CN102906935A - Photoelectric conversion element, photoelectrochemical battery, dye for photoelectric conversion element, and dye solution for photoelectric conversion element - Google Patents

Abstract

A photoelectric conversion element involving a photosensitive material layer comprising a dye represented by general formula (1) and semiconductor microparticles, wherein the dye is a compound having a C5-18 aliphatic group and represented by general formula (1). In general formula (1), Q represents a tetravalent aromatic group; X1 and X2 independently represent a sulfur atom, an oxygen atom, or a group CR1R2 (wherein R1 and R2 independently represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group which can be bound through a carbon atom contained therein); R and R' independently represent an aliphatic group, an aromatic group, or a heterocyclic group which can be bound through a carbon atom contained therein; P1 and P2 independently represent a dye residue; and W1 represents a counter ion which is required for the neutralization of an electric charge.

Description

Photoelectric conversion element, photoelectrochemical cell, dye for photoelectric conversion element, and dye solution for photoelectric conversion element

technical field

The invention relates to a photoelectric conversion element and a photoelectrochemical cell with high conversion efficiency and excellent durability, in particular to a pigment for a photoelectric conversion element and a pigment solution for a photoelectric conversion element.

Background technique

The photoelectric conversion element can be used in various photosensors, copiers, solar cells, and the like. In the photoelectric conversion element, various forms such as metals, semiconductors, organic pigments or pigments, or combinations of these can be used to put them into practical use. In particular, a solar cell using a non-dry solar energy source does not require fuel and can use inexhaustible clean energy, so its true practical use is highly expected. Among them, silicon-based solar cells have been researched and developed for a long time, and are continuing to be popularized and developed in consideration of the policies of various countries. However, silicon (silicon) is an inorganic material, which has its natural limits for throughput and molecular modification.

Therefore, research on Dye-Sensitized Solar Cells has been actively carried out. In particular, Graetzel and others at the Lausanne University of Technology in Switzerland have developed a dye-sensitized solar cell in which a dye formed by a ruthenium complex (ruthenium complex) is fixed on the surface of a porous titanium oxide film. Realize the conversion efficiency of commonly used amorphous silicon. Therefore, the dye-sensitized solar cell has attracted the attention of researchers all over the world at once.

Patent Document 1 describes a dye-sensitized photoelectric conversion element using the above-mentioned technology and using semiconductor fine particles sensitized with a ruthenium complex dye. However, known ruthenium complex dyes can perform photoelectric conversion using visible light, but can hardly absorb infrared light with a long wavelength of more than 700 nm, so the photoelectric conversion performance in the infrared region (infrared region) is low.

In one proposal, there is provided a photoelectric conversion element capable of high conversion efficiency in the infrared region with a high wavelength of 700 nm or more by using a polymethine dye having a specific structure (for example, refer to Patent Document 2).

In addition, the photoelectric conversion element must have a high initial conversion efficiency in a wide wavelength region, and be excellent in durability with little reduction in conversion efficiency after use. However, in terms of durability, the photoelectric conversion element described in Patent Document 2 is not sufficiently described.

Therefore, there is a need for photoelectric conversion elements and photoelectrochemical cells with high conversion efficiency and excellent durability. Furthermore, a dye for a photoelectric conversion element and a dye solution for a photoelectric conversion element are also necessary.

prior art literature

patent documents

Patent Document 1: Specification of US Patent No. 5463057

Patent Document 2: Japanese Patent No. 4217320

Contents of the invention

An object of the present invention is to provide a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability. Another object of the present invention is to provide a dye for photoelectric conversion elements and a dye solution for photoelectric conversion elements.

As a result of repeated intensive studies by the inventors of the present invention, it was found that a photoreceptor comprising a layer of porous semiconductor fine particles having a polymethine dye (pigment compound) having a specific structure adsorbed on a conductive support, a charge transfer body, and The photoelectric conversion element with a laminated structure of the opposite electrode, and the photoelectrochemical cell using the same, have high conversion efficiency in a wide wavelength region and are excellent in durability. The present invention is carried out based on the above knowledge.

The subject of this invention is achieved by the following aspects.

<1> A photoelectric conversion element characterized in that it includes a photoreceptor layer equipped with a dye represented by the general formula (1) and semiconductor fine particles, and the above-mentioned dye includes a general formula (1) having an aliphatic group having 5 to 18 carbon atoms. ) The pigment of the compound represented by ).

[chemical 1]

General formula (1)

[In the general formula (1), Q represents a tetravalent aromatic group. X ¹ and X ² are independently represented as sulfur atom, oxygen atom or CR ¹ R ² . Wherein, R ¹ and R ² independently represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded by a carbon atom, and they may also be substituted. R and R' independently represent an aliphatic group, an aromatic group, or a heterocyclic group bonded to a carbon atom, and they may also be substituted. P ¹ and P ² are independently represented as pigment residues. W ¹ represents the counter ion necessary to neutralize the charge. ]

<2> The photoelectric conversion element according to <1>, wherein the aliphatic group having 5 to 18 carbon atoms is a branched alkyl group.

<3> The photoelectric conversion element according to <1> or <2>, wherein Q in the above general formula (1) represents a benzene ring or a naphthalene ring.

<4> The photoelectric conversion element according to any one of <1> to <3>, wherein ^P1 and ^P2 in the above-mentioned general formula (1) are respectively independently general formula (2) or general formula ( 3) expressed.

[Chem 2]

General formula (2)

[Chem 3]

一般式(3)

General formula (3)

[In the above general formula (2) or general formula (3), V represents a hydrogen atom or a ^substituent . n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be bonded to each other to form a ring.

Y is represented as S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein, ^R represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom. R ¹⁰ and R ¹¹ represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, which may be the same or different, and may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group, or a heterocyclic group bonded to carbon atoms, and it may also have a substituent.

R ³ to R ⁶ and R ⁸ are each independently represented by a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and they may also have substituents.

R ⁷ is an oxygen atom or a carbon atom having two substituents, and the sum of the substitution constants (σ _p ) of the two substituents is a positive number. ]

<5> The photoelectric conversion element according to <1>, wherein P ¹ and P ² in the above general formula (1) are independently represented by the following general formula (4) or general formula (5).

[chemical 4]

General formula (4)

[chemical 5]

一般式(5)

General formula (5)

[In general formula (4) or general formula (5), V ¹ represents a hydrogen atom or a substituent. n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, and may be bonded to each other to form a ring.

Y is represented as S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein, ^R represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom. R ¹⁰ and R ¹¹ represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, which may be the same or different, and may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group, or a heterocyclic group bonded to carbon atoms, and it may also have a substituent. ]

<6> The photoelectric conversion element according to <4> or <5>, wherein V ¹ has an acidic group.

<7> The photoelectric conversion element according to any one of <4> to <6>, wherein V ¹ is a hydrogen atom, 5-carboxy, 5-sulfonic acid, 5-methyl or 4,5 - benzene ring condensation.

<8> The photoelectric conversion element according to <6> or <7>, wherein Z and V ¹ are acidic groups or groups having acidic groups.

<9> The photoelectric conversion element according to any one of <4>, <6> to <8>, wherein the above-mentioned general formula (2) is represented by the following general formula (6), and the above-mentioned general formula ( 3) is represented by the following general formula (7).

[chemical 6]

一般式(6)

General formula (6)

[chemical 7]

一般式(7)

General formula (7)

In the above general formula (6) or general formula (7), Y, Z, R ³ -R ⁸ have the same definitions as Y, Z, R ³ -R ⁸ in general formula (2) or general formula (3). V ¹² represents an acidic group. At least one of E ¹¹ to E ¹³ represents an electron withdrawing group. p is an integer of 2 or more.

<10> The photoelectric conversion element according to <4>, wherein the above-mentioned general formula (2) is represented by the following general formula (8), and the above-mentioned general formula (3) is represented by the following general formula (9) .

[chemical 8]

一般式(8)

General formula (8)

[chemical 9]

一般式(9)

General formula (9)

[chemical 10]

Type A Type B Type C Type D

In general formula (8) or general formula (9), Y, Z, R ³ to R ⁸ have the same definitions as Y, Z, R ³ to R ⁸ in general formula (2) or general formula (3). L is represented by the above formulas A to D, m represents an integer of 0 or 1 or more, and when m is 2 or more, L may be different from each other. In Formula A, Xa represents NRe, O, S, and Re represents a hydrogen atom or a substituent. In Formula A and Formula C, Ra to Rd represent acidic groups. In the general formula (8), p represents an integer of 2 or more, and Rx represents an acidic group.

<11> The photoelectric conversion element according to any one of <4> to <10>, wherein Y is represented by S, NCH ₃ or C(CH ₃ ) ₂ , and Z is represented by carbon number 5 to 18. Aliphatic base.

<12> The photoelectric conversion element according to any one of <4>, <6> to <11>, wherein said R ⁷ is represented by any one of the following formulas (10) to (13) .

[chemical 11]

General formula (10) General formula (11) General formula (12) General formula (13)

[In the above formulas (10) to (13), Rf represents a hydrogen atom or a substituent. ]

<13> The photoelectric conversion element according to any one of <4>, <6> to <12>, wherein R ⁷ is represented by the following formula (14) or formula (15).

[chemical 12]

General formula (14) General formula (15)

<14> The photoelectric conversion element according to any one of <1> to <13>, wherein in the general formula (1), Q represents a benzene ring, and X ¹ and X ² independently represent a sulfur atom, Oxygen atom or C(CH ₃ ) ₂ , R, R' each independently represents an aliphatic group having 5-18 carbon atoms.

<15> The photoelectric conversion element according to any one of <1> to <14>, wherein the semiconductor fine particles are titanium oxide fine particles.

<16> A photoelectrochemical cell characterized by comprising the photoelectric conversion element according to any one of <1> to <15>.

<17> A dye for a photoelectric conversion element characterized by comprising a compound represented by the following general formula (1) having an aliphatic group having 5 to 18 carbon atoms.

[chemical 13]

General formula (1)

[In the general formula (1), Q represents a tetravalent aromatic group. X ¹ and X ² are independently represented as sulfur atom, oxygen atom or CR ¹ R ² . Wherein, R ¹ and R ² independently represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded by a carbon atom, and these may also be substituted. R and R' each independently represent an aliphatic group, an aromatic group, or a heterocyclic group bonded to a carbon atom, and these may be substituted. P ¹ and P ² are independently represented as pigment residues. W ¹ represents the counter ion necessary to neutralize the charge. ]

<18> A dye solution for a photoelectric conversion element characterized by containing and dissolving the dye for a photoelectric conversion element described in <17> in an organic solvent.

The present invention can provide a photoelectric conversion element and a photoelectrochemical cell having high conversion efficiency and excellent durability. In addition, the present invention can provide a dye for a photoelectric conversion element and a dye solution for a photoelectric conversion element.

The above-mentioned description and other characteristics and advantages of the present invention will become more apparent and comprehensible from the following description with appropriate reference to the attached drawings.

Description of drawings

Fig. 1 is a schematic cross-sectional view of an example of a photoelectric conversion element according to the present invention.

Detailed ways

As a result of repeated studies by the inventors of the present invention, it has been found that a photoelectric conversion element having a photoreceptor layer having a specific pigment and semiconductor fine particles, and a photoelectric conversion cell using the photoelectric conversion cell have high photoelectric conversion efficiency and durability, especially photoelectric conversion efficiency. The decrease is less. The present invention is carried out based on the above knowledge.

Next, preferred examples of the photoelectric conversion element of the present invention will be described with reference to the drawings. As shown in FIG. 1 , the photoelectric conversion element 10 includes a conductive support 1 , a photoreceptor layer 2 , a charge transfer layer 3 and a counter electrode 4 , and is arranged in this order on the conductive support 1 . Among them, the above-mentioned conductive support body 1 and photoreceptor layer 2 are used to constitute the light-receiving electrode 5 . The photoreceptor layer 2 has semiconductor fine particles 22 and a sensitizing dye 21, and at least a part of the dye 21 is adsorbed on the semiconductor fine particles 22 (the dye is in an adsorption equilibrium state, and a part of the dye may also exist in the charge carrier layer.) . The conductive support 1 on which the photoreceptor layer 2 is formed functions as a working electrode in the photoelectric conversion element 10 . This photoelectric conversion element 10 can be operated as a photoelectrochemical cell 100 by operating the external circuit 6 .

The light-receiving electrode 5 is an electrode including a conductive support 1 and a photoreceptor layer (semiconductor film) 2 containing semiconductor fine particles 22 adsorbing a dye 21 coated on the conductive support. The light incident on the photoreceptor layer (semiconductor film) 2 excites the dye, and the excited dye has high-energy electrons. Therefore, the above-mentioned electrons can be transferred from the pigment 21 to the conduction band of the semiconductor particle 22 , and then reach the conductive support 1 by diffusion, and at this time, the molecules of the pigment 21 will form oxides. The electrons on the electrodes return to the pigment oxidation body while working in the external circuit, thereby functioning as a photoelectrochemical cell. In this case, the light-receiving electrode 5 functions as the negative electrode of the above-mentioned battery.

The photoelectric conversion element of the present invention has a photoreceptor layer on a conductive support, and the photoreceptor layer has a porous semiconductor fine particle layer on which a specific dye described later is adsorbed. The photoreceptor layer may be designed as a single-layer structure or a multi-layer structure depending on the purpose. In addition, the dye in the photoreceptor layer may be mixed with various kinds of dyes, but at least the dyes described later must be used. When semiconductor fine particles containing the dye adsorbed above are used as the photoreceptor layer of the photoelectric conversion element of the present invention, a photoelectric conversion element having high sensitivity to light in a wide wavelength region can be obtained. When the above-mentioned photoelectric conversion element is used as a photoelectrochemical cell, a photoelectric conversion element capable of obtaining high conversion efficiency with little reduction in conversion efficiency and excellent durability can be obtained.

