WO2006100785A1

WO2006100785A1 - Electrolyte composition and photoelectric transducer

Info

Publication number: WO2006100785A1
Application number: PCT/JP2005/006217
Authority: WO
Inventors: Masaki Minami; Tsuyoshi Asano; Takaya Kubo; Yoshinori Nishikitani
Original assignee: Nippon Oil Corporation
Priority date: 2005-03-24
Filing date: 2005-03-24
Publication date: 2006-09-28

Abstract

A photoelectric transducer having its short-circuit current increased to thereby attain an enhancement of transduction efficiency by adding cyclodextrin and/or a cyclodextrin derivative to an electrolyte containing a redox pair.

Description

Electrolyte composition and photoelectric conversion element

[Technical field]

The present invention relates to a novel electrolyte composition and a photoelectric conversion element using the same. [Background]

Photoelectric conversion elements such as so-called wet solar cells, which are typified by dye-sensitized solar cells, have a structure in which a dye is adsorbed on semiconductor fine particles and a metal thin film is sandwiched between an electrolyte layer containing a redox pair on the counter electrode. Have. When sunlight enters this dye-sensitized solar cell, the dye is excited and separated into electrons and holes. Electrons become semiconductor fine particles

It flows and becomes current.

Such a solar cell is known to have a slow movement of electrons in semiconductor fine particles and a large loss due to recombination. For this reason, various methods for improving the conversion efficiency have been studied. For example, a method for improving the conversion efficiency of a dye-sensitized solar cell by post-processing semiconductor fine particles adsorbed with a dye with t-butylpyridine. It has been proposed (see Patent Document 1).

However, when treated with t-butylpyridine, the open-circuit voltage of the solar cell is improved, but the short-circuit current is reduced. Therefore, the conversion efficiency of this solar cell is not necessarily high enough. (See Non-Patent Document 1).

(1) Patent Document 1: Japanese Patent Laid-Open No. 1 2 2 0 3 80

(2) Non-Patent Document 1 _: Hironori Arakawa et al., “Solar Energy Materials & Solar Cells”, Netherlands, 2003, 8th 卷, p. 16 7-1 7 9

[Disclosure of the Invention]

An object of the present invention is to increase the short-circuit current of a photoelectric conversion element such as a solar cell and improve the conversion efficiency.

As a result of earnest research to solve the above problems, the present inventor has included a redox pair. It was found that the inclusion of cyclodextrin and / or a cyclodextrin derivative in the electrolyte increases the short-circuit current value of the photoelectric conversion element and improves the conversion efficiency, and thus the present invention has been completed here. .

That is. The present invention relates to an electrolyte composition comprising a redox couple and a cyclodextrin and / or cyclodextrin derivative. Moreover, this invention relates to the photoelectric conversion element using the said electrolyte composition. Hereinafter, the present invention will be described in detail.

The electrolyte composition of the present invention comprises at least a redox couple and a cyclodextrin and / or cyclodextrin derivative.

The redox couple used in the electrolyte composition of the present invention refers to a substance exhibiting reversible electrochemical redox characteristics, and is not particularly limited in its type. Such substances include, for example, pheucene, p-benzoquinone, 7,7,8,8-tetracyanoquinodimethane, N, N, N ', N'-tetramethyl mono-ρ-phenylenediamine, tetrathiafulvalene , Thianthracene, ρ-tolylamine and the like. In addition, iodine and iodine compounds, or bromine and bromine compounds are listed. Examples of iodine compounds include metal iodides, pyridinium salts, imidazolium salts, ammonium salts such as ammonium salts, and bromine compounds. Indium salt bromine compounds, and complex salts such as ferrocyanic acid monoferricyanate-salt, polysulfurium sulfide, alkylthiol-alkyl disulfide, hydroquinone monoquinone, and viologen dye.

Examples of pyridinium salts include those represented by the following formula.

Here, R represents an alkyl group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, and X 1 represents a halogen ion. Examples of the imidazolium salt include those represented by the following formula.

Here, 1 ^{1 and} 1 ^ ² are each an alkyl group having 1 to 10 carbon atoms (preferably a methyl group or an ethyl group), or an aralkyl having 7 to 20 carbon atoms, preferably 7 to 13 carbon atoms. Group (preferably benzyl group), which may be the same or different. X represents a halogen ion. Examples of ammonium salts include those represented by the following formula.

