JPH1167285A - Photoelectric conversion element and photo electrochemical cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coloring matter sensitizing photoelectric conversion element with high conversion efficiency and low price, using an organic coloring matter by including semiconductor fine particles sensitized with the specified coloring matter in a photosensitive layer. SOLUTION: A photosensitive layer contains semiconductor fine particles sensitized with at least one kind selected from coloring matters represented by formulas I and II. In formula I, R11 and R12 each represents a monovalent substituting group, n11 is an integer of 0-4, and n12 is an integer of 0-3. X1 and Y1 represent oxygen, sulfur, selenium, tellurium, an imino group, or the like. In formula II, R21 , R22 , and R24 each represents a monovalent substituting group, 1121 and n24 are an integer of 0-4, n22 is an integer of 0-3. R23 represents hydrogen, an alkyl group, an aryl group, or a heterocyclic residue. X2 and Y2 represent oxygen, sulfur, selenium, tellurium, an imino group, or the like. B2 represents nitrogen or a methine group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photoelectric conversion element and a photoelectrochemical cell using the same, and more particularly, to a photoelectric conversion element and a photoelectrochemical cell using semiconductor fine particles sensitized with a dye.

[0002]

2. Description of the Related Art Photoelectric conversion elements are used in various optical sensors, copying machines, and photovoltaic devices. Various types of photoelectric conversion elements have been put into practical use, such as those using metals, those using semiconductors, those using organic pigments and dyes, and those combining these.

[0003] US Patent Nos. 4,927,721 and 46,845
No. 37, No. 5,084,365, No. 5,350,644, No. 5,463,057, No. 5,525,440 and JP-A-7-249790 describe a photoelectric conversion element using semiconductor fine particles sensitized with a dye (hereinafter, referred to as a photoelectric conversion element). Dye-sensitized photoelectric conversion elements), or materials and manufacturing techniques for producing the same. The first advantage of this method is that an inexpensive oxide semiconductor such as titanium dioxide can be used without purification to a high degree of purity, so that a relatively inexpensive photoelectric conversion element can be provided. The second advantage is that since the absorption of the dye used is broad, light in almost all visible wavelength regions can be converted into electricity. Since these features are advantageous when applied to a photoelectric conversion element (so-called solar cell) for converting solar energy into electricity, application to this area is being actively studied.

However, the ruthenium complex dye used in this type of dye-sensitized photoelectric conversion element is extremely expensive, and causes a rise in cost, although its use is relatively small. For these reasons, development of a dye-sensitized photoelectric conversion element using an inexpensive organic dye has been demanded.

[0005]

A first object of the present invention is to provide an inexpensive dye-sensitized photoelectric conversion element having an excellent conversion efficiency using an organic dye, and a second object of the present invention is to provide such a photoelectric conversion element. An object of the present invention is to provide a photoelectrochemical cell using a conversion element.

[0006]

As a result of research, it has been found that the following (1) to (5) are suitable for the purpose of the present invention. (1) A photoelectric conversion device having at least a conductive support and a photosensitive layer, wherein the photosensitive layer is sensitized by at least one selected from dyes represented by the following general formulas (I) and (II). A photoelectric conversion element, characterized in that the photoelectric conversion element contains semiconductor fine particles.

[0007]