(A) Pigment

(A1) Pigment of general formula (1)

In the photoelectric conversion element of the present invention, a dye using a compound represented by the following general formula (1) is used. The above-mentioned dye can be used as a photoelectric conversion element, and has an aliphatic group having 5 to 18 carbon atoms. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. The most preferred is an alkyl group, such as pentyl (pentyl), hexyl (hexyl), heptyl (heptyl), octyl (octyl), nonyl (nonyl), decyl (decyl), undecyl ( undecyl), dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc. Among the alkyl groups, branched alkyl groups are preferred, such as 2-ethylhexyl, 2-methylhexyl (2-methylhexyl), 2-methylpentyl (2-methyl pentyl), 3,5,5- Trimethylhexyl (3,5,5-trimethylhexyl), 2-cyclopentylethyl (2-cyclopentylethyl), 2-cyclohexylethyl (2-cyclohexylethyl), etc. The presence of an alkyl group with 5 to 18 carbons can suppress the decomposition of the pigment caused by water and nucleophiles, and can also suppress the reduction in durability caused by the separation of the pigment from the semiconductor fine particles by water approaching the adsorption point. Furthermore, since aggregation or excessive adsorption of pigments can be suppressed, inefficient electron transfer can be suppressed, and photoelectric conversion efficiency can be improved. In addition, since the alkyl group is branched, the above-mentioned effects, especially the effect of improving durability can be more remarkably obtained.

[chemical 14]

General formula (1)

In formula (1), Q represents at least a tetrafunctional or higher aromatic group. Examples of the aromatic group include aromatic hydrocarbons and aromatic heterocycles. Among them, the aromatic hydrocarbons are, for example, benzene, naphthalin, anthracene, phenanthrene, etc., and the aromatic heterocycles are, for example, anthraquinone, carbazole, pyridine, quinone, etc. Quinoline, thiophene, furan, xanthene, thianthrene, and the like may have substituents other than the linking portion. The aromatic group represented by Q is preferably an aromatic hydrocarbon, more preferably benzene or naphthalene. Here, the bond between ^X2 and N(R') toward Q is also included in the illustrated formula, and the bond is performed at the N(R') position ^X2 and is carried out at the ^X2 position N(R') Bonded bond.

In addition, X ¹ and X ² are each independently represented as a sulfur atom, an oxygen atom or CR ¹ R ² . X ¹ and X ² are preferably sulfur atoms or CR ¹ R ² , more preferably CR ¹ R ² . Wherein, R ¹ and R ² independently represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded by a carbon atom. A heterocyclic group bonded to a carbon atom, for example, pyrrole (pyrrole), furan, thiophene, imidazole (imidazole), oxazole (oxazole), thiazole (thiazole), pyrazole (pyrazole), isoxazole (isoxazole) , isothiazole, pyridine, pyridazine, pyrimidine, pyran, etc. R ¹ and R ² are preferably aliphatic groups or aromatic groups. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. The alkyl group can be a straight chain or branched alkyl group, preferably an alkyl group with 5 to 18 carbons (for example, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, deca diyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, branched alkyl groups are preferred, for example, 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentyl Ethyl, 2-cyclohexylethyl, etc. Having an alkyl group with 5 to 18 carbons can suppress the decomposition of the pigment caused by water and a nucleophile, and can suppress the reduction in durability caused by the separation of the pigment from the semiconductor fine particles by water approaching the adsorption point. Furthermore, since aggregation or excessive adsorption of pigments can be suppressed, inefficient electron transfer can be suppressed, and photoelectric conversion efficiency can be improved. In addition, since the alkyl group is branched, the above-mentioned effects, especially the effect of improving durability can be more remarkably obtained. The aromatic group is preferably benzene, naphthalene, anthracene or the like.

R and R' independently represent an aliphatic group, an aromatic group, or a heterocyclic group bonded to a carbon atom, and these may also be substituted. The heterocyclic group bonded to a carbon atom includes, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, hydrazine, pyrimidine, pyran, and the like. R and R' are preferably an aliphatic group or an aromatic group, and the number of carbon atoms in the aromatic group is preferably 5-16, more preferably 5 or 6. The unsubstituted aromatic group is preferably phenyl, naphthyl or the like. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group, and more preferably an alkyl group with 5 to 18 carbon atoms (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, preferred are branched alkyl groups such as 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentyl Ethyl, 2-cyclohexylethyl, etc. Having an alkyl group with 5 to 18 carbons can suppress the decomposition of the pigment caused by water and nucleophiles, and can also suppress the reduction in durability caused by the separation of the pigment from the semiconductor microparticles by water approaching the adsorption point. Furthermore, since aggregation or excessive adsorption of pigments can be suppressed, inefficient electron transfer can be suppressed, and photoelectric conversion efficiency can be improved. In addition, since the alkyl group is branched, the above-mentioned effects, especially the effect of improving durability can be more remarkably obtained.

P ¹ and P ² are represented as pigment residues. The term "dye residue" refers to a group of atoms necessary to constitute a dye compound as a whole together with structures other than P ¹ and P ² in the general formula (1). P ¹ and P ² are directly bonded or bonded through a linking group to form a pigment of the general formula (1). The pigment (pigment compound) formed by ^P1 and ^P2 , such as cyanine, merocyanine, rhodacyanine, trinuclear anthocyanin, arobo Polymethine pigments such as allopolar, hemicyanine, styryl, oxonol, and cyanine, containing acridine, dibenzopyran, diarylmethine, triarylmethine, coumarin, indoaniline, indophenol, diarylmethine, etc. diazine, oxazine, thiazine, diketopyrrolopyrrole, indigo, anthraquinone, perylene, quinacridone, naphthoquinone ), bipyridyl, terpyridyl, tetrapyridyl, phenanthroline, etc.

Preferred are cyanine, merocyanidin, rose anthocyanin, trinuclear merocyanin, allopolar, semicyanine, cinnamon, and the like. In this case, dyes in which substituents on the methine chain forming the dye in cyanine form squarylium rings and croconium rings are also included. The details about the above-mentioned pigments are written in F, M, Hammer (Harmer), John Wiley (JOHNWILEY & SONS) Press, New York, London 1964 "Heterocyclic Compounds-cyanine dyes and related compounds (Heterocyclic Compounds- Cyanine Dyes and Related Compounds)". The general formulas of cyanine, merocyanidin, and rose anthocyanin are preferably represented by (XI), (XII), and (XIII) on pages 21 and 22 of US Patent No. 5,340,694. In addition, it is preferable that at least one of the methine chain moieties of the pigment residues formed by ^P1 and ^P2 have a squarylium ring and a clonacyl ring, and it is more preferable that they have both.

In the pigment with the structure of the above-mentioned general formula (1), P ¹ and P ² are preferably independently as follows:

Represented by general formula (2) or general formula (3).

[chemical 15]

一般式(2)

General formula (2)

[chemical 16]

一般式(3)

General formula (3)

In the above-mentioned general formula (2) and general formula (3), ^V represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, ^V may be the same or different, and may be mutually bonded. Knot to form a ring. n is preferably 0-3, more preferably 0-2.

Y is represented by a sulfur atom, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein, ^R represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom. The heterocyclic group bonded to a carbon atom includes, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, hydrazine, pyrimidine, pyran, and the like. A preferable example of ^R9 is an aliphatic group, and it is preferably an alkyl, alkenyl or alkynyl, more preferably an alkyl or alkenyl. In addition, it is more preferably an alkyl group having 5 to 18 carbons (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 - ethylhexyl, etc.). The aromatic group is preferably benzene, naphthalene, anthracene or the like.

R ¹⁰ and R ¹¹ represent a hydrogen atom, an aliphatic group, an aromatic group, or a heterocyclic group bonded to a carbon atom. R ¹⁰ and R ¹¹ may be the same or different, and may be bonded to each other to form a ring. A heterocyclic group bonded to a carbon atom includes, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, hydrazine, pyrimidine, and pyran. Preferable examples of R ¹⁰ and R ¹¹ are aliphatic groups, which are preferably alkyl, alkenyl or alkynyl, more preferably alkyl or alkenyl. In addition, it is more preferably an alkyl group having 5 to 18 carbons (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 - ethylhexyl, etc.). The aromatic group is preferably benzene, naphthalene, anthracene or the like.

Z represents an aliphatic group, an aromatic group, or a heterocyclic group bonded to carbon atoms, and it may also have a substituent. A preferable example of the substituent is an acidic group, more preferably a group having a carboxyl group. R ³ to R ⁶ and R ⁸ represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and they may also have substituents. The heterocyclic group bonded to a carbon atom includes, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, hydrazine, pyrimidine, pyran, and the like. R ³ to R ⁶ and R ⁸ are preferably hydrogen atoms or aliphatic groups. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. In addition, it is more preferably an alkyl group having 5 to 18 carbons (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 - ethylhexyl, etc.). R ³ to R ⁶ and R ⁸ are more preferably hydrogen atoms. R ⁷ represents an oxygen atom or a divalent carbon atom in which the sum of the substitution constant (σ _p ) of the two bonded substituents in Hammett's law is a positive number.

In the general formula (1), it is preferred that at least one of R, R', P ¹ and P ² has an acidic group. The so-called acid group here refers to a substituent with a dissociative proton, such as carboxyl group, phosphonyl group, sulfonyl group, boricacid group, etc., or A group having these groups is preferably a group having a carboxyl group. In addition, the acidic group may be in a dissociated form by releasing a proton.

In the general formula (1), W ¹ represents a counter ion when a counter ion (counter ion) is required to neutralize charges. Generally, whether a pigment is cationic, anionic, or has a net ionic charge depends on the auxochrome and substituents in the pigment. When a dye having a structure of the general formula (1) has a dissociative substituent, it can be dissociated to have a negative charge. At this time, the charge of the molecule as a whole can be neutralized by W ¹ .

When W ¹ is a cation, it is, for example, an inorganic or organic ammonium ion (eg, tetraalkylammonium ion, pyridinium ion), or an alkali metal ion. In addition, when W ¹ is an anion, it may be either an inorganic anion or an organic anion. For example, halogen anion (halogen anion) (for example, fluoride ion, chloride ion, bromide ion, iodide ion), substituted arylsulfonic acid ion (arylsulfonic acid) (for example, p-toluenesulfonic acid ion ( p-toluenesulfonic acid ion), p-chlorobenzenesulfonic acid ion (p-chlorobenzenesulfonic acid ion)), aryldisulfonic acid ion (aryldisulfonic acid ion) (for example, 1,3-benzenedisulfonic acid ion (1,3-benzenedisulfonic acid ion) acid ion), 1,5-naphthalenedisulfonic acid ion (1,5-naphthalenedisulfonic acid ion), 2,6-naphthalenedisulfonic acid ion), alkyl sulfate ion (for example, methyl sulfate ion ), sulfate ion, thiocyanic acid ion, perchloric acid ion, tetrafluoroboric acid ion, picric acid ion, acetate ion (acetic acidion), trifluoromethanesulfonic acid ion (trifluoromethane sulfonic acid ion), etc. And, can use ionic polymer (ionic polymer) as charge balancing counter ion, or have other pigments with the opposite charge of pigment, and also can be to use metal zirconium ion (for example bisphenyl-1,2-nickel disulfide) (III) (bisbenzene-1,2-dithiolato nickel (III))).

In the above-mentioned general formula (1), ^P1 and ^P2 are preferably respectively independently represented by the following general formula (4) or general formula (5), and accordingly can become a pigment with a high molar absorptivity.

[chemical 17]

一般式(4)

General formula (4)

[chemical 18]

一般式(5)

General formula (5)

V ¹ , n, Z and Y are as defined in the above-mentioned general formula (2) and general formula (3).

In the above general formula (4) or general formula (5), ^V1 represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, ^V1 may be the same or different, or mutually Bond to form a ring.

Y is represented as S, NR ⁹ or CR ¹⁰ R ¹¹ . Wherein, ^R represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom. R ¹⁰ and R ¹¹ represent a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, which may be the same or different, and may be bonded to each other to form a ring.

Z represents an aliphatic group, an aromatic group, or a heterocyclic group bonded to carbon atoms, and it may also have a substituent.

In the above general formula (4) or general formula (5), Y is preferably represented by a sulfur atom, NCH ₃ or C(CH ₃ ) ₂ , and Z is preferably represented by an aliphatic group with 5-18 carbons. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group. In addition, it is more preferably an alkyl group having 5 to 18 carbons (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2 - ethylhexyl, etc.). By making Z an aliphatic group having 5 to 18 carbon atoms, the amount of adsorption per unit area can be increased. In addition, aliphatic groups may also be substituted.

In the above general formulas (2) to (5), V ¹ preferably has an acidic group. The acidic group is a substituent having a dissociative proton. V ¹ may have an acidic group as long as it has an acidic group, and an acidic group may be bonded via a linking group. The acidic group is not particularly limited, such as carboxyl, phosphonic acid group, sulfo group, sulfonate group, hydroxyl radical, hydroxamic group, phosphoric acid Phosphoryl group, phosphono group, sulfino group, sulfinyl group, phosphinyl group, phosphono group, thiol group and sulfonate acyl groups, and salts of these groups. The above-mentioned salts are not particularly limited, and they may be any of organic salts and inorganic salts. Representative examples such as alkali metal ions (lithium (Li), sodium (Na), potassium (K), etc.), alkaline earth metal ions (magnesium (Mg), calcium (Ca), etc.), ammonium (ammonium), alkyl Ammonium (alkylammonium) (for example, diethylammonium (diethylammonium), tetrabutylammonium (tetrabutylammonium) and the like), pyridinium (pyridinium), alkylpyridinium (alkylpyridinium) (for example, methylpyridinium (methylpyridinium)), Salts such as guanidinium and tetraalkylphosphonium. In the general formula (1), when there are plural acidic groups, they may be the same or different.

