JP2006244919A - Photoelectric conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection preventing film with high cost performance and a photoelectric conversion element using the reflection preventing film by designing the reflection preventing film matched to a photoelectric conversion electrode used for a dye-sensitized solar battery. <P>SOLUTION: The photoelectric conversion element is composed of at least a photoelectric conversion electrode formed by arranging a semiconductor layer modified by sensitizer on a conductive face of a transparent conductive substrate, and a reflection preventing film on a non-conductive face; an electrolyte layer containing a material at least showing reversible electrochemical redox property; and a conductive substrate arranged through the conductive substrate. On an absorption spectrum of the photoelectric conversion electrode, on condition that the wave length of maximum optical density at 450 nm or longer is λ<SB>1</SB>, and the maximum value of the wave length at the optical density equivalent to 1/3 of that at λ<SB>1</SB>is λ<SB>2</SB>, a reflection rate measured at reflection preventing film side of the photoelectric conversion electrode becomes 5% or less at the wave length ranging from (2λ<SB>1</SB>-λ<SB>2</SB>) to λ<SB>2</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-performance photoelectric conversion element.

  In order to improve the conversion efficiency of a solar cell, it is a common practice to provide an antireflection film on the light incident side surface. The lower the surface reflection over a wide wavelength range, the more incident light reaches the photoelectric conversion electrode, but the production cost of the antireflection film increases. Although it is necessary to design an antireflection film that strikes a balance between the solar cell performance and the production cost of the antireflection film, there has been almost no such study, particularly in dye-sensitized solar cells.

  The present invention has been made in view of such a situation, and by designing an antireflection film that matches a photoelectric conversion electrode used in a dye-sensitized solar cell, an antireflection film having high cost performance and the same are used. An object is to provide a photoelectric conversion element. Another object of the present invention is to provide a photoelectric conversion element having high durability by a simple manufacturing method by applying the above method to a solid electrolyte.

That is, the present invention relates to a photoelectric conversion electrode in which a semiconductor layer modified with a sensitizer is provided on a conductive surface of a transparent conductive substrate and an antireflection film is provided on a non-conductive surface, and at least a reversible electrochemical oxidation. A photoelectric conversion element comprising at least an electrolyte layer containing a substance exhibiting reduction characteristics and a conductive substrate disposed via the electrolyte layer, wherein the absorption spectrum of the photoelectric conversion electrode is 450 nm or more. ₁ wavelength optical density becomes maximum _lambda, when the ₂ maximum value of the wavelength lambda of the equal optical density to 1/3 of the optical density at _{λ 1, (2λ 1 -λ 2} ) wavelengths to [lambda] ₂ range In the photoelectric conversion element, the reflectance measured from the antireflection film side of the photoelectric conversion electrode is 5% or less.

The present invention also relates to a photoelectric conversion element, wherein the electrolyte layer is a solid electrolyte.
The present invention also relates to a photoelectric conversion element, wherein the solid electrolyte is an ion conductive film comprising at least (a) a polymer matrix and (b) a substance exhibiting reversible electrochemical redox characteristics. .
The present invention also relates to a photoelectric conversion element, wherein the polymer matrix is a polyvinylidene fluoride polymer compound.
The present invention also relates to a photoelectric conversion element, wherein the polyvinylidene fluoride polymer compound contains a carboxyl group.
Furthermore, the present invention relates to a photoelectric conversion element, wherein the substance exhibiting reversible electrochemical redox characteristics is a room temperature molten salt.

  Hereinafter, the present invention will be described in detail.

In the photoelectric conversion element of the present invention, the photoelectric conversion electrode has a configuration in which a semiconductor layer modified with a sensitizer is provided on a conductive surface of a transparent conductive substrate and an antireflection film is provided on a non-conductive surface. In the present invention, in the absorption spectrum of the photoelectric conversion electrode, the wavelength at which the optical density at 450 nm or more is maximum is λ ₁ , and the maximum value of the wavelength at which the optical density is equal to 1/3 of the optical density at λ ₁ is in case of a lambda _2, it is to set such that (2λ ₁ -λ ₂₎ in the wavelength range of to [lambda] _2, the measured reflectance antireflection film side of the photoelectric conversion electrode 5% or less.

The antireflection film used in the present invention is not particularly limited as long as the above conditions can be satisfied, and a general antireflection film can be used. One preferred antireflection film is an alternating laminated film of a high refractive index film and a low refractive index film. Here, in the high refractive index film and the low refractive index film, the higher refractive index film is called a high refractive index film, and the lower refractive index film is called a low refractive index film. As the low refractive index film, those having a refractive index of 1.55 or less are preferable. Examples of these films are silicon oxide, fluorine compound or aluminum compound (for example, SiO ₂ , MgF ₂ or Al ₂ O ₃ ). The film | membrane which becomes is mentioned. A low refractive index film made of such a material can be formed by a vapor deposition method such as vacuum evaporation, sputtering, or ion plating. Alternatively, a low refractive index film can be obtained by preparing a coating liquid containing the powder of the above material and an organic polymer binder or an inorganic polymer binder, coating the substrate on the substrate, drying, and curing as necessary. In the case of using an ultraviolet curable or thermosetting resin as the binder, it is particularly preferable because the formation becomes easy. For example, when a SiO ₂ film is formed by coating, the SiO ₂ content of the film is suitably 30 to 50% by mass. A low refractive index film made of these materials can be formed by a casting method, a dip coating method, a screen printing method, a roll coater method, a spin coating method, a spray method, or the like.

The high refractive index film preferably has a refractive index exceeding 1.55. Examples of these films include tin-doped indium oxide (ITO), ZnO, aluminum-doped zinc oxide (ZAO), TiO ₂ , SnO _{2, and} ZrO. These metal oxide films can be mentioned. A high refractive index film made of such a material can be formed by a vapor deposition method or the like. Alternatively, a high-refractive-index film can be obtained by preparing a coating liquid containing the above-mentioned powder and an organic polymer binder or an inorganic polymer binder, applying the coating liquid to a substrate, drying, and curing as necessary. When an ultraviolet curable resin or a thermosetting resin is used as the binder, it is particularly preferable because the formation becomes easy. For example, when an ITO film is formed by coating, an ITO content of the film is suitably 80 to 89% by mass. High refractive index films made of these materials can be formed by a casting method, a dip coating method, a screen printing method, or the like.