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[In the general formula (I), R ₁₁ and R ₁₂ each represent a monovalent substituent, n ₁₁ is an integer of 0 to 4, and n ₁₂
Is an integer of 0 to 3. X ₁ represents oxygen, sulfur, selenium, tellurium, imino group, alkylene group or alkenylene group, Y ₁ represents oxygen, sulfur, selenium, tellurium, imino group,
Represents an immonium group or a methylene group. When n ₁₁ is an integer of 2 or more, R ₁₁ may be bonded to each other to form a ring, and when n ₁₂ is an integer of 2 or more, R ₁₂ may be bonded to each other to form a ring, Y ₁ and R ₁₂ may combine to form a ring. In the general formula (II), R ₂₁ , R ₂₂ and R ₂₄ each represent a monovalent substituent, n ₂₁ and n ₂₄ are each an integer of 0 to 4, and n ₂₂ is an integer of 0 to 3. . R ₂₃ is hydrogen,
Represents an alkyl group, an aryl group or a heterocyclic residue. X ₂
Represents oxygen, sulfur, selenium, tellurium, imino group, alkylene group or alkenylene group, and Y ₂ represents oxygen, sulfur, selenium, tellurium, imino group, immonium group or methylene group. B ₂ represents a nitrogen or methine group. When n ₂₁ is an integer of 2 or more, R ₂₁ may be bonded to each other to form a ring, and when n ₂₂ is an integer of 2 or more, R ₂₂ may be bonded to each other to form a ring, When n ₂₄ is an integer of 2 or more, R
₂₄ may combine with each other to form a ring, and R ₂₂ , B ₂ , R
Two or more selected from ₂₄ and Y ₂ may combine to form a ring. (2) The photoelectric conversion device according to the above (1), wherein X ₁ in the general formula (I) is oxygen or sulfur, and X ₂ in the general formula (II) is oxygen or sulfur. (3) The above-mentioned (1), wherein the dye represented by the general formula (I) has at least one acidic group as a substituent, and the dye represented by the general formula (II) has at least one acidic group as a substituent. ) Or (2). (4) The photoelectric conversion element according to (3), wherein at least one of the acidic groups is selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid monoester group, and a phosphoric acid diester group. (5) A photoelectrochemical cell having the photoelectric exchange element according to any one of (1) to (4), and further having at least a charge transfer layer and a counter electrode.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The photoelectric conversion element of the present invention has a photosensitive layer on a conductive support, and the photosensitive layer contains semiconductor fine particles sensitized by the dyes represented by formulas (I) and (II). ing. By using such a dye, a dye-sensitized photoelectric conversion element having excellent conversion efficiency can be obtained at low cost.

The general formulas (I) and (II) will be described. In the general formula (I), R ₁₁ and R ₁₂ each represent a monovalent substituent, n ₁₁ is an integer of 0 to 4, ₁₂ is an integer of 0 to 3. X ₁ represents oxygen, sulfur, selenium, tellurium, an imino group, an alkylene group or alkenylene group, Y ₁
Represents oxygen, sulfur, selenium, tellurium, imino, immonium or methylene. n ₁₁ is 2 or more integer which when R ₁₁ may combine with each other to form a ring, n ₁₂ is 2
When it is the above integer, R ₁₂ may be bonded to each other to form a ring, or Y ₁ and R ₁₂ may be bonded to each other to form a ring.

In the general formula (II), R ₂₁ , R ₂₂ and R ₂₄ each represent a monovalent substituent, n ₂₁ and n ₂₄ each represent an integer of 0 to 4, and n ₂₂ represents 0 to 4 It is an integer of 3. R ₂₃
Represents hydrogen, an alkyl group, an aryl group or a heterocyclic residue. X ₂ represents oxygen, sulfur, selenium, tellurium, imino group, alkylene group or alkenylene group, Y ₂ represents oxygen,
Represents sulfur, selenium, tellurium, imino group, immonium group or methylene group. B ₂ represents a nitrogen or methine group. When n ₂₁ is an integer of 2 or more, R ₂₁ may be bonded to each other to form a ring, and when n ₂₂ is an integer of 2 or more, R ₂₂ may be bonded to each other to form a ring, When n ₂₄ is an integer of 2 or more, R ₂₄ may combine with each other to form a ring,
Two or more selected from R ₂₂ , B ₂ , R ₂₄ and Y ₂ may combine to form a ring.