The aforementioned acidic group in the present invention is preferably carboxyl, phosphoric acid or phosphono, more preferably carboxyl.

V ¹ preferably has a hydrogen atom, 5-carboxyl group, 5-sulfonic acid group (5-sulfonic acid group), 5-methyl group or 4,5-condensed benzene ring (4,5-Condensed benzene-ring). Here, the position number is indicated by rotating counterclockwise with N ⁺ being 1.

Accordingly, the effects of improving the molar absorptivity or improving the electron injection efficiency can be obtained.

In addition, in general formula (2) to general formula (5), in addition to V ¹ , Z is also preferably a group having an acidic group. Z can be set to the same acidic group as ^V1 . The acidic group has the function of being adsorbed to the semiconductor fine particles in the dye of the present invention. The number of acidic groups in the dye is preferably at least one, more preferably 1-2. Furthermore, by setting both V ¹ and Z as acidic groups, it is possible to achieve an improvement in durability due to an increase in adsorption force.

The above general formula (2) can be represented by the following general formula (6), and the above general formula (3) can be represented by the following general formula (7).

[chemical 19]

一般式(6)

General formula (6)

[chemical 20]

一般式(7)

General formula (7)

In the general formula (6) or (7), V ¹² represents an acidic group, at least one of E ¹¹ to E ¹³ represents an electron-withdrawing group, and p is an integer of 2 or more. Examples of the acidic group include the same acidic groups as those listed in V ¹ above.

The electron-withdrawing group is preferably cyano group, nitro group, sulfonyl group, sulfoxy group, acyl group, alkoxycarbonyl group, amine Formyl (carbamoyl group), more preferably cyano, nitro, sulfonyl, more preferably cyano.

In the above general formula (6), p is an integer of 2 or more, and p is preferably 2-5, more preferably 2-3. In the above general formula (6) and general formula (7), since V ¹² is represented as an acidic group, and at least one of E ¹¹ to E ¹³ is represented as an electron-withdrawing group, the excited electrons can be strongly attracted to the semiconductor particle layer In the vicinity of the adsorption point, the transport of electrons to the semiconductor particle layer is efficiently carried out, and the effect of improving the photoelectric conversion efficiency can be realized. Among E ¹¹ to E ¹³ , E ¹¹ and E ¹² are more preferably electron-withdrawing groups.

The above general formula (2) is preferably represented by the following general formula (8), and the above general formula (3) is preferably represented by the following general formula (9).

[chem 21]

General formula (8)

[chem 22]

一般式(9)

General formula (9)

[chem 23]

Type A Type B Type C Type D Type E

In general formula (8) or general formula (9), Y, Z, R ³ to R ⁸ have the same definitions as Y, Z, R ³ to R ⁸ in general formula (2) or general formula (3). L is represented by the above formulas A to D, m represents 0 or an integer of 1 or more, and when m is 2 or more, each L may be different. In the above formula A, Xa represents NRe, O, S, and Re represents a hydrogen atom or a substituent. In the above formula A and formula C, Ra to Rd represent substituents. As a substituent in Ra-Re, the substituent represented by the following substituent is mentioned as a specific example.

As a substituent, it shows, for example, an aliphatic group, an aromatic group, or a heterocyclic group bonded to a carbon atom, and these groups may also be substituted. The heterocyclic group bonded to a carbon atom includes, for example, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, isoxazole, isothiazole, pyridine, hydrazine, pyrimidine, pyran, and the like. R and R' are preferably an aliphatic group or an aromatic group, and the number of carbon atoms in the aromatic group is preferably 5-16, more preferably 5 or 6. The unsubstituted aromatic group is preferably phenyl, naphthyl or the like. The aliphatic group is preferably an alkyl group, an alkenyl group or an alkynyl group, more preferably an alkyl group or an alkenyl group, and more preferably an alkyl group with 5 to 18 carbon atoms (such as pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, octadecyl, cyclohexyl, 2-ethylhexyl, etc.). Among the alkyl groups, branched alkyl groups are preferred, such as 2-ethylhexyl, 2-methylhexyl, 2-methylpentyl, 3,5,5-trimethylhexyl, 2-cyclopentyl 2-cyclohexylethyl, 2-cyclohexylethyl, etc. Having an alkyl group with 5 to 18 carbons can suppress the decomposition of the pigment caused by water and nucleophile, and can suppress the reduction in durability caused by the peeling of the pigment from the semiconductor microparticles due to water approaching the adsorption point. Furthermore, since aggregation or excessive adsorption of pigments can be suppressed, inefficient electron transfer can be suppressed, and photoelectric conversion efficiency can be improved. In addition, since the alkyl group is branched, the above-mentioned effects, especially the effect of improving durability can be more remarkably obtained.

In the general formula (8), p represents an integer of 2 or more, and Rx represents an acidic group. Examples of the acidic group include the same acidic groups as those listed in ^V1 above. Rx is preferably a group represented by formula E.

Since the above-mentioned general formula (2) is expressed by the above-mentioned general formula (8), and the above-mentioned general formula (3) is expressed by the above-mentioned general formula (9), the effect of expanding the absorption area or improving the absorption coefficient can be obtained, and photoelectricity can be generated. The effect of improving the conversion efficiency.

In the above general formula (3), general formula (5) and general formula (9), R ⁷ is preferably represented by any one of formula (10) to formula (13).

[chem 24]

General formula (10) General formula (11) General formula (12) General formula (13)

In the above formula, Rf is a hydrogen atom or a substituent. Examples of substituents include aliphatic groups, aromatic groups, and heterocyclic groups bonded to carbon atoms, and these substituents may also be substituted. Among them, the substituent is preferably an aliphatic group or an aromatic group. Thereby, absorption on the short-wavelength side can be enhanced.

In the above general formula (3), general formula (5) and general formula (9), R ⁷ is preferably represented by the following general formula (14) or general formula (15).

[chem 25]

General formula (14) General formula (15)

Thereby, an effect of improving electron injection efficiency can be obtained.

The pigment of the present invention represented by the general formula (1) has a maximum absorption wavelength preferably in the range of 670nm to 1100nm, more preferably in the range of 700nm to 900nm in tetrahydrofuran: ethanol = 1: 1 self-spoon solution.

The following shows preferred specific examples of the compound represented by the general formula (1) in the present invention, but the present invention is not limited thereto.

[chem 26]

[chem 27]

[chem 28]

[chem 29]

In addition, the following shows preferred specific examples of the dyes having the structures of general formula (6) to general formula (9) of the present invention, but the present invention is not limited thereto.

[chem 30]

(Example 1)

[chem 31]

(Specific example 2)

[chem 32]

(Example 3)

[chem 33]

(Example 4)

In the above specific examples 1 to 4, the basic structure A is represented by any one of the following A-1 to A-12, and the basic structure B is represented by any one of the following B-1 to B-11 , the basic structure C is represented by any one of the following C-1 to C-4. In addition, Z is represented by the following Z-1 to Z-5, and the linking group L is represented by any one of the following L-1 to L-12.

In specific examples 1 to 4, the carbon atoms of the basic structure A and the basic structure B are bonded by carbon-carbon double bonds at * each other, and the carbon atoms of the basic structure B and the basic structure C are bonded by carbon-carbon double bonds at * each other bond.

[chem 34]

[chem 35]

[chem 36]

[chem 37]

[chem 38]

For example, in the above specific examples, if T-2, T-6, T-9, T-10, T-12, T-16, T-17, T-18, T-24, T-30, T The structural formulas of -37 and T-40 to T-50 are as follows.

[chem 39]

[chemical 40]

[chem 41]

[chem 42]

[chem 43]

[chem 44]

In addition, the following dyes are also mentioned.

[chem 45]

For the synthesis of pigments with the above structures, please refer to Ukrainskii Khimicheskii Zhurnal, Vol. 40, No. 3, pages 253-258, and Dyes and Pigments, Vol. 21, pages 227-234. and the descriptions of the documents cited in these documents, etc.

(B) Conductive support

As shown in FIG. 1 , in the photoelectric conversion element of the present invention, a photoreceptor layer 2 in which a dye 21 is adsorbed to porous semiconductor fine particles 22 is formed on a conductive support 1 . As will be described later, for example, a photoreceptor can be produced by immersing the conductive support in the dye solution of the present invention after applying and drying a dispersion of semiconductor fine particles.

As the conductive support, a support that is itself conductive such as metal, or a glass or a polymer material with a conductive film layer on the surface can be used. The conductive support is preferably substantially transparent. Substantially transparent means that the light transmittance is 10% or more, preferably 50% or more, more preferably 80% or more. In addition, a support obtained by coating a conductive metal oxide on glass or a polymer material can be used as the conductive support. At this time, the coating amount of the conductive metal oxide is preferably 0.1 to 100 g per 1 m ² of the support of glass or polymer material. When using a transparent conductive support, light is preferably incident from the side of the support. Preferred examples of the polymer material used include tetraacetylcellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PolyethyleneNaphthalate, PEN ), polystyrene (syndiotactic polystyrene, SPS), polyphenylene sulfide (polyphenylene sulfide, PPS), polycarbonate (polycarbonate, PC), polyarylate (polyarylate, PAR), polysulfone (polysulfone, PSF ), polyether sulfone (PES), polyetherimide (PEI), cyclic polyolefin (cyclic polyolefin), brominated phenoxy (brominated phenoxy), etc.

In the present invention, a metal support can be used as a preferable conductive support. As the conductive metal support, a conductive metal support composed of any element belonging to Groups 4 to 13 can also be used as the conductive support. Here, Groups 4 to 13 refer to elements in the long-period periodic table.

The thickness of the conductive metal support of the present invention is preferably from 10 μm to 2000 μm, more preferably from 10 μm to 1000 μm, still more preferably from 50 μm to 500 μm. If the thickness of the conductive metal substrate is too thick, the flexibility will be insufficient, and thus failure will occur when used as a photoelectric conversion element. Also, if the thickness is too thin, the photoelectric conversion element may be damaged during use, which is not preferable.

The surface resistance of the conductive metal support used in the present invention is preferably low surface resistance. A preferable range of surface resistance is less than 10Ω/m ² , more preferably less than 1Ω/m ² , more preferably less than 0.1Ω/m ² . When the value of the surface resistance is too high, it becomes difficult to conduct electricity and cannot function as a photoelectric conversion element.

As the conductive metal support, it is preferable to use at least one kind selected from the group consisting of titanium, aluminum, copper, nickel, iron, stainless steel, zinc, molybdenum, tantalum, niobium, and zirconium. These metals may also be alloys. Among these, titanium, aluminum, copper, nickel, iron, stainless steel, and zinc are preferable, titanium, aluminum, and copper are more preferable, and titanium and aluminum are still more preferable. When aluminum is used, it is preferable to use an aluminum alloy stretch material, 1000 series to 7000 series (Light Metal Association: Aluminum Handbook, Light Metal Association (1978), 26) and the like.

The conductive metal support can reduce the internal resistance of the photoelectrochemical cell due to its small surface resistance, and thus can obtain a high-output battery. In addition, in the case of using a conductive metal support, the support does not soften even when the conductive metal support coated with the semiconductor fine particle dispersion described later is heated and dried at an elevated temperature for firing. Therefore, by appropriately selecting heating conditions, a porous semiconductor fine particle layer having a large specific surface area can be formed. According to the above, the amount of dye adsorption can be increased, and a photoelectric conversion element with high conversion efficiency at high output can be provided.

In addition, a porous conductive support can be obtained by coating the metal sheet with a dispersion of semiconductor fine particles while continuously sending out the wound metal sheet, followed by heating. Thereafter, the dye of the present invention is continuously applied, whereby a photosensitive layer can be formed on the conductive support. By going through the above process, a photoelectric conversion element or a photoelectrochemical cell can be manufactured at low cost.

For the conductive metal support of the present invention, it is preferable to use a substrate in which a conductive layer is provided on a polymer material layer. The polymer material layer is not particularly limited, but a material that melts when heated and does not retain its shape after coating the semiconductor fine particle dispersion on the conductor layer is selected. The conductive layer is produced by laminating on the polymer material layer by a conventional method such as extrusion coating.

The polymer material layer that can be used is, for example, tetraacetate cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), para polystyrene (SPS), Polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyetherimide (PEI), cyclic polyolefin, bromine Phenoxyl, etc.

By using a support provided with a conductive layer on a polymer material layer as the conductive metal support of the present invention, the polymer material layer can function as a protective layer of a photoelectric conversion element or a photoelectrochemical cell. If an electrically insulating material is used as the polymer material, the polymer material layer can function not only as a protective layer but also as an insulating layer. According to the above, the insulation property of the photoelectric conversion element itself can be ensured. When the polymer material layer is used as the insulating layer, it is preferable to use a polymer material layer with a volume resistivity of 10 ¹⁰ to 10 ²² Ω·cm, more preferably a volume resistivity of 10 ¹¹ to 10 ¹⁹ Ω·cm. When the above materials are used, unless a conductive material is specially prepared, a conductive metal support having an insulating layer having a volume resistivity within the above range can be obtained. The conductive metal support is preferably substantially transparent. Substantially transparent means that the transmittance of light having a wavelength of 400 nm to 1200 nm is 10% or more, preferably 50% or more, more preferably 80% or more.

On the conductive metal support, a light management mechanism can also be provided on the surface, for example, an anti-reflection film or a light guide mechanism can be provided by alternately laminating high-refractive film and low-refractive-index oxide film. .