Here, RR ² , R ³ and R ⁴ are each an alkyl group having 1 or more carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, an aryl group (such as a phenyl group) having 6 to 12 carbon atoms, or a methoxymethyl group. May be the same or different. X represents a halogen ion. The content of the oxidation-reduction pair in the electrolyte composition is not particularly limited and is arbitrary, but is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 10%, based on the total amount of the electrolyte composition. An amount of 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less can be contained. As the cyclodextrin used in the electrolyte composition of the present invention, any of _α- type, / 3-type and γ-type cyclodextrins can be used. Two or more of these may be used in combination. Usually, it is preferably used after being dissolved in the electrolyte composition, but it can also be used after being dispersed. Examples of cyclodextrin derivatives include those in which any of _α- type, 0-type and γ-type cyclodextrins is used as a starting material, and any hydroxyl group is alkylated, arylated, aralkylated or acylated.

Examples of the alkyl group include alkyl groups having 1 to 20 carbon atoms, preferably 1 to 8 carbon atoms. Specifically, methyl, ethyl, η-propyl, i-propyl, n-butyl, s-butyl, t —Butyl, pentinole, hexyl, heptyl, octyl and the like. Examples of aryl groups include aromatic hydrocarbon groups having 6 to 15 carbon atoms, and specific examples include phenyl, o-tolyl, p-tolyl, m-tolyl, and naphthyl. Examples of the aralkyl group include aralkyl groups having 7 to 12 carbon atoms, and specific examples include a benzyl group and a phenethyl group. Examples of the acyl group include an acetyl group and a benzoyl group. The content of cyclodextrin and / or cyclodextrin derivative in the electrolyte composition is not particularly limited and is arbitrary, but usually 0.5% by mass or more, preferably 1% by mass or more, based on the total amount of the electrolyte composition, Preferably it is 2 mass% or more, 50 mass% or less, Preferably it is 40 mass. / ₀ or less, more preferably 30% by mass or less. The electrolyte composition of the present invention may contain a plasticizer as desired. The plasticizer acts as a solvent for the redox couple. Any plasticizer can be used as long as it can be used as an electrolyte solvent in electrochemical cells and batteries. Specific examples include acetic anhydride, methanol, ethanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, dimethylformamide, dimethylsulfoxide, hexamethylphosphoamide, ethylene carbonate, dimethoxetane, γ. —Butylactone, γ-Valentine Rataton, sulfolane, dimethoxetane, propiononitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethylsulfoxide, dioxolane, sulfolane, trimethyl phosphate Triethyl phosphate, Tripropyl phosphate, Ethyl dimethyl phosphate, Tributyl phosphate, Tripentyl phosphate, Trihexyl phosphate, Triheptyl phosphate Such as chill, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl terephthalate polyethylene dallicol, and polyethylene darlicol. It can be used. In particular, propylene carbonate, ethylene carbonate, dimethylsulfoxide, dimethoxetane, acetotril, γ-butyrolacton, sulfolane, dioxolan, dimethylformamide, dimethoxetane, tetrahydrofuran, adiponitrile, methoxyacetonitrile, methoxypropionitrile Dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, and triethyl phosphate are preferable. Also, room temperature molten salts can be used. Here, the room temperature molten salt is a salt composed of ion pairs that are melted at room temperature (that is, in a liquid state), and usually has a melting point of 20 ° C or lower.

It indicates a salt composed of an ion pair that is liquid at a temperature exceeding 20 ° C. Examples of the room temperature molten salt include the following.

(Wherein, R represents 2 to 20 carbon atoms, preferably an alkyl group of 2 to 1 0, X one is a halogen ion, S CN-, S e CN-, C 10 4 -, BF 4 _, CF 3 S0 ₃ _, (CF 3 S 0 ₂ ) ₂ N-, (C ₂ F ₅ S 0 ₂ ) ₂ N-, PF _6- , A s F ₆ —, CH ₃ COO_, CH ₃ (C ₆ H ₄ ) S 0 ₃ ^_ , (C 2 F ₅ S 0 ₂ ) ₃ C-, dicyandiamide ion, 卜 licyanomethane ion or thiocyanate.)