More specifically, the general formula (I):
In (II), examples of the monovalent substituent represented by R ₁₁ , R ₁₂ , R ₂₁ , R ₂₂ and R ₂₄ include an alkyl group (eg, methyl, ethyl, isobutyl, n-dodecyl, cyclohexyl, vinyl , Allyl, benzyl, etc.), aryl groups (eg, phenyl, naphthyl, etc.), heterocyclic residues (eg, pyrrolidinyl, pyridyl, imidazolyl, furyl, thienyl, oxazolyl, thiazolyl, benzimidazolyl, quinolyl) Etc.), halogen atoms (for example,
Fluorine, chlorine, bromine), alkoxy groups (eg, methoxy, ethoxy, benzyloxy, etc.), aryloxy groups (eg, phenoxy, etc.), mercapto groups, sulfur anions, alkylthio groups (eg, methylthio, ethylthio, etc.), arylthio groups (eg, Phenylthio, etc.), hydroxy group and oxygen anion (which may form a salt with Na ⁺ , K ^+, etc.), nitro group, cyano group, amide group (eg, acetylamino, benzoylamino etc.), sulfonamide group ( For example, methanesulfonylamino, benzenesulfonylamino, etc.), a ureido group (eg, 3-phenylureido), a urethane group (eg, isobutoxycarbonylamino, carbamoyloxy, etc.), and an ester group (eg, acetoxy, benzoyloxy, methoxycarbonyl, phenoxy) Cal Sulfonyl, etc.), a carbamoyl group (such as N- methylcarbamoyl, N, N- diphenylcarbamoyl, etc.), a sulfamoyl group (e.g., N- phenylsulfamoyl), an acyl group (e.g. acetyl,
Benzoyl, etc.), amino group (eg, amino, methylamino, dimethylamino, methylethylamino, diethylamino, anilino, diphenylamino, etc.), sulfonyl group (eg, methylsulfonyl, etc.), phosphonyl group and its ester, phosphonyloxy group and its ester,
Examples thereof include a carboxyl group (including a carboxylate group and a salt) and a sulfo group (including a sulfonato group and a salt). These may further have a substituent.

At least one of the monovalent substituents represented by R ₁₁ is selected from the group consisting of amino groups, hydroxy groups, oxygen anions, alkoxy groups, mercapto groups, sulfur anions, alkylthio groups, and arylthio groups. The chosen one
It is preferably a valent substituent.

R ₂₃ in the formula (II) represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic residue. These may have a substituent. R ₂₃ is preferably a hydrogen atom, an alkyl group, or an aryl group.

Alkyl groups, aryl groups denoted by R _23,
Specific examples of the heterocyclic residue include R ₁₁ , R ₁₂ , R ₂₁ ,
It can be exemplified the same ones at the R _22, R _24.

N ₁₁ , n ₂₁ and n ₂₄ are each an integer of 0 to 4,
n ₁₂ and n ₂₂ represents an integer of 0 to 3. n ₁₁ and n ₂₄ are 1
To 4 are preferable. There are no particular restrictions on n ₁₂ , n ₂₁ and n ₂₂ .

X ₁ and X ₂ represent oxygen, sulfur, selenium, tellurium, imino, alkylene (eg, methylene, ethylene, benzylidene) and alkenylene (eg, vinylene). The imino group, alkylene group, and alkenylene group may have a substituent. At this time, the substituent of the alkylene group or alkenylene group is not particularly limited, and examples thereof include an alkyl group. Also,
In the alkylene group and the alkenylene group, the substituents may be bonded to each other to form a ring, and examples of such a ring include a benzene ring. As a substituent of the imino group,
Preferred are an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group, a carboxyl group, and a carbamoyl group.
Of these, X ₁ and X ₂ are preferably oxygen and sulfur.

Y ₁ and Y ₂ represent oxygen, sulfur, selenium, tellurium, imino, immonium or methylene. Of these, the imino group, immonium group, and methylene group may have a substituent. At this time, preferred examples of the substituent of the imino group are as described above.

Examples of the substituted immonium group include an alkyl immonium group (such as a methyl immonium group, a benzyl immonium group and a cyclohexyl immonium group), and a dialkyl immonium group (such as a dimethyl immonium group and a diethyl immonium group). ), An alkylaryl immonium group (such as a methylphenyl immonium group), an aryl immonium group (such as a phenyl immonium group), and a diaryl immonium group (such as a diphenyl immonium group). These may further have a substituent. Further, the substituents may be bonded to each other to form a ring.

Examples of the substituted methylene group include dicyanomethylene group, 1-acetyl-1-cyanomethylene group, 1,1
-Diacetylmethylene group, 1-cyano-1carboxymethylene group, 1-methoxycarbonyl-1-cyanomethylene group, 1,1-bis (methoxycarbonyl) methylene group and the like.