  As such a laminated structure of alternating laminated films, the film farthest from the transparent substrate is preferably a low refractive index film. Furthermore, it is preferable that one high refractive index film and one low refractive index film are formed on the transparent substrate in this order, and the total number of layers of the alternately laminated film is 3 to 6 layers.

Examples of the specific configuration of the antireflection film include the following configurations.
(1) Consisting of a single transparent film having a lower refractive index than the transparent substrate.
(2) A high-refractive-index film and a low-refractive-index film are laminated on a transparent substrate in this order, a total of two layers.
(3) A film in which a high refractive index film, a low refractive index film, a high refractive index film, and a low refractive index film are laminated in this order, for a total of four layers, on a transparent substrate.
(4) A low-refractive index film, a high-refractive index film, and a low-refractive index film are laminated in this order on a transparent substrate in a total of three layers. In this case, the first low refractive index film on the transparent substrate side preferably has an intermediate refractive index between the second high refractive index film and the third low refractive index film.
(5) On a transparent substrate, a high refractive index film, a low refractive index film, a high refractive index film, a low refractive index film, a high refractive index film, and a low refractive index film are laminated in this order, for a total of 6 layers. .

1 and 2 are sectional views of typical examples of the structure of the antireflection film. This corresponds to (2) and (4) of the antireflection film.
In FIG. 1, a high refractive index film H <b> 1 and a low refractive index film L <b> 1 are laminated in this order on the nonconductive surface of the transparent conductive substrate 1. These two layers constitute the antireflection film 2. For example, TiO 2 as a high refractive index _film, SiO ₂ is generally used because of easy availability as a low refractive index film.
In FIG. 2, a low refractive index film L2, a high refractive index film H2, and a low refractive index film L3 are laminated on the transparent conductive substrate 1 in this order. These three layers constitute the antireflection film 4. For example, TiO ₂ as a high refractive index film or SiO ₂ as an ITO low refractive index film is generally used because it is easily available.

  The film thicknesses of these high and low refractive index films are appropriately determined in order to lower the reflectance in the visible light region due to light interference, but this depends on the number of layers in the laminated film, the material used, and the center wavelength. . For example, in the case of a four-layer structure, the high refractive index film of the first layer on the transparent substrate side is 5 to 50 nm, the low refractive index film of the second layer is 5 to 50 nm, and the high refractive index film of the third layer is 50 to 100 nm. The low refractive index film of the fourth layer is preferably in the range of 50 to 150 nm. For example, in the case of a two-layer structure, the high refractive index film of the first layer on the transparent substrate side is preferably 50 to 150 nm, and the low refractive index film of the second layer is preferably 50 to 150 nm.

  Further, a contamination prevention film may be further formed on such an antireflection film to improve the surface contamination resistance. As this contamination-preventing film, a fluorine-based resin thin film or a silicone-based resin thin film (film thickness of 1 to 1000 nm) is preferable.

  Although the measurement of the optical density of the photoelectric conversion electrode in this invention is not specifically limited, For example, the method of measuring the optical density of the produced photoelectric conversion electrode using an ultraviolet and visible spectrophotometer (Hitachi Ltd. make, U4000). Is mentioned. The measurement of the reflectance is not particularly limited. For example, the reflectance can be measured by attaching a specular reflection measurement unit to the spectrophotometer.

In the photoelectric conversion element of the present invention, in the absorption spectrum of the photoelectric conversion electrode, the wavelength at which the optical density at 450 nm or more is the maximum is λ ₁ , the wavelength at which the optical density is equal to 1/3 of the optical density at λ ₁ . the maximum value when the _{λ 2, (2λ 1 -λ 2} ) in the wavelength range of to [lambda] _2, in which the measured reflectance antireflection film side of the photoelectric conversion electrode is set to be 5% or less is there.
That is, in order to produce a photoelectric conversion element with high conversion efficiency, it is necessary to make the reflectance of the photoelectric conversion electrode as low as possible in the widest possible wavelength range. There is a problem that the layer structure becomes complicated and costs increase. As a result of various studies by the present inventors, by producing an antireflection film satisfying the above-mentioned requirements, it was possible to produce a high-performance photoelectric conversion element with good cost performance for the first time in the above-mentioned wavelength range. When the reflectivity exceeds 5%, the conversion efficiency of the photoelectric conversion element is greatly lowered, which is not preferable.

The transparent conductive substrate used in the present invention has a conductive layer (transparent electrode layer) on one surface of the transparent substrate, and the other surface is a non-conductive surface.
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 block, etc. are used, and colorless. Alternatively, a colored transparent resin may be used. Examples of the resin include polyesters such as polyethylene terephthalate, polyamide, polysulfone, polyethersulfone, polyetheretherketone, polyphenylene sulfide, polycarbonate, polyimide, polymethyl methacrylate, polystyrene, cellulose triacetate, and polymethylpentene. 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 metal oxide, etc. Is mentioned. Examples of the metal oxide include Indium Tin Oxide (ITO (In ₂ O ₃ : Sn)) obtained by doping a metal oxide such as tin and zinc with a small amount of other metal elements, Fluorine doped Tin Oxide (FTO (SnO ₂ )). : F)), Aluminum doped Zinc Oxide (AZO (ZnO: Al)) and the like are preferably used.
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, but is usually 0.5 to 500 Ω / sq, preferably 2 to 50 Ω / sq.

  The method for forming the transparent electrode layer is not particularly limited, and a known method is appropriately selected and used depending on the kind of the metal or metal oxide used as the electrode layer. Usually, a vacuum deposition method, an ion plating method is used. The method, CVD, sputtering method or the like is used. In any case, it is desirable that the substrate is formed within a range of 20 to 700 ° C.

  The other substrate, that is, the counter substrate, may be any substrate 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. In addition to various metal electrodes, examples of the opaque conductive substrate include Ti, Ni, 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 , CdS, CdSe, CdTe, CuInS ₂ , CuInSe ₂ , Fe ₂ O ₃ , GaP, GaAs, InP, Nb ₂ O ₅ , PbS, Si, SnO ₂ , TiO ₂ , WO ₃ , ZnO, ZnS and the like can be mentioned, preferably CdS, CdSe, CuInS ₂ , CuInSe ₂ , Fe ₂ O ₃ , GaAs, InP, Nb ₂ O ₅ , PbS, SnO ₂ , TiO ₂ , WO ₃ , ZnO, and a plurality of combinations may be used. Particularly preferred are TiO ₂ , ZnO, SnO ₂ and Nb ₂ O ₅ , and most preferred are TiO ₂ and ZnO.