On the conductive support, it is preferable to have a function of blocking ultraviolet light. For example, a method in which a fluorescent material capable of converting ultraviolet light into visible light is present inside or on the surface of the polymer material layer is mentioned. In addition, other preferable methods include, for example, a method using an ultraviolet absorber. The functions described in Japanese Patent Application Laid-Open No. 11-250944 and the like can also be imparted to the conductive support.

As the battery area increases, the resistance value of the conductive film increases, so a collector electrode can also be arranged. As for the shape and material of the preferable current collecting electrode, those described in Japanese Patent Application Laid-Open No. 11-266028 and the like can be used. In addition, a gas barrier film and/or an ion diffusion preventing film may also be disposed between the polymer material layer and the conductive layer. The gas barrier film may be either a resin film or an inorganic film.

(C) Semiconductor microparticles

As shown in FIG. 1 , in the photoelectric conversion element of the present invention, a photoreceptor layer 2 in which a dye 21 is adsorbed to porous semiconductor fine particles 22 is formed on a conductive support 1 . As will be described later, for example, a photoreceptor can be produced by immersing in the dye solution of the present invention after coating and drying the dispersion of semiconductor fine particles on the above-mentioned conductive support.

It is preferable to use fine particles of metal chalcogenides (for example, oxides, sulfides, selenides, etc.) or perovskites as semiconductor fine particles. The metal chalcogenides are preferably titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum (lanthanum), vanadium, niobium or tantalum oxides, cadmium sulfide, cadmium selenide, etc. The perovskite is preferably strontium titanate, calcium titanate or the like. Among them, titanium oxide, zinc oxide, tin oxide, and tungsten oxide are more preferable.

Regarding conduction in semiconductors, there are n-type in which carriers are electrons and p-type in which carriers are holes, but it is preferable to use n-type in the device of the present invention from the viewpoint of conversion efficiency. In n-type semiconductors, in addition to the intrinsic semiconductor (intrinsic semiconductor) (or intrinsic semiconductor) in which the concentration of conduction band electrons without impurity levels is equal to that of valence electrons with hole carriers, there are electrons due to structural defects from impurities An n-type semiconductor with a high carrier concentration. The n-type inorganic semiconductors preferably used in the present invention are TiO ₂ , TiSrO ₃ , ZnO, Nb ₂ O ₃ , SnO ₂ , WO ₃ , Si, CdS, CdSe, V ₂ O ₅ , ZnS, ZnSe, SnSe, KTaO ₃ , FeS ₂ , PbS, InP, GaAs, CuInS ₂ , CuInSe ₂ , etc. Among them, the most preferred n-type semiconductors are TiO ₂ , ZnO, SnO ₂ , WO ₃ and Nb ₂ O ₃ . In addition, a semiconductor material obtained by compounding a plurality of these semiconductors can also be preferably used.

The particle diameter of the semiconductor fine particles is preferably such that the average particle diameter of the primary particles is not less than 2 nm and not more than 50 nm in order to keep the viscosity of the semiconductor fine particle dispersion high. In addition, ultrafine particles having an average particle diameter of primary particles of 2 nm to 30 nm are more preferable. Two or more types of fine particles having different particle size distributions may be mixed, and in this case, the average size of the small particles is preferably 5 nm or less. In addition, for the purpose of scattering incident light and increasing the light capture rate, large particles having an average particle diameter of more than 50 nm may be added at a low content rate to the above-mentioned ultrafine particles. In this case, the content of large particles is preferably not more than 50% of the mass of particles having an average particle diameter of not more than 50 nm, more preferably not more than 20%. The average particle diameter of the large particles added and mixed for the above purpose is preferably at least 100 nm, more preferably at least 250 nm.

A preferred method for producing semiconductor fine particles is the sol-gel method described in "Science of the Sol-Gel Method" by Tsukasa Kazuo, AGNE Chengfeng Publishing House (1998) and the like. In addition, it is a method of producing oxides by decomposing chlorides developed by Degussa in hydrogen acid salts with high-temperature hydrolysis. When the semiconductor microparticles are titanium oxide, it is preferable to use any one of the above-mentioned sol-gel method, gel-sol method, and high-temperature hydrolysis method in hydrogen acid salts of chlorides, and it is more preferable to use Kiyono's method. The sulfuric acid method and chlorine method described in "Physical Properties and Application Technology of Titanium Oxide" published by Jibodo (1997). In addition, the sol-gel method is preferably the method described in Barbe et al. (Journal of American Ceramic Society) Vol. 80, No. 12, pages 3157-3171, or Burnside ( Burnside) et al in the method described in Materials Chemistry (Chemistry of Materials) Vol. 10, No. 9, pp. 2419-2425.

In addition, as a method for producing semiconductor microparticles, for example, as a method for producing titanium oxide nanoparticles, a method using flame hydrolysis of titanium tetrachloride, a combustion method of titanium tetrachloride, and a stable chalcogenide complex Hydrolysis of substances, hydrolysis of orthotitanic acid, method of dissolving and removing soluble part after forming semiconductor particles from soluble part and insoluble part, hydrothermal synthesis of peroxide aqueous solution, or using sol-gel A method for producing titanium oxide having a core/shell structure.

The crystal structure of titanium oxide is, for example, anatase, brookite or rutile, and is preferably anatase or brookite.

Titanium oxide nanotubes, nanowires, and nanocolumns may also be mixed with titanium oxide fine particles.

Titanium oxide can also be doped by non-metal elements, etc., and in addition to the dopant as an additive to titanium oxide, in order to improve the bonding of necking and prevent reverse electron movement, it can be used in Additives are used on the surface. Examples of preferable additives include indium tin oxide (Indium Tin Oxide, ITO), tin oxide (SnO) particles, whiskers, fibrous graphite carbon nanotubes, zinc oxide necked coupling Zinc oxide necking couple, fibrous substances such as cellulose, metals, organosilicon, dodecyl benzene sulfonic acid, silane, etc. Mobile binding molecules, and potential tilting dendrimers (dendrimer), etc.

For the purpose of removing surface defects on titanium oxide, acid-base or redox treatment can also be performed on titanium oxide before pigment adsorption. In addition, etching, oxidation treatment, hydrogen peroxide treatment, dehydrogenation treatment, UV-ozone, oxygen plasma, and other treatments may also be performed.

(D) Semiconductor fine particle dispersion

In the present invention, a porous semiconductor fine particle coating layer can be obtained by coating the semiconductor fine particle dispersion liquid on the above-mentioned conductive support and heating it appropriately.

The preparation method of semiconductor fine particle dispersion liquid, besides above-mentioned sol-gel method, can enumerate the method of precipitating fine particle in the solvent when synthesizing semiconductor and using as it is, the method of irradiating ultrasonic etc. to fine particle and pulverizing into ultrafine particle, or A method of mechanically pulverizing and crushing using a grinder, a mortar, or the like. As the dispersion solvent, water and/or various organic solvents can be used. And organic solvents, such as alcohols such as methanol, ethanol, isopropyl alcohol, citronellol, terpineol, ketones such as acetone, ethyl acetate, etc. (ethyl acetate) and other esters, dichloromethane (dichloromethane), acetonitrile (acetonitrile), etc.

When dispersing, a small amount of polymers such as polyethylene glycol (polyethylene glycol), hydroxyethyl cellulose (hydroxyethyl cellulose), carboxymethyl cellulose (carboxymethyl cellulose), surfactants, acid, etc. Or chelating agent, etc. are regarded as dispersion aids. However, before performing the film forming process on the conductive support, it is preferable to remove most of these dispersing aids in advance by filtration, using a separation membrane, or telecentric separation.

If the viscosity of the semiconductor microparticle dispersion is too high, the dispersion will coagulate and cannot be formed into a film. Conversely, if the viscosity of the semiconductor microparticle dispersion is too low, the solution will flow off and cannot be formed into a film. Therefore, the viscosity of the dispersion is preferably 10N·S/m ² to 300N·S/m ² at 25°C, more preferably 50N·S/m ² to 200N·S/m ² at 25°C.

As a coating method of the semiconductor fine particle dispersion liquid, a roller method, a dip method, etc., which are application methods, can be used. In addition, an air knife method, a blade method, etc., which are metering methods, can also be used. In addition, the method that can use the application type method and the measurement type method in the same part is preferably the wire bar method disclosed in Japanese Patent Publication No. 58-4589, and described in US Patent No. 2681294 specification. The inclined plate feeding method (slide hopper method), extrusion method (extrusion method), curtain method (curtain method) and so on. Furthermore, it is preferable to apply by a spin method or a spraying method using a general machine. Wet printing methods are mainly three major printing methods: relief printing, offset and gravure, and gravure, rubber plate, screen printing, etc. are preferred. Therefore, from the above methods, a better film-making method can be selected according to the liquid viscosity and wet thickness. Because the semiconductor fine particle dispersion liquid of the present invention has high viscosity and viscous property, it has strong cohesive force, so it may not be easily compatible with the support body during coating. In the above case, the surface can be cleaned and hydrophilized by UV ozone treatment to increase the adhesion between the coated semiconductor microparticle dispersion and the surface of the conductive support, making the coating of the semiconductor microparticle dispersion easier. easy to do.

The preferred thickness of the semiconductor fine particle layer as a whole is 0.1 μm to 100 μm, and the thickness of the semiconductor fine particle layer is more preferably 1 μm to 30 μm, still more preferably 2 μm to 25 μm. The loading capacity per 1 m ² of the support of semiconductor fine particles is preferably 0.5 g to 400 g, more preferably 5 g to 100 g.

The layer coated with semiconductor fine particles is subjected to heat treatment in order to strengthen the electronic contact between the semiconductor fine particles, to improve the adhesion to the support, and to dry the coated semiconductor fine particle dispersion. The porous semiconductor fine particle layer can be formed by the above heat treatment.

In addition, light energy can also be used in addition to heat treatment. For example, when titanium oxide is used as the semiconductor fine particles, it is also possible to activate the surface by giving the semiconductor fine particles absorbable light such as ultraviolet light, and to activate only the surface of the semiconductor fine particles with laser light or the like. By irradiating semiconductor fine particles with light absorbable by the fine particles, impurities adsorbed on the particle surface can be decomposed by activating the particle surface, and can be set to a preferred state for the above-mentioned purpose. In the case of combining heat treatment and ultraviolet light, it is preferable to heat the semiconductor fine particles at a temperature between 100°C and 250°C, more preferably between 100°C and 150°C, while irradiating light that the fine particles can absorb. . As mentioned above, by photoexciting the semiconductor microparticles, it is possible to photodecompose and clean the impurities mixed in the microparticle layer, and at the same time strengthen the physical bonding between the microparticles.

In addition, other treatments may be performed besides coating the semiconductor fine particle dispersion on the above-mentioned conductive support, followed by heating or irradiating light. Preferable methods include, for example, energization, chemical treatment, and the like.

Pressure may also be applied after application|coating, and the method of applying pressure is mentioned, for example in Japanese Patent Application Publication No. 2003-500857 and the like. Examples of light irradiation include Japanese Patent Application Laid-Open No. 2001-357896 and the like. Examples of plasma, microwave, and energization include Japanese Patent Application Laid-Open No. 2002-353453 and the like. The chemical treatment includes, for example, JP-A-2001-357896 and the like.

The above-mentioned method of coating semiconductor fine particles on a conductive support, in addition to the above-mentioned method of coating a dispersion of semiconductor fine particles on a conductive support, can use Japanese Patent No. 2664194 communique on a conductive support. A method such as a method of obtaining a film of semiconductor fine particles by hydrolyzing the precursor of semiconductor fine particles described in , by using moisture in the air.

Examples of precursors include (NH ₄ ) ₂ TiF ₆ , titanium peroxide, metal alkoxides, metal complexes, metal organic acid salts, and the like.

In addition, a method of forming a semiconductor film by applying a slurry that coexists with a metal organic oxide (alkoxide, etc.) and heat treatment, light treatment, etc., and a slurry that coexists with an inorganic precursor and A method of specifying the pH of the slurry and the properties of the dispersed titanium particles. A small amount of binder can also be added to these slurries, and the binder can include cellulose, fluoropolymer, cross-linked rubber, polybutyltitanate, carboxymethyl fiber Su and so on.

The technology related to the formation of semiconductor microparticles or their precursor layers, for example, is a method of hydrophilizing by physical methods such as corona discharge (corona discharge), plasma, UV, etc., by alkali or polyethylenedioxy Chemical treatment of thiophene (polyethylenedioxythiophene) and polystyrene sulfonate (polystyrene sulfonate), etc., formation of interlayer film for bonding of polyaniline, etc.

The method of coating the semiconductor fine particles on the conductive support can also be used in combination with the above-mentioned (1) wet method (2) dry method and (3) other methods. (2) The dry method is preferably JP-A-2000-231943 and the like. (3) Other methods are preferably JP-A-2002-134435 and the like.

The dry method is, for example, vapor deposition or sputtering, aerosol deposition method, etc. In addition, electrophoresis and electrolysis can also be used.

In addition, a method of temporarily forming a coating film on a heat-resistant substrate and then transferring it to a film such as plastic can also be used. Preferably, as described in Japanese Patent Laid-Open No. 2002-184475, the method of transferring by ethylene vinyl acetate (Ethylene Vinyl Acetate, EVA), or including ultraviolet light, which can be recorded in Japanese Patent Laid-Open No. 2003-98977, A method in which a semiconductor layer and a conductive layer are formed on a sacrificial substrate of an inorganic salt removed by an aqueous solvent, transferred to an organic substrate, and then the sacrificial substrate is removed.

