JP2000251532A - Electrolyte, photoelectric converting element and photoelectric chemical battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the durability of an electrolyte to improve the photoelectric converting characteristic and durability of an element and a battery by including a polymer compound obtained by polymerizing an acrylate monomer containing two kinds of compounds. SOLUTION: This electrolyte contains a cross-linked polymer obtained by radically polymerizing an acrylate monomer represented by formula I and containing a cyclic ureide group with a bifunctional or more acrylate monomer represented by formula II. This electrolyte has satisfactory photoelectric converting characteristic, and is less deteriorated with the lapse of time. This photoelectric converting element is provided with a charge moving layer containing this electrolyte, a conductive support having a fine particle semiconductor-containing layer sensitized with a metal complex or a pigment such as polymethine, and a counter electrode. In formulae I and II, R1, R4, R5 are each hydrogen or an alkyl group; R2 and R3 are each hydrogen or an alkyl group or aryl group, wherein each of the above groups may contain a substituent, and R2 and R3 may form a ring; L1 and L2 are each a divalent connecting group; L3 is a z-valent connecting group wherein z is an integer of 2-6; X is -COO- or -CONR6-, wherein R6 is hydrogen or an alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel electrolyte used for electrochemical devices such as batteries, capacitors, sensors, display devices, recording devices and the like. Furthermore, the present invention relates to a photoelectric conversion element and a photoelectrochemical cell using the electrolyte.

[0002]

2. Description of the Related Art Conventionally, batteries, capacitors, sensors,
Liquids have been used as electrolytes for electrochemical devices such as display devices and recording devices. However, the liquid electrolyte has a problem in that the liquid electrolyte may leak when used or stored for a long period of time, and thus lacks reliability. Similarly, Nature (Vol. 353,
737-740, 1991) and U.S. Pat. No. 4,492,721, etc., using a photoelectric conversion element using semiconductor particles sensitized by a dye (hereinafter abbreviated as a dye-sensitized photoelectric conversion element).
Also in a wet type solar cell using, a liquid electrolyte is used for the charge transfer layer, and therefore there is a concern that the electrolyte will be depleted due to long-term use and the photoelectric conversion efficiency will be remarkably reduced, or will not function as an element. In order to overcome such drawbacks, the use of solid polymer electrolytes has been studied since the discovery of polyethylene glycol derivatives having ionic conductivity. It was difficult. In recent years, as a method of improving the low ion conductivity, a material in which an organic solvent electrolyte is held in a gel of a polymer compound has been actively studied in recent years. JP-A-8-236165, JP-A-9-27352
Japanese Patent Application Laid-Open Publication No. H11-157, describes a photoelectric conversion element solidified using a crosslinked polyethylene oxide-based polymer solid electrolyte. However, it has been found that the gel electrolyte holding these electrolytes has insufficient retention of the electrolyte, and therefore, deterioration of the photoelectric conversion characteristics over time is observed.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrolyte having excellent durability. Another object is to provide a photoelectric conversion element and a photoelectrochemical cell having excellent photoelectric conversion characteristics and durability.

[0004]

The above object has been attained by the following items which specify the present invention and preferred embodiments thereof. (1) An electrolyte containing a polymer compound obtained by polymerizing a monomer containing at least two compounds represented by the following formulas (I) and (II).

[0005]

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[0006]

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[0007] _{wherein, R 1, R 4, R} 5 each represent a hydrogen atom or a substituted or unsubstituted alkyl group, R _2,
R ₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, respectively. R ₂
And R ₃ may combine with each other to form a ring. L ₁ and L ₂ each represent a divalent linking group. L ₃ represents a z-valent linking group, and z is an integer of 2 or more and 6 or less. X represents -COO- or -CONR _6- , and R ₆ represents a hydrogen atom or an alkyl group. (2) In the formulas (I) and (II), R ₁ , R ₂ , R ₃ ,
R ₄ , R ₅ , and R ₆ are each a hydrogen atom or an unsubstituted alkyl group having 1 to 6 carbon atoms, and L ₁ , L ₂ , and L ₃ are each a lower alkylene group or — (CH ₂ CH ₂ O) _k -CH ₂ CH ₂ -group (k is 1 to 3
(An integer of 0). (3) In the formula (1), R ₁ , R ₄ , and R ₅ are each a hydrogen atom, a methyl group or an ethyl group, and R ₂ , R ₃ , and R ₆ are each a hydrogen atom or a methyl group, L ₁ , L ₂ , L ₃ is a lower alkylene group or a — (CH ₂ CH ₂ O) _k —CH ₂ CH ₂ — group (k is an integer of 1 to 30)
The electrolyte according to the above (1), which is: (4) The electrolyte according to any one of the above (1) to (3), comprising a solvent selected from a carbonate-based compound, a nitrile-based compound, and a heterocyclic compound-based compound, and an iodine salt. (5) A photoelectric conversion having a charge transfer layer containing the electrolyte according to any one of (1) to (4) above, a conductive support, a semiconductor-containing layer coated on the conductive support, and a counter electrode. element. (6) The photoelectric conversion element according to (6), wherein the semiconductor is a fine particle semiconductor sensitized by a dye. (7) The photoelectric conversion element according to the above (5) or (6), wherein the semiconductor is a metal chalcogenide. (8) The photoelectric conversion device according to the above (6) or (7), wherein the dye is a metal complex dye or a polymethine dye. (9) A photoelectrochemical cell using the photoelectric conversion element according to any of (5) to (8).

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The electrolyte of the present invention, a photoelectric conversion element and a photoelectrochemical cell,
Acrylic monomer containing cyclic ureide group and 2
It is characterized by using a crosslinked polymer obtained by reacting an acrylate monomer having a functionality higher than that of a crosslinked polymer. Thereby, an electrolyte, a photoelectric conversion element, and a photoelectrochemical cell having excellent photoelectric conversion characteristics and preventing deterioration with time can be obtained.

Formula (I) will be described. R ₁ and R ₄ each represent a hydrogen atom or an alkyl group which may have a substituent. Examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), a hydroxyl group, a carboxy group, a sulfo group, an acylamino group (for example, acetamido and benzamide), a sulfonamido group, a carbamoyl group and an acyloxy group. Group, alkoxycarbonyl group, acyl group, alkoxy group (for example, methoxy,
Examples thereof include ethoxy, methoxyethoxy), an aryloxy group (for example, phenoxy), a nitro group, a formyl group, an alkylsulfonyl group, an arylsulfonyl group, an amino group, and an aryl group. R ₁ and R ₄ are preferably
It is a hydrogen atom or an unsubstituted alkyl group having 1 to 6 carbon atoms.
R ₂ and R ₃ represent a hydrogen atom or an alkyl group or an aryl group which may have a substituent. The alkyl group which may have a substituent represented by R ₂ or R ₃ has the same meaning as the alkyl group represented by R ₁ or R ₄ . The aryl group which may have a substituent represented by R ₂ and R ₃ is an aryl group having 6 to 10 carbon atoms, such as a phenyl group and a naphthyl group. Examples of the substituent include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), a hydroxyl group, a carboxy group, a sulfo group, an acylamino group (for example, acetamido and benzamide), a sulfonamido group, a carbamoyl group and an acyloxy group. Group, alkoxycarbonyl group,
Acyl group, alkoxy group (for example, methoxy, ethoxy,
Methoxyethoxy), an aryloxy group (for example, phenoxy), a nitro group, a formyl group, an alkylsulfonyl group, an arylsulfonyl group, and an amino group. R ₂ and R ₃ may be linked to each other to form a ring.
The number of ring members is preferably a 5-membered ring or a 6-membered ring. R ₂ and R ₃ are preferably a hydrogen atom or an unsubstituted alkyl group having 1 to 6 carbon atoms.