The semiconductor used in the present invention may be single crystal or polycrystalline. As the crystal system, for example, in the case of titanium oxide, anatase type, rutile type, brookite type and the like are mainly used, but anatase type is preferable. A known method can be used for forming the semiconductor layer.
As a method for forming the semiconductor layer, the semiconductor nanoparticle dispersion, the 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 examples include a method of obtaining a thin film by a casting method, a spin coating method, a dip coating method, a bar coating method, and various printing methods including a screen printing method. .
Although the thickness of a semiconductor layer is arbitrary, it is 0.5 micrometer or more and 100 micrometers or less, Preferably they are 1 micrometer or more and 50 micrometers or less.

The sensitizer used in the present invention is not particularly limited as long as it improves the light absorption efficiency of the semiconductor layer. Usually, one or more of various metal complex dyes and organic dyes are used. be able to. In addition, in order to impart adsorptivity to the semiconductor layer, a functional group such as a carboxyl group, a hydroxyl group, a sulfonyl group, a phosphonyl group, a carboxylalkyl group, a hydroxyalkyl group, a sulfonylalkyl group, or a phosphonylalkyl group is included in the dye molecule. Those having 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, R < ¹ > -R < ⁴ > has shown the hydrogen atom, the C1-C10 alkyl group, and the tetraalkylammonium cation like following formula, respectively, and may mutually be same or different.

(Here, R ^{1 to} R ⁴ each represent an alkyl group having 1 to 10 carbon atoms, and may be the same as or different from each other.)

  Moreover, although X shows a monovalent anion, two X may be independent or may be bridge | crosslinked. For example, the following is exemplified.

Z ⁺ represents a tetraalkylammonium cation represented by the following formula.

(Here, R ^{1 to} R ⁴ each represent an alkyl group having 1 to 10 carbon atoms, and may be the same as or different from each other.)

(Dye 2)

Here, X represents a monovalent anion. For example, the following is exemplified.

Y is a monovalent anion, which is a halogen ion, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) _{2 ^{N -, PF 6 -, AsF}} 6 -, CH 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - , and the like.

(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.

Y is a monovalent anion, which is a halogen ion, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) _{2 ^{N -, PF 6 -, AsF}} 6 -, CH 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - , and the like.

(Dye 4)

  As the organic dye, a cyanine dye, a hemicyanine dye, a merocyanine dye, a xanthene dye, a triphenylmethane dye, or a metal-free phthalocyanine dye can be used. Examples of the dye used in the present invention are as follows.

  As a method for adsorbing the sensitizer on the semiconductor layer, a solution in which the sensitizer is dissolved in a solvent is applied by spray coating or spin coating on the semiconductor layer and then dried. . 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 sensitizer is sufficiently adsorbed, but is preferably 1 to 30 hours, particularly preferably 5 to 20 hours. Moreover, when immersing as needed, a solvent and a board | substrate may be heated or you may irradiate an ultrasonic wave. Preferably, the concentration of the sensitizer in the case of a solution is about 0.01 to 100 mmol / L, preferably about 0.1 to 40 mmol / L.

  The solvent to be used is not particularly limited as long as the sensitizer is dissolved and the semiconductor layer is not dissolved, but methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t- Alcohols such as butanol, nitrile solvents such as acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, benzene, toluene, o-xylene, m-xylene, p-xylene, pentane, heptane, hexane, cyclohexane, Ketones such as heptane, acetone, methyl ethyl ketone, diethyl ketone, 2-butanone, diethyl ether, tetrahydrofuran, ethylene carbonate, propylene carbonate, nitromethane, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoa , Dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethoxyethane, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, Ethyldimethyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris phosphate (trifluoromethyl), tris phosphate (pentafluoro) Ethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol and the like can be used.

An electrolyte layer containing a substance exhibiting at least reversible electrochemical redox characteristics is disposed between the photoelectric conversion electrode substrate and the counter electrode substrate.
The electrolyte layer used in the present invention must contain a substance exhibiting reversible electrochemical redox characteristics. Here, showing reversible electrochemical redox characteristics means that a reversible electrochemical redox reaction can occur in a potential region where the photoelectric conversion element acts. Typically, it is usually desirable to be reversible in the potential range of −1 to +2 V vs NHE with respect to the hydrogen reference electrode (NHE).

A substance exhibiting reversible electrochemical oxidation-reduction characteristics is usually referred to as a so-called redox material, but the type is not particularly limited. Examples of such substances include ferrocene, p-benzoquinone, 7,7,8,8-tetracyanoquinodimethane, N, N, N ′, N′-tetramethyl-p-phenylenediamine, tetrathiafulvalene, and anthracene. , P-toluylamine and the like. Further, LiI, NaI, KI, CsI , CaI 2, 4 quaternary imidazolium iodide salt, iodine tetraalkylammonium Motoshio, Br ₂ and LiBr, NaBr, KBr, CsBr, and metal bromides, such as CaBr ₂ and the like, Also, Br ₂ and tetraalkylammonium bromide, bipyridinium bromide, bromine salts, complex salts such as ferrocyanic acid-ferricyanate, sodium polysulfide, alkylthiol-alkyl disulfides, hydroquinone-quinones, viologen dyes, cobalt complexes, etc. be able to.

As the redox material, only one of an oxidant and a reductant may be used, or the oxidant and the reductant may be mixed and added at an appropriate molar ratio. Further, these redox pairs may be added so as to show electrochemical responsiveness. Materials exhibiting such properties include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N _{^{-, PF 6 -, AsF 6}} -, CH 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - , such as ferrocenium having a counter anion selected from metallocenium of In addition to salts, halogens such as iodine, bromine and chlorine can also be used.

In addition, as another substance exhibiting reversible electrochemical redox characteristics, a salt having a counter anion (X ⁻ ) selected from halogen ion, SCN ⁻ and SeCN ⁻ can be mentioned. Examples of these salts include quaternary ammonium salts, phosphonium salts, imidazolium salts, guanidinium salts and the like.

等が挙げられる。 Specific examples of the quaternary ammonium salt include (CH ₃ ) ₄ N ⁺ X ⁻ , (C ₂ H ₅ ) ₄ N ⁺ X ⁻ , (nC ₄ H ₉ ) ₄ N ⁺ X ⁻ , ,

Etc.