As Y ₁ and Y ₂ , oxygen, imino group, immonium group and methylene group are preferable.

B ₂ represents a nitrogen or methine group. The methine group may have a substituent. Of these, nitrogen is more preferred.

In the general formula (I), when n ₁₁ ≧ 2, R
₁₁ may combine with each other to form a carbon ring such as a benzene ring or a hetero ring containing nitrogen or the like, and these rings may further have a substituent. When n ₁₂ ≧ 2, R ₁₂ may combine with each other to form a ring such as a benzene ring, and these rings may further have a substituent. Further, Y ₁ and R ₁₂ (which may be two or more R ₁₂ ) may combine to form a carbon ring or a hetero ring, and these rings may further have a substituent. Good.

In the general formula (II), n ₂₁ ,
When n ₂₂ and n ₂₄ ≧ 2, R _{21 s} , R _{22 s} , and R _{24 s} may be bonded to each other to form a ring. R ₂₂ ,
Two or more selected from R _24, B ₂ and Y ₂ may be combined with each other to form a ring, as such rings, for example, R ₂₂
Heterocyclic or where the R ₂₄ is formed by bonding a, R ₂₄ and Y ₂
And a heterocyclic ring which may have a condensed ring formed by bonding to the above. These rings may further have a substituent.

The compound represented by the general formula (I) or (II) preferably has an acidic group in order to improve the adsorptivity to semiconductor fine particles. Here, the acidic group is defined as pKa in a mixed solvent of water and tetrahydrofuran (volume ratio of 50 to 50).
Means 10 or less, preferably a carboxylic acid group, a sulfonic acid group, a sulfinic acid group, a hydroxyl group, a phosphonic acid group,
Phosphoric acid monoester and diester groups and the like, particularly preferably carboxylic acid group, sulfonic acid group, phosphoric acid monoester and diester groups. These groups may form a salt with an alkali metal or the like. Further, an inner salt may be formed.

When the compound represented by the general formula (I) or (II) has a charge as a whole molecule, it may have a counter ion for neutralizing the charge. The counter ion is not particularly limited and may be either organic or inorganic. Representative examples include halogen ions (fluorine ions, chloride ions, bromine ions, and iodine ions), hydroxide ions, perchlorate ions, tetrafluoroborate ions, hexafluorophosphate ions, acetate ions, and trifluoroacetate ions. , Methanesulfonic acid ion, paratoluenesulfonic acid ion,
Anions such as trifluoromethanesulfonic acid ion, alkali metals (lithium, sodium, potassium, etc.), alkaline earth metals (magnesium, calcium, etc.), ammonium, alkylammonium (eg, diethylammonium, tetrabutylammonium, etc.), pyridinium, alkylpyridinium Cations such as (eg, methylpyridinium), guanidinium, and tetraalkylphosphonium.

Next, preferred specific examples of the compound represented by formula (I) or (II) are shown below, but the present invention is not limited thereto.

[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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Next, the method of synthesizing the dye used in the present invention will be described with reference to specific examples, but the present invention is not limited thereto.

Synthesis Examples Exemplified compounds (10) and (1)
Synthesis of 1) According to the synthesis method described in JP-A-2-275446, pp. 11-12, p-toluenesulfonic acid salt of 3- (methoxycarbonylamino) -4-amino-N, N-diethylaniline (compound A) Was synthesized.

1-hydroxy-2-naphthoic acid 18.8
g, compound A 52.5 g, sodium hydrogen carbonate 82 g,
500 ml of water, 500 ml of ethanol and 1 liter of ethyl acetate were mixed in a glass container, and 20 g of potassium persulfate was gradually added at room temperature with vigorous stirring. After stirring for 1 hour, the reaction mixture was poured into 2 liters of water containing 100 ml of concentrated hydrochloric acid, the organic layer was separated, and the solvent was distilled off. The residue was separated and purified by silica gel column chromatography (eluent: 1: 1 volume mixture of hexane and ethyl acetate) to give 3.5 g of compound (10) of the present invention and (11)
2.2 g were obtained.