(Where 1 ^ Oyobi 1 ² each alkyl group (preferably methyl group or Echiru group with carbon number 1-1 0), or the number of carbon atoms from 7 to 20, preferably 7-1 3 Ararukiru group (Preferably a benzyl group), which may be the same or different. Also,

X is halogen ion, S CN―, Se CN―, C 1 0 ₄ —, BF ₄ —, CF ₃ S 0 ₃ —,

(CF ₃ S0 ₂ ) ₂ N-, (C ₂ F ₅ S0 ₂ ) ₂ N-, PF ₆ ^_ , A s F _6- , CH ₃ COO-, CH ₃ (C ₆ H ₄ ) S0 _3- , ( C 2 F ₅ S 0 ₂ ) ₃ C—, dicyandiamide ion, tricyanmethane ion or thiocyanate. )

(Where RR ² , R ³ and R ⁴ are each an alkyl group having 1 or more carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms (such as a phenyl group), or methoxymethyl. . group indicates etc., may be the same or different from each other, X is Harogeni on, S CN -, S e CN -, C 10 4 -, BF 4 -, CF 3 S0 3 -, (CF 3 S0 2) ₂ N-, (C 2 F 5 S 0 ₂ ) ₂ N_, PF _6- , As F ₆ ^_ , CH ₃ COO—, CH ₃ (C ₆ H ₄ ) S0 ₃ ^_ , (C ₂ F ₅ S 0 ₂₎ ₃ C-, di Shianjiami Doion shows bird Shianome Tan'ion or thio Xia sulfonate ion.)

One plasticizer may be used alone, or two or more plasticizers may be mixed and used. The content of the plasticizer in the electrolyte composition is not particularly limited, but is generally 20% by mass or more, preferably 50% by mass or more, more preferably 70% by mass based on the total amount of the electrolyte composition. /. These are 98 mass% or less, preferably 95 mass% or less, and more preferably 90 mass% or less. If desired, the electrolyte can contain a polymer compound, and the electrolyte can be gelled. Examples of the polymer compound that can be contained include a poly (vinylidene fluoride) polymer compound, a polyacrylonitrile polymer compound, a polyether polymer compound, and a polyacrylic polymer compound. The polymer compound may be linear or cross-linked, and may be a homopolymer or a copolymer. Also, use a mixture of two or more polymer compounds. Also good.

Preferably, a polyvinylidene fluoride polymer compound is used. Examples of the polyvinylidene fluoride polymer compound include a homopolymer of vinylidene fluoride, or a copolymer of vinylidene fluoride and another polymerizable monomer, preferably a radical polymerizable monomer. Specific examples of the other polymerizable monomer copolymerized with vinylidene fluoride include hexafluoropropylene, tetrafluoroethylene, and trifluoroethylene. Also, a carboxyl group-containing monomer can be copolymerized. The carboxyl group-containing monomer is not particularly limited, but examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic acid monomethyl ester, maleic acid monoethyl ester, citraconic acid monomethyl ester, citraconic acid mono Ethinoreestenole, maleic anhydride, fumanoleic acid monomethyl ester and the like.

The content of the polymer compound in the electrolyte composition must be such that the performance of the device does not deteriorate. If the content is large, the mobility of ions decreases, and the performance may decrease. Therefore, when used as a solar cell, the content of the polymer compound in the electrolyte composition is usually 50% by mass or less, preferably 40% by mass or less, based on the total amount of the electrolyte composition. The electrolyte can further contain other components. Examples of other components include ultraviolet absorbers and amine compounds.

The ultraviolet absorber that can be contained is not particularly limited, but typical examples include organic ultraviolet absorbers such as a compound having a benzotriazole skeleton and a compound having a benzophenone skeleton.

Preferred examples of the compound having a benzotriazole skeleton include compounds represented by the following general formula (1).

In the general formula (1), R ¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Examples of the halogen atom include fluorine, chlorine, bromine and iodine. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an i-propyl group, a butyl group, a t-butyl group, a cyclohexyl group, and the like. The substitution position of R ¹ is the 4-position or 5-position of the benzotriazole skeleton, but the halogen atom and the alkyl group are usually located at the 4-position. R ² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an i-propyl group, a butyl group, a t-butyl group, and a cyclohexyl group. R ³ represents an alkylene group or alkylidene group having 1 to 10 carbon atoms, preferably 1 to ³ carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, and a propylene group. Examples of the alkylidene group include an ethylidene group and a propylidene group.