等が挙げられる。 Specific examples of the phosphonium salt include (CH ₃ ) ₄ P ⁺ X ⁻ , (C ₂ H ₅ ) ₄ P ⁺ X ⁻ , (C ₃ H ₇ ) ₄ P ⁺ X ⁻ , and (C ₄ H ₉ ). ₄ P ⁺ X ⁻ ,

Etc.

Examples of the imidazolium salt include those represented by the following general formula.

Here, R ¹ and R ² each represent an alkyl group having 1 to 10 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 13 carbon atoms, and may be the same or different. R ^{3 to} R ⁵ each represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 13 carbon atoms, and may be the same or different. X ⁻ represents a halogen ion, SCN ⁻ or SeCN ⁻ .

  Specific examples of such imidazolium salts include 1-propyl-2,3-dimethyl-imidazolium salt, 1-propyl-3-methylimidazolium salt, 1-ethyl-3-methylimidazolium salt, Examples include hexyl-3-methylimidazolium salt.

  Of course, a mixture of these can also be used suitably.

In addition, redox room temperature molten salts can also be used as substances exhibiting reversible electrochemical redox properties. Here, the redox room temperature molten salt is a salt composed of an ion pair melted at room temperature (that is, in a liquid state), and usually has a melting point of 20 ° C. or lower and is a liquid at a temperature exceeding 20 ° C. A salt consisting of a pair is shown, and a reversible electrochemical redox reaction can be performed. When redox room temperature molten salts are used as the substance exhibiting reversible electrochemical redox properties, the solvent may be used or may not be used.
The redox room temperature molten salt can be used alone or in combination of two or more.

Examples of redox room temperature molten salts include the following.

(Here, R represents an alkyl group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, and X ⁻ represents a halogen ion, SeCN ⁻ or SCN ⁻ ).

(Wherein R ¹ and R ² are each an alkyl group having 1 to 10 carbon atoms (preferably a methyl group or an ethyl group), or an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 13 carbon atoms (preferably a benzyl group). And may be the same as or different from each other, and X ⁻ represents a halogen ion, SeCN ⁻ or SCN ⁻ ).

(Here, R ¹ , R 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 methoxy. . indicates a methyl group, may be the same or different from each other, X ^- is a halogen ion, SeCN ^- shows a) ^- or SCN.

The electrolyte layer of the present invention is not particularly limited as long as it contains the above-described substance exhibiting reversible electrochemical redox characteristics, and may be either a liquid system or a solid system.
There are no particular limitations on the liquid electrolyte, and usually a solvent, a substance exhibiting the above-described reversible electrochemical oxidation-reduction characteristics (soluble in a solvent), and a supporting electrolyte as necessary are basically used. Configured as an ingredient. In addition to these, other optional components such as an ultraviolet absorber and an amine compound may be further contained as desired.

  Any solvent can be used as long as it is generally used in electrochemical cells and batteries. Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, 3-methyl-2-oxazolidinone, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, ethylene carbonate, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, 3-methylsulfolane, dimethoxyethane, propionitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, dimethylacetamide, methylpyrrolidinone, dioxolane, trimethyl phosphate, triethyl phosphate , Tripropyl phosphate, ethyldimethyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl phosphate Chill, trioctyl phosphate, trinonyl phosphate, tridecyl phosphate, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol, and the like can be used. In particular, propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, 3-methyl-2-oxazolidinone, γ-butyrolactone, sulfolane, 3-methylsulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, dimethylacetamide, methylpyrrolidinone, trimethyl phosphate and triethyl phosphate are preferred. Also, room temperature molten salts can be used. Here, the room temperature molten salt is a salt composed of an ion pair that is melted at room temperature (that is, in a liquid state) and usually has a melting point of 20 ° C. or lower and is a liquid at a temperature exceeding 20 ° C. Is a salt.

Examples of the room temperature molten salt include the following.

(Here, R represents an alkyl group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, and X ⁻ represents a halogen ion, SeCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO _{^{2) 2 N -, (C}} 2 F 5 SO 2) 2 N -, PF 6 -, AsF 6 -, CH 3 COO -, CH 3 (C 6 H 4) SO 3 -, (C 2 F 5 SO 2 ₃ C ^{− represents} dicyandiamide ion, tricyanomethane ion or thiocyanate ion.)

（ここで、Ｒ^１およびＲ^２は各々炭素数１〜１０のアルキル基（好ましくはメチル基またはエチル基）、または炭素数７〜２０、好ましくは７〜１３のアラルキル基（好ましくはベンジル基）を示しており、互いに同一でも異なっても良い。また、Ｘ⁻はハロゲンイオン、ＳｅＣＮ⁻、ＣｌＯ_４ ⁻、ＢＦ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻、（ＣＦ_３ＳＯ_２）_２Ｎ⁻、（Ｃ_２Ｆ_５ＳＯ_２）_２Ｎ⁻、ＰＦ_６ ⁻、ＡｓＦ_６ ⁻、ＣＨ_３ＣＯＯ⁻、ＣＨ_３（Ｃ_６Ｈ_４）ＳＯ_３ ⁻、（Ｃ_２Ｆ_５ＳＯ_２）_３Ｃ⁻、ジシアンジアミドイオン、トリシアノメタンイオンまたはチオシアネートイオンを示す。）

(Wherein R ¹ and R ² are each an alkyl group having 1 to 10 carbon atoms (preferably a methyl group or an ethyl group), or an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 13 carbon atoms (preferably a benzyl group). X ⁻ represents a halogen ion, SeCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C _{2 F 5 SO 2) 2 N} -, PF 6 -, AsF 6 -, CH 3 COO -, CH 3 (C 6 H 4) SO 3 -, (C 2 F 5 SO 2) 3 C -, dicyandiamide ions, (Indicates tricyanomethane ion or thiocyanate ion.)

(Here, R ¹ , R 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 methoxy. Represents a methyl group, etc., and may be the same or different from each other, and X ⁻ represents a halogen ion, SeCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , ( C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₃ C ⁻ , dicyandiamide ion Represents tricyanomethane ion or thiocyanate ion.)

  The solvent may be used alone or in combination of two or more.

  Further, as the supporting electrolyte added as necessary, salts, acids, alkalis, and room temperature molten salts that are usually used in the field of electrochemistry or the field of batteries can be used.

