JP2014067534A - Method of manufacturing semiconductor electrode, semiconductor electrode, and dye-sensitized solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor electrode for a dye-sensitized solar cell having an excellent photoelectric conversion efficiency.SOLUTION: A method of manufacturing a semiconductor electrode for a dye-sensitized solar cell includes a step of: coating a dye-containing liquid which contains an organic dye represented by at least any one of general formula [I] and the like, on a semiconductor layer; or immersing the semiconductor layer in the dye-containing liquid. Cyclopentylmethylether is used as a medium of the dye-containing liquid.

Description

  The present invention relates to a semiconductor electrode manufacturing method, a semiconductor electrode using the manufacturing method, and a dye-sensitized solar cell.

  Global warming due to the increase in carbon dioxide concentration caused by the use of large amounts of fossil fuels, and the increase in energy demand accompanying population growth are recognized as problems related to the survival of humankind. Therefore, in recent years, the use of sunlight that does not generate infinite and harmful substances has been energetically studied. Examples of solar energy that is currently used as a clean energy source include 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 terms of long payback to the user, and there has been 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 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, photoelectric conversion efficiency is often as low as 1% or less, and there is a problem that durability is poor.

  Under such circumstances, a solar cell exhibiting good characteristics has been reported by Dr. Gretzell of Switzerland (see, for example, Non-Patent Document 1). This document also discloses materials and manufacturing techniques necessary for battery fabrication. This solar cell 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 (Ru) complex as a working electrode. The advantage of this method is that it is not necessary to purify inexpensive semiconductors such as titanium oxide to high purity, so that the manufacturing cost can be reduced compared to the inorganic solar cells described above, and the available light is in the visible light region. Therefore, it is possible to effectively convert sunlight, which has a high energy intensity in the visible light region, into electricity.

  However, since noble metal Ru, which has resource limitations, is used, there is a possibility that a problem may occur in the stable supply of the Ru complex when a dye-sensitized solar cell is put into practical use. In addition, due to this resource limitation, the Ru complex itself is expensive, and there may be a problem in terms of cost during mass production. In order to solve such a problem, various proposals have been made for the purpose of changing at least part of the Ru complex to a cheaper organic dye. As examples thereof, various merocyanine dyes, cyanine dyes, 9-phenylxanthene dyes, coumarin dyes and the like are disclosed, but these are considerably inferior to Ru complexes in photoelectric conversion efficiency. In addition, there are problems with adsorption stability to semiconductors, and most of them have poor practicality. (For example, see Patent Documents 1 to 4).

  Organic dyes having photoelectric conversion efficiency comparable to Ru complexes have been disclosed as dyes for color-sensitized solar cells (see, for example, Patent Documents 5, 6 and 7). However, its performance is insufficient and further photoelectric conversion efficiency improvement is demanded.

  Recently, organic dyes having excellent adsorption stability to semiconductors and good photoelectric conversion efficiency have been found, but they are still slightly inferior to the photoelectric conversion efficiency of Ru complexes, and further improvement of photoelectric conversion efficiency is achieved. (For example, see Patent Document 8).

JP 11-238905 A JP 2001-76773 A Japanese Patent Laid-Open No. 10-92477 International Publication No. 2002/045199 Pamphlet JP 2004-200068 A Japanese Patent No. 4326272 JP 2007-115673 A International Publication No. 2010/016612 Pamphlet

Brian O'Regan & Michael Gratzel, “A low-cost, high-efficiency solar cell based on dyed-sensitive TiO2 films”, Nature, 1991, 53. 737-740

  The subject of this invention is providing the manufacturing method of the semiconductor electrode which has the outstanding photoelectric conversion efficiency.

  As a result of intensive studies to achieve the above-mentioned problems, a dye-containing liquid containing an organic dye represented by at least one of general formula [I], general formula [II], general formula [III], and general formula [IV] In the method for producing a semiconductor electrode for a dye-sensitized solar cell including a step of coating or immersing the dye in a semiconductor layer, the object could be achieved by using cyclopentyl methyl ether as a medium for the dye-containing liquid.

In the general formula [I], R ₁ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₂ and R ₃ represent a hydrogen atom or an alkyl group, and both may be linked to form a cyclopentane ring or a cyclohexane ring. L ₁ represents a conjugated methine group, and l represents an integer of 1 to 3. Y ₁ represents an acidic group having a pKa of less than 6.

In the general formula [II], R ₄ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₅ and R _{6 each} represent a hydrogen atom or an alkyl group, and both may combine to form a cyclopentane ring or a cyclohexane ring. m shows the integer of 1-3. Y ₂ represents an acidic group having a pKa of less than 6. R ₇ represents an alkyl group or an aralkyl group, and may have an acidic group having a pKa of less than 6 as a substituent. L ₂ represents a conjugated methine group.