Specific examples of the compound represented by the general formula (1) include 3- (5-chloro-2H-benzotriazolone 2-inole) 1-5- (1,1-dimethinoleethyl) 1-4 1-hydroxylbenzenepropanoic acid, 3-(2 H-benzotriazole-2-yl) 1 5 — (1, 1 -dimethylethyl) 1 4-hydroxylbenzene ethanoic acid, 3 — (2 H-base 1_Hydroxybenzeneethanoic acid, 3-

(5 _ methyl _ 2 H-benzotriazole 1-yl) — 5— (1-methylethyl) 1-hydroxybenzenepropanoic acid, 2— (2, 1 hydroxy-5, 1 methinorefinole) Benzotriazolene, 2— (2, 1 Hydroxyl 3 ', 5, 1 Bis

(a, a-dimethylbenzyl) phenyl) benzotriazole, 2- (2, hydroxy 1 3 ', 5' ― tert-butynolephenyl) benzotriazole, 2- (2, hydroxy 1 3 '— 5-Black mouth Benzotriazole, 3-(5-Black mouth-2 H-Benzotriazole 1-2 yl) 1 5 1 (1, 1 dimethyl ethinole) 1-hydroxyl-benzenepropanoic acid octinole ester and the like. Suitable examples of the compound having a benzophenone skeleton include compounds represented by the following general formulas (2) to (4).

In the general formulas (2) to (4), R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹ \ and R ¹² are the same or different from each other, and are a hydroxyl group, a carbon number of 1 to 1 0, preferably 1-6 alkyl or alkoxy groups. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an i-propyl group, a butyl group, a t-butyl group, and a cyclohexyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, i-propoxy group, and a butoxy group.

R ⁴ , R and R ¹ . Represents an alkylene group or alkylidene group having 1 to 10 carbon atoms, preferably 1 to 3 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, and a propylene group. Examples of the alkylidene group include an ethylidene group and a propylidene group.

pl, p2, p3, ql, q2, and q3 each independently represent an integer of 0 to 3. Preferred examples of the compound having a benzophenone skeleton represented by the above general formulas (2) to (4) include 2-hydroxy-1, 4-methoxybenzophenone, 5-canolepo ' Acid, 2, 2 '— Dihydroxy 4-methoxybenzophenone 5—Strong rubonic acid, 4 (2-hydroxybenzoinole) 1 3-Hydroxybenzenepropanoic acid, 2, 4-dihi Droxybenzophenone, 2-hydroxyl 4-methoxybenzophenone, 2-hydroxyl 4-methoxybenzophenone 5-sulfonic acid, 2-hydroxyl 4-n-o 4-hydroxybenzophenone, 2,2'-hydroxy-4-, 4-,-dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydrobenzophenone, 2-hydroxy-4-hydroxy 1 2 '— Carboxybenzophenone and the like.

Of course, two or more of these can be used in combination.

The use of a UV absorber is optional, and the amount used is not particularly limited. When used, the total amount of the electrolyte composition is 0.1% by mass or more, preferably 1% by mass or more, and 20% by mass or less, preferably 10% by mass or less. desirable. The amine compound that can be contained in the electrolyte is not particularly limited, and various types of aliphatic amines and aromatic amines are used. For example, pyridine derivatives, aniline derivatives, quinoline derivatives, imidazole derivatives, etc. A typical example. The addition of these amine compounds is expected to improve the open circuit voltage. Specific examples of these compounds include pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 4-ethylpyridine, 4-propylpyridine, 4-tert-butyl-pyridine, 4-dimethylaminopyridine. , 2-dimethylaminopyridine, 2, 6-dimethylpyridine, 2, 4, 6-trimethylpyridine, 4-monopyridinopyridine, 4_pyrrolidinopyridine, 4_ (2-aminoethyl) pyridine, 2- (2 —Aminoethyl) Pyridine, 2-methoxymethyl pyridine, picolinic acid, 2-pyridinemethanol, 2-pyridineethanol, 3-pyridineethanol, 2, 3-sucral pentenopyridine, nicotinamide, nicotinic acid , 4, 4, 1 biviridine, 2, 2'—bipyridine and other pyridine derivatives, and aniline, dimethylaniline and other aniline derivatives Body, quinoline, quinoline Li down derivative conductor such isoquino phosphorus, Benzuimidazo Ichiru include Imidazoru derivatives such as N- Mechinorebenzui imidazole. The use of the amine compound is optional, and the amount used is not particularly limited. When used, it is 0.1% by mass or more, preferably 1% by mass or more, and 20% by mass or less, preferably 10% by mass based on the total amount of the electrolyte composition. It is desirable to include an amount in the range of ₀ or less. Next, a photoelectric conversion element using the electrolyte composition of the present invention will be described.