In order to be able to absorb more pigments, it is better for the semiconductor microparticles to have a large surface area. For example, in the state where semiconductor fine particles are coated on the support, the surface area thereof is preferably 10 times or more, more preferably 100 times or more, the projected area. The above-mentioned upper limit is not particularly limited, and it is usually about 5000 times. A preferred structure of semiconductor microparticles may include Japanese Patent Application Laid-Open No. 2001-93591 and the like.

Generally speaking, although the thicker the layer of semiconductor fine particles is, the amount of pigment that can be carried per unit area will increase, so the light absorption efficiency will become higher, but the diffusion distance of the generated electrons will increase, so the charge recombination will increase. losses will also increase. The preferred thickness of the semiconductor fine particle layer varies depending on the application of the device, but is typically 0.1 μm to 100 μm. In addition, when used as a photoelectrochemical cell, the thickness of the semiconductor fine particle layer is preferably from 1 μm to 50 μm, more preferably from 3 μm to 30 μm. In order to make the semiconductor fine particles adhere to each other after coating on the support, heating may be performed at a temperature of 100° C. to 800° C. for 10 minutes to 10 hours. When glass is used as a support, the film forming temperature is preferably 400°C to 600°C.

When using a polymer material as a support, it is preferable to heat it after film formation at 250° C. or lower. The film-making method under the above-mentioned circumstances can be any one of (1) wet method, (2) dry method, (3) electrophoresis method (including electrolysis method), preferably (1) wet method or (2) ) dry method, more preferably (1) wet method.

Furthermore, the coating amount of the semiconductor microparticles per 1 m ² of the support is 0.5 g to 500 g, preferably 5 g to 100 g.

In order to adsorb the dye to the semiconductor microparticles, it is preferable to immerse the formed semiconductor electrode in a dye solution for dye adsorption formed of a solution and the dye of the present invention. The solution used for the dye solution for dye adsorption is not particularly limited as long as it can dissolve the dye for photoelectric conversion elements of the present invention. For example, organic solvents such as ethanol, methanol, isopropanol, toluene, tert-butanol, acetonitrile, acetone, n-butanol and the like can be used. Among them, ethanol and toluene are preferably used. In addition, the organic solvent may be used alone or in combination of a plurality of them. In order to uniformly adsorb the pigment into the semiconductor microparticles, the concentration of the above-mentioned pigment is preferably 0.01 mmole/L˜1.0 mmole/L, more preferably 0.1 mmole/L˜1.0 mmole/L.

The dye solution for dye adsorption formed from the solution and the dye of the present invention can be heated to 50°C to 100°C as needed. Adsorption of the dye may be performed before or after coating of the semiconductor fine particles. In addition, it is also possible to apply the semiconductor fine particles and the dye at the same time to allow the dye to adsorb. Unadsorbed pigments can be removed by washing. When firing the coating film, it is preferable to adsorb the pigment after the firing, and it is more preferable to quickly adsorb the pigment before the surface of the coating film absorbs water after firing. Pigments having other structures may also be mixed within a range not deviating from the gist of the present invention. When mixing the dyes, in order to dissolve all the dyes, it is necessary to use a dye solution for dye adsorption.

As a whole, the amount of the pigment used is preferably 0.01 mmole to 100 mmole, more preferably 0.1 mmole to 50 mmole, more preferably 0.1 mmole to 10 mmole per 1 m ² of the support. In this case, the usage amount of the pigment of the present invention is preferably 5 mole % or more.

In addition, the adsorption amount of the pigment to the semiconductor fine particles is preferably 0.001 mmole to 1 mmole, more preferably 0.1 mmole to 0.5 mmole, relative to 1 g of the semiconductor fine particles.

The sensitization effect in a semiconductor can fully be acquired by setting it as the amount of dyes mentioned above. Accordingly, if the amount of the dye is small, the sensitization effect will be insufficient, and if the amount of the dye is too large, the dye that has not adhered to the semiconductor will be suspended, causing a decrease in the sensitization effect.

In addition, colorless compounds may also be co-adsorbed for the purpose of reducing the interaction between pigments such as aggregation. Examples of the co-adsorbed hydrophobic compound include carboxyl group-containing steroid compounds (eg, cholic acid, pivaloyl acid) and the like.

After the dye is adsorbed, the surface of the semiconductor microparticles can also be treated with amines. Preferred amines include 4-tert-butylpyridine, polyvinylpyridine, and the like. The above-mentioned amines may be used as they are in liquid form or dissolved in an organic solvent for use.

The counter electrode can function as the positive electrode of the photoelectrochemical cell. The counter electrode is generally synonymous with the above-mentioned conductive support, but the support is not necessarily required as long as it has a structure that can maintain sufficient strength. However, those having a support body are advantageous from the viewpoint of airtightness. The material of the counter electrode is, for example, platinum, carbon, or conductive polymer, and preferably platinum, carbon, or conductive polymer.

The structure of the counter electrode is preferably a structure with a high current collecting effect, and a preferable example is Japanese Patent Application Laid-Open No. 10-505192 and the like.

A composite electrode of titanium oxide and tin oxide (TiO ₂ /SnO ₂ ) may be used as the light-receiving electrode, and the mixed electrode of titanium oxide may be, for example, those described in Japanese Patent Application Laid-Open No. 2000-113913. Mixed electrodes other than titanium oxide may, for example, be those described in JP-A-2001-185243 and JP-A-2003-282164.

In order to improve the utilization rate of the incident light, etc., the light-receiving electrodes may be of a tandem type, and examples of a preferable tandem-type structure include those described in Japanese Patent Application Laid-Open No. 2002-90989 and the like.

A light management function that efficiently scatters and reflects light may also be provided inside the photoreceiving electrode layer, and a preferred example is one described in Japanese Patent Laid-Open No. 2002-93476.

Between the conductive support and the porous semiconductor fine particle layer, it is preferable to form a short-circuit preventing layer in order to prevent reverse current caused by direct contact between the electrolytic solution and the electrode. Preferable examples include those described in JP-A-06-507999 and the like.

In order to prevent the light-receiving electrode from being in contact with the counter electrode, it is preferable to use a spacer or a separator. Preferable examples include those described in Japanese Patent Application Laid-Open No. 2001-283941.

(E) Electrolyte

Representative redox couples such as the combination of iodine and iodide (e.g., lithium iodide, tetrabutylammonium iodide, tetrapropylammonium iodide, etc.), alkylviologen (e.g., formazan Base viologen chloride (methyl viologen chloride), hexyl viologen bromide (hexylviologen bromide), benzyl viologen tetrafluoroborate (benzyl viologen tetrafluoroborate)) and the combination thereof, polyhydroxybenzene (polyhydroxybenzene) (such as , hydroquinone (hydroquinone), naphthhydroquinone (naphthhydroquinone, etc.) and their oxides, divalent and trivalent iron complexes (for example, red prussiate and yellow prussiate )) combination etc. Among them, the combination of iodine and iodide is preferred. An organic solvent for dissolving the above-mentioned redox couple is preferably an aprotic polar solvent (for example, acetonitrile, propylene carbonate (propylenecarbonate), ethylene carbonate (ethylene carbonate), dimethylformamide (dimethylformamide), Dimethyl sulfoxide, sulfolane, 1,3-dimethyl imidazolinone, 3-methyloxazolidinone, etc.). Polymers used in the matrix of the gel electrolyte, such as polyacrylonitrile, polyvinylidene fluoride, and the like. The molten salt can be exemplified by mixing polyethylene oxide (polyethylene oxide) in lithium iodide and at least one other lithium salt (for example, lithium acetate (lithium acetate), lithium perchlorate (lithium perchlorate) etc.), A molten salt that imparts fluidity at room temperature. The addition amount of the polymer in the above case is 1% by mass to 50% by mass. In addition, γ-butyrolactone (γ-butyrolactone) may be contained in the electrolytic solution, thereby increasing the diffusion efficiency of iodide ions and improving the conversion efficiency.

Additives in the electrolyte, in addition to the above-mentioned 4-tert-butylpyridine, can add aminopyridine (aminopyridine)-based compounds, benzimidazole (benzimidazole)-based compounds, aminetriazole (aminotriazole)-based compounds and aminothiazole ( Aminothiazole) compounds, imidazole compounds, amino triazine compounds, urea derivatives, amide compounds, pyrimidine compounds, and nitrogen-free heterocycles.

In addition, in order to improve the efficiency, a method of controlling the water content of the electrolytic solution may also be adopted. A preferred method of controlling moisture includes a method of controlling concentration and a method of coexisting with a dehydrating agent. In order to reduce the toxicity of iodine, a clathrate compound of iodine and cyclodextrin (cyclodextrin) can be used, and conversely, the method of frequent replenishment of water can also be used. In addition, cyclic amididine may be used, and an oxidation inhibitor, a hydrolysis inhibitor, a decomposition inhibitor, and zinc iodide may be added.

In addition, molten salts can also be used as electrolytes. Preferred molten salts include ionic liquids containing imidazolium or triazolium type cations, oxazolium-based, pyridinium-based, guanidine systems and their combinations. These cations may be combined with specific anions, and additives may be added to the above-mentioned molten salts, and liquid crystalline substituents may also be included. In addition, molten salts of quaternary ammonium salts can also be used.

Examples of molten salts other than the above include ones that impart fluidity at room temperature by mixing polyethylene oxide with lithium iodide and at least one other lithium salt (for example, lithium acetate, lithium perchlorate, etc.). Those who wait.

In addition, it is also possible to gel the electrolyte by adding a gelling agent to the electrolyte solution including the electrolyte and the solvent, so that the electrolyte is pseudo-solidified. The gelling agent is, for example, an organic compound with a molecular weight of 1,000 or less, a Si-containing compound with a molecular weight of 500 to 5,000, an organic salt formed of a specific acidic compound and a basic compound, a sorbitol derivative, polyethylene base pyridine.

Alternatively, a method of encapsulating a matrix polymer, a cross-linked polymer compound or a monomer, a cross-linking agent, an electrolyte, and a solvent in the polymer may also be used. The matrix macromolecule is preferably a macromolecule having a nitrogen-containing heterocycle in the repeating unit of the main chain or side chain and a crosslinking agent to react with an electrophilic compound, a macromolecule having a triazine structure, a macromolecule having a ureide ( Polymer with ureide structure, polymer containing liquid crystal compound, polymer with ether linkage, polyvinylidene fluoride, methacrylate, acrylate, thermosetting resin, cross-linked polysilicon Oxygen, polyvinyl alcohol (polyvinyl alcohol, PVA), crystal cage compounds such as polycarbylene glycol and dextrin, oxygen-containing or sulfur-containing polymer systems, natural polymers, etc. Among the above, an alkali-swellable polymer, a polymer having a compound capable of forming a charge transfer complex of a cation site and iodine in one polymer, and the like may be added.

As the matrix polymer, a cross-linked polymer including a bifunctional or higher-functional isocyanate (isocyanate) as a part and reacting with a functional group such as a hydroxyl group, an amine group, or a carboxyl group can also be used. In addition, a cross-linked polymer obtained by combining a hydrosilyl group with a double bond compound, polysulfone acid or polycarboxylic acid, etc. can be used to react with a metal ion compound having a divalent or higher valence. cross-linking methods, etc.

Solvents that can be preferably used in combination with the above-mentioned quasi-solid electrolyte include specific phosphoric acid esters, mixed solvents containing ethylene carbonate, and specific dielectric constants ( Dielectric constant) solvent. In addition, it is also possible to hold a solid electrolyte membrane or hold a liquid electrolyte solution in pores, and the method is preferably a cloth-like solid such as a conductive polymer film, a fibrous solid, and a filter membrane.

In addition, solid charge transport layers such as p-type semiconductors or hole transport materials can also be used to replace the above liquid electrolytes and pseudo-solid electrolytes. The solid charge transport layer can also use organic hole transport materials. The hole transport layer preferably includes conductive polymers such as polythiophene, polyaniline, polypyrrole, and polysilane, spiro compounds whose two rings share a tetrahedral structure such as C and Si as central elements, and triaryl compounds. Aromatic amine derivatives such as triarylamine, triphenylene derivatives, nitrogen-containing heterocyclic derivatives, and liquid crystalline cyanide derivatives.

Since redox pairs can serve as electron carriers, a certain concentration is necessary, and the total concentration is preferably 0.01 mole/L or more, more preferably 0.1 mole/L, and more preferably 0.3 mole/L or more. The upper limit of the above-mentioned concentration is not particularly limited, and is usually about 5 mole/L.

[example]

Hereinafter, the present invention will be better described in detail based on examples, but the present invention is not limited thereto.

Pigment modulation

0.45 g of the following (SA-1) and 0.26 g of the following (SB-1) were mixed in a mixed solvent of 10 ml of 1-butanol and 10 ml of toluene, and stirred while heating at 100° C. for 4 hours. After that, the obtained crystals were filtered by suction filtration, and purified by silica gel column chromatography to prepare the above-mentioned pigment S-140.26g.

[chem 46]

[Experiment 1]

(Production of photoelectric conversion elements)

The photoelectric conversion element shown in FIG. 1 was produced in the following manner.

On a glass substrate, fluorine-doped tin oxide was formed as a transparent conductive film by sputtering, and then the transparent conductive film was divided into two parts by laser cutting. Anatase-type titanium oxide particles are sintered on one of the conductive films to make a light-receiving electrode. Next, a dispersion liquid containing silica particles and rutile-type titanium oxide at a ratio of 40:60 (mass ratio) was applied and fired on the photoreceiving electrode to form an insulating porous body. The coating amount of the semiconductor fine particles was 20 g/m ² , and then a carbon electrode was formed as a counter electrode.

Next, the dyes listed in Table 1 below were immersed in ethanol solutions (3×10 ^-4 mole/L each) for 48 hours. Then, the glass stained with the sensitizing dye was immersed in a 10% ethanol solution of 4-tert-butylpyridine for 30 minutes, washed with ethanol and allowed to dry naturally. The obtained photoreceptor had a thickness of 10 μm. The amount of the pigment is suitably selected from the range of 0.1 mmole/m ² to 10 mmole/m ² according to the type of the pigment.

