyte in addition to the electrolytic solution, the dipping method, the roller method, the dipping method, the air knife method, and the extrusion method can be used as in the case of applying the semiconductor fine particle-containing layer and the dye. , Slide hopper method, wire bar method, spin method, spray method,
Casting method, various printing methods and the like can be mentioned.

As the counter electrode, a support having a conductive layer can be used as in the case of the above-mentioned conductive support, but the support is not always necessary in a structure in which the strength and the sealing property are sufficiently maintained. . As a specific example of the material used for the counter electrode,
Examples thereof include metals such as platinum, gold, silver, copper, aluminum, rhodium and indium, and conductive metal oxides such as carbon, ITO and FTO. There is no limitation on the thickness of the counter electrode, but 3 nm
It is preferably 10 μm.

In order for light to reach the photosensitive layer, at least one of the above-mentioned conductive support and counter electrode must be substantially transparent. In the photoelectric conversion element of the present invention, the method in which the conductive support is transparent and sunlight is incident from the support side is preferable. In this case, it is preferable to use a material that reflects light for the counter electrode, and a metal, glass on which a conductive oxide is deposited, plastic, or a metal thin film is preferable.

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

[0049]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 To a flask were added 2.92 g of ethylenediaminetetraacetic acid and 20 ml of methanol with stirring at room temperature with 2.56 g of titanium tetraisopropoxide and 1.0 ml of 30% hydrogen peroxide solution.
Were sequentially added, and after the addition was completed, stirring was continued at 60 ° C. for 1 hour. Then, 3.5 g of di-n-butylamine was added, and stirring was continued at the same temperature for 4 hours. After cooling to room temperature, a transparent orange semiconductor layer forming solution was obtained. No crystal precipitation was observed even when this solution was allowed to stand for 1 week. Next, this solution was applied onto an ITO glass substrate with a spin coater. After coating, dry at 80 ° C for 1 hour, then in air 50
Baking at 0 ° C. for 1 hour.

[0051]

[Chemical 1]

0.1 part by mass of the dye represented by (1) was dissolved in 100 parts by mass of ethanol. The semiconductor electrode prepared above was immersed in this solution for a whole day and night and subjected to adsorption treatment. As the electrolytic solution, a solution prepared by dissolving 0.60 parts by mass of iodine and 0.46 parts by mass of tetra-n-propylammonium iodide in 800 parts by mass of ethylene carbonate and 200 parts by mass of acetonitrile was used. A platinum thin film was used for the counter electrode.

A photoelectric conversion element was produced by immersing the electrolytic solution between both electrodes. Here, light of 400 nm or less was cut from the working electrode side with a cut filter UV-39 manufactured by Toshiba.
Irradiation with a xenon lamp with mW / cm ² intensity. As a result, open circuit voltage 0.50V, short circuit current density 5.0mA / c
m ² , the shape factor was 0.63, and the conversion efficiency was 3.15%, which were favorable values.

Example 2 2.92 g of ethylenediaminetetraacetic acid was added to malic acid 3.8.
A semiconductor layer forming solution was prepared in the same manner as in Example 1 except that the amount was changed to 4 g. No precipitation of crystals was observed even after standing still for 1 week in this solution. Example 1 using this solution
A photoelectric conversion element was prepared and evaluated in the same manner as in. As a result, open circuit voltage 0.54V, short circuit current density 4.7mA / c
m ² , the shape factor was 0.62, and the conversion efficiency was 3.15%, which were favorable values.

Example 3 A semiconductor layer forming solution was prepared in the same manner as in Example 1 except that 3.5 g of di-n-butylamine was changed to 3.2 g of N-methylaniline. No precipitation of crystals was observed even after standing still for 1 week in this solution. Using this solution, a photoelectric conversion element was prepared and evaluated in the same manner as in Example 1. As a result, open circuit voltage 0.52V, short circuit current density 4.6mA /
cm ² , the shape factor was 0.64, and the conversion efficiency was 3.06%, which were favorable values.

Example 4 A semiconductor layer forming solution was prepared in the same manner as in Example 1 except that 2.56 g of titanium tetraisopropoxide was changed to 0.43 g of titanium. No precipitation of crystals was observed even after standing still for 1 week in this solution. Using this solution, a photoelectric conversion element was prepared and evaluated in the same manner as in Example 1. As a result, open circuit voltage 0.52V, short circuit current density 4.7mA
/ Cm ² , the shape factor was 0.61, and the conversion efficiency was 2.98%, which were favorable values.

Comparative Example 1 Malic acid (5.7 g) was dissolved in methanol (50 ml), titanium tetraisopropoxide (2.0 g) and 30% hydrogen peroxide solution (1.0 ml) were sequentially added, and the mixture was stirred at 60 ° C. for 5 hours. After cooling to room temperature, a transparent orange semiconductor layer forming solution was obtained. When this solution was allowed to stand for 1 day, precipitation of white crystals was observed. From these results, it can be seen that unless an amino compound is added as in the present invention, the solution becomes unstable and crystal precipitation easily occurs. Next, using this solution, a photoelectric conversion element was prepared and evaluated in the same manner as in Example 1. As a result, an open circuit voltage of 0.12 V and a short circuit current density of 0.
9 mA / cm ² , form factor 0.47, conversion efficiency 0.10
%, Which was a low value.

Example 5 2.1 g of titanium dioxide (TTO-55N manufactured by Ishihara Sangyo),
Copolyamide (Amilan CM-8000 manufactured by Toray)
3.9 g, methanol 36.4 g, dioxolane 24.
3 g was dispersed with zirconia beads in a paint conditioner for 10 hours. 1.0 g of the obtained titanium dioxide dispersion was mixed with 4.0 g of the semiconductor layer-forming solution prepared in Example 1. No precipitation of crystals was observed even when this liquid was allowed to stand for 1 week. Next, using this mixed solution, a photoelectric conversion element was prepared and evaluated in the same manner as in Example 1.
As a result, open circuit voltage 0.50V, short circuit current density 4.8m
A / cm ² , a shape factor of 0.67, and a conversion efficiency of 3.22% were good values.

[0059]

As is apparent from the above, according to the present invention, it is possible to provide a photoelectric conversion element having good conversion efficiency.

Claims (5)

[Claims] 1. An electrode in which a semiconductor layer carrying a dye is coated on at least one surface, a counter electrode facing the semiconductor layer of the electrode, and a charge between the semiconductor layer of the electrode and the counter electrode. In a photoelectric conversion element having a transfer layer, the semiconductor layer is characterized by being prepared from a polycarboxylic acid or a salt thereof and a metal compound, and a semiconductor layer forming solution in which an amino compound is dissolved in an alcohol solution. Photoelectric conversion element. 2. The semiconductor layer comprises titanium, tin, zinc,
Iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, cadmium,
The photoelectric conversion element according to claim 1, comprising at least one metal chalcogenide compound selected from lead, silver, antimony, bismuth, molybdenum, aluminum, gallium, chromium, cobalt, and nickel. 3. The photoelectric conversion element according to claim 2, wherein the metal chalcogenide is titanium oxide. 4. The dye supported on the semiconductor layer is selected from metal complex compounds, cyanine dyes, merocyanine dyes, 9-arylxanthene compounds, triarylmethane compounds, coumarin compounds, acridine compounds, azo compounds, phthalocyanine compounds, and porphyrin compounds. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element is at least one compound. 5. A dispersion of metal chalcogenide is contained in a semiconductor layer-forming solution obtained by dissolving a polycarboxylic acid or a salt thereof and a metal compound and an amino compound in an alcohol solution. The photoelectric conversion element according to claim 1.