In the general formula [III], R ₈ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₉ and R _{10 each} represent a hydrogen atom or an alkyl group, and both may combine to form a cyclopentane ring or a cyclohexane ring. n shows the integer of 1-3. Y ₃ represents an acidic group having a pKa of less than 6. R ₁₁ and R ₁₂ represent an alkyl group or an aralkyl group, and may have an acidic group having a pKa of less than 6 as a substituent. L ₃ represents a conjugated methine group.

In the general formula [IV], R ₁₃ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₁₄ and R ₁₅ represent a hydrogen atom or an alkyl group, and they may be linked to form a cyclopentane ring or a cyclohexane ring. L ₄ represents a divalent linking group. p represents 0 or 1. Y ₄ represents a carboxylate anion that forms an ion pair with a carboxy group or a salt-forming cation.

  Ruthenium complexes and organic dyes generally used for dye-sensitized solar cells are hydrophilic polar organic solvents such as ethanol and alcohols such as t-butanol, nitriles such as acetonitrile, tetrahydrofuran (THF), 1 It dissolves in ethers such as 1,4-dioxane, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and the like, and is hardly soluble in a hydrophobic polar organic solvent (for example, diethyl ether). In the present invention, it is found that the organic dye according to the present invention is dissolved in cyclopentyl methyl ether, which is a hydrophobic polar organic solvent, unlike the general organic dye, and the organic dye according to the present invention is adsorbed on the semiconductor layer. The object was achieved by using cyclopentyl methyl ether as a medium for the dye-containing liquid upon loading.

  The production of a semiconductor electrode used in a dye-sensitized solar cell is usually performed by applying or immersing a dye-containing liquid containing a ruthenium complex or an organic dye in a semiconductor layer, but in an organic solvent used as a medium. In order to prevent deterioration of the semiconductor electrode due to water contained in the water, it was necessary to give sufficient consideration to the water content of the hydrophilic organic solvent used.

  Since the manufacturing method of the semiconductor electrode of the present invention uses hydrophobic cyclopentyl methyl ether as a medium used in the dye-containing liquid for coating or immersion, the semiconductor electrode is deteriorated by water contained in the organic solvent. It is characterized in that it can be prevented.

  For the purpose of improving the conversion efficiency of the semiconductor electrode, when the organic dye according to the present invention and the ruthenium complex are used together and adsorbed and supported on the semiconductor layer, the ruthenium complex is contained and the medium has a hydrophilic polarity. Application or immersion with a dye-containing liquid using an organic solvent, application or immersion with a dye-containing liquid containing the organic dye according to the present invention and using cyclopentyl methyl ether as a medium, and thereby the ruthenium complex and the organic dye Adsorption and loading can be performed without disturbing the mutual adsorption state on the semiconductor layer, and the conversion efficiency can be improved efficiently.

  The dye represented by the general formula [I] will be described.

In general formula [I], R ₂ and R ₃ represent a hydrogen atom or an alkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. Group, an alkyl group having a side chain such as an isohexyl group, an alkylene group linked with R ₁ and R ₂ such as a 1,4-butylene group and a 1,5-pentylene group to form a cyclopentane ring or a cyclohexane ring. It is done.

R ₁ represents an aromatic hydrocarbon residue or a heterocyclic residue, and preferred examples include AR-1 to AR-22 shown below, but are not limited thereto. R ₁ may further have an acidic group having a pKa of less than 6 as a substituent in these aromatic hydrocarbon residues or heterocyclic residues. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

L ₁ represents a conjugated methine group, among which one having 1 carbon atom is particularly preferable. l shows the integer of 1-3.

Y ₁ represents an acidic group having a pKa of less than 6. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

  The dye represented by the general formula [II] will be described.

In the general formula [II], R ₄ represents an aromatic hydrocarbon residue or a heterocyclic residue. Specific examples of the aromatic hydrocarbon residue or heterocyclic residue include those similar to R _{1 in} formula [I]. R ₄ may further have an acidic group having a pKa of less than 6 as a substituent. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

R ₅ and R ₆ represent a hydrogen atom or an alkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. Group, an alkyl group having a side chain such as an isohexyl group, an alkylene group linked with R ₅ and R ₆ such as a 1,4-butylene group and a 1,5-pentylene group to form a cyclopentane ring or a cyclohexane ring. It is done.

L ₂ represents a conjugated methine group, among which one having 1 carbon atom is particularly preferable. m shows the integer of 1-3.

Y ₂ represents an acidic group having a pKa of less than 6. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

R ₇ represents an alkyl group or an aralkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. And alkyl groups having a side chain such as an isohexyl group, among which a linear alkyl group having 4 or more carbon atoms is particularly preferable. Specific examples of the aralkyl group include a benzyl group, a phenethyl group, and a 4-phenylbutyl group. Among them, a benzyl group is particularly preferable. R ₇ may further have an acidic group having a pKa of less than 6 as a substituent. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

  The dye represented by the general formula [III] will be described.