  The salt is not particularly limited, and examples thereof include inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, cyclic quaternary ammonium salts, quaternary phosphonium salts, cyclic quaternary phosphonium salts, and imidazolium. Salts, guanidinium salts and the like can be used.

Specific examples of the salts include ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ and AsF ₆ ^−. , CH ₃ COO ⁻ , CH ₃ (C ₆ H ₄ ) SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₃ C ⁻ , and an alkali metal salt having a counter anion selected from dicyandiamide ion (DCA ⁻ ), alkaline earth Examples thereof include metal salts, quaternary ammonium salts, cyclic quaternary ammonium salts, quaternary phosphonium salts, cyclic quaternary phosphonium salts, imidazolium salts, and guanidinium salts.

Specific examples of the alkali metal and alkaline earth metal salts include LiClO ₄ , LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, _{CH 3 COOLi, CH 3 (C} 6 H 4) SO 3 Li, Li (C 2 F 5 SO 2) 3 C, LiDCA, Mg (ClO 4) 2, Mg (BF 4) 2, Mg (PF 6) 2 Mg (CF ₃ SO ₃ ) ₂ , Mg [(CF ₃ SO ₂ ) ₂ N] ₂ , Mg [(C ₂ F ₅ SO ₂ ) ₂ N] ₂ , Mg (CH ₃ COO) ₂ , Mg [CH ₃ (C ₆ H ₄ ) SO ₃ ] ₂ , Mg [(C ₂ F ₅ SO ₂ ) ₃ C] ₂ , Mg (DCA) _{2 and the} like.

Specific examples of the quaternary ammonium salt and the cyclic quaternary ammonium salt include (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n-C ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H ₅ ) ₄ NSO ₃ CF ₃ , (n-C ₄ H ₉ ) ₄ NSO ₃ CF ₃ ,

等が挙げられる。

Etc.

等が挙げられる。 Specific examples of phosphonium salts and cyclic phosphonium salts include (CH ₃ ) ₄ PBF ₄ , (C ₂ H ₅ ) ₄ PBF ₄ , (C ₃ H ₇ ) ₄ PBF ₄ , (C ₄ H ₉ ) ₄ PBF _4. ,Moreover,

Etc.

  Specific examples of imidazolium salts include 1-propyl-2,3-dimethyl-imidazolium tetrafluoroborate, 1-propyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetra Examples thereof include fluoroborate and 1-hexyl-3-methylimidazolium tetrafluoroborate.

  Specific examples of the guanidinium salt include guanidinium hydrochloride, guanidinium thiocyanate, and guanidinium nitrate.

  Moreover, these mixtures can also be used suitably.

The acids are not particularly limited, and inorganic acids, organic acids, and the like can be used. Specifically, sulfuric acid, hydrochloric acid, phosphoric acids, sulfonic acids, carboxylic acids, and the like can be used.
The alkalis are not particularly limited, and any of sodium hydroxide, potassium hydroxide, lithium hydroxide and the like can be used.
As the room temperature molten salts, the aforementioned compounds are used.

  There is no restriction | limiting in particular about the usage-amount of the above supporting electrolyte, Usually, it is 0.01-10 mol / L as a density | concentration in electrolyte, Preferably it is made to contain about 0.05-1 mol / L. it can.

  Next, optional components to be added as desired will be described. Examples of optional components include ultraviolet absorbers and amine compounds. Although it does not specifically limit as a ultraviolet absorber which can be used, Organic UV absorbers, such as a compound which has a benzotriazole skeleton and a compound which has a benzophenone skeleton, are mentioned as a typical thing.

As the compound having a benzotriazole skeleton, for example, a compound represented by the following general formula (1) is preferably exemplified.

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, and a cyclohexyl group. 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-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy-benzenepropanoic acid. 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy-benzeneethanoic acid, 3- (2H-benzotriazol-2-yl) -4-hydroxybenzene Ethanoic acid, 3- (5-methyl-2H-benzotriazol-2-yl) -5- (1-methylethyl) -4-hydroxybenzenepropanoic acid, 2- (2′-hydroxy-5′-methylphenyl) Benzotriazole, 2- (2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5 '-Di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 3- (5-chloro-2H-benzo And triazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy-benzenepropanoic acid octyl ester.

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 ¹¹ , and R ¹² are the same or different from each other, and are a hydroxyl group, 1 to 10 carbon atoms, Preferably 1-6 alkyl groups or alkoxy groups are shown. 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, an i-propoxy group, and a butoxy group.

R ⁴ , R ⁷ and R ¹⁰ represent 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.
p1, p2, p3, q1, q2, and q3 each independently represent an integer of 0 to 3.

Preferred examples of the compound having a benzophenone skeleton represented by the general formulas (2) to (4) include 2-hydroxy-4-methoxybenzophenone-5-carboxylic acid and 2,2′-dihydroxy-4-methoxybenzophenone. -5-carboxylic acid, 4- (2-hydroxybenzoyl) -3-hydroxybenzenepropanoic acid, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfone Acid, 2-hydroxy-4-n-octoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy -2'-carboxybenzophenone and the like.
Of course, two or more of these can be used in combination.

  The use of the ultraviolet absorber is optional, and the amount used is not particularly limited, but when used, the concentration in the electrolyte is 0.001 to 10 mol / L, preferably 0.01. It is desirable that it is ˜1 mol / L.

Next, the amine compound that can be contained in the electrolyte of the present invention is not particularly limited, and various aliphatic amines and aromatic amines are used. For example, pyridine derivatives, aniline derivatives, quinoline derivatives, imidazole derivatives, etc. Is a typical example. By adding these amine compounds, an improvement in open circuit voltage is expected. Specific examples of these compounds include pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 4-ethylpyridine, 4-propylpyridine, 4-t-butyl-pyridine, 4-dimethylaminopyridine, 2-dimethylaminopyridine, 2,6-dimethylpyridine, 2,4,6-trimethylpyridine, 4-pyridinopyridine, 4-pyrrolidinopyridine, 4- (2-aminoethyl) pyridine, 2- (2-amino Ethyl) pyridine, 2-methoxymethylpyridine, picolinic acid, 2-pyridinemethanol, 2-pyridineethanol, 3-pyridinemethanol, 2,3-cyclopentenopyridine, nicotinamide, nicotinic acid, 4,4′-bipyridine, Pyridine derivatives such as 2,2′-bipyridine, and anilines such as aniline and dimethylaniline Emissions derivatives, quinoline, quinoline derivatives such as isoquinoline, benzimidazole, imidazole derivatives such as N- methyl benzimidazole.
The use of the amine compound is optional, and the amount used is not particularly limited, but when used, the concentration in the electrolyte is 0.001 to 10 mol / L, preferably 0.01. It is desirable that it is ˜1 mol / L.