L ₁ represents a divalent linking group, preferably a lower alkylene group or a — (CH ₂ CH ₂ O) _k —CH ₂ CH ₂ — group. k is an integer of 1 to 30.

Examples of the monomer represented by the formula (I) are shown below, but it should not be construed that the invention is limited thereto.

[0012]

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[0013]

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The compound represented by the formula (I) can be easily obtained, for example, by reacting a compound represented by the following formula (Ia) with (meth) acrylic chloride. The compounds of the formula (Ia) are described, for example, in DE 8558
No. 49, U.S. Pat.No. 2,517,750, Collect.
It can be synthesized according to the method described in Czech. Chem. Commun., Vol. 4, page 32 (1932).

[0015]

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Next, the formula (II) will be described. R ₅ is R ₁
Is synonymous with X represents -COO- or -CONR _6- , and R ₆
Represents a hydrogen atom or an alkyl group. R ₆ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. z is an integer of 2 or more and 6 or less, preferably an integer of 2 to 4. L ₂ has the same meaning as that of L _1. L ₃ represents a z-valent linking group. z
When = 2, L ₃ is an alkylene group, an arylene group, -O-, -S
-, -NH -, - N ( CH 3) -, or represents a linking group which has combined them. These groups preferably have 1 to 16 carbon atoms, and these groups may have a substituent.
Examples of the substituent include the substituents described for R ₂ or R ₃ . Preferred examples of L ₃ when z = 2 include —CH ₂ −,
_{-CH 2 CH 2 -, - CH} 2 CH 2 CH 2 -, -CH 2 CH 2 CH 2 CH 2 -, - CH 2 OCH 2 -
, -CH ₂ CH ₂ OCH ₂ CH _2- , -CH ₂ NHCH _2- , -CH ₂ CH ₂ NHCH ₂ CH
_{In addition to 2-} , -CH ₂ CH (CH ₃ ) OCH ₂ CH (CH ₃ )-and -OCH ₂ CH ₂ O-, the following linking groups can be mentioned.

[0017]

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[0018]

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When z = 3, L ₃ is represented by the following formula (III).

[0020]

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In the formula, A represents any of the following trivalent linking groups.

[0022]

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R ₁₀ is a hydrogen atom or an alkyl or alkoxy group having 1 to 8 carbon atoms. L ₄ , L ₅ , and L ₆ may be the same or different, and have the same meaning as L ₃ when z = 2. a, b, and c are each independently 0 or 1. These groups may have a substituent, and examples of the substituent include the substituents described for R ₃ . Preferred examples of L ₃ when z = 3 include the following linking groups.

[0024]

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When z = 4, L ₃ is represented by the following equation (IV).

[0026]

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In the formula, B represents any of the following tetravalent linking groups.

[0028]

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L ₇ , L ₈ , L ₉ , and L ₁₀ may be the same or different, and have the same meaning as L ₃ when z = 2. t, u
, V, and w are each independently 0 or 1. Preferred examples of L ₃ when z = 4 include the following linking groups.

[0030]

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As L ₃ when z = 5 and z = 6, z = 4
In addition to the following combinations of linking groups, 5-membered and 6-membered linking groups, or those in which a divalent linking group is bonded thereto can be used.

Specific examples of the compound represented by the formula (II) are shown below, but are not limited thereto.

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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The compound represented by the formula (II) can be easily obtained, for example, by reacting a compound represented by the following formula (II-b) or (II-c) with (meth) acrylic acid chloride. it can.

[0040]

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The polymer compound used for the electrolyte of the present invention is
It can be obtained by polymerizing the monomer represented by the formula (I) and the monomer represented by the formula (II), but may contain other monomer components together with these monomers.

Examples of other monomer components include esters or amides derived from acrylic acid or α-alkylacrylic acid (eg, methacrylic acid) (eg, N-iso-propylacrylamide, Nn-butylacrylamide) , Nt-butylacrylamide, N, N-
Dimethylacrylamide, N-methylmethacrylamide,
Acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylamidopropyltrimethylammonium chloride, methacrylamide, diacetone acrylamide, N-methylolacrylamide, N-methylolmethacrylamide, methyl acrylate, ethyl acrylate, hydroxyethyl acrylate, n-propyl Acrylate, iso-propyl acrylate, 2-hydroxypropyl acrylate, 2-methyl-2-nitropropyl acrylate, n-butyl acrylate, iso-butyl acrylate, t-butyl acrylate, t-pentyl acrylate, 2-methoxyethyl acrylate, 2 -Ethoxyethyl acrylate, 2-methoxyethoxyethyl acrylate, 2,2,2-trifluoroethyl acrylate, 2,2-dimethylbutyl acrylate, 3-methoxy Chill acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, n- pentyl acrylate, 3-pentyl acrylate, octafluoropentyl acrylate,
n-hexyl acrylate, cyclohexyl acrylate, cyclopentyl acrylate, cetyl acrylate, benzyl acrylate, n-octyl acrylate,
2-ethylhexyl acrylate, 4-methyl-2-propylpentyl acrylate, heptadecafluorodecyl acrylate, n-octadecyl acrylate, methyl methacrylate, 2-methoxyethoxyethyl methacrylate,
Ethylene glycol ethyl carbonate methacrylate, 2,2,2-trifluoroethyl methacrylate, tetragluoropropyl methacrylate, hexafluoropropyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, t- Butyl methacrylate, t-pentyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, benzyl methacrylate, heptadecafluorodecyl methacrylate, n-octadecyl methacrylate, 2-
Isobornyl methacrylate, 2-norbornylmethyl methacrylate, 5-norbornen-2-ylmethyl methacrylate, 3-methyl-2-norbornylmethyl methacrylate, dimethylaminoethyl methacrylate, etc.), acrylic acid or α-alkylacrylic acid (eg, Acrylic acid, methacrylic acid, itaconic acid, etc.), vinyl esters (eg, vinyl acetate, etc.), esters derived from maleic acid or fumaric acid (dimethyl maleate,
Dibutyl maleate, diethyl fumarate, etc.), maleic acid, fumaric acid, sodium salt of p-styrenesulfonic acid, acrylonitrile, methacrylonitrile, dienes (eg, butadiene, cyclopentadiene, isoprene, etc.), aromatic vinyl compounds ( For example, styrene, p-
Chlorostyrene, t-butylstyrene, α-methylstyrene, sodium styrenesulfonate), N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, vinylsulfone Acid, sodium vinyl sulfonate, sodium allyl sulfonate, sodium methallyl sulfonate, vinylidene fluoride, vinylidene chloride,
Vinyl alkyl ethers (eg, methyl vinyl ether), ethylene, propylene, 1-butene, isobutene, N-phenylmaleimide, maleic ester, N-
Vinyl-2-pyrrolidone, N-vinylpyridine and 2-, 4-vinylpyridine. These monomer components may be used in combination. Other compounds than those described in Research Disclosure No. 1955 (July 1980) can be used.