In the general formula [III], R ₈ represents an aromatic hydrocarbon residue or a heterocyclic residue. Specific examples of the aromatic hydrocarbon residue or heterocyclic residue include those similar to R _{1 in} formula [I]. R ₈ may further have an acidic group having a pKa of less than 6 as a substituent. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

R ₉ and R ₁₀ represent a hydrogen atom or an alkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. And an alkylene group having a side chain such as an isohexyl group, an alkylene group linked to R ₉ and R ₁₀ such as a 1,4-butylene group and a 1,5-pentylene group to form a cyclopentane ring or a cyclohexane ring. .

L ₃ represents a conjugated methine group, among which one having 1 carbon atom is particularly preferable. n shows the integer of 1-3.

Y ₃ represents an acidic group having a pKa of less than 6. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

R ₁₁ and R ₁₂ represent an alkyl group or an aralkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. And alkyl groups having a side chain such as an isohexyl group, among which a linear alkyl group having 4 or more carbon atoms is particularly preferable. Specific examples of the aralkyl group include a benzyl group, a phenethyl group, and a 4-phenylbutyl group. Among them, a benzyl group is particularly preferable. R ₁₁ and R ₁₂ may further have an acidic group having a pKa of less than 6 as a substituent. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

  The dye represented by the general formula [IV] will be described.

In the general formula [IV], R ₁₄ and R ₁₅ represent a hydrogen atom or an alkyl group. Specific examples of the alkyl group include linear alkyl groups such as ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group and n-octyl group, isopropyl group, isobutyl group and isopentyl group. Group, an alkyl group having a side chain such as an isohexyl group, an alkylene group linked with R ₁₄ and R ₁₅ such as a 1,4-butylene group and a 1,5-pentylene group to form a cyclopentane ring or a cyclohexane ring. It is done.

R ₁₃ represents an aromatic hydrocarbon residue or a heterocyclic residue, and preferred examples include those similar to R ₁ of the general formula [I], but are not limited thereto. R ₁₃ may further have an acidic group having a pKa of less than 6 as a substituent. Specific examples of the acidic group having a pKa of less than 6 include a carboxy group, a sulfo group, a sulfino group, a sulfeno group, a phosphono group, and a phosphinico group, among which a carboxy group is particularly preferable.

L ₄ represents a divalent linking group, and preferred examples include, but are not limited to, those shown below. p represents 0 or 1.

Y ₄ represents a carboxylate anion that forms an ion pair with a carboxy group or a salt-forming cation.

  Examples of cations capable of forming a salt with the carboxylate anion include ammonium cations such as ammonium, triethylammonium, tetraethylammonium, piperidinium, pyrrolidinium, and pyridinium, and alkali metal cations such as lithium, sodium, and potassium.

  Next, specific examples of the compound of the general formula [I] according to the present invention will be given, but the present invention is not limited thereto.

  Next, although the specific example of the compound of general formula [II] of this invention is given, it is not limited to these.

  Next, specific examples of the compound of the general formula [III] of the present invention will be given, but the present invention is not limited thereto.

  Next, specific examples of the compound of the general formula [IV] of the present invention will be given, but the present invention is not limited thereto.

  These compounds can be synthesized with reference to the synthesis methods described in, for example, JP-A-8-269345 and WO 2004/01155 pamphlet.

  The dye-sensitized solar cell includes a conductive support, a semiconductor layer (semiconductor electrode) sensitized with a dye provided on the surface of the conductive support, a charge transfer layer, and a counter electrode. The semiconductor 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 semiconductor layer of the conductive support, the boundary between the semiconductor layer and the moving layer, the constituent components of each layer may diffuse or mix 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. And the like (hereinafter abbreviated as “FTO”). 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 conductive support by vapor deposition, sputtering, pressure bonding, etc., and a method of providing ITO or FTO thereon, or a method of installing a metal lead wire on a transparent substrate having conductivity on the surface. is there.

  Examples of the semiconductor include a single semiconductor such as silicon and germanium, a compound semiconductor typified by a metal chalcogenide, and a compound having a perovskite structure. Metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxides; cadmium, zinc, lead, silver, antimony or bismuth Preferable examples include sulfides of cadmium or selenides of lead or cadmium tellurides. Other compound semiconductors are preferably phosphides such as zinc, gallium, indium, and 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. From the viewpoint of photoelectric conversion efficiency, a single crystal is preferable, but from the viewpoint of manufacturing costs, securing raw materials, etc., a polycrystal is preferable. The particle size of the semiconductor is preferably 2 nm or more and 1 μm or less. Regarding the measurement of the particle size, a method by observation with a transmission electron microscope is preferable.