Next, the dye-sensitized photoelectric conversion device to which the dyes represented by formulas (I) and (II) of the present invention are applied and a photoelectrochemical cell will be described in detail. In the present invention, the dye-sensitized photoelectric conversion element is an electrode composed of a conductive support and a layer (photosensitive layer) of semiconductor fine particles having a dye adsorbed thereon, which is coated on the conductive support. The photosensitive layer is designed according to the purpose and may have a single-layer structure or a multilayer structure. The dye in one photosensitive layer may be one kind or a mixture of many kinds. Light incident on the photosensitive layer excites the dye. The excited dye has high-energy electrons, which are transferred from the dye to the conduction band of the semiconductor fine particles and reach the conductive support by diffusion. At this time, the dye molecules are in an oxidized form, but the photoelectrochemical cell returns electrons to the oxidized form while the electrons on the electrodes work in an external circuit, and the dye-sensitized photoelectric conversion element is the negative electrode of this battery. Work as

Hereinafter, the conductive support and the photosensitive layer will be described in detail. The conductive support is a support such as a metal, which has conductivity, or a glass or plastic support having a conductive agent layer on the surface.
In the latter case, a preferred conductive agent is a metal (eg, 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). In this case, the thickness of the conductive agent layer is 0.0
It is preferably from 5 to 10 μm.

The lower the surface resistance of the conductive support, the better.
The preferable range of the surface resistance is 50 Ω / cm ² or less, and more preferably 10 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 light transmittance is 10%
It means that it is at least 50%, preferably at least 50%, particularly preferably at least 80%. As the transparent conductive support, glass or plastic coated with a conductive metal oxide is preferable. At this time, the coating amount of the metal oxide is preferably 0.1 to 100 g per 1 m ² of the support.
When a transparent conductive support is used, light is preferably incident from the support side.

The semiconductor fine particles used in the photosensitive layer are metal chalcogenides (eg, oxides, sulfides, selenides, etc.).
Alternatively, it is fine particles of perovskite. The metal chalcogenide preferably includes titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, or tantalum oxide, cadmium sulfide, cadmium selenide, and the like. As the perovskite, strontium titanate, calcium titanate and the like are preferably mentioned. Among these, titanium oxide, zinc oxide, tin oxide and tungsten oxide are particularly preferred. The particle diameter of these semiconductor fine particles is 0.001 to 1 μm as the primary particle as the average particle diameter using the diameter when the projected area is converted into a circle, and 0.01 as the average particle diameter of the dispersion.
It is preferably from 100 to 100 μm.

The method of coating the semiconductor fine particles on the conductive support includes a method of coating a dispersion or a colloid solution of the semiconductor fine particles on the conductive support, and a method of coating the precursor of the semiconductor fine particles on the conductive support. A method of coating and hydrolyzing with water in the air to obtain a semiconductor fine particle film, and the like can be given. Examples of a method for preparing a dispersion of semiconductor fine particles include a method of grinding in a mortar, a method of dispersing while grinding using a mill, and a method of precipitating and using fine particles in a solvent when synthesizing a semiconductor. . Examples of the dispersion medium include water and various organic solvents (eg, methanol, ethanol, 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.

The semiconductor fine particles preferably have a large surface area so that many dyes can be adsorbed. For example, in a state where the semiconductor fine particles are coated on the support, the surface area is preferably 10 times or more the projected area,
More preferably, it is 100 times or more. The upper limit is not particularly limited, but is usually about 5000 times.

In general, as the thickness of the layer of semiconductor fine particles increases, the amount of dye that can be supported per unit area increases, so that the light absorption efficiency increases. However, the diffusion distance of generated electrons increases, so that the loss due to charge recombination also increases. growing. The preferred thickness of the semiconductor fine particle layer (that is, the photosensitive layer) varies depending on the use of the device, but is typically 0.1 to 100 μm. When used as a photoelectrochemical cell, the thickness is preferably 1 to 50 μm, more preferably 3 to 30 μm. The semiconductor fine particles are applied at a temperature of 100 to 800 ° C. for 10 minutes to adhere the particles to each other after being applied to the support.
You may bake for 10 hours. The coating amount of the semiconductor fine particles per 1 m ² of the support is 0.5 to 500 g, and more preferably 5 to 500 g.
100 g is preferred.