Preferred as these other monomer components are acrylic acid esters, methacrylic acid esters or acrylonitrile. More preferably, it is an acrylic ester or a methacrylic ester.

The total weight of the monomers represented by the formulas (I) and (II) and other monomers used in the present invention is preferably from 1% by weight to 70% by weight based on the total amount of the electrolyte. More preferably, 1 wt% or more and 50
% By weight, particularly preferably 2% by weight or more and 30% by weight or less.
% By weight or less. The weight of the monomers represented by the formulas (I) and (II) is preferably 50% or more of the total weight of the monomers.

The above monomers used in the present invention can be dissolved in a solvent to form a polymer matrix by polymerization.

The polymer compound of the present invention is disclosed in Takayuki Otsu and Masayoshi Kinoshita: Experimental Method for Polymer Synthesis (Chemical Doujin) and Takatsu Otsu: Lecture Polymerization Reaction Theory 1 Radical Polymerization (1) (Chemical Doujin)
Can be synthesized by radical polymerization, which is a general polymer synthesis method described in (1). The polymer of the present invention can be subjected to radical polymerization by heating, light, an electron beam, or electrochemically, but it is particularly preferable to perform radical polymerization by heating.

When the polymer compound of the present invention is formed by heating, it is preferable to add a polymerization initiator in an amount of 0.01 to 10 mol% based on all monomers, since the polymerization time can be shortened. As the polymerization initiator, azobis compounds, peroxides, hydroperoxides, redox catalysts and the like can be used, and specifically, potassium persulfate,
Ammonium persulfate, tert-butyl peroctoate,
Lauryl peroxide, benzoyl peroxide, isopropyl percarbonate, 2,4-dichlorobenzoyl peroxide, methyl ethyl ketone peroxide,
Cumene hydroperoxide, dicumyl peroxide, azobisisobutyronitrile, 2,2-azobis (2,4-
Dimethylvaleronitrile), 2,2-azobis (2-amidinopropane) hydrochloride, dimethyl-2,2-azobis (2-methylpropionate), dimethyl-2,2-azobisisobutyrate and the like. Heat polymerization temperature is 40-1
50 ° C is preferred, and more preferably 50 to 120 ° C. The heating polymerization time is preferably from 1 to 180 minutes,
More preferably, it is 2 to 60 minutes, particularly preferably 3 minutes.
~ 20 minutes.

When a polymer matrix is formed by polymerization of the monomer of the present invention by irradiation with radiation, a method of irradiating active light such as ultraviolet light, visible light, electron beam and γ-ray is used. In the case of ultraviolet visible light, 0.01 to 10
The polymerization time can be shortened by adding a mole% of a radiation polymerization initiator.

As the radiation polymerization initiator, known radiation polymerization initiators can be used. Examples thereof include carbonyl compounds,
Azobis compounds, peroxides, sulfur compounds, halogen compounds, redox compounds, cationic polymerization initiators and the like, specifically, benzoin, 2-methylbenzoin, trimethylsilylbenzoin, 4-methoxybenzophenone, Michler's ketone, benzoin methyl ether, Acetophenone, anthraquinone, benzyl-2-chlorothioxanthone, 2,2-dimethoxy-2-phenylacetophenone, benzoyl peroxide, azobispropane, thiophenol, 2-bromopropane, 1-chloromethylnaphthalene, p-methoxyphenyl-2 , 4-Dichloromethyl-1,3,5-triazine, benzophenone / triethanolamine, 2-stilbene-4,6-trichloromethyl-1,3,
5-triazine, diphenyliodonium tetrafluoroborate and the like can be mentioned.

Table 1 shows examples of combinations of monomers used for polymerizing the high molecular compound used in the present invention, but the present invention is not limited thereto.

[0051]

[Table 1]

The salt used in the electrolyte of the present invention is composed of I ₂ and various iodides (eg, LiI, NaI, KI, Cs
Metal iodides such as I and CaI ₂ , iodine salts of quaternary imidazolium compounds, iodine salts of quaternary pyridinium compounds, iodine salts of tetraalkylammonium compounds, etc., Br ₂ and various bromides (eg, LiBr, Na
Br, KBr, CsBr, metal bromide such as CaBr _2, a bromine salt of a quaternary ammonium compound such as tetraalkylammonium bromide and pyridinium bromide), ferrocyanide - ferricyanide or ferrocene - metal complexes such as ferricinium ion , A combination of sulfur compounds such as sodium polysulfide, alkyl thiol-alkyl disulfide, alkyl viologen (for example, methyl viologen chloride,
Hexyl viologen bromide, benzyl viologen tetrafluoroborate) and its reduced form in combination,
A combination of polyhydroxybenzenes (eg, hydroquinone, naphthohydroquinone, etc.) and oxidized products thereof can be used. Among them, LiI, NaI,
KI, CsI, the metal iodide CaI _2, iodine salt of a quaternary imidazolium compound, a combination of iodine salt and I ₂ of the iodide salt or a tetraalkyl ammonium compound of the quaternary pyridinium compound.

For the electrolyte used in the present invention, it is preferable to use a solvent capable of dissolving the salt in addition to the above-mentioned polymer compound and salt. The solvent used for the electrolyte is preferably a compound that has low viscosity and improves ion mobility, or has high dielectric constant and improves effective carrier concentration, and can exhibit excellent ion conductivity. Representative examples of such solvents include, for example, carbonate derivatives; for example, ethylene carbonate,
Propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, dipropyl carbonate, etc., lactone derivatives;
ether derivatives such as γ-caprolactone and δ-valerolactone; for example, ethyl ether, 1,2-dimethoxyethane, diethoxyethane, trimethoxymethane, ethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, 1,3-dioxolan, 1,4 Alcohol derivatives such as dioxane; for example, methanol, ethanol,
Ethylene glycol monomethyl ether, propylene glycol monoethyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, etc., polyhydric alcohol derivatives; ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, etc., tetrahydrofuran derivatives; , 2-methyltetrahydrofuran and the like; nitrile derivatives; for example, acetonitrile, glutarodinitrile, propionitrile, methoxyacetonitrile, benzonitrile and the like, carboxylate derivatives; for example, methyl formate, methyl acetate, ethyl acetate, methyl propionate and the like, Triester phosphate; for example, trimethyl phosphate, triethyl phosphate, etc. Ring compounds; for example, N- methylpyrrolidone, 4-methyl
-1,3-dioxane, 2-methyl-1,3-dioxolane, 3-methyl-2-oxazolidinone, 1,3-propane sultone, sulfolane, etc., dimethyl sulfoxide, formamide, N, N-dimethylformamide, nitromethane, etc. And aprotic organic solvents such as water.