Examples of the photoelectric conversion element include an element having a cross section shown in FIG. This element has a semiconductor layer 3 that adsorbs a dye on a transparent conductive substrate 1 and a counter electrode substrate 2, and an electrolyte layer 4 is disposed between the semiconductor layer 3 and the counter electrode substrate 2, The periphery is sealed with a sealant 5. The lead wire is connected to the conductive portions of the transparent conductive substrate 1 and the counter electrode substrate 2 so that electric power can be taken out. The transparent conductive substrate usually has a transparent electrode layer on the transparent substrate.

The transparent substrate is not particularly limited, and the material, thickness, dimensions, shape, and the like can be appropriately selected according to the purpose. For example, colorless or colored glass, meshed glass, glass spout, etc. are used. In addition, a colorless or colored transparent resin may be used. Specifically, polyesters such as polyethylene terephthalate, polyamides, polysulfones, polyether sulfones, polyether ether ketones, polyphenylene sulfide, polycarbonates, polyimides, polymethyl methacrylate, polystyrene, cellulose triacetate, polymethyl Examples include pentene. The term “transparent” in the present invention means a transmittance of 10 to 100%, preferably a transmittance of 50% or more, and the substrate in the present invention has a smooth surface at room temperature. The surface may be a flat surface or a curved surface, or may be deformed by stress.

Further, the transparent electrode layer acting as an electrode is not particularly limited as long as it fulfills the object of the present invention. For example, a metal thin film such as gold, silver, chromium, copper, and tungsten, a conductive film made of a metal oxide, etc. Is mentioned. Examples of metal oxides include Indium Tin Oxide (I TO (I n ₂ 0 ₃ : Sn)), Fluorine doped Tin Oxide (F TO (S n 0 ₂ : F)), Aluminum doped Zinc Oxide (AZ O (Z n O: A 1)) Used as appropriate.

The film thickness is usually 10 to 5000 nm, preferably 100 to 3000 nm. The surface resistance (resistivity) is appropriately selected depending on the use of the substrate of the present invention, and is usually 0.5 to 500 QZsq, preferably 2 to 500 5. The method for forming the transparent electrode layer is not particularly limited, and a known method is appropriately selected and used depending on the type of the metal or metal oxide used as the electrode layer. Usually, the vacuum deposition method, the ion plating method is used. Method, CVD or sputtering method is used. In either case, it is desirable that the substrate temperature be in the range of 20 to 700 ° C.

The other substrate, that is, the counter substrate may be the substrate itself as long as the substrate itself is conductive or at least one surface is conductive, and may be the transparent transparent conductive substrate described above or an opaque conductive substrate. Examples of the opaque conductive substrate include various metal electrodes and, for example, Au, Pt, and Cr formed on a glass substrate. In the photoelectric conversion element of the present invention, the semiconductor layer used is not particularly limited. For example, Bi ₂ S ₃ , C d S, C d Se, C dTe, Cu In S ₂ , Cu I n S e ₂ , F e ₂ 0 ₃ , G a P, G a As, I n P, Nb ₂ 0 ₅ , P b S, S i, S n 0 ₂ , T i 0 ₂ , WO ₃ , Z n 0, Z n S, etc. are mentioned, preferably C d S, C d Se, Cu In S ₂ , Cu In Se ₂ , F e ₂ 0 ₃ , G a A s, In P _{_{, n b 2 0 5, P}} b S, an S n0 _2, T I_〇 _{_{2, W0 3, Z n O}} , multiple Kumiawasedea Tsutemoyore. Particularly preferably T i 〇 _2, Z nO, a S N_〇 _{_2,} Nb ₂ 0 _5, and most preferably T I_〇 _2, Z nO.