  The electrolyte used in the present invention may be a liquid as described above, but a polymer solid electrolyte is particularly preferable from the viewpoint that solidification is possible. As the polymer solid electrolyte, it is particularly preferable that (a) the polymer matrix (component (a)) contains at least (b) a substance (component (b)) exhibiting reversible electrochemical redox characteristics. If desired, those further containing (c) a plasticizer (component (c)) may be mentioned. In addition to these, other optional components such as the above-described supporting electrolyte, room temperature molten salt, ultraviolet absorber, and amine compound may be further contained as desired. As the polymer solid electrolyte, the component (b), the component (b) and the component (c), or a further optional component is held in a polymer matrix to form a solid state or a gel state.

As a material that can be used as a polymer matrix in the present invention, a solid state or a gel state can be formed by a polymer matrix alone, or by adding a plasticizer, a supporting electrolyte, or a plasticizer and a supporting electrolyte. There is no restriction | limiting in particular and what is called a high molecular compound generally used can be used.
Examples of the polymer compound exhibiting characteristics as the polymer matrix include hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, vinylidene chloride, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, methyl Examples thereof include polymer compounds obtained by polymerizing or copolymerizing monomers such as acrylate, ethyl acrylate, methyl methacrylate, styrene, and vinylidene fluoride. These polymer compounds may be used alone or in combination. Among these, a polyvinylidene fluoride polymer compound is particularly preferable.

  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 other polymerizable monomers copolymerized with vinylidene fluoride (hereinafter referred to as copolymerizable monomers) include hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, ethylene, propylene, acrylonitrile, and vinylidene chloride. Acrylic acid, methacrylic acid, maleic acid, maleic anhydride, methyl acrylate, ethyl acrylate, methyl methacrylate, styrene and the like can be exemplified. Among these, a copolymer with a monomer having a carboxyl group is particularly preferable. That is, as the polyvinylidene fluoride polymer compound, those containing a carboxyl group are preferable.

  These copolymerizable monomers can be used in the range of 0.1 to 50 mol%, preferably 1 to 25 mol%, based on the total amount of monomers.

  As the copolymerizable monomer, hexafluoropropylene is preferably used. In the present invention, in particular, it can be preferably used as an ion conductive film using a vinylidene fluoride-hexafluoropropylene copolymer obtained by copolymerizing 1-25 mol% of hexafluoropropylene with vinylidene fluoride as a polymer matrix. Further, two or more kinds of vinylidene fluoride-hexafluoropropylene copolymers having different copolymerization ratios may be mixed and used.

  Further, two or more of these copolymerizable monomers can be used for copolymerization with vinylidene fluoride. For example, vinylidene fluoride + hexafluoropropylene + tetrafluoroethylene, vinylidene fluoride + hexafluoropropylene + acrylic acid, vinylidene fluoride + hexafluoropropylene + maleic anhydride, vinylidene fluoride + tetrafluoroethylene + ethylene, vinylidene fluoride A copolymer obtained by copolymerization with a combination of + tetrafluoroethylene + propylene can also be used.

  Furthermore, in the present invention, a polyacrylic acid polymer compound, a polyacrylate polymer compound, a polymethacrylic acid polymer compound, a polymethacrylate polymer compound, One or more polymer compounds selected from acrylonitrile polymer compounds and polyether polymer compounds may be used in combination. Alternatively, one or more kinds of copolymers obtained by copolymerizing two or more kinds of monomers of the above-described polymer compound with a polyvinylidene fluoride polymer compound may be used. In this case, the blending ratio of the homopolymer or copolymer is usually preferably 200 parts by mass or less with respect to 100 parts by mass of the polyvinylidene fluoride polymer compound.

  The weight average molecular weight of the polyvinylidene fluoride polymer compound used in the present invention is usually 10,000 to 2,000,000, preferably 100,000 to 1,000,000. can do.

The plasticizer (component (c)) acts as a solvent for substances exhibiting reversible electrochemical redox properties. Any plasticizer can be used as long as it can be generally used as an electrolyte solvent in an electrochemical cell or battery, and specific examples thereof include various solvents exemplified in liquid electrolytes. In particular, propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, 3-methyl-2-oxazolidinone, γ-butyrolactone, sulfolane, 3-methylsulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, dimethylacetamide, methylpyrrolidinone, trimethyl phosphate and triethyl phosphate are preferred. Moreover, the above-mentioned room temperature molten salts can also be used.
One plasticizer may be used alone, or two or more plasticizers may be mixed and used.

  The amount of the plasticizer (component (c)) used is not particularly limited, but is usually 20% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, and 98% by mass in the polymer solid electrolyte. It can be contained in an amount of not more than mass%, preferably not more than 95 mass%, more preferably not more than 90 mass%.

Moreover, there is no restriction | limiting in particular about the usage-amount of the substance (component (b)) which shows a reversible electrochemical oxidation-reduction characteristic, Usually 0.1 mass% or more in a polymer solid electrolyte, Preferably it is 1 mass% or more. More preferably, the content is 10% by mass or more and 70% by mass or less, preferably 60% by mass or less, and more preferably 50% by mass or less.
When the component (b) and the component (c) are used in combination, it is desirable that the component (b) has a mixing ratio that dissolves in the component (c) and does not cause precipitation even when the polymer solid electrolyte is formed. Preferably component (b) / component (c) is 0.01-0.5 by mass ratio, More preferably, it is the range of 0.03-0.3.
For component (a), the mass ratio of component (a) / (component (b) + component (c)) is preferably 1/20 to 1/1, more preferably 1/10 to 1/2. It is desirable to be in the range.

  In addition to these, the solid electrolyte may further contain other optional components such as a supporting electrolyte, a room temperature molten salt, an ultraviolet absorber, and an amine compound as desired. The types and contents of these optional components are as exemplified in the liquid electrolyte.