  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. As a method for producing a dispersion, a sol-gel method, a method of mechanically pulverizing with a mortar, a method of dispersing while pulverizing using a mill, or a fine particle in a solvent when synthesizing a semiconductor, The method of using it as it is is mentioned.

  In the case of a dispersion prepared by mechanical pulverization or pulverization using a mill, the dispersion is prepared 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.

  As a medium for dispersing the semiconductor fine particles, alcohol-based media such as water, methanol, ethanol, isopropyl alcohol; ketone-based media such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based media such as ethyl formate, ethyl acetate, and n-butyl acetate Medium: Ether-based medium such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane; Amide-based medium such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone; Dichloromethane, chloroform, Bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, 1-chloronaphtha Halogenated hydrocarbon media such as n; pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p- Examples thereof include hydrocarbon-based media such as xylene, ethylbenzene, cumene. These can be used alone or as a mixed medium of two or more.

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

  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. Also, different types of semiconductors, and coating layers having different compositions of resins and additives can be applied in multiple layers. Multi-layer coating is an effective means when the film thickness is insufficient with a single coating.

  In general, as the semiconductor layer thickness increases, the amount of supported dye increases per unit projected area, which increases the light capture rate, but also increases the diffusion distance of the generated electrons, resulting in more charge recombination. turn into. 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, heat treatment is preferred from the viewpoints of electronic contact between fine particles, improvement in coating film strength, and improvement in adhesion to the support. Further, microwave irradiation, press treatment, or electron beam irradiation may be performed. 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. 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 performed at 9.8 × 10 ⁶ N / m ² or more, and more preferably at 9.8 × 10 ⁷ N / m ² or more. The pressing time is not particularly limited, but is preferably 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 organic dyes represented by the general formulas [I] to [IV] according to the present invention may be used singly or in combination of two or more. Further, for the purpose of reducing the amount of Ru used in a dye-sensitized solar cell using a ruthenium (Ru) complex, the dye according to the present invention may be used in combination with the Ru complex. Other merocyanine dyes, cyanine dyes, 9-phenylxanthene dyes, coumarin dyes, phthalocyanine dyes, naphthalocyanine dyes, and the like may be used in combination. Among them, when the dye according to the present invention and the Ru complex are used in combination, the production method of the present invention is particularly effective in sequentially adsorbing the dye according to the present invention and the Ru dye on the semiconductor layer.

  As a method for adsorbing the dye to the semiconductor layer, a method in which the semiconductor layer is immersed in a dye-containing liquid containing a dye, or a method in which a dye-containing liquid containing a dye is applied to the semiconductor layer and adsorbed can be used. 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. The dye may be either dissolved in the medium or dispersed in the medium.

  When adsorbing the dye, a condensing agent may be used in combination. The condensing agent may be either one that acts as a catalyst that physically or chemically binds the dye to the inorganic surface, or one that acts stoichiometrically to favorably shift the chemical equilibrium. . Further, a thiol or hydroxy compound may be added as a condensation aid.

  For the dye-containing liquid containing the organic dye according to the present invention, cyclopentyl methyl ether is used as a medium. Cyclopentyl methyl ether is a hydrophobic organic solvent that is difficult to mix with water, unlike hydrophilic ethers such as THF and 1,4-dioxane. Therefore, when the dye is adsorbed to the semiconductor layer, the influence of moisture contained in the solvent can be reduced, and the organic dye can be adsorbed to the semiconductor layer stably. In addition, cyclopentyl methyl ether has a boiling point of 106 ° C., and is generally used as a medium for the dye-containing liquid. Acetonitrile (boiling point: 82 ° C.), t-butanol (boiling point: 82 ° C.), THF (boiling point: 65 ° C.) The boiling point of the dye-containing liquid is high, and it is difficult to evaporate at room temperature.

  In the sequential adsorption of two or more kinds of dyes to the semiconductor layer, dyes other than the dyes according to the present invention (for example, Ru complexes, other merocyanine dyes, cyanine dyes, 9-phenylxanthene dyes, coumarin dyes, phthalocyanine) A dye-containing liquid medium containing water-based dye, naphthalocyanine-based dye, etc.) alcohol-based medium such as water, methanol, ethanol, isopropyl alcohol; ketone-based medium such as acetone, methyl ethyl ketone, methyl isobutyl ketone; ethyl formate, Ester media such as ethyl acetate and n-butyl acetate; Ether media such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane and cyclopentyl methyl ether; Nitrile media such as acetonitrile and propionitrile; N, N-dimethyl Amide-based media such as formamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone; dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene Halogenated hydrocarbon media such as iodobenzene, 1-chloronaphthalene; n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene , M-xylene, p-xylene, ethylbenzene, cumene, and other hydrocarbon-based media. These can be used alone or in admixture of two or more.