As the electrolytic solution, a methoxypropionitrile (methoxypropionitrile) solution of dimethylpropylimidazolium iodide (0.5 mole/L) and iodine (0.1 mole/L) can be used.

(Measurement of Maximum Absorption Wavelength of Pigment)

Table 1 shows the results of measuring the maximum absorption wavelengths of the dyes used. The measurement of the maximum absorption wavelength can be performed using a spectrophotometer (U-4100 (trade name), manufactured by Hitachi High-Technology Co., Ltd.), and the solution can be adjusted to 2 μM using THF:ethanol=1:1.

(Measurement of Photoelectric Conversion Efficiency)

By making the light of a 500W xenon lamp (manufactured by Ushio) pass through an AM1.5G filter (manufactured by Oriel) and a sharp cutoff filter (Kenko L-42, trade name), different Simulated sunlight with UV rays. The above light intensity was 89 mW/cm ² . The above-mentioned light was irradiated on the produced photoelectric conversion element, and the photoelectric conversion characteristics were measured with a current-voltage measuring device (Keithley 238 type, trade name).

The measurement results of the initial value of the conversion efficiency of the photoelectrochemical cell are shown in Table 1 below as conversion efficiency. The conversion efficiency above 2.5% is indicated by ◎, the one above 1% and less than 2.5% is indicated by ○, the one above 0.3% and less than 1% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the decrease in the conversion efficiency after 500 hours was evaluated as durability. In the above results, 90% or more was rated as ◎, 60% or more and less than 90% was rated as ○, 40% or more and less than 60% was rated as △, and less than 40% was rated as ×. As for the initial value of the conversion efficiency, the conversion efficiency after 500 hours was 60% or more, and the case of less than 60% was unacceptable.

Table 1

Sample number pigment Pigment maximum absorption wavelength (nm) conversion efficiency Durability Remark 1-1 S-1 741 △ ○ this invention 1-2 S-2 739 ○ ○ this invention 1-3 S-3 735 ○ ○ this invention 1-4 S-4 727 ○ ○ this invention 1-5 S-5 727 ○ ○ this invention 1-6 S-6 746 ○ ○ this invention 1-7 S-7 782 ◎ ◎ this invention 1-8 S-8 769 ○ ○ this invention 1-9 S-9 752 ◎ ○ this invention 1-10 S-10 745 ○ ○ this invention 1-11 S-11 788 △ ○ this invention 1-12 S-12 786 ○ ○ this invention 1-13 S-13 765 ○ ○ this invention 1-14 S-14 772 ◎ ◎ this invention 1-15 S-15 772 ◎ ◎ this invention 1-16 S-16 773 ◎ ◎ this invention 1-17 S-17 761 ○ ○ this invention 1-18 S-18 791 ◎ ◎ this invention 1-19 T-2 790 ○ ◎ this invention 1-20 T-6 785 ◎ ◎ this invention 1-21 T-9 800 ◎ ◎ this invention 1-22 T-10 810 ◎ ◎ this invention 1-23 T-12 800 ◎ ◎ this invention 1-24 T-16 770 ◎ ◎ this invention 1-25 T-17 770 ◎ ◎ this invention 1-26 T-18 770 ◎ ◎ this invention 1-27 T-24 770 ◎ ◎ this invention 1-28 T-30 800 ◎ ◎ this invention 1-29 T-37 820 ◎ ◎ this invention 1-30 T-41 795 ○ ◎ this invention 1-31 T-42 810 ◎ ◎ this invention 1-32 T-43 810 ◎ ◎ this invention 1-33 A-1 731 ○× comparative example 1-34 A-2 770 ○× comparative example

In Experiments 1 to 10, the following A-1 and A-1 were used as comparative dyes.

[chem 47]

As can be seen from Table 1, using the photoelectrochemical cell of the pigment of the present invention, the initial value of the conversion efficiency is a qualified standard, and the conversion efficiency after 500 hours is more than 60% of the initial value, and shows excellent durability.

Regarding the above, in the case of using a comparative dye, the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

[Experiment 2]

A transparent conductive film is produced by forming an ITO film on a glass substrate and then laminating an FTO film on top of it. Thereafter, a transparent electrode plate is obtained by forming a porous oxide semiconductor film on the transparent conductive film. Next, a photoelectrochemical cell was produced using this transparent electrode plate, and the conversion efficiency was measured. The above-mentioned method is as follows (1)-(5).

(1) Preparation of raw material compound solution for ITO (indium tin oxide) film

Dissolve 5.58 g of indium (III) chloride tetrahydrate and 0.23 g of tin (II) chloride dihydrate in 100 ml of ethanol to form an ITO membrane With starting compound solution.

(2) Preparation of raw material compound solution for FTO (fluorine-doped tin oxide) film

Dissolve 0.701 g of tin (IV) chloride pentahydrate in 10 ml of ethanol, then add a saturated aqueous solution of 0.592 g of ammonium fluoride, then put the above mixture into an ultrasonic cleaner for about 20 minutes until it is completely dissolved, as Feedstock compound solutions for FTO membranes.

(3) Fabrication of ITO/FTO transparent conductive film

After the surface of the heat-resistant glass plate with a thickness of 2 mm was chemically cleaned and dried, the glass plate was placed in a reactor and heated with a heater. When the heating temperature of the heater becomes 450°C, the raw material compound solution for the ITO film obtained in (1) is passed through a nozzle with a diameter of 0.3 mm under a pressure of 0.06 MPa, and the distance to the glass plate is set at 400 mm for 25 minutes. spray.

After the above-mentioned spraying of the raw material compound solution for the ITO film, 2 minutes passed (during this period, ethanol was continuously sprayed on the surface of the glass substrate to suppress the rise of the surface temperature of the substrate), and when the heating temperature of the heater became 530° C., the The solution of the raw material compound for the FTO membrane obtained in (2) was sprayed for 2 minutes and 30 seconds under the same conditions. As described above, a transparent electrode plate in which an ITO film with a thickness of 530 nm and an FTO film with a thickness of 170 nm were sequentially formed on a heat-resistant glass plate was obtained.

For comparison, a transparent electrode plate with only an ITO film with a thickness of 530 nm and a transparent electrode plate with an FTO film with a thickness of 180 nm were produced in the same manner on a heat-resistant glass plate with a thickness of 2 mm.

The above three kinds of transparent electrode plates were heated at 450° C. for 2 hours in a heating furnace.

(4) Fabrication of photoelectrochemical cells

Next, a photoelectrochemical cell having the structure shown in FIG. 2 of Japanese Patent No. 4260494 was fabricated using the above-mentioned three types of transparent electrode plates. The oxide semiconductor porous film is formed by dispersing titanium oxide microparticles with an average particle diameter of about 230 nm in acetonitrile to form a paste, and then applying the paste to the transparent electrode 11 by using a bar coating method. It was coated on top to have a thickness of 15 μm, dried, and then calcined at 450° C. for 1 hour. Next, the dyes listed in Table 2 were supported on the oxide semiconductor porous membrane.

Furthermore, a conductive substrate in which an ITO film and an FTO film were laminated on a glass plate was used as the counter electrode, and a non-aqueous electrolyte solution containing iodine/iodide was used as the electrolyte layer. The planar size of the photoelectrochemical cell is 25mm×25mm.

(5) Evaluation of photoelectrochemical cells

The photoelectrochemical cell obtained in (4) was irradiated with similar sunlight (AM1.5), and the photoelectric conversion characteristics were measured by the same method as in Experiment 1 to obtain the conversion efficiency. The results are shown in Table 2. Regarding the conversion efficiency, it is expressed as a relative value when the sample numbers 2-9 are regarded as 1. Regarding the durability, compared to the initial value of the conversion efficiency, the conversion efficiency after 500 hours is ◎ for 90% or more, ○ for 60% or more and less than 90%, △ for 40% or more and less than 60%, Those with less than 40% were rated as x, those with a conversion efficiency of 60% or more after 500 hours were acceptable, and those with a conversion efficiency of less than 60% were unacceptable.

Table 2

Sample number Conductive film pigment conversion efficiency Durability Remark 2-1 ITO only S-2 055 ○ this invention 2-2 FTO only S-2 059 ○ this invention 2-3 ITO+FTO S-2 089 ○ this invention 2-4 ITO only S-8 061 ○ this invention 2-5 FTO only S-8 063 ○ this invention 2-6 ITO+FTO S-8 091 ○ this invention 2-7 ITO only S-13 065 ○ this invention 2-8 FTO only S-13 076 ○ this invention 2-9 ITO+FTO S-13 100 ○ this invention 2-10 ITO only T-16 099 ◎ this invention 2-11 FTO only T-16 097 ◎ this invention 2-12 ITO+FTO T-16 110 ◎ this invention 2-13 ITO only T-24 097 ◎ this invention 2-14 FTO only T-24 093 ◎ this invention 2-15 ITO+FTO T-24 107 ◎ this invention 2-16 ITO only T-12 100 ◎ this invention 2-17 FTO only T-12 105 ◎ this invention 2-18 ITO+FTO T-12 130 ◎ this invention 2-19 ITO only A-2 062× comparative example 2-20 FTO only A-2 068× comparative example 2-21 ITO+FTO A-2 082× comparative example

As can be seen from Table 2, when the conductive layer is only the situation of the ITO film or only the situation of the FTO film, even if it is the photoelectrochemical cell of the present invention, its conversion efficiency will also become low, and the conductive layer is formed on the ITO film. In the case of a membrane, the conversion efficiency tends to be high. The above-mentioned tendency also existed in the case of the photoelectrochemical cell of the comparative example.

Nevertheless, the conversion efficiency of the photoelectrochemical cell of the present invention is more than 60% after 500 hours, and shows excellent durability, compared to the conversion efficiency of the photoelectrochemical cell of this comparative example after 500 hours is less than 40%. %, and learned to have durability issues.

[Experiment 3]

Collecting electrodes were arranged on the FTO film to make a photoelectrochemical cell, and the conversion efficiency was evaluated. Two types of test battery (i) and test battery (iv) were produced as follows for evaluation.

(Test battery (i))

After the surface of the heat-resistant glass plate of 100mm×100mm×2mm is chemically cleaned and dried, the glass plate is placed in the reactor, and after heating with a heater, the FTO (fluorine-doped Tin oxide, fluorine-doped tin oxide) film raw material compound solution, sprayed for 25 minutes from a nozzle with a diameter of 0.3mm, at a pressure of 0.06MPa, at a distance of 400mm from the glass plate, to prepare a glass substrate with an FTO film.

On the surface of the above-mentioned substrate, trenches with a depth of 5 μm were formed on the grid-like circuit pattern by an etching method. Then, after forming a pattern by photolithography (photolithographic), etching is performed using hydrofluoric acid. In order to form metal plating, a metal conductive layer (seed layer) is formed on it by sputtering, and a metal wiring layer can be formed by additional plating. The metal wiring layer is formed in a convex lens shape to a height of 3 μm from the surface of the transparent substrate. The circuit width is 60 μm. A 400-nm-thick FTO film serving as a shielding layer 5 was formed thereon by the SPD method as an electrode substrate (i). The cross-sectional shape of the electrode substrate (i) becomes as shown in FIG. 2 in Japanese Patent Laid-Open No. 2004-146425.

On the electrode substrate (i), a titanium oxide dispersion liquid having an average particle diameter of 25 nm was applied and dried, followed by heating and sintering at 450° C. for 1 hour. Then, the dyes were dipped in ethanol solutions of the dyes shown in Table 3 for 40 minutes to carry the dyes. In addition, the solubility of the pigment used in the present invention to various organic solvents is to be studied. From the above results, it was found that it could be dissolved in toluene, so as described in Table 3, an article soaked in the toluene solution for 40 minutes and loaded was also prepared.

A platinum sputtered FTO substrate was arranged to face the above-mentioned substrate through a thermoplastic polyolefin resin sheet (polyolefin resin sheet) with a thickness of 50 μm, and the resin sheet was thermally melted to fix the bipolar plates.

However, from the injection port of the electrolyte solution opened in advance on the platinum sputtering electrode side, inject liquid into methoxy acetonitrile (methoxy acetonitrile) containing 0.5M iodide salt and 0.05M iodine in the main components, and fill between the electrodes. Furthermore, the peripheral portion and the electrolyte solution injection port were sealed with an epoxy-based sealing resin, and silver paint was applied to the collector terminal portion to obtain a test battery (i). Next, in the same manner as in Experiment 1, the test cell (i) was irradiated with similar sunlight of AM 1.5 to measure the conversion efficiency, and the results are shown in Table 3.

(test battery (iv))

In the same manner as the test cell (i), a 100 mm×100 mm glass substrate on which the FTO film was arranged was prepared. On the above-mentioned FTO glass substrate, a metal wiring layer (gold circuit) was formed by an overplating method. The above-mentioned metal wiring layer (gold circuit) was formed in a lattice shape on the surface of the substrate, and the circuit width was 50 μm, and the circuit thickness was 5 μm. Then, on the surface thereof, an FTO film with a thickness of 300 nm was formed as a masking layer by the SPD method to serve as an electrode substrate (iv). When the cross-section of the electrode substrate (iv) was checked using SEM-EDX, it was found that the bottom of the wiring may have infiltrated the skirt-like bottom that may be caused by the plating resist, and the shaded part was not covered with FTO.

Using the electrode substrate (iv), the test battery (iv) was produced in the same manner as the test battery (i). Using the same method as Experiment 1, irradiate AM1.5 similar sunlight on the test cell (iv) to measure the conversion efficiency. The results of the initial values of the above-mentioned conversion efficiencies are shown in Table 3 as conversion efficiencies.