  Next, in the present invention, the polymer solid electrolyte can be used as an ion conductive film. For example, an ion conductive film can be obtained by forming a polymer solid electrolyte comprising the components (a) and (b) or an optional component further blended as desired into a film by a known method. The molding method in this case is not particularly limited, and examples thereof include extrusion molding, a method obtained in a film state by a casting method, a spin coating method, a dip coating method, an injection method, and an impregnation method.

Extrusion molding can be performed by a conventional method, and after the mixture is melted by heating, film molding is performed.
Regarding the casting method, the mixture can be formed into a film by further adjusting the viscosity with an appropriate diluent, applying the mixture with a normal coater used in the casting method, and drying. As the coater, a doctor coater, a blade coater, a rod coater, a knife coater, a reverse roll coater, a gravure coater, a spray coater, and a curtain coater can be used, and they can be selectively used depending on the viscosity and the film thickness.
As for the spin coating method, the mixture can be formed into a film by further adjusting the viscosity with an appropriate diluent, applying the mixture with a commercially available spin coater, and drying.
As for the dip coating method, a film can be formed by adjusting the viscosity of the mixture with an appropriate diluent to prepare a mixture solution, pulling up an appropriate base from the mixture solution, and drying.

The ion conductive film of the present invention has an ionic conductivity of usually 1 × 10 ⁻⁷ S / cm or more, preferably 1 × 10 ⁻⁶ S / cm or more, more preferably 1 × 10 ⁻⁵ S / cm at room temperature. The above is shown. The ionic conductivity can be obtained by a general method such as a complex impedance method.
The ion conductive film of the present invention has an oxidant diffusion coefficient of 1 × 10 ⁻⁹ cm ² / s or more, preferably 1 × 10 ⁻⁸ cm ² / s or more, and more preferably 1 × 10 ⁻⁷ cm. ² / s or more is shown. The diffusion coefficient is an index indicating ion conductivity, and can be obtained by a general method such as constant potential current characteristic measurement or cyclic voltammogram measurement.

  The thickness of the ion conductive film is not particularly limited, but is usually 1 μm or more, preferably 10 μm or more, and usually 3 mm or less, preferably 1 mm or less.

Moreover, it is desirable that the ion conductive film has self-supporting properties. In that case, the characteristic that the tensile modulus at 25 ° C. is usually 5 × 10 ⁴ N / m ² or more, preferably 1 × 10 ⁵ N / m ² or more, and most preferably 5 × 10 ⁵ N / m ² or more. It is desirable to have In addition, this tensile elasticity modulus is a value at the time of measuring by a 2 cm x 5 cm strip sample with the tensile tester used normally.

  As an example of the photoelectric conversion element of this invention, the element which has the cross section shown in FIG. 3 can be mentioned, for example. This element is a photoelectric conversion in which a semiconductor layer (for example, titanium oxide layer) 6 adsorbing a sensitizer is formed on a conductive surface of a transparent conductive substrate 5 and an antireflection film 7 is formed on a non-conductive surface on the opposite side. It has an electrode (substrate A) and a counter electrode substrate 8 (substrate B), and an electrolyte layer (for example, ion conductive film) 9 is disposed between the semiconductor layer 6 and the counter electrode substrate 8, and the periphery is It is sealed with a seal member 10. Note that the lead wire is connected to the conductive portions of the substrate A and the substrate B, and power can be taken out.

  A method for producing a solar cell using the photoelectric conversion element of the present invention is not particularly limited. Usually, the substrate A, the ion conductive film and the substrate B are laminated, and the peripheral portion is appropriately sealed by a known method. Can be easily manufactured. As a method of sealing the peripheral part, after placing an ion conductive film on one of the substrates, a sealant is placed on the outside and the other substrate is aligned, and the seal and the ion conductive film are placed on the same substrate. It is possible to use a distribution method.

  By designing the antireflection film provided on the light incident surface side so as to satisfy a certain relational expression, a highly efficient photoelectric conversion element with good cost performance can be manufactured.

  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 transparent conductive glass with antireflection film >>
As an antireflection film, transparent conductive glass (TEC15, manufactured by Opton Japan Co., Ltd.) was placed in a magnetron sputtering apparatus so that the non-conductive surface side would be a film formation surface, and then a titanium oxide thin film ( 15 nm) first layer, using silicon oxide target, second layer of silicon oxide thin film (30 nm), using titanium oxide target, third layer of titanium oxide thin film (100 nm), and using silicon oxide target A fourth layer of a silicon oxide thin film (100 nm) was formed (transparent conductive glass (A) with an antireflection film). The reflection spectrum of this transparent conductive glass with an antireflection film is shown in FIG. The reflection spectrum was measured using an ultraviolet-visible spectrum measuring apparatus (U-4000, manufactured by Hitachi, Ltd.) with a 5 ° specular reflection unit attached.

As another antireflection film, a coating solution of an ultraviolet curable acrylic resin in which ITO fine powder having a refractive index of 1.7 is dispersed is applied to the nonconductive surface side of transparent conductive glass (TEC15, manufactured by Opton Japan). Then, a coating film (ITO content: 84 mass%) having a dry film thickness of 100 nm was formed, and cured by irradiation with ultraviolet rays under a condition of 300 mJ / cm ² in a nitrogen atmosphere. Next, a coating solution of an ultraviolet curable acrylic resin in which silicon oxide fine powder having a refractive index of 1.5 is dispersed is applied to form a coating film having a dry film thickness of 100 nm (silicon oxide content: 40% by mass), It was cured by irradiating ultraviolet rays under a condition of 300 mJ / cm ^{2 in} a nitrogen atmosphere. Thus, a two-layered antireflection film was formed (transparent conductive glass (B) with an antireflection film). The reflection spectrum of this transparent conductive glass with an antireflection film is shown in FIG.
Moreover, the reflection spectrum of the transparent conductive glass without an antireflection film is shown in FIG.