In the present invention, the semiconductor fine particles are sensitized by the adsorption of the dyes represented by the general formulas (I) and (II). Generally, a method of immersing the semiconductor fine particles thus obtained for a long time is used. The dye solution may be heated to 50 ° C to 100 ° C as needed. The dye may be adsorbed before or after the application of the semiconductor fine particles. Further, the semiconductor fine particles and the dye may be simultaneously applied and adsorbed. Unadsorbed dye is removed by washing. When baking the coating film, it is preferable that the dye is adsorbed after baking. It is particularly preferable that the dye be quickly adsorbed before water is adsorbed on the surface of the coating film after baking, or the dye is adsorbed in an atmosphere from which water has been removed. One type of dye may be adsorbed,
You may mix and use several types. In the case of mixing, the dyes represented by formulas (I) and (II) of the present invention may be mixed with each other, and US Pat. Nos. 4,927,721 and 4,684,537.
Nos. 5084365, 5350644, 54
Complex dyes described in JP-A-63057 and JP-A-5525440 and JP-A-7-249790 may be mixed with the dye of the present invention. When the application is a photoelectrochemical cell, a dye to be mixed is selected so as to widen the wavelength range of photoelectric conversion as much as possible.

The total amount of the dye used is preferably from 0.01 to 100 mmol, more preferably from 0.1 to 50 mmol, particularly preferably from 0.5 to 10 mmol, per 1 m ² of the support. In this case, the ratio of the amount of the dyes represented by formulas (I) and (II) of the present invention is preferably 5 mol% or more.

The amount of the dye adsorbed on the semiconductor fine particles is preferably 0.001 to 1 mmol, more preferably 0.1 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.

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).

After the dye is adsorbed, the surface of the semiconductor fine particles may be treated with an amine. 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. In the present invention, the conductive agent and the semiconductor fine particles may be mutually diffused and mixed in the vicinity of the interface between the conductive support and the photosensitive layer.

The dye-sensitized photoelectric conversion element thus produced can be applied to various sensors and photoregeneration type electrochemical cells, so-called photoelectrochemical cells. When applied to a photoelectrochemical cell, a charge transfer layer and a counter electrode are required as shown in FIG. The photoelectrochemical cell 1 shown in FIG. 1 has a photosensitive layer 3 on a conductive support 2, and further has a charge transfer layer 4 and a counter electrode 5 provided on the photosensitive layer 3.

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. Representative examples include a liquid 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.

As the redox couple, for example, a combination of iodine and iodide (eg, lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.), an alkyl viologen (eg, methyl viologen chloride, hexyl viologen bromide, benzyl viologen) Combination of tetrafluoroborate) and its reduced form, combination of polyhydroxybenzenes (eg, hydroquinone, naphthohydroquinone, etc.) and its oxidized form, divalent and trivalent iron complexes (eg, red blood salt and yellow blood salt)
And the like. Of these, a combination of iodine and iodide is preferred. As an organic solvent for dissolving them, aprotic polar solvents (for example, acetonitrile, propylene carbonate, ethylene carbonate, dimethylformamide, dimethylsulfoxide, sulfolane, 1,3-dimethylimidazolinone, 3-methyloxazolidinone, etc.) are preferable. Examples of the polymer used for the matrix of the gel electrolyte include polyacrylonitrile and polyvinylidene fluoride. Examples of the molten salt include lithium iodide and at least one other lithium salt (eg, lithium acetate, lithium perchlorate, etc.). May be increased. In this case, the amount of the polymer added is 1 to 50% by weight.

Since the redox couple becomes a carrier of electrons, a certain concentration is required. When used as a liquid or gel electrolyte, the total concentration in the solution is preferably at least 0.01 mol / l, more preferably at least 0.1 mol / l, particularly preferably at least 0.3 mol / l. It is. The upper limit in this case is not particularly limited, but is usually 5
It is about mol / l.

The counter electrode functions as a positive electrode of the photoelectrochemical cell. The counter electrode is usually synonymous with the above-mentioned conductive support, but the support is not necessarily required in a configuration in which the strength is sufficiently maintained. However, having a support is advantageous in terms of hermeticity.