Among these, carbonate-based, nitrile-based and heterocyclic compound-based solvents are preferred. These solvents may be used alone or in combination of two or more.

Since the redox couple becomes a carrier of electrons, a certain concentration is required. A preferred concentration in the solution when used as a liquid or gel electrolyte is 0.01 mol / liter or more in total, and more preferably 0.1 mol / L or more.
Mol / l or more, particularly preferably 0.3 mol / l or more. There is no particular upper limit in this case,
Usually, it is about 5 mol / l.

The electrolyte of the present invention is prepared by preparing a solution from the above-mentioned monomers constituting the polymer, a polymerization initiator, a salt and a solvent in which these are dissolved, and casting, coating, dipping,
It is preferable that the electrolyte layer is formed on an electrode supporting a dye by an impregnation method or the like, and then the monomer is polymerized by a heating reaction to form an electrolyte layer containing a polymer compound.

When the electrolyte-containing layer is formed by a coating method, an additive such as a coating property improving agent such as a leveling agent is added to a coating solution comprising a solvent in which a monomer and a salt are dissolved, and the prepared homogeneous solution is spin-coated. , Dip coating method,
An air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, or an extrusion coating method using a hopper described in US Patent No. 2,681,294, or US Patent No. 276141.
No. 8, No. 3,508,947, and No. 2,276,791 can be applied by a method such as a multilayer simultaneous application method and then heated to form an electrolyte of the present invention. When a compound such as iodine is introduced into the electrolyte, for example, after the formation of the electrolyte, a sample containing the electrolyte can be placed in a closed container together with a compound such as iodine, and the sample can be introduced by a method of diffusing into the electrolyte. Further, a compound such as iodine can be introduced into the device by a method of coating or vapor-depositing on a counter electrode.

Next, the structure and materials of the photoelectric conversion element and the photoelectrochemical cell of the present invention will be described in detail. In the present invention, the dye-sensitized photoelectric conversion element includes a conductive support, a semiconductor film (photosensitive layer) sensitized by a dye or the like provided on the conductive support, a charge transfer layer, and a counter electrode. A photoelectrochemical cell that can use this photoelectric conversion element for a battery that works in an external circuit is used. The photosensitive layer is designed according to the purpose, and may have a single-layer structure or a multilayer structure. Light incident on the photosensitive layer excites dyes and the like. The excited dye or the like has high-energy electrons, which are transferred from the dye or the like to the conduction band of the semiconductor fine particles and reach the conductive support by diffusion. At this time, molecules such as dyes are oxidized. In a photoelectrochemical cell, electrons on a conductive support return to an oxidant such as a dye via a counter electrode and a charge transfer layer while working in an external circuit, and the dye or the like is regenerated. The semiconductor film functions as a negative electrode of this battery. In the present invention, at the boundaries between the layers (for example, the boundary between the conductive layer and the photosensitive layer of the conductive support, the boundary between the photosensitive layer and the charge transfer layer, the boundary between the charge transfer layer and the counter electrode, etc.) They may be mutually diffused and mixed.

In the present invention, the semiconductor is a so-called photoreceptor, and plays a role of absorbing light to separate electric charges to generate electrons and holes. In a dye-sensitized semiconductor, light absorption and the resulting generation of electrons and holes mainly occur in the dye, and the semiconductor is responsible for receiving and transmitting the electrons. As the semiconductor, besides a simple semiconductor such as silicon or germanium, a so-called compound semiconductor represented by a metal chalcogenide (for example, oxide, sulfide, selenide, or the like) or a compound having a perovskite structure can be used. . Preferably as a metal chalcogenide titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium,
Cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc,
Lead, silver, antimony, bismuth sulfide, cadmium,
Examples include lead selenide and cadmium telluride. Other compound semiconductors include phosphides such as zinc, gallium, indium and cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide and the like. Further, as the compound having a perovskite structure, strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate are preferably exemplified. More preferably, as the semiconductor used in the present invention, specifically, Si, TiO ₂ , SnO ₂ , Fe
₂ O ₃ , WO ₃ , ZnO, Nb ₂ O ₅ , CdS, ZnS, PbS, Bi ₂ S ₃ , Cd
Se, CdTe, GaP, InP, GaAs, CuInS ₂ , and CuInSe ₂ are mentioned. More preferably _{TiO 2, ZnO, SnO 2,} Fe 2 O 3, WO
_{3, Nb 2 O 5, CdS} , PbS, CdSe, InP, GaAs, CuInS 2, CuI
a nSe _2, particularly preferably TiO ₂ or Nb ₂ O _5, and most preferably TiO _2.

The semiconductor used in the present invention may be single crystal or polycrystal. Although a single crystal is preferable as the conversion efficiency, a polycrystal is preferable in terms of manufacturing cost, securing of raw materials, energy payback time, and the like, and a fine particle semiconductor having a nanometer to micrometer size is particularly preferable. The particle diameter of these semiconductor fine particles is an average particle diameter using the diameter when the projected area is converted into a circle, and is 5% as a primary particle.
It is preferably from 200 to 200 nm, particularly preferably from 8 to 100 nm. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is 0.01 to 100 μm.
It is preferred that Further, two or more kinds of fine particles having different particle size distributions may be mixed and used, and in this case, the average size of the small particles is preferably 5 nm or less. In addition, semiconductor particles having a large particle size, for example, about 300 nm may be mixed for the purpose of improving the light capture rate by scattering incident light.

The method for producing semiconductor fine particles is described in "Sol-Gel Method Science" by Agao Sakuhana (Agne Shofusha, 1988), "Thin Film Coating Technology by Sol-Gel Method" (1995) by the Technical Information Association, etc. Tadao Sugimoto, "Synthesis of Monodisperse Particles and Size Morphology Control by New Synthetic Gel-Sol Method", Materia, Vol. 35, No. 9, 1012
The gel-sol method described on pages 10 to 1018 (1996) is preferred. Further, a method of producing an oxide by hydrolyzing a chloride in an oxyhydrogen flame at a high temperature developed by Degussa is also preferable. In the case of titanium oxide, the above sol-gel method,
The gel-sol method and the high-temperature hydrolysis method of chloride in an oxyhydrogen flame are both preferable, but the sulfuric acid method and chlorine method described in Manabu Kiyono's "Titanium oxide physical properties and applied technology" Gihodo Shuppan (1997) are also used. You can also. In the case of titanium oxide, among the sol-gel methods described above, in particular, Barb et al., Journal of American Ceramic Society No. 8
Vol. 0, No. 12, pages 3157 to 3171 (1997) "and the method described in Burnside et al.," Chemical Materials Vol. 10, No. 9, pages 2419 to 2425 "are preferred.