  The temperature for adsorbing the dye is preferably -50 ° C or higher and 200 ° C or lower. Further, the 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 from 5 seconds to 1000 hours, more preferably from 10 seconds to 500 hours, and even more preferably from 1 minute to 150 hours.

  In the present invention, when the dye is adsorbed on the semiconductor layer, a steroidal compound may be used in combination and co-adsorbed.

  Specific examples of the steroidal compounds include those shown in E-1 to E-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 after co-adsorbing the dye and the steroidal compound, a basic compound such as t-butylpyridine, 2-picoline, 2,6-lutidine, or phosphoric acid, phosphate ester, alkyl You may immerse in the organic solvent containing acidic compounds, such as phosphoric acid, an acetic acid, and propionic acid.

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

  The electrolytic solution 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, calcium iodide; quaternary grades such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc. Iodine salt of ammonium compound-iodine combination; metal bromide-bromine combination such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, calcium bromide; quaternary ammonium such as tetraalkylammonium bromide, pyridinium bromide Bromine-bromine combinations of compounds; metal complexes such as ferrocyanate-ferricyanate and ferrocene-ferricinium ions; sulfur compounds such as sodium polysulfide and alkylthiol-alkyldisulfides ; Viologen dyes, hydroquinone - such as 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 and 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. Moreover, you may use together basic compounds, such as t-butyl pyridine, 2-picoline, and 2, 6- lutidine.

  The electrolyte can be gelled by techniques such as polymer addition, oil gelling agent addition, polymerization including polyfunctional monomers, and polymer crosslinking reaction. Preferable polymers for gelation by addition of polymer include polyacrylonitrile, polyvinylidene fluoride, and the like. Preferred gelling agents for gelation by adding an oil gelling agent include dibenzylidene-D-sorbitol, cholesterol derivatives, amino acid derivatives, trans- (1R, 2R) -1,2-cyclohexanediamine alkylamide derivatives, alkyl Examples include urea derivatives, N-octyl-D-gluconamidobenzoate, double-headed amino acid derivatives, quaternary ammonium derivatives, and the like.

  Preferred monomers for polymerization with polyfunctional monomers include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and the like. Can do. 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 Dienes such as pentadiene, aromatic vinyl compounds such as styrene, p-chlorostyrene, sodium styrenesulfonate, vinyl esters, acrylonitrile, methacrylonitrile, vinyl compounds having a nitrogen-containing heterocyclic ring, vinyls having a quaternary ammonium salt A monofunctional monomer such as a compound, N-vinylformamide, vinyl sulfonic acid, vinylidene fluoride, vinyl alkyl ethers, and 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), peroxide initiators such as benzoyl peroxide, and the like 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 reactive group necessary for the crosslinking reaction include nitrogen-containing heterocycles such as pyridine, imidazole, thiazole, oxazole, triazole, morpholine, piperidine and piperazine. Preferred cross-linking agents include bifunctional or higher functional reagents capable of electrophilic reaction with nitrogen atoms such as alkyl halides, halogenated aralkyls, sulfonic acid esters, acid anhydrides, acid chlorides, and isocyanates.

  When an inorganic hole transport material 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, or electrolytic plating.

  It is also possible to use an organic charge transport material instead of the electrolyte. Charge transport materials include hole transport materials and electron transport materials. Examples of the former include, for example, oxadiazoles shown in Japanese Patent Publication No. 34-5466, triphenylmethanes shown in Japanese Patent Publication No. 45-555, and Japanese Patent Publication No. 52-4188. Pyrazolines shown in JP-A-55-42380, hydrazones shown in JP-B-56-123544, oxadiazoles shown in JP-A-56-123544, etc., JP-A-54-58445 And tetrasylbenzidines disclosed in JP-A-58-65440, and stilbenes disclosed in JP-A-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, or 1,3,7-trinitrodibenzothiophene-5,5-dioxide . These electron transport materials can be used alone or as a mixture of two or more.

  Furthermore, for the purpose of improving the charge transfer efficiency in the charge transfer layer, a certain kind of electron withdrawing compound can be added to the charge transfer layer. 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, 3,3 ', 5,5'-tetranitrobenzophenone; phthalic anhydride, 4-chloronaphthalic anhydride, etc. Cyano compounds such as terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, 4- (p-nitrobenzoyloxy) benzalmalononitrile; 3-benzalphthalide, 3 -(Α-cyano-p-ni Robenzaru) phthalide, 3- (alpha-cyano -p- Nitorobenzaru) -4,5,6,7 such phthalides such as tetrachloro phthalide can be cited.

  When forming a charge transfer layer using a charge transport material, a resin may be used in combination. When the 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 given. 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 bonded onto a semiconductor layer that has adsorbed a dye, and a liquid charge transfer layer is sandwiched in the gap. The other is a method in which a charge transfer layer is provided directly on a semiconductor layer adsorbed with a dye. In the latter case, a counter electrode is newly provided on the charge transfer layer.