The conversion efficiency above 2.5% is indicated by ◎, the one above 1% and less than 2.5% is indicated by ○, the one above 0.3% and less than 1% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were evaluated as ×, which is shown in Table 3 as durability. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

table 3

Sample number test battery pigment Solvent for pigment solution conversion efficiency Durability Remark 3-1 (i) S-3 ethanol ○ ○ this invention 3-2 (iv) S-3 ethanol ○ ○ this invention 3-3 (i) S-3 toluene ◎ ○ this invention 3-4 (iv) S-3 Toluene ◎ ○ this invention 3-5 (i) S-9 ethanol ◎ ◎ this invention 3-6 (iv) S-9 ethanol ○ ◎ this invention 3-7 (i) S-9 Toluene ◎ ◎ this invention 3-8 (iv) S-9 Toluene ◎ ◎ this invention 3-9 (i) T-17 ethanol ○ ○ this invention 3-10 (iv) T-17 ethanol ○ ○ this invention 3-11 (i) T-17 Toluene ◎ ◎ this invention 3-12 (iv) T-17 toluene ◎ ◎ this invention 3-13 (i) T-18 ethanol ○ ○ this invention 3-14 (iv) T-18 ethanol ○ ○ this invention 3-15 (i) T-18 toluene ◎ ○ this invention 3-16 (iv) T-18 Toluene ◎ ◎ this invention 3-17 (i) A-1 ethanol ○× comparative example 3-18 (iv) A-1 ethanol ◎× comparative example 3-19 (i) A-2 ethanol ○ △ comparative example 3-20 (iv) A-2 ethanol ○ △ comparative example

According to Table 3, the conversion efficiency of the test cell using the dye of the present invention is 1% or more, which shows a high value. In addition, it was found that the conversion efficiency can be improved by appropriately selecting the solvent used in the dye solution (comparison of samples 3-1 and 3-2 with samples 3-3 and 3-4). In the case of using a comparative pigment, the initial value of the conversion efficiency may be as high as that of the present invention, but the conversion efficiency after 500 hours is greatly reduced. Compared to this, the reduction in durability of the pigment of the present invention is significantly lower. less, and exhibits excellent properties.

[Experiment 4]

Peroxotitanic acid and titanium oxide fine particles are prepared and used to form an oxide semiconductor film. Then, using this oxide semiconductor film, a photoelectrochemical cell was fabricated and evaluated.

(Production of photoelectrochemical cell (A))

(1) Preparation of coating liquid (A1) for oxide semiconductor film formation

After suspending 5 g of titanium hydride in 1 L of pure water, 400 g of a 5% by mass (%) hydrogen peroxide solution was added over 30 minutes, followed by heating to 80° C. and dissolving to prepare a peroxotitanic acid solution. Take out 90% by volume (vol%) from the full amount of the above solution, then add concentrated ammonia water to adjust the pH value to 9, put it in an autoclave, and perform hydrothermal treatment at 250°C for 5 hours under saturated steam pressure to prepare oxidation Titanium colloidal particles (A2). The obtained titanium oxide colloidal particles were anatase-type titanium oxide with high crystallinity as a result of X-ray diffraction.

Next, the titanium oxide colloidal particles (A2) obtained above were concentrated to 10% by mass, and the above-mentioned peroxotitanic acid solution was mixed, and the titanium in the above-mentioned mixed solution was converted into TiO ₂ so that 30% by mass of the mass of TiO ₂ %, hydroxypropyl cellulose (hydroxypropyl cellulose) was added as a film-forming auxiliary agent to prepare a semiconductor film-forming coating solution (A1).

(2) Formation of oxide semiconductor film (A3)

Next, on the transparent glass substrate formed by fluorine-doped tin oxide as an electrode layer, apply the above-mentioned coating solution (A1) and dry it naturally, and then use a low-pressure mercury lamp to irradiate 6000mJ/cm ² of ultraviolet rays to make the peroxyacid (peroxo acid) decomposes and hardens the coating film. The coating film was heated at 300° C. for 30 minutes to decompose and anneal the hydroxypropyl cellulose to form an oxide semiconductor film (A3) on the glass substrate.

(3) Adsorption of dye to the oxide semiconductor film (A3)

Next, an ethanol solution having a concentration of 3×10 ^-4 mole/L of the dye of the present invention as a spectrosensitizing dye was prepared. The dye solution was applied on the metal oxide semiconductor film (A3) while rotating at 100 rpm, and dried. Then, the above-mentioned coating and drying processes were performed 5 times.

(4) Preparation of electrolyte solution

In a mixed solvent of acetonitrile and ethyl carbonate at a volume ratio of 1:5, 0.46 mole/L of tetrapropylammonium iodide was dissolved so that the concentration of iodine in it was 0.07 mole/L to prepare an electrolyte solution.

(5) Fabrication of photoelectrochemical cell (A)

The glass substrate formed by the dye-adsorbed oxide semiconductor film (A3) prepared in (2) was used as one electrode, and fluorine-doped tin oxide was formed as an electrode as the other electrode. Next, on the electrodes, a transparent glass substrate carrying platinum was placed facing each other, the sides were sealed with resin, and the electrolytic solution of (4) was sealed between the electrodes. Then, wires were connected between the electrodes to fabricate a photoelectrochemical cell (A).

(Production of photoelectrochemical cell (B))

In addition to irradiating ultraviolet rays to decompose peroxyacid to harden the film, and then performing argon (Ar) ion irradiation (manufactured by Nisshin Electric Co., Ltd.: ion implantation equipment, irradiating at 200eV for 10 hours), the oxide semiconductor film (A3) In the same manner, an oxide semiconductor film (B3) is formed.

Like the oxide semiconductor film (A3), the dye is adsorbed on the oxide semiconductor film (B3). Then, a photoelectrochemical cell (B) was produced in the same manner as the photoelectrochemical cell (A).

(Production of photoelectrochemical cell (C))

18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO ₂ . While stirring the above-mentioned aqueous solution, 15% by mass of ammonia water was added to obtain a white slurry with pH 9.5. The slurry was filtered and washed to obtain a cake of 10.2% by mass of water and titanium oxide gel in terms of TiO ₂ . Then, the above-mentioned filter cake and 400 g of a 5% by mass hydrogen peroxide solution were mixed, followed by heating and dissolving at 80° C. to prepare a solution of peroxytitanic acid. 90 vol% of the above solution was taken out, then concentrated ammonia water was added to adjust the pH to 9, and it was placed in an autoclave, and hydrothermal treatment was carried out at 250° C. under saturated vapor pressure for 5 hours to prepare titanium oxide colloidal particles (C2).

Next, using the peroxotitanic acid solution and titanium oxide colloidal particles (C2) obtained above, the oxide semiconductor film (C3) was formed in the same manner as the oxide semiconductor film (A3), and then the oxide semiconductor film (A3) was formed. ) In the same manner, adsorption of the dye of the present invention as a spectrally sensitizing dye is carried out. Then, a photoelectrochemical cell (C) was fabricated in the same manner as the photoelectrochemical cell (A).

(Production of photoelectrochemical cell (D))

18.3 g of titanium tetrachloride was diluted with pure water to obtain an aqueous solution containing 1.0% by mass in terms of TiO ₂ . While stirring the above-mentioned aqueous solution, 15% by mass of ammonia water was added to obtain a white slurry with a pH of 9.5. After filtering and cleaning the above slurry, suspend it in pure water to make a slurry of water and titanium oxide gel with TiO ₂ of 0.6% by mass, add hydrochloric acid to pH 2, put it in an autoclave, and heat it under saturated steam at 180°C. Hydrothermal treatment was carried out under pressure for 5 hours to prepare titanium oxide colloidal particles (D2).

Next, the titanium oxide colloidal particles (D2) were concentrated to 10% by mass, and hydroxypropyl cellulose was added thereto as a film formation auxiliary agent so as to be 30% by mass in terms of TiO ₂ , to prepare a coating liquid for forming a semiconductor film. Next, on a transparent glass substrate formed of fluorine-doped tin oxide as an electrode layer, the above-mentioned coating liquid was applied and dried naturally, and then irradiated with 6000 mJ/cm ² of ultraviolet rays using a low-pressure mercury lamp to harden the coating film. Subsequently, the coating film was heated at 300° C. for 30 minutes to decompose and anneal the hydroxypropyl cellulose, thereby forming an oxide semiconductor film ( D3 ).

Next, in the same manner as the oxide semiconductor film (A3), adsorption of the dye of the present invention as a spectral sensitizing dye is carried out. Then, a photoelectrochemical cell (D) was produced in the same manner as the photoelectrochemical cell (A).

The photoelectrochemical cells (A) to (D) were irradiated with similar sunlight (AM1.5), and the photoelectric conversion efficiency was measured by the same method as in Experiment 1 to obtain the conversion efficiency. Table 4 shows the results of the initial values of the above-mentioned conversion ratios as conversion efficiencies. The conversion efficiency above 2.5% is indicated by ◎, the one above 1% and less than 2.5% is indicated by ○, the one above 0.3% and less than 1% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were evaluated as ×, and the above-mentioned values are shown in Table 4 as durability. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

Table 4

Sample number photoelectrochemical cell pigment conversion efficiency Durability Remark 4-1 (A) S-12 ○ ○ this invention 4-2 (B) S-12 ○ ○ this invention 4-3 (C) S-12 ○ ○ this invention 4-4 (D) S-12 △ ○ this invention 4-5 (A) S-14 ◎ ◎ this invention 4-6 (B) S-14 ◎ ◎ this invention 4-7 (C) S-14 ◎ ◎ this invention 4-8 (D) S-14 ○ ◎ this invention 4-9 (A) T-2 ○ ◎ this invention 4-10 (B) T-2 ○ ◎ this invention 4-11 (C) T-2 ○ ◎ this invention 4-12 (D) T-2 △ ◎ this invention 4-13 (A) T-9 ◎ ◎ this invention 4-14 (B) T-9 ◎ ◎ this invention

4-15 (C) T-9 ◎ ◎ this invention 4-16 (D) T-9 ○ ◎ this invention 4-17 (A) A-1 ○× comparative example 4-18 (B) A-1 ○× comparative example 4-19 (C) A-1 ○× comparative example 4-20 (D) A-1 ○× comparative example 4-21 (A) A-2 ◎ △ comparative example 4-22 (B) A-2 ◎ △ comparative example 4-23 (C) A-2 ◎ △ comparative example 4-24 (D) A-2 ○ △ comparative example

As can be seen from Table 4, using the photoelectrochemical cell of the dye of the present invention, the initial value of the conversion efficiency is a qualified standard, and the conversion efficiency after 500 hours is more than 60% of the initial value, and shows excellent durability.

In contrast to the above, it is known that when a comparative dye is used, the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

[Experiment 5]

Titanium oxide was prepared by changing the method, and an oxide semiconductor film and a photoelectrochemical cell were produced from the obtained titanium oxide, and their evaluation was performed.

(1) Prepare titanium oxide by heat treatment

(Titanium oxide 1 (brookite type), etc.)

Using commercially available anatase-type titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., trade name ST-01), it was heated to about 900° C. to convert it into brookite-type titanium oxide, and then heated to about 1,200° C. to produce Titanium oxide of the rutile type. Then, they were sequentially designated as comparative titanium oxide 1 (anatase type), titanium oxide 1 (brookite type), and comparative titanium oxide 1 (rutile type).

(2) Synthesis of titanium oxide by wet method

(Titanium oxide 2 (brookite type), etc.)

954 ml of distilled water was put into the reaction tank equipped with the reflux cooler, and it heated to 95 degreeC. While maintaining a stirring speed of 200 rpm, 46 ml of an aqueous solution of titanium tetrachloride (titanium content: 16.3%, specific gravity 1.59, purity 99.9%) was dropped into distilled water in the reaction tank at a rate of about 5.0 ml/min. At this time, care should be taken not to lower the temperature of the reaction solution. From the above results, the concentration of titanium tetrachloride was 0.25 mole/L (2% by mass in terms of titanium oxide). In the reaction tank, the reaction solution started to become cloudy immediately after the instillation, and kept at the same temperature. After the instillation was completed, the temperature was raised to about boiling point (104°C), and the reaction was kept in the above state for 60 minutes to complete the reaction.

The sol obtained by the reaction was filtered, and then powdered using a vacuum dryer at 60°C. As a result of quantitative analysis of the powder by X-ray diffraction method, the ratio of (peak intensity of brookite type 121 plane)/(peak intensity at three overlapping positions) is 0.38, (main peak intensity of rutile type )/(peak intensity at three overlapping positions) ratio is 0.05. The titanium oxide obtained from the above has a crystallinity of about 70.0% by mass of the brookite type, about 1.2% by mass of the rutile type, and about 28.8% by mass of the anatase type. In addition, when the above-mentioned fine particles were observed with a transmission electron microscope, the average particle diameter of the primary particles was 0.015 μm.

(Titanium oxide 3 (brookite type), etc.)

Titanium trichloride aqueous solution (titanium content: 28%, specific gravity: 1.5, purity: 99.9%) was diluted with distilled water to prepare a solution of 0.25 mol/L in terms of titanium concentration. At this time, ice cooling was performed so that the liquid temperature would not rise, and it was kept at 50° C. or lower. Then, take 500ml of the above solution and put it into a reaction tank equipped with a reflux cooler, and while heating to 85°C, an ozone gas generator with a purity of 80% is bubbling (bubbling) at 1L/min to oxidize reaction. The above state was maintained for 2 hours to complete the reaction. The obtained sol was filtered and vacuum-dried to make a powder. As a result of quantitative analysis of the above powder by X-ray diffraction method, the ratio of (peak intensity of brookite-type 121 plane)/(peak intensity at three overlapping positions) is 0.85, (main peak of rutile type Intensity)/(peak intensity at three overlapping positions) ratio is 0. The titanium dioxide obtained from the above was about 98% by mass of the brookite type, about 0% by mass of the rutile type, about 0% by mass of the anatase type, and about 2% was amorphous. In addition, when the above-mentioned fine particles were observed with a transmission electron microscope, the average particle diameter of the primary particles was 0.05 μm.