As the conductive support, use is made of a support such as metal, which has conductivity, or a glass or plastic support having a conductive layer containing a conductive agent (conductive agent layer) on the surface. Can be. In the latter case, a preferable conductive agent is a metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), carbon, or a conductive metal oxide (indium-tin composite oxide, tin oxide doped with fluorine). And the like). The conductive agent layer preferably has a thickness of about 0.02 to 10 μm. The lower the surface resistance of the conductive support, the better.
The preferred range of the surface resistance is 100 Ω / cm ² or less, and more preferably 40 Ω / cm ² or less. The lower limit is not particularly limited, but is usually about 0.1 Ω / cm ² . Preferably, the conductive support is substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more,
70% or more is particularly preferred. As the transparent conductive support, glass or plastic coated with a conductive metal oxide is preferable. Among them, conductive glass in which a conductive layer made of tin dioxide doped with fluorine is deposited on a transparent substrate made of low-cost soda-lime float glass is particularly preferable. In addition, for a low-cost and flexible photoelectric conversion element or solar cell, a transparent polymer film provided with the above conductive layer is preferably used. For the transparent polymer film, tetraacetyl cellulose (TA
C), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndioctatic polysterene (SPS), polyphenylene sulfide (P
PS), polycarbonate (PC), polyacrylate (PAr), polysulfone (PSF), polyestersulfone (PES), polyetherimide (PE)
I), cyclic polyolefins, brominated phenoxy and the like. When a transparent conductive support is used, it is preferable that light be incident from the support side. In this case, the coating amount of the conductive metal oxide is preferably 0.01 to 100 g per 1 m ² of a glass or plastic support.

It is also preferable to use a metal lead for the purpose of lowering the resistance of the transparent conductive substrate. The material of the metal lead is preferably a metal such as aluminum, copper, silver, gold, platinum and nickel, and particularly preferably aluminum and silver. It is preferable that the metal lead is provided on a transparent substrate by vapor deposition, sputtering, or the like, and a transparent conductive layer made of tin oxide doped with fluorine or an ITO film is provided thereon. It is also preferable to provide a metal lead on the transparent conductive layer after providing the transparent conductive layer on a transparent substrate. The decrease in the amount of incident light due to the installation of metal leads is 1 to 10%, more preferably 1 to 5%.
It is.

Examples of the method of applying the semiconductor fine particles on the conductive support include a method of applying a dispersion or colloidal solution of the semiconductor fine particles on the conductive support, and the above-mentioned sol-gel method. In consideration of mass production of photoelectric conversion elements, liquid physical properties, and flexibility of a support, a wet film forming method is relatively advantageous. As a wet type film applying method, a coating method and a printing method are typical. In addition to the sol-gel method described above, a method of preparing a dispersion of semiconductor fine particles, a method of grinding in a mortar, a method of dispersing while grinding using a mill, or a method of precipitating as fine particles in a solvent when synthesizing a semiconductor. And a method of using it as it is. Examples of the dispersion medium include water and various organic solvents (eg, methanol, ethanol, isopropyl alcohol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). At the time of dispersion, a polymer, a surfactant, an acid, a chelating agent, or the like may be used as a dispersing aid, if necessary. As a coating method, a roller method as an application system,
Dip method, air knife method, blade method and the like as metering system, and wire bar method disclosed in JP-B-58-4589, U.S. Pat.
The slide hopper method, the extrusion method, the curtain method, and the like described in JP-A Nos. 294, 2761419, and 2761791 are preferable. As a general-purpose machine, a spin method or a spray method is also preferably used. As a wet printing method, intaglio, rubber printing, screen printing, and the like are conventionally preferable, including three major printing methods of letterpress, offset, and gravure. From the above methods, a preferable film-forming method is selected according to the liquid viscosity and the wet thickness.

The liquid viscosity is greatly affected by the type and dispersibility of the semiconductor fine particles, the type of solvent used, and additives such as a surfactant and a binder. High viscosity liquid (for example, 0.01 to 500 Po
In ise), an extrusion method or a casting method is preferable, and in a low-viscosity liquid (for example, 0.1 Poise or less), a slide hopper method, a wire bar method, or a spin method is preferable, and a uniform film can be formed. It should be noted that even in the case of applying a low-viscosity liquid by the extrusion method, the application is possible as long as the application amount is a certain amount. Screen printing is often used for applying a high-viscosity paste of semiconductor fine particles, and this method can also be used. As described above, a method of applying a wet film may be appropriately selected according to parameters such as the liquid viscosity of the coating liquid, the coating amount, the support, and the coating speed.

Further, the semiconductor fine particle layer need not be limited to a single layer. It is also possible to apply a multi-layer coating of dispersions having different particle diameters of fine particles.Also, it is possible to apply a multi-layer coating of different types of semiconductors or different coating compositions of binders and additives. Even when the film thickness is insufficient, the multilayer coating is effective. The extrusion method or slide hopper method is suitable for multi-layer coating. In the case of multi-layer coating, multiple layers may be coated at the same time,
It may be applied several times to several tens of times sequentially. Furthermore, a screen printing method can also be preferably used in the case of successive coating.

In general, as the thickness of the semiconductor fine particle-containing layer increases, the amount of dye carried per unit projected area increases, so that the light capture rate increases. However, the diffusion distance of generated electrons increases, and the loss due to charge recombination also increases. growing. Therefore, the semiconductor fine particle-containing layer has a preferable thickness, but typically has a thickness of 0.1 to 100 μm. When used as a photoelectrochemical cell, the thickness is preferably 1 to 30 μm, and more preferably 2 to 25 μm. The coating amount of the semiconductor fine particles per 1 m ² of the support is 0.5 to 400.
g, more preferably 5 to 100 g. The semiconductor fine particles are preferably subjected to a heat treatment in order to electronically contact the particles after being applied to the conductive support, and to improve the strength of the coating film and the adhesion to the support. A preferred range of the heat treatment temperature is 40 ° C. or more and less than 700 ° C., and more preferably 100 ° C. or more and 600 ° C. or less. The heat treatment time is about 10 minutes to 10 hours.
When a support having a low melting point or softening point, such as a polymer film, is used, high-temperature treatment is not preferable because the support is deteriorated. Further, it is preferable that the temperature is as low as possible from the viewpoint of cost. The lowering of the temperature can be achieved by the above-mentioned combination of small semiconductor particles having a size of 5 nm or less, heat treatment in the presence of a mineral acid, and the like. Further, after the heat treatment, for example, chemical plating or trichloride using an aqueous solution of titanium tetrachloride for the purpose of increasing the surface area of the semiconductor particles, increasing the purity in the vicinity of the semiconductor particles, and increasing the efficiency of electron injection from the dye into the semiconductor particles. Electrochemical plating using an aqueous titanium solution may be performed. The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For this reason, the surface area in the state where the semiconductor fine particle layer is coated on the support is preferably at least 10 times, more preferably at least 100 times the projected area. The upper limit is not particularly limited, but is usually about 1000 times.