  In the former case, examples of the method for sandwiching the charge transfer layer include a normal pressure process using capillary action 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 electrolytic solution, the organic charge transport material solution and gel electrolyte can be applied in the same manner as the semiconductor layer and pigment application, as well as the immersion method, roller method, dipping method, air knife method, extrusion method, slide Examples include the hopper method, wire bar method, spin method, spray method, casting method, and various printing methods.

  The counter electrode can be used on a support having a conductive layer in the same manner as the substrate having conductivity on the surface, but the support is not necessarily required when the conductive layer itself has sufficient strength and sealing properties. 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 semiconductor layer, at least one of the conductive substrate and the counter electrode on the surface holding the semiconductor layer must be substantially transparent. In the photoelectric conversion element of this invention, the board | substrate which has electroconductivity on the surface holding the semiconductor layer is transparent, and the method of making sunlight inject from the electroconductive board | substrate side holding the semiconductor layer 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 layer. In any case, the counter electrode material can be appropriately formed on the charge transfer layer or the semiconductor 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 conductive material by a method such as coating, vapor deposition, or chemical vapor deposition (CVD).

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

Example 1
<Preparation of dye-sensitized solar cell>
Titanium oxide paste: 1.2 g of PST-18NR (catalyst chemical industry, average particle size 18 nm) and titanium oxide paste: PST-400C (catalyst chemical industry, average particle size 400 nm) 0.3 g in a mortar Were sufficiently kneaded for 10 minutes to prepare an electrode manufacturing paste. This paste was applied onto an FTO glass substrate (manufactured by AGC Fabrytec, product name: VU) so as to have a film thickness of 5 μm, dried at room temperature, baked at 100 ° C. for 30 minutes, and further at 450 ° C. for 1 hour, A semiconductor electrode was obtained.

  The dye (B-2) was dissolved in cyclopentyl methyl ether to prepare a dye-containing solution having a concentration of 0.5 mM. The dye electrode-containing semiconductor electrode (working electrode) was prepared by immersing the previously prepared semiconductor electrode in this dye-containing solution for 3 hours at room temperature and performing an adsorption treatment. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

(Comparative Example 1)
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the medium for dissolving the dye (B-2) was changed to THF.

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, simulated sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Example 1 and Comparative Example 1 was evaluated using an electrochemical measurement device (manufactured by Solartron, device name: SI-1280B). The results are shown in Table 1. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Example 1 were shown as relative values based on the evaluation results of Comparative Example 1.

(Examples 2 to 16)
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that the dye (B-2) was changed to the dye shown in Table 2.

(Comparative Examples 2 to 16)
A dye-sensitized solar cell was produced in the same manner as in Comparative Example 1 except that the dye (B-2) was changed to the dye shown in Table 2.

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, artificial sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Examples 2 to 16 and Comparative Examples 2 to 16 was evaluated using an electrochemical measurement apparatus (manufactured by Solartron, apparatus name: SI-1280B). The results are shown in Table 2. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Examples 2 to 16 are shown as relative values based on the evaluation results of Comparative Examples 2 to 16.

(Example 17)
<Preparation of dye-sensitized solar cell>
The dye (C-5) was dissolved in cyclopentyl methyl ether to prepare a dye-containing solution having a concentration of 0.5 mM. A semiconductor electrode produced in the same manner as in Example 1 was immersed in this dye-containing solution at room temperature for 3 hours to perform an adsorption treatment, thereby producing a working electrode. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

(Comparative Example 17)
A dye-sensitized solar cell was produced in the same manner as in Example 13 except that the medium for dissolving the dye (C-5) was changed to a mixed solution of t-butanol / acetonitrile (1/1: volume ratio).

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, artificial sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Example 17 and Comparative Example 17 was evaluated using an electrochemical measurement apparatus (manufactured by Solartron, apparatus name: SI-1280B). The results are shown in Table 3. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Example 17 are shown as relative values based on the evaluation results of Comparative Example 17.

(Examples 18 to 32)
A dye-sensitized solar cell was produced in the same manner as in Example 17 except that the dye (C-5) was changed to the dye shown in Table 3.

(Comparative Examples 18-32)
A dye-sensitized solar cell was produced in the same manner as in Comparative Example 17 except that the dye was changed to the dye shown in Table 3.

<Evaluation 1: Photoelectric conversion efficiency>
The photoelectric conversion efficiency of the dye-sensitized solar cell was evaluated in the same manner as in Example 17. The results are shown in Table 3. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Examples 17 to 32 are shown as relative values based on the evaluation results of Comparative Examples 17 to 32.