<< Preparation of dye-adsorbed titanium oxide electrode >>
On the conductive film of the transparent conductive glass with antireflection film (A) prepared above, Ti-Nanoxide T / SP (manufactured by SOLARONIX) is coated using an applicator with a gap of 130 μm, dried, and baked at 450 ° C. for 1 hour. Thus, a titanium oxide layer having a thickness of 10 μm was formed.
This electrode was immersed in a 0.2 mol / L titanium tetrachloride aqueous solution, left in a sealed state at 40 ° C. for 2 hours, washed with pure water, dried, and then fired at 450 ° C. for 1 hour. This was immersed in a ruthenium dye represented by the following formula (Rutenium-535-bisTBA, manufactured by Solaronics) / ethanol solution (3.0 × 10 ⁻⁴ mol / L) for 15 hours, and then the excess dye was washed with ethanol. The dye was adsorbed by air drying. When the absorption spectrum of this dye-adsorbed titanium oxide electrode was measured, a spectrum as shown in FIG. 5 was obtained, and λ ₁ and λ ₂ were determined to be 528 nm and 614 nm, respectively, (2λ ₁ −λ ₂ ) to λ _2. The wavelength range indicated by is found to be 442 to 614 nm.
To prepare a dye-adsorbed titanium oxide electrode with a transparent conductive glass without an antireflection film with a transparent conductive glass (B) and the antireflection film in the same manner, from the absorption spectrum, with (2λ ₁ -λ ₂₎ ~λ ₂ It was found that the wavelength ranges shown are as shown in Run 2 and Run 3 of Table 1, respectively.

<< Production of photoelectric conversion element >>
Next, the photoelectric conversion element was produced by the method shown below using the three types of dye-adsorbed titanium oxide electrodes produced above.
The titanium oxide surface of the titanium oxide electrode and the Pt surface of the conductive glass with the Pt thin film are placed facing each other with a 44 μm PET film as a spacer, 0.1 mol / L lithium iodide in the gap, A 3-methoxypropionitrile solution containing 0.5 mol / L of 1-propyl-2,3-dimethylimidazolium iodide, 0.5 mol / L of 4-t-butylpyridine and 0.05 mol / L of iodine It was injected by capillary action, and the periphery was sealed with an ultraviolet curable sealing material to obtain a photoelectric conversion element.
About these photoelectric conversion elements, when the pseudo-sunlight was irradiated and the current-voltage characteristic was measured, the result as shown in Table 1 was obtained. Run 1 is a photoelectric conversion element using a transparent conductive glass (A) with an antireflection film, Run 2 is a photoelectric conversion element using a transparent conductive glass (B) with an antireflection film, and Run 3 is a transparent conductive glass without an antireflection film. It is the result of the photoelectric conversion element using this.
As is apparent from this result, only Run 1 having a reflectance of 5% or less exhibits good characteristics.

[Example 2]
<< Preparation of Ion Conductive Film-1 >>
1 g of polyvinylidene fluoride polymer (KF9300, Kureha Chemical Co., Ltd.), 0.1 mol / L lithium iodide, 0.5 mol / L 1-propyl-2,3-dimethylimidazolium iodide, 0.5 mol / L 2 g of γ-butyrolactone solution containing 4-t-butylpyridine and 0.05 mol / L iodine was diluted with acetone and heated to obtain a uniform solution. This solution was applied onto a PET film substrate by a doctor blade method and dried by heating to obtain a uniform ion conductive film having a thickness of 112 μm.

<< Production of photoelectric conversion element >>
The ion conductive film is placed on the upper side of the titanium oxide surface dye-adsorbed titanium oxide layer of the dye-adsorbed titanium oxide electrode using the transparent conductive glass (A) with antireflection film prepared in Example 1, and Pt is further formed thereon. The Pt surface of the glass with a thin film was sandwiched with the ion conductive film side, and the periphery was sealed with an ultraviolet curable sealant to obtain a photoelectric conversion element.
Moreover, the photoelectric conversion element was similarly produced about the pigment | dye adsorption titanium oxide electrode produced using the transparent conductive glass (B) with an antireflection film, and the transparent conductive glass without an antireflection film.
When these photoelectric conversion elements were irradiated with pseudo-sunlight and current-voltage characteristics were measured, the results shown in Table 2 were obtained. Run 4 is a photoelectric conversion element using a transparent conductive glass (A) with an antireflection film, Run 5 is a photoelectric conversion element using a transparent conductive glass (B) with an antireflection film, and Run 6 is a transparent conductive glass without an antireflection film. It is the result of the photoelectric conversion element using this.
As is clear from this result, only Run 4 having a reflectance of 5% or less exhibits good characteristics.

It is an example of a structure of an antireflection film. It is an example of a structure of an antireflection film. It is an example of the cross section of a photoelectric conversion element. It is an example of the reflection spectrum of transparent conductive glass with an antireflection film. It is an example of the absorption spectrum of a photoelectric conversion electrode. It is an example of the reflection spectrum of transparent conductive glass with an antireflection film. It is an example of the reflection spectrum of transparent conductive glass without an antireflection film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent conductive substrate 2 Antireflection film 3 Transparent conductive film 4 Antireflection film 5 Transparent conductive substrate 6 Semiconductor layer 7 Antireflection film 8 Counter electrode substrate 9 Electrolyte layer 10 Sealing member
H1 High refractive index film H2 High refractive index film L1 Low refractive index film
L2 Low refractive index film L3 Low refractive index film

Claims (6)

A photoelectric conversion electrode in which a semiconductor layer modified with a sensitizer is provided on a conductive surface of a transparent conductive substrate and an antireflection film is provided on a non-conductive surface, and a substance exhibiting at least reversible electrochemical redox characteristics A photoelectric conversion element comprising at least a contained electrolyte layer and a conductive substrate disposed via the electrolyte layer, wherein the optical density at 450 nm or more is maximized in the absorption spectrum of the photoelectric conversion electrode. _{If 1} wavelength _lambda, the lambda ₁ to the maximum value of the wavelength at which equal optical density to 1/3 of the optical density was _{λ 2, (2λ 1 -λ 2} ) in the wavelength range of to [lambda] _2, the photoelectric conversion electrode A photoelectric conversion element having a reflectance measured from the antireflection film side of 5% or less.   The photoelectric conversion element according to claim 1, wherein the electrolyte layer is a solid electrolyte.   3. The photoelectric conversion element according to claim 2, wherein the solid electrolyte is an ion conductive film comprising at least (a) a polymer matrix and (b) a substance exhibiting reversible electrochemical redox characteristics.   4. The photoelectric conversion element according to claim 3, wherein the polymer matrix is a polyvinylidene fluoride polymer compound.   The photoelectric conversion element according to claim 4, wherein the polyvinylidene fluoride polymer compound contains a carboxyl group. The photoelectric conversion element according to claim 1, wherein the substance exhibiting reversible electrochemical oxidation-reduction characteristics is a room temperature molten salt.

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