The dye used in the present invention is preferably a complex dye, particularly a metal complex dye or a polymethine dye. In the present invention, two or more kinds of dyes can be mixed in order to widen the wavelength range of photoelectric conversion as much as possible and to increase the conversion efficiency. Dyes to be mixed and their proportions can be selected so as to match the intended wavelength range and intensity distribution of the light source. Such a dye preferably has an appropriate interlocking group for the surface of the semiconductor fine particles. Preferred linking groups, COOH groups, SO ₃ H group, a cyano group, -P (O) (OH) 2 group, -OP (O) (OH) 2 group, or, oxime, dioxime, hydroxyquinoline, salicylate and Chelating groups having π conductivity, such as α-keto enolate. Among them, COOH group, -P (O) (OH) ₂
The group, -OP (O) (OH) _2, is particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an intramolecular salt. In the case of a polymethine dye, if the methine chain contains an acidic group as in the case of forming a squarylium ring or a croconium ring, this portion may be used as a bonding group.

When the dye used in the present invention is a metal complex dye,
Are preferably ruthenium complex dyes, and
The dye represented by (V) is preferred. Equation (V) (A₁)_pRuB_aB_bB_c In the formula, p is 0 to 2, preferably 2. Ru is
Represents ruthenium. A ₁Is Cl, SCN, H_TwoO, B
r, I, CN, NCO and SeCN
It is a child. B_a, B_b, B_cAre each independently
It is an organic ligand selected from B-1 to B-8.

[0070]

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[0071]

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Here, _Ra is a hydrogen atom, a halogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms (hereinafter referred to as C number), an aralkyl group substituted or unsubstituted with 7 to 12 carbon atoms, or a substituted or unsubstituted with 6 to 12 carbon atoms Represents an aryl group. The above alkyl group,
The alkyl portion of the aralkyl group may be linear or branched, and the aryl portion of the aralkyl group may be monocyclic or polycyclic (condensed ring, ring assembly). . Examples of the ruthenium complex dye used in the present invention include, for example, U.S. Pat.Nos. 4,492,721, 4,684,537 and 5,084.
And complex dyes described in JP-A Nos. 365, 5350644, 5463057, 5525440 and JP-A-7-249790. Preferred specific examples of the metal complex dye used in the present invention are shown below, but the present invention is not limited thereto.

[0073]

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[0074]

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[0075]

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When the dye used in the present invention is a polymethine dye, a dye represented by the following formula (VI) or (VII) is preferred.

[0077]

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In the formula, R _b and R _f each represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and R _{c to} R _e
Represents a hydrogen atom or a substituent. R _{b to} R _f may combine with each other to form a ring. X ₁₁ and X ₁₂ each represent nitrogen, oxygen, sulfur, selenium, or tellurium. m ₁₁ and m
₁₃ represents an integer of 0 to 2, and m ₁₂ represents an integer of 1 to 6. The compound represented by the formula (VI) may have a counter ion depending on the charge of the whole molecule. The alkyl group in the above,
The aryl group and the heterocyclic group may have a substituent.
The alkyl group may be linear or branched, and the aryl group and the heterocyclic group may be monocyclic or polycyclic (condensed ring, ring assembly). The ring formed by R _{b to} R _f may have a substituent and may be a single ring or a condensed ring.

[0079]

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[0080] In the formula, Z _a represents a non-metallic atomic group necessary for forming a nitrogen-containing heterocyclic ring. R _g is an alkyl group or an aryl group. Q represents a methine group or a polymethine group necessary for the compound represented by the formula (VII) to form a methine dye. X ₁₃ represents a charge balancing counter ion, and m ₁₄ represents an integer of 0 or more and 10 or less necessary for neutralizing the charge of the molecule. Nitrogen-containing heterocyclic ring formed by the above Z _a may have a substituent, it may be a condensed ring may be a single ring. Further, the alkyl group and the aryl group may have a substituent, the alkyl group may be linear or branched, and the aryl group may be monocyclic or polycyclic (condensed ring, Ring set). The dye represented by the formula (VII) is preferably a dye represented by the following formulas (VII-a) to (VII-d).

[0081]

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In the formulas (VII-a) to (VII-d), R _a1 to
R _a5 , R _{b1 to} R _b4 , R _{c1 to} R _c3 , and R _{d1 to} R _d3 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group, and Y ₁₁ , Y ₁₂ , Y ₂₁ , Y _22, Y ₃₁ ~Y
₃₅ and Y ₄₁ to Y ₄₆ each independently represent oxygen, sulfur, selenium, tellurium, -CR _e1 R _e2 - represents a -, or -NR _e3. Y ₂₃ represents O ⁻ , S ⁻ , Se ⁻ , Te ⁻ , or NR _e4 ⁻ . R _{e1 to} R _e4 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. V _11, V _12,
V ₂₁ , V ₂₂ , V ₃₁ and V ₄₁ each independently represent a substituent, and m ₁₅ , m ₃₁ and m ₄₁ each independently represent an integer of 1 to 6. The alkyl group, aryl group and heterocyclic group in the above may have a substituent, the alkyl group may be linear or branched, and the aryl group and heterocyclic group may be monocyclic. Or polycyclic (condensed ring, ring assembly). Specific examples of such polymethine dyes are described in M. Okawar
a, T.Kitao, T.Hirasima, M.Matuoka by Organic Colorants
(Elsevier) and the like. The formula (V
Preferred specific examples of the polymethine dye represented by I) or (VII) are shown below, but the present invention is not limited thereto.

[0083]

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[0084]

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[0085]

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[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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The compounds represented by the formulas (VI) and (VII) are described in FM Harmer, "Heterocyclic Compounds-Cyanine Soybean and Related Compounds (Heterocyclic Compounds-Cy)".
anine Dyes and Related Compounds), John Wiley & Sons, New York, London, 1964, DMSturmer, Heterogeneous Cyclic Compounds Special Topics・ In ・ Complex Cyclic Chemistry (Heterocyclic Compounds-Special
topics in heterocyclic chemistry), Chapter 18, Section 14, 482-515, John Wiley & Sons, Inc.-New York,
London, 1977, "Rodd's Chemistry of Car Compounds
bon Compounds) "2nd.Ed.vol.IV, partB, 1977, Chapter 15, Chapters 369-422, Elsevier Scienc Inc.
e Publishing Company Inc.), New York, UK Patent No. 1,077,611, and the like.

To adsorb a dye to semiconductor fine particles, a method of immersing well-dried semiconductor fine particles in a solution of a dye or the like for several hours is general. The dye may be adsorbed at room temperature or may be heated and refluxed as described in JP-A-7-249790. The dye may be adsorbed before or after coating the semiconductor fine particles on the conductive support, or the semiconductor fine particles and the dye may be simultaneously coated and adsorbed. Is preferably adsorbed on the semiconductor fine particle film. The method of adsorbing the dye on the semiconductor fine particle film coated on the conductive support is performed by immersing the dried semiconductor fine particle film in the dye solution or by applying the dye solution onto the semiconductor fine particle film and adsorbing the dye solution. be able to.
In the former case, a dipping method, a dipping method, a roller method, an air knife method, or the like can be used. As the latter coating method, a wire bar method, a slide hopper method, an extrusion method,
There are a curtain method, a spin method, and a spray method, and examples of the printing method include letterpress, offset, gravure, and screen printing.