(Production and evaluation of photoelectrochemical cells)

Titanium oxides 1 to 3 prepared by the above method were used as semiconductors, and a photoelectrochemical cell using a photoelectric conversion element having the structure shown in FIG. 1 described in JP 2000-340269 A was produced by the following method.

Fluorine-doped tin oxide is coated on a glass substrate as a conductive transparent electrode. On the electrode surface, individual titanium oxide particles were used as a raw material to make a coating, and after coating with a thickness of 50 μm by bar coating method, it was calcined at 500° C. to form a thin layer with a film thickness of about 20 μm.

As discussed in Experiment 1, it was found that the pigment used in the present invention has high solubility in various organic solvents, so ethanol was used as a solvent, and those whose concentration of the pigment solution was changed were evaluated. The pigment used in the present invention is 2 standard pigment solutions of 3×10 ^-4 M and 6×10 ^-4 M. Comparative pigments have low solubility in solvents and cannot prepare 6×10 ^-4 M solutions, so only 3×10 ^-4 M pigment solutions were used for evaluation.

An ethanol solution having the concentration of the dye shown in Table 5 was prepared, and the glass substrate on which the above-mentioned thin layer of titanium oxide was formed was immersed in the solution and kept at room temperature for 12 hours. As a result, the above-mentioned dye was adsorbed on the thin layer of titanium oxide.

Tetrapropylammonium iodide and lithium iodide in acetonitrile were used as the electrolyte and platinum as the counter electrode to fabricate a photoelectric conversion element having the structure shown in FIG. 1 of Japanese Patent Application Laid-Open No. 2000-340269. For photoelectric conversion, the above-mentioned element was irradiated with light from a 160W high-pressure mercury lamp (infrared rays were cut with a filter), and the initial value of conversion efficiency was measured in the same manner as in Experiment 1. The above results are shown in Table 5 as conversion efficiencies.

The conversion efficiency above 2.5% is indicated by ◎, the one above 1% and less than 2.5% is indicated by ○, the one above 0.3% and less than 1% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were evaluated as ×, and the above results are shown in Table 5 as durability. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

table 5

As can be seen from Table 5, when the dye of the present invention is used, the initial value of the conversion efficiency becomes higher by increasing the concentration of the dye solution. This is considered to be because by increasing the concentration of the dye solution, the adsorption of the dye to titanium oxide also increases. When a comparison dye is used, the initial value of the conversion efficiency is also a pass standard.

However, in terms of durability, when the comparative dyes were used, all were unacceptable, while the case of using the dyes of the present invention showed excellent characteristics.

[Experiment 6]

Titanium oxide with different particle sizes was used to prepare coatings in which semiconductor microparticles were dispersed, and then used to fabricate photoelectrochemical cells and evaluate their characteristics.

[Preparation of paint]

(Paint 1)

Spherical TiO ₂ particles (anatase type, average particle diameter: 25 nm, hereinafter referred to as spherical TiO ₂ particles 1) were put into a nitric acid solution, and stirred to prepare a titanium oxide slurry. Next, a cellulose-based binder is added to the titanium oxide slurry as a thickener, and kneaded to prepare a paint.

(Paint 2)

Spherical TiO ₂ particles 1 and spherical TiO ₂ particles (anatase type, average particle diameter: 200nm, hereinafter referred to as spherical TiO ₂ particles 2) were put into a nitric acid solution and stirred to prepare a titanium oxide slurry. Next, a cellulose-based binder was added to the titanium oxide slurry as a thickener, and kneaded to prepare a paint (mass of TiO ₂ particle 1:mass of TiO ₂ particle 2=30:70).

(Paint 3)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 100 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 1) were mixed to adjust the mass of rod-shaped TiO ₂ particles 1: Mass = 10:90 paint.

(Paint 4)

In paint 1, rod-shaped TiO ₂ particles 1 were mixed to prepare a paint in which the mass of rod-shaped TiO ₂ particles 1:mass of paint 1=30:70.

(Paint 5)

In paint 1, rod-shaped TiO ₂ particles 1 were mixed to prepare a paint in which the mass of rod-shaped TiO ₂ particles 1:mass of paint 1=50:50.

(Paint 6)

In paint 1, plate-shaped mica particles (straight particle diameter: 100 nm, aspect ratio: 6, hereinafter referred to as plate-shaped mica particles 1) were mixed to adjust the mass of plate-shaped mica particles 1: Mass of paint 1 = 20 : 80 paint.

(Paint 7)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 30nm, aspect ratio: 6.3, hereinafter referred to as rod-shaped TiO ₂ particles 2) were mixed to adjust the mass of rod-shaped TiO ₂ particles 2: Mass = 30:70 paint.

(Paint 8)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 50nm, aspect ratio: 6.1, hereinafter referred to as rod-shaped TiO ₂ particles 3) were mixed to adjust the mass of rod-shaped TiO ₂ particles 3: Mass = 30:70 paint.

(Paint 9)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 75nm, aspect ratio: 5.8, hereinafter referred to as rod-shaped TiO ₂ particles 4) were mixed to adjust the mass of rod-shaped TiO ₂ particles 4: Mass = 30:70 paint.

(paint 10)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 130nm, aspect ratio: 5.2, hereinafter referred to as rod-shaped TiO ₂ particles 5) were mixed to adjust the mass of rod-shaped TiO ₂ particles 5: Mass = 30:70 paint.

(paint 11)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 180 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 6) were mixed to adjust the mass of rod-shaped TiO ₂ particles 6: Mass = 30:70 paint.

(Paint 12)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 240 nm, aspect ratio: 5, hereinafter referred to as rod-shaped TiO ₂ particles 7) were mixed to adjust the mass of rod-shaped TiO ₂ particles 7: of paint 1 Mass = 30:70 paint.

(paint 13)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 110 nm, aspect ratio: 4.1, hereinafter referred to as rod-shaped TiO ₂ particles 8) were mixed to adjust the mass of rod-shaped TiO ₂ particles 8: Mass = 30:70 paint.

(paint 14)

In paint 1, rod-shaped TiO ₂ particles (anatase type, diameter: 105 nm, aspect ratio: 3.4, hereinafter referred to as rod-shaped TiO ₂ particles 9) were mixed to adjust the mass of rod-shaped TiO ₂ particles 9: Mass = 30:70 paint.

(Photoelectrochemical Cell 1)

According to the procedure shown below, a photoelectrode having the same structure as the photoelectrode 12 described in FIG. 5 of Japanese Patent Application Laid-Open No. 2002-289274 is produced, and then the photoelectrode is used to fabricate a photoelectrode having a dye sensitization function other than this photoelectrode. The solar cell 20 is a photoelectrochemical cell 1 of the same structure with a size of 10×10 mm.

Prepare a transparent electrode in which a fluorine-doped SnO ₂ conductive film (film thickness: 500 nm) is formed on a glass substrate.

On the SnO ₂ conductive film, the above-mentioned paint was screen printed and then dried. Thereafter, calcination is performed in air at 450°C. Next, using the coating material 4, by repeating screen printing and firing, a semiconductor electrode having the same structure as the semiconductor electrode 2 shown in _FIG . ×10mm, layer thickness: 10μm, layer thickness of the semiconductor layer: 6μm, layer thickness of the light scattering layer: 4μm, content rate of rod-shaped _TiO2 particles in the light scattering layer: 30% by mass), and made without sensitization Pigmented photoelectrodes.

Next, the dye is adsorbed to the semiconductor electrode as follows. First, absolute ethanol dehydrated from magnesium ethoxide was used as a solvent, and the dyes described in Table 6 were dissolved therein so that the individual concentrations thereof became 3×10 ^-4 mol/L to prepare a dye solution. Then, the semiconductor electrode was immersed in the above-mentioned solution, thereby adsorbing about 1.5×10 ⁻⁷ mol/cm ² of the total amount of the dye on the semiconductor electrode, and the photoelectrode 10 was produced.

Next, an iodine-based redox solution containing iodine and lithium iodide was prepared as an electrolyte with a platinum electrode (Pt thin film thickness: 100 nm) having the same shape and size as the photoelectrode described above as a counter electrode. Then, prepare a spacer S (trade name: "Surlyn") manufactured by DuPont (DUPONT) Co., Ltd. with a shape corresponding to the size of the semiconductor electrode, and pass the spacer through the spacer as shown in FIG. S arranges the photoelectrode 10 and the counter electrode CE to face each other, and fills the inside with the above-mentioned electrolyte to complete the photoelectrochemical cell 1 .

(Photoelectrochemical Cell 2)

Except that the manufacture of the semiconductor electrode is carried out as follows, according to the same procedure as the photoelectrochemical cell 1, the photoelectrode 10 shown in Fig. 1 as described in the Japanese Patent Laid-Open No. A photoelectrochemical cell 2 having the same structure as the dye-sensitized solar cell 20 shown in FIG. 3 described in Publication No. 289274.

Paint 2 was used as a paint for forming a semiconductor layer. Then, the above-mentioned paint 2 was screen printed on the SnO ₂ conductive film, followed by drying. Thereafter, calcination is performed in air at 450° C. to form a semiconductor layer.

Paint 3 was used as the innermost layer-forming paint of the light-scattering layer, and Paint 5 was used as the outermost layer-forming paint of the light-scattering layer. Then, in the same manner as in the photoelectrochemical cell 1, a light scattering layer was formed on the semiconductor layer.

Next, on the _SnO2 conductive film, form a semiconductor electrode having the same structure as the semiconductor electrode 2 shown in FIG. , layer thickness of the semiconductor layer: 3 μm, layer thickness of the innermost layer: 4 μm, content rate of rod-shaped TiO ₂ particles 1 contained in the innermost layer: 10 mass %, layer thickness of the outermost layer: 3 μm, the outermost layer The content of rod-shaped TiO ₂ particles 1 contained in the inner layer: 50% by mass), and then a photoelectrode not containing a sensitizing dye was produced. Thereafter, similarly to the photoelectrochemical cell 1 , the photoelectrode and the counter electrode CE are arranged to face each other through the spacer S, and the above-mentioned electrolyte is filled inside to complete the photoelectrochemical cell 2 .

(Photoelectrochemical Cell 3)

In the manufacture of the semiconductor electrode, except that the coating material 1 is used as the coating material for forming the semiconductor layer, and the coating material 4 is used as the coating material for forming the light scattering layer, according to the same procedure as the photoelectrochemical cell 1, a method such as Japanese Patent Application Laid-Open 2002 is produced. - Photoelectrode 10 shown in FIG. 5 described in Japanese Patent Application Laid-Open No. 289274, and photoelectrochemical cell 3 having the same structure as photoelectrochemical cell 20 shown in FIG. 3 described in Japanese Patent Application Laid-Open No. 2002-289274.

Among them, the semiconductor electrode has an area of the light-receiving surface: 10 mm × 10 mm, a layer thickness: 10 μm, a layer thickness of the semiconductor layer: 5 μm, a layer thickness of the light scattering layer: 5 μm, and the content of the rod-shaped _TiO2 particles 1 contained in the light scattering layer. Rate: 30% by mass.

(photoelectrochemical cell 4)

During the manufacture of the semiconductor electrode, except that the coating 2 is used as the coating for forming the semiconductor layer, and the coating 6 is used as the coating for the formation of the light scattering layer, according to the same procedure as that of the photoelectrochemical cell 1, the electrode shown in Figure 5 is produced. A photoelectrode 10, and a photoelectrochemical cell 4 having the same structure as the photoelectrochemical cell 20 shown in FIG. 3 described in Japanese Patent Laid-Open No. 2002-289274. Among them, the semiconductor electrode has an area of the light receiving surface: 10mm×10mm, a layer thickness: 10μm, a layer thickness of the semiconductor layer: 6.5μm, a layer thickness of the light scattering layer: 3.5μm, and plate-shaped mica particles contained in the light scattering layer. The content rate of 1: 20% by mass.

(Photoelectrochemical Cell 5)

In the manufacture of the semiconductor electrode, the photoelectrochemical cell 5 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the coating material for forming the semiconductor layer and the coating material 8 was used as the coating material for forming the light scattering layer. Among them, the content rate of the rod-shaped TiO ₂ particles 3 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(Photoelectrochemical Cell 6)

In the manufacture of the semiconductor electrode, except that the coating material 2 was used as the coating material for forming the semiconductor layer and the coating material 9 was used as the coating material for forming the light scattering layer, the photoelectrochemical cell 6 was produced according to the same procedure as the photoelectrochemical cell 1. Among them, the content rate of the rod-shaped TiO ₂ particles 4 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(Photoelectrochemical Cell 7)

The photoelectrochemical cell 7 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the semiconductor layer-forming coating material and the coating material 10 was used as the light-scattering layer-forming coating material during the manufacture of the semiconductor electrode. Among them, the content rate of the rod-shaped TiO ₂ particles 5 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(photoelectrochemical cell8)

The photoelectrochemical cell 8 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the semiconductor layer-forming coating material and the coating material 11 was used as the light-scattering layer-forming coating material during the manufacture of the semiconductor electrode. Among them, the content rate of the rod-shaped TiO ₂ particles 6 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(Photoelectrochemical Cell 9)

The photoelectrochemical cell 9 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the semiconductor layer-forming coating material and the