The semiconductor used in the present invention may be single crystal or polycrystalline. As the crystal system, an anatase type, a rutile type, a brookite type and the like are mainly used, and an anatase type is preferred. A known method can be used for forming the semiconductor layer.

As a method for forming the semiconductor layer, the above-mentioned semiconductor nanoparticle dispersion, sol solution, or the like can be obtained by coating on a substrate by a known method. The coating method in this case is not particularly limited, and various printing methods such as a screen printing method including a method obtained in a thin film state by a cast method, a spin coating method, a dip coating method, a bar coating method, and the like. Can be mentioned.

The thickness of the semiconductor layer is arbitrary, but 0.5 μπι or more and 50 m or less, preferably 1 5 006217 μm or more and 20 m or less Various dyes can be adsorbed or contained in the semiconductor layer for the purpose of improving the light absorption efficiency of the semiconductor layer.

The dye that can be used in the present invention is not particularly limited as long as it is a dye that improves the light absorption efficiency of the semiconductor layer, and usually one or two of various metal complex dyes and organic dyes. The above can be used. In addition, in order to provide adsorption to the semiconductor layer, a carboxyl group, a hydroxyl group, a sulfonyl group, a phosphonyl group, a carboxylalkyl group, a hydroxyalkyl group, a sulfonylalkyl group, a phosphonylalkyl group in the dye molecule. Those having a functional group such as a group are preferably used.

As the metal complex dye, ruthenium, osmium, iron, cobalt, zinc complex, metal phthalocyanine, chlorophyll and the like can be used.

Examples of the metal complex dye used in the present invention are as follows.

(Dye 1)

Here, x ₁ represents a monovalent anion, but each x may be independent or cross-linked. For example, the following is exemplified.

N = C = SN = C = NAr C to _C≡N

(Dye 2)

Here, X represents the same as X described above. X ₂ represents a monovalent anion, for example:

Fe

The Y, a monovalent Anion, halogen _{^{ions, S CN-, C 10 4 _}} , BF 4 -, CF 3 S0 3 -, (CF 3 S 0 2) 2 N -, (C 2 F 5 S 0 ₂ ) ₂ N-, PF _6- , A s F _6- , CH ₃ COO-, CH ₃ (C ₆ H ₄ ) S0 ₃ _, and (C ₂ F ₅ S0 ₂ ) ₃ C- etc. Can do. (Dye 3)

Here, Z is an atomic group having an unshared electron pair, and the two Zs may be independent or bridged. For example, the following is exemplified.

The Y, a monovalent Anion, halogen ions, S CN _{_{one, C 10 4 -, BF 4}} -, CF 3 S0 3 -, (CF 3 S 0 2) 2 N-, (C 2 F 5 S ○ ₂ ) ₂ N-, PF _6- , As F _6- , CH ₃ COO, CH ₃ (C ₆ H ₄ ) S0 ₃ —, and (C ₂ F ₅ S0 ₂ ) ₃ C "etc. Can do.

(Dye 4)

Examples of organic dyes include cyanine dyes, hemicyanine dyes, merocyanine dyes, xanthene dyes, triphenylmethane dyes, metal-free phthalocyanine dyes, and the like. Absent. Examples of the organic dye used in the present invention are as follows.

(Xi represents nitrogen or sulfur, and n represents 10 to 5, 0 0 0.) As a method of adsorbing the dye to the semiconductor layer, a solution in which the dye is dissolved in a solvent is sprayed on the semiconductor layer. The coating can be formed by applying it by spin coating and then drying it. In this case, the substrate may be heated to an appropriate temperature. Alternatively, a method in which a semiconductor layer is immersed in a solution and adsorbed can be used. The immersion time is not particularly limited as long as the dye is sufficiently adsorbed, but is preferably 1 to 30 hours, particularly preferably 5 to 20 hours. Further, the solvent and the substrate may be heated when dipping as required. The concentration of the dye in the case of forming a solution is preferably 1 to: 10 0 O m MZ L, preferably about 10 to 50 O mM ^ L.