As in the case of the formation of the semiconductor fine particle layer, the liquid viscosity can be determined by various printing methods other than the extrusion method for a high-viscosity liquid (for example, 0.01 to 500 Poise) and the low-viscosity liquid (for example, 0.1 Poise or less). A slide hopper method, a wire bar method, or a spin method is suitable, and a uniform film can be obtained. As described above, an application method may be appropriately selected in accordance with parameters such as the liquid viscosity of the dye coating liquid, the coating amount, the support, and the coating speed. The time required for dye adsorption after coating should be as short as possible in consideration of mass production.

The amount of the dye used is preferably from 0.01 to 100 mmol per 1 m ² of the support. The amount of the dye adsorbed on the semiconductor fine particles is preferably 0.01 to 1 mmol per 1 g of the semiconductor fine particles. With such an amount of the dye, a sensitizing effect in the semiconductor can be sufficiently obtained. On the other hand, if the amount of the dye is small, the sensitizing effect becomes insufficient, and if the amount of the dye is too large, the dye not adhering to the semiconductor floats and causes a reduction in the sensitizing effect.

Since the presence of unadsorbed dye causes disturbance of device performance, it is preferable to remove the dye by washing immediately after adsorption. It is preferable to perform cleaning with a polar solvent such as acetonitrile and an organic solvent such as an alcohol solvent using a wet cleaning tank. In order to increase the amount of the adsorbed dye, it is preferable to perform the heat treatment before the adsorption. After the heat treatment, in order to avoid adsorption of water on the surface of the semiconductor fine particles, it is also preferable to quickly adsorb the dye at 40 to 80 ° C. without returning to normal temperature.

A colorless compound may be co-adsorbed for the purpose of reducing the interaction between dyes such as association. Examples of the hydrophobic compound to be co-adsorbed include steroid compounds having a carboxyl group (for example, cholic acid). In addition, an ultraviolet absorber can be co-adsorbed for the purpose of preventing light deterioration due to ultraviolet light. For the purpose of accelerating the removal of excess dye, the surface of the semiconductor fine particles may be treated with an amine after adsorbing the dye. Preferred amines include pyridine, 4-tert-butylpyridine, polyvinylpyridine and the like. When these are liquid, they may be used as they are, or may be used by dissolving them in an organic solvent.

Hereinafter, the charge transfer layer and the counter electrode will be described in detail. The charge transfer layer is a layer having a function of replenishing the oxidized dye with electrons. Typical examples are a liquid (electrolytic solution) in which a redox couple is dissolved in an organic solvent, a so-called gel electrolyte in which a liquid in which a redox couple is dissolved in an organic solvent is impregnated in a polymer matrix, and a molten salt containing a redox couple. Is mentioned. In the present invention, the charge transfer layer is an electrolyte-containing layer containing the electrolyte of the present invention. The thickness of the electrolyte-containing layer is preferably 0.001 to 200 μm,
More preferably, it is 0.1 to 100 μm. The electrolyte of the present invention is prepared by preparing a solution from a compound of the present invention in which a salt is dissolved, and forming an electrolyte layer on an electrode supporting a dye by a casting method, a coating method, an immersion method, an impregnation method, or the like. Is preferred.

When the electrolyte layer is formed by a coating method,
Spin coating, dip coating, air knife coating, curtain coating, and roller coating are applied to a uniform solution prepared by adding additives such as a coating agent such as a leveling agent to a coating solution composed of a solvent in which salt is dissolved. , Wire bar coating method, gravure coating method, or US Patent No.
Extrusion coating method using hopper described in 2681294, or U.S. Patent Nos. 2,761,418 and 3,508,947
And the multi-layer simultaneous coating method described in JP-A-2761791 can form the electrolyte layer of the present invention. When a compound such as iodine is introduced into the electrolyte layer, for example, after the formation of the electrolyte layer, a sample including the electrolyte layer may be placed in a closed container together with a compound such as iodine, and the sample may be introduced by a method of diffusing into the electrolyte. Further, a compound such as iodine can be introduced into the device by a method of coating or vapor-depositing on a counter electrode.

The water content in the charge transfer layer was 10,
2,000 ppm or less, more preferably 2,0 ppm
It is at most 00 ppm, particularly preferably at most 100 ppm.

The counter electrode functions as a positive electrode of the photoelectrochemical cell when the photoelectric conversion element is a photoelectrochemical cell. As the counter electrode, a support having a conductive layer can be used as in the case of the above-described conductive support. However, the support is not necessarily required in a configuration in which the strength and the sealing property are sufficiently maintained. Specifically, as the conductive material used for the counter electrode, a metal (for example, platinum, gold, silver, copper, aluminum, rhodium,
Indium, etc.), carbon, or a conductive metal oxide (indium-tin composite oxide, tin oxide doped with fluorine, or the like). The thickness of the counter electrode is not particularly limited, but is preferably 3 nm or more and 10 μm or less. If it is a metal material, its thickness is preferably 5 μm.
m, more preferably 5 nm or more and 3 μm or less. In order for light to reach the photosensitive layer, at least one of the conductive support and the counter electrode described above must be substantially transparent. In the photoelectrochemical cell of the present invention, it is preferable that the conductive support is transparent and sunlight is incident from the support side. In this case, it is more preferable that the counter electrode has a property of reflecting light. In the present invention, as the counter electrode, glass or plastic on which a metal or a conductive oxide is deposited, or a metal thin film can be used.

The counter electrode is applied on the charge transfer layer in two ways: first, on the charge transfer layer, and first, on the semiconductor fine particle-containing layer. In any case, depending on the type of the counter electrode material and the type of the charge transfer layer, the counter electrode material can be appropriately formed on the charge transfer layer or the semiconductor fine particle-containing layer by a method such as application, lamination, vapor deposition, or bonding. For example, in the case of attaching a counter electrode, a substrate provided as a conductive layer can be attached by a method such as application, evaporation, or CVD of the above conductive material.

Further, a layer having other necessary functions such as a protective layer and an antireflection film may be provided on the conductive support or the counter electrode of the working electrode. When such layers are separated in function by multiple layers, simultaneous multilayer coating and sequential coating can be performed, but simultaneous multilayer coating is more preferable in terms of productivity. In the simultaneous multi-layer coating, the slide hopper method and the extrusion method are suitable in consideration of productivity and uniformity of film formation. In addition, these functional layers can be provided by a technique such as vapor deposition or pasting depending on the material.

In the photoelectrochemical cell of the present invention, it is preferable to seal the side surface of the cell with a polymer, an adhesive or the like in order to prevent deterioration of components and volatilization of the contents.

[0107]

〔Example〕

1. Preparation of Coating Solution Containing Titanium Dioxide Particles Barb's Journal of American Ceramic Society except that the autoclave temperature was 230 ° C.
In a manner similar to that described in Vol. 80, p. 3157, a titanium dioxide dispersion having a titanium dioxide concentration of 11% by weight was obtained. The average size of the resulting titanium dioxide particles was about 10 nm. To this dispersion was added 30% by weight of polyethylene glycol (molecular weight: 20,000, manufactured by Wako Pure Chemical Industries) based on titanium dioxide, and mixed to obtain a coating solution.