(Example 33)
<Preparation of dye-sensitized solar cell>
The dye (A-3) was dissolved in cyclopentyl methyl ether to prepare a dye-containing solution having a concentration of 0.5 mM. A semiconductor electrode produced in the same manner as in Example 1 was immersed in this dye-containing solution at room temperature for 3 hours to perform an adsorption treatment, thereby producing a working electrode. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

(Comparative Example 33)
A dye-sensitized solar cell was produced in the same manner as in Example 25 except that the medium for dissolving the dye (A-3) was changed to a mixed solution of t-butanol / acetonitrile (1/1: volume ratio).

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, artificial sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Example 33 and Comparative Example 33 was evaluated using an electrochemical measurement device (manufactured by Solartron, device name: SI-1280B). The results are shown in Table 4. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Example 33 are shown as relative values based on the evaluation results of Comparative Example 33.

(Examples 34 to 48)
A dye-sensitized solar cell was produced in the same manner as in Example 33 except that the dye (A-3) was changed to the dye shown in Table 4.

(Comparative Examples 34 to 48)
A dye-sensitized solar cell was produced in the same manner as in Comparative Example 33 except that the dye was changed to the dye shown in Table 4.

<Evaluation 1: Photoelectric conversion efficiency>
The photoelectric conversion efficiency of the dye-sensitized solar cell was evaluated in the same manner as in Example 33. The results are shown in Table 4. The open circuit voltage, the short circuit current density, and the photoelectric conversion efficiency of Examples 34 to 48 are shown as relative values based on the evaluation results of Comparative Examples 34 to 48.

(Example 49)
<Preparation of dye-sensitized solar cell>
The dye (D-5) was dissolved in cyclopentyl methyl ether to prepare a dye-containing solution having a concentration of 0.5 mM. A semiconductor electrode produced in the same manner as in Example 1 was immersed in this dye-containing solution at room temperature for 3 hours to perform an adsorption treatment, thereby producing a working electrode. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

(Comparative Example 49)
A dye-sensitized solar cell was produced in the same manner as in Example 49 except that the medium for dissolving the dye (D-5) was changed to THF.

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, artificial sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Example 49 and Comparative Example 49 was evaluated using an electrochemical measurement apparatus (manufactured by Solartron, apparatus name: SI-1280B). The results are shown in Table 5. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Example 49 were shown as relative values based on the evaluation results of Comparative Example 49.

(Examples 50 to 60)
A dye-sensitized solar cell was produced in the same manner as in Example 49 except that the dye (D-5) was changed to the dye shown in Table 5.

(Comparative Examples 50-60)
A dye-sensitized solar cell was produced in the same manner as in Comparative Example 49 except that the dye was changed to the dye shown in Table 5.

<Evaluation 1: Photoelectric conversion efficiency>
The photoelectric conversion efficiency of the dye-sensitized solar cell was evaluated in the same manner as in Example 49. The results are shown in Table 5. The open circuit voltage, the short circuit current density, and the photoelectric conversion efficiency of Examples 50 to 60 are shown as relative values based on the evaluation results of Comparative Examples 50 to 60.

(Examples 61-120, Comparative Examples 61-120)
<Evaluation 2: Stability of dye adsorption solution>
The dye-containing liquids used in Examples 1 to 60 and Comparative Examples 1 to 60 were placed in a glass transparent sample bottle, shielded from light, sealed and heated to 30 ° C., and stored for 30 days. The state of the dye-containing liquid after 30 days was visually observed. The results are shown in Tables 6 and 7.
○: Uniform solution.
Δ: Dye precipitation crystals are slightly seen.

(Example 121)
Ru complex (F-1) was dissolved in a mixed solution of t-butyl alcohol / acetonitrile (1/1: volume ratio) to prepare a dye-containing solution having a concentration of 0.5 mM. The semiconductor electrode produced in Example 1 was immersed in this dye-containing liquid for 1.5 hours at room temperature, and an adsorption treatment was performed. Subsequently, a dye-adsorbing semiconductor electrode (working electrode) in which the Ru complex and the dye D-5 according to the present invention were co-adsorbed was prepared by immersing in the dye-containing solution prepared in Example 49 at room temperature for 1.5 hours. did. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

(Comparative Example 121)
The dye (D-5) according to the present invention was dissolved in a mixed solution of t-butyl alcohol / acetonitrile (1/1: volume ratio) to prepare a dye-containing liquid having a concentration of 0.5 mM. The semiconductor electrode prepared in Example 1 was immersed in the dye-containing solution of t-butyl alcohol / acetonitrile (1/1: volume ratio) of the Ru complex (F-1) prepared in Example 121 for 1.5 hours at room temperature. Then, the semiconductor electrode is immersed in a dye-containing solution of t-butyl alcohol / acetonitrile (1/1: volume ratio) of the dye (D-5) according to the present invention for 1.5 hours at room temperature. By performing sequential adsorption treatment, a dye-adsorbing semiconductor electrode (working electrode) in which the Ru complex and the dye according to the present invention were co-adsorbed was produced. As the counter electrode, a titanium plate on which platinum was sputtered was used. Both electrodes were placed so as to face each other, and an electrolyte was injected between them to produce a dye-sensitized solar cell. The electrolyte was 3-methoxypropionitrile of lithium iodide 0.1M, iodine 0.05M, 1,2-dimethyl-3-n-propylimidazolium iodide 0.5M, 4-t-butylpyridine 0.05M. The solution was used.