The solvent to be used is not particularly limited as long as the dye is not dissolved and the semiconductor layer is not dissolved, but water and an organic solvent are preferably used. Examples of organic solvents include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, etc., alcohol, alcohol, propionitol, methoxypropionitrile. Nitrinolic solvents such as glutaronitrile, benzene, toluene, o-xylene, m-xylene, p_xylene, pentane, heptane, hexane, cyclohexane, heptane, acetone, methinoethyl ethyl ketone, jetyl ketone, 2-butanone and other ketones, jetyl ether, tetrahydrofuran, ethylene carbonate, propylene carbonate, nitromethane, dimethylformamide, dimethyl sulfoxide, hexamethylphosphate, dimethoxetane, _γ —Butyrolactone, γ-valerolactone, sulfolane, dimethoxetane, adiponi turinole, methoxyacetonitrile, dimethylacetamide, methyl pyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, triethyl phosphate Propyl, Ethyldimethyl phosphate, Tributyl phosphate, Tripentyl phosphate, Trihexyl phosphate , Triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl polyethylene glycol phosphate, and Polyethylene glycol or the like can be used.

[Industrial applicability]

The electrolyte composition of the present invention can be easily prepared by adding a cyclodextrin and / or a cyclodextrin derivative to an electrolyte containing a redox pair, and a photoelectric conversion element using the electrolyte composition of the present invention is Short-circuit current value increases and high conversion efficiency.

[Best Mode for Carrying Out the Invention]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Example 1>

<< Production of photoelectric conversion element >>

Film resistance value 1 5 QZsq Sn 0 ₂ : F glass (Sn 0 ₂ : Transparent conductive glass with F film formed on glass substrate) SO Ti-N anoxide T made by SO LARON IX One coat was dried. The coated substrate was baked at 45 ° C. for 1 hour to form a semiconductor layer. This was soaked in a ruthenium dye (Rutenium 5 35-bis TBA manufactured by SOL ARON IX) / ethanol solution (5.0 X 10 “ ⁴ mo 1 / L) for 15 hours to adsorb the dye.

Next, the Pt surface of the glass with the semiconductor layer adsorbed to the dye and the Pt thin film is placed facing each other using a polyethylene terephthalate film as a spacer, and the electrolyte solution is inserted into the gap between the capillaries. It was injected due to the phenomenon, and the periphery was sealed with an ultraviolet curable sealant to obtain a photoelectric conversion element. As the electrolyte, a solution of acetonitrile containing 0.5M lithium iodide, 0.05M iodine, and 0.05M triacetinol-1-cyclodextrin was used.

The cells obtained in this way are irradiated with AM I .5 G artificial sunlight to obtain the current-voltage characteristics. When measured, a good conversion efficiency (η) of 4.7% was obtained.

In Example 1, a photoelectric conversion element was produced using triacetyl-α-cyclodextrin instead of triacetyl-] 3-cyclodextrin. When the cells obtained in this way were irradiated with AM 1.5 G artificial sunlight and the current-voltage characteristics were measured, a good conversion efficiency () of 4.3% was obtained.

In Example 1, a photoelectric conversion element was produced using triacetyl-γ-cyclodextrin in place of triacetyl-] 3-cyclodextrin. When the cells obtained in this way were irradiated with AM 1.5 G simulated sunlight and the current-voltage characteristics were measured, a good conversion efficiency (η) of 4.6% was obtained. Comparative Example 1>

In Example 1, a photoelectric conversion element was produced except for triacetyl- / 3-cyclodextrin. When the cell obtained in this way was irradiated with AMI.5G artificial sunlight and the current-voltage characteristics were measured, the conversion efficiency (T?) Was 3.6%.

[Brief description of drawings]

Figure 1 shows an example of a cross section of a photoelectric conversion element.

(Explanation of symbols)

1 Transparent conductive substrate

2 Counter electrode substrate

3 Semiconductor layer

4 Electrolyte layer

5 Seal material

Claims

The scope of the claims

1. An electrolyte composition comprising a redox couple and cyclodextrin and a Z or cyclodextrin derivative.

2. The electrolyte composition according to item 1, wherein the redox couple is composed of iodine and an iodine compound.

3. A photoelectric conversion element using the electrolyte composition according to item 1 or 2.