2. Preparation of dye-adsorbed titanium dioxide electrode (electrode A) This coating solution is applied to the conductive surface of transparent conductive glass (made by Nippon Sheet Glass, surface resistance is about 10Ω / cm ² ) coated with fluorine-doped tin oxide. It was applied with a blade to a thickness of 140 μm, dried at 25 ° C. for 30 minutes, and then baked at 450 ° C. for 30 minutes in an electric furnace (Yamato Scientific muffle furnace FP-32). The coating amount of titanium dioxide was 15 g / m ² , and the film thickness was 10 μm. After the glass was taken out and cooled, it was immersed in an ethanol solution of the dye shown in Table 2 (3 × 10 ⁻⁴ mol / l) for 3 hours. The dyed glass is
After being immersed in tert-butylpyridine for 15 minutes, it was washed with ethanol and dried naturally. The coating amount of the dye was appropriately selected from the range of 0.1 to 10 mmol / m ² according to the type of the dye.

3. Preparation of Photoelectrochemical Cell Containing Electrolyte On the color-sensitized TiO ₂ electrode substrate (electrode A: 2 cm × 2 cm) prepared in the above-described example, a mixture of the monomer of the present invention shown in Table 1 (P -1) A mixed solution containing 0.1 g, 1 g of methoxyacetonitrile (MAN) as a solvent, 0.48 g of iodine salt of 1-methyl-3-hexylimidazolium (MHIm) as a salt and 0.003 g of benzoyl peroxide as a polymerization initiator. It was degassed under reduced pressure for 10 minutes and applied. Next, by placing the porous material to which the mixed solution was applied under reduced pressure to remove bubbles in the porous material and promote penetration of the monomer, the temperature was raised to 80 ° C.
For 30 minutes to polymerize. The electrode substrate containing the electrolyte thus obtained was exposed to an iodine atmosphere for 30 minutes to diffuse iodine into the electrolyte, and then superposed on a counter electrode obtained by depositing platinum on glass to form a photoelectrochemical cell (battery N).
o. 1: Table 2) was obtained. The above steps were performed with the combination of the dye and the electrolyte composition changed as shown in Table 2. In the table, PC is propylene carbonate.
According to this embodiment, as shown in FIG.
A photoelectrochemical cell was prepared in which (a conductive agent layer 2 was provided on glass), a TiO ₂ electrode 3, a dye layer 4, an electrolyte layer 5, a platinum layer 6, and glass 7 were laminated in this order.

[0110]

[Table 2]

[0111] 4. Measurement of photoelectric conversion characteristics The light of a 500 W xenon lamp (Ushio) was converted to an AM1.5 filter (Oriel) and a sharp cut filter (K
enko L42) to generate simulated sunlight without UV rays. The light intensity was 84 mW / cm ² . An alligator clip was connected to each of the conductive glass and the platinum-deposited glass of the above-mentioned photoelectrochemical cell, simulated sunlight was irradiated, and the generated electricity was measured with a current-voltage measuring device (Keisley SMU238 type). The open-circuit voltage (Voc), short-circuit current density (Jsc), form factor (FF), and conversion efficiency (η) of the photoelectrochemical cell and the rate of decrease in short-circuit current density after 300 hours of continuous irradiation are summarized. The results are shown in Table 3.

[0112]

[Table 3]

[Comparative Example] Preparation of comparative photoelectrochemical cell A (using an electrolyte described in JP-A-9-27352) The color-sensitized TiO ₂ electrode substrate (electrode A: 2 cm × 2 cm), 1 g of hexaethylene glycol methacrylate (Blenmer PE350 manufactured by NOF CORPORATION)
Lithium iodide 500 mg was dissolved in a mixed solution containing 1 g of ethylene glycol, 1 g of ethylene glycol, and 20 mg of 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173 manufactured by Ciba-Geigy Japan) as a polymerization initiator. Then, it was degassed under vacuum for 10 minutes and applied. Next, by placing the porous material coated with the mixed solution under reduced pressure to remove the bubbles in the porous material and to promote the penetration of the monomer, and then polymerize by irradiation with ultraviolet light to form a uniform polymer compound. The gel was in the pores of the porous material. The material thus obtained was exposed to an iodine atmosphere for 30 minutes to diffuse iodine into the polymer compound, thereby obtaining a comparative photoelectrochemical cell A. As in the example,
The photoelectric conversion characteristics were measured, and the results are shown in Table 3.

It can be seen that, as compared with the comparative example, the photoelectrochemical cell using the electrolyte of the present invention has excellent photoelectric conversion characteristics and little deterioration with time.

[0115]

According to the novel electrolyte of the present invention, a photoelectric conversion element and a photoelectrochemical cell having excellent photoelectric conversion characteristics and little deterioration of characteristics over time can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a photoelectrochemical cell prepared in an example.

[Explanation of symbols]

1 conductive glass 2 conductive agent layer 3 TiO ₂ electrode 4 dye layer 5 electrolyte 6 platinum layer 7 Glass

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01M 14/00 F-term (Reference) 4J100 AL03R AL04R AL05R AL08P AL61Q AL63Q AL71Q AM02R AM54Q BA02Q BA08P BA08Q BA11P BA28P BA28Q BC43P BC43Q BC45Q BC73P DA55 JA46 5F051 AA14 5G301 CA08 CA16 CA30 CD01 5H032 AA06 AS16 EE04 EE20

Claims (5)

[Claims] 1. At least the following formulas (I) and (II)
An electrolyte containing a polymer compound obtained by polymerizing a monomer containing two kinds of compounds represented by the formula: Embedded image Embedded image [Wherein, R ₁ , R ₄ and R ₅ each represent a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₂ and R ₃ each represent a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkyl group. Represents a substituted aryl group. R ₂ and R ₃ may be linked together to form a ring. L ₁ and L ₂ each represent a divalent linking group. L ₃ represents a z-valent linking group;
It is an integer of 6 or more and 6 or less. X is -COO- or -CONR _6-
And R ₆ represents a hydrogen atom or an alkyl group. ] 2. In the formulas (I) and (II), R ₁ ,
R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ are each a hydrogen atom or carbon atom 1
To 6 unsubstituted alkyl groups, wherein L ₁ , L ₂ , and L ₃ are each a lower alkylene group or a — (CH ₂ CH ₂ O) _k —CH ₂ CH ₂ — group (k
Is an integer of 1 to 30). 3. A photoelectric conversion device comprising a charge transfer layer containing the electrolyte according to claim 1 or 2, a conductive support, a semiconductor-containing layer coated on the conductive support, and a counter electrode. 4. The photoelectric conversion device according to claim 3, wherein the semiconductor is a fine particle semiconductor sensitized by a dye. 5. A photoelectrochemical cell using the photoelectric conversion element according to claim 3.