In order for light to reach the photosensitive layer, at least one of the above-described conductive support and the counter electrode 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. As the counter electrode of the photoelectrochemical cell, glass or plastic on which metal or a conductive oxide is deposited is preferable, and glass on which platinum is deposited is particularly preferable. In a photoelectrochemical cell, it is preferable to seal the side surface of the cell with a polymer, an adhesive, or the like in order to prevent the components from evaporating.

The characteristics of the photoelectrochemical cell obtained in this manner are as follows: when the AM 1.5 G is 100 mW / cm ² , the open-circuit voltage is 0.01 to 3 V, and the short-circuit current density is 0.001 to 20 mA / c.
m ² , form factor 0.1 ~ 0.99, conversion efficiency 0.001 ~
25%.

[0056]

EXAMPLES Hereinafter, the method for producing the dye-sensitized photoelectric conversion element and the photoelectrochemical cell of the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

Example 1 Preparation of Titanium Dioxide Dispersion 15 g of titanium dioxide (Degussa P-25, Nippon Aerosil Co., Ltd.), 45 g of water, and a dispersant (Triton X, manufactured by Aldrich Co., Ltd.) were placed in a 200-ml stainless steel vessel whose inside was coated with Teflon. -100) 1
g, 30 g of zirconia beads (manufactured by Nikkato) having a diameter of 0.5 mm were dispersed in a sand grinder mill (manufactured by Imex) at 1500 rpm for 2 hours. The zirconia beads were removed from the dispersion by filtration. The average particle size of the titanium dioxide in this case was measured by a master sizer manufactured by MALVERN and found to be 25 μm.

Preparation of Photoelectric Conversion Element Conductive glass coated with fluorine-doped tin oxide (TCO glass manufactured by Asahi Glass, 20 mm × 20 mm
Surface resistance of about 30Ω / cm ² )
The above dispersion was applied to the conductive surface side of using a glass rod. At this time, an adhesive tape was stretched on a part (3 mm from the end) on the conductive surface side to form a spacer, and glass was lined up so that the adhesive tape came to both ends and applied eight sheets at a time. After application,
It was air-dried at room temperature for one day, and the adhesive tape was peeled off (the part with the adhesive tape was used to make electrical contact with a measuring instrument during photoelectric conversion measurement). Next, this glass was put into an electric furnace (muffle furnace FP-32 manufactured by Yamato Scientific Co., Ltd.) and fired at 450 ° C. for 30 minutes. After the glass was taken out and cooled, it was immersed in an ethanol solution (3 × 10 ⁻⁴ mol / l) of the dye of the present invention shown in Table 1 for 3 hours. The glass on which the dye was dyed was immersed in a 10% ethanol solution of 4-tert-butylpyridine for 30 minutes, then washed with ethanol and dried naturally. The photosensitive layer thus obtained has a thickness of 10 μm, and the coating amount of the semiconductor fine particles is 20 g / m ^2.
Met. The coating amount of the dye was appropriately selected from the range of 0.5 to 10 mmol / m ² according to the type of the dye.

Measurement of reflection spectrum The reflection spectrum was measured using a spectrophotometer (U-3500, manufactured by Hitachi, Ltd.) equipped with an integrating sphere for the above photoelectric conversion element. Table 1 shows the values of the absorbance at the absorption peak on the longest wavelength side.

Preparation of Photoelectrochemical Cell As one embodiment of the photoelectrochemical cell of FIG. 1, a photoelectrochemical cell as shown in FIG. 2 was prepared. The photoelectrochemical cell 10 of FIG.
Uses the above-mentioned photoelectric conversion element having a configuration in which a photosensitive layer 13 is provided on a conductive support having a conductive agent layer 12 on a glass support 11, and is a charge transfer layer on the photosensitive layer 13. It has an electrolyte layer 14 and a platinum-deposited glass 15 as a counter electrode. In this creation,
The above-mentioned photoelectric conversion element was overlapped with platinum-deposited glass of the same size (FIG. 2, the uncoated portion of the photoelectric conversion element was shifted so as not to contact the platinum-deposited glass).
Next, an electrolytic solution (a mixture of acetonitrile and N-methyl-2-oxazolidinone at a volume ratio of 90:10, iodine 0.05
Mol / l, 0.5 mol / l of lithium iodide).