<Evaluation 1: Photoelectric conversion efficiency>
From the working electrode side of the dye-sensitized solar cell, artificial sunlight (AM1.5G, irradiation intensity 100 mW / cm ² ) generated from a solar simulator (manufactured by Yamashita Denso Co., Ltd., device name: YSS-40S) as a light source. The photoelectric conversion efficiency of the dye-sensitized solar cells of Example 121 and Comparative Example 121 was evaluated using an electrochemical measurement apparatus (manufactured by Solartron, apparatus name: SI-1280B). The results are shown in Table 8. The open circuit voltage, short circuit current density, and photoelectric conversion efficiency of Example 121 were shown as relative values based on the evaluation results of Comparative Example 121.

  As is apparent from Tables 1 to 5, it can be seen that the dye-sensitized solar cell produced by the method for producing a semiconductor electrode of the present invention has excellent performance. This is presumably because the use of hydrophobic cyclopentyl methyl ether as the medium used in the dye-containing liquid prevented the semiconductor electrode from being deteriorated by water contained in the organic solvent. Further, as is apparent from Tables 6 to 7, it can be seen that the cyclopentyl methyl ether used in the present invention is excellent in terms of the temporal stability of the dye-containing liquid.

  As is apparent from Table 8, it can be seen that the dye-sensitized solar cell produced by the method for producing a semiconductor electrode of the present invention has superior performance. This effect is manifested by using a dye-containing liquid containing the dye according to the present invention and using hydrophobic cyclopentyl methyl ether as a medium when performing sequential adsorption of the dye to the semiconductor layer. By using low-solubility Ru dye and hydrophobic cyclopentyl methyl ether as a medium for sequential adsorption in the dye according to the present invention, the adsorption arrangement of the Ru complex and the dye according to the present invention on the semiconductor layer is disturbed. It is estimated that high performance is manifested because it is difficult to occur.

  The method for producing a semiconductor electrode of the present invention and the method for producing a semiconductor electrode can be used for an optical sensor sensitive to light of a specific wavelength in addition to a dye-sensitized solar cell.

Claims (3)

A step of applying or dipping a dye-containing liquid containing an organic dye represented by at least one of the following general formula [I], general formula [II], general formula [III], and general formula [IV] to a semiconductor layer A method for producing a semiconductor electrode for a dye-sensitized solar cell, comprising using cyclopentyl methyl ether as a medium for the dye-containing liquid in a method for producing a semiconductor electrode for a dye-sensitized solar cell comprising:
(In the general formula [I], R ₁ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₂ and R ₃ are hydrogen atoms. Or an alkyl group, which may be linked to form a cyclopentane ring or a cyclohexane ring, L ₁ represents a conjugated methine group, l represents an integer of 1 to 3, and Y ₁ represents a pKa of Indicates an acidic group of less than 6.)
(In the general formula [II], R ₄ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₅ and R ₆ represent hydrogen. An atom or an alkyl group, which may combine to form a cyclopentane ring or a cyclohexane ring, m represents an integer of 1 to _3. Y ₂ represents an acidic group having a pKa of less than 6. R ₇ represents an alkyl group or an aralkyl group, and may have an acidic group having a pKa of less than 6 as a substituent, and L ₂ represents a conjugated methine group.)
(In the general formula [III], R ₈ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₉ and R ₁₀ represent hydrogen. An atom or an alkyl group, which may combine to form a cyclopentane ring or a cyclohexane ring, n represents an integer of 1 to _3. Y ₃ represents an acidic group having a pKa of less than 6. R ₁₁ and R _{12 each} represents an alkyl group or an aralkyl group, and may have an acidic group having a pKa of less than 6 as a substituent, and L ₃ represents a conjugated methine group.)
(In the general formula [IV], R ₁₃ represents an aromatic hydrocarbon residue or a heterocyclic residue, and may have an acidic group having a pKa of less than 6 as a substituent. R ₁₄ and R ₁₅ represent hydrogen. An atom or an alkyl group, which may be linked to each other to form a cyclopentane ring or a cyclohexane ring, L ₄ represents a divalent linking group, p represents 0 or 1, and Y ₄ represents (The carboxylate anion formed an ion pair with a carboxyl group or a salt-forming cation.)   A semiconductor electrode manufactured by the method for manufacturing a semiconductor electrode according to claim 1.   A dye-sensitized solar cell comprising the semiconductor electrode according to claim 2.