Measurement of Photoelectric Conversion Efficiency The light of a 500 W xenon lamp (made by Ushio) was applied to AM1.
Simulated sunlight containing no ultraviolet rays was generated by passing through a 5G filter (manufactured by Oriel) and a sharp cut filter (Kenko L-42). The intensity of this light was 50 mW / cm ² .

The photoelectric conversion element of the present invention is irradiated with this light,
The generated electricity is measured by a current-voltage measuring device (Keithley 238).
(Type). Table 1 shows the open-circuit voltage, short-circuit current, form factor, and conversion efficiency of the photochemical cell obtained in this way.
Summarized in

[0063]

[Table 1]

As described above, photoelectric conversion characteristics are recognized for all the dyes.

[0065]

It has been clarified that the present invention provides an inexpensive dye-sensitized photoelectric conversion element using an organic dye and having excellent conversion efficiency. It was also confirmed that a photoelectrochemical cell could be obtained using this.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one configuration example of a photoelectrochemical cell of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration example of a photoelectrochemical cell used in Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 10 Photoelectrochemical cell 2 Conductive support 3, 13 Photosensitive layer 4 Charge transfer layer 5 Counter electrode 11 Glass support 12 Conductive agent layer 14 Electrolyte layer 15 Platinum vapor deposition glass

Claims (5)

[Claims] 1. A photoelectric conversion element having at least a conductive support and a photosensitive layer, wherein the photosensitive layer is formed of at least one selected from dyes represented by the following general formulas (I) and (II). A photoelectric conversion element comprising sensitized semiconductor fine particles. Embedded image [In the general formula (I), R ₁₁ and R ₁₂ each represent a monovalent substituent, n ₁₁ is an integer of 0 to 4, and n ₁₂ is an integer of 0 to 3. X ₁ represents oxygen, sulfur, selenium, tellurium, imino group, alkylene group or alkenylene group, and Y ₁ represents oxygen, sulfur, selenium, tellurium, imino group, immonium group or methylene group. When n ₁₁ is an integer of 2 or more, R ₁₁ may be bonded to each other to form a ring, and when n ₁₂ is an integer of 2 or more, R ₁₂ may be bonded to each other to form a ring, Y ₁ and R ₁₂ may combine to form a ring. In the general formula (II), R ₂₁ , R ₂₂ and R ₂₄ each represent a monovalent substituent, n ₂₁ and n ₂₄ each represent an integer of 0 to 4,
₂₂ is an integer of 0 to 3. R ₂₃ represents hydrogen, an alkyl group, an aryl group or a heterocyclic residue. X ₂ is oxygen, sulfur,
Represents selenium, tellurium, imino group, alkylene group or alkenylene group, and Y ₂ represents oxygen, sulfur, selenium, tellurium,
Represents an imino group, an immonium group or a methylene group. B
₂ represents a nitrogen or methine group. When n ₂₁ is an integer of 2 or more, R ₂₁ may be bonded to each other to form a ring, and when n ₂₂ is an integer of 2 or more, R ₂₂ may be bonded to each other to form a ring, When n ₂₄ is an integer of 2 or more, R ₂₄ may combine with each other to form a ring, and two or more selected from R ₂₂ , B ₂ , R ₂₄ and Y ₂ may combine to form a ring May be. ] 2. The photoelectric conversion device according to claim 1, wherein X ₁ in the general formula (I) is oxygen or sulfur, and X ₂ in the general formula (II) is oxygen or sulfur. 3. The dye represented by the general formula (I) has at least one acidic group as a substituent, and the dye represented by the general formula (II) has at least one acidic group as a substituent. Item 6. The photoelectric conversion element according to item 1 or 2. 4. The photoelectric conversion device according to claim 3, wherein at least one of the acidic groups is selected from a carboxylic acid group, a sulfonic acid group, a phosphoric acid monoester group and a phosphoric acid diester group. 5. A photoelectrochemical cell comprising the photoelectric exchange element according to claim 1, and further comprising at least a charge transfer layer and a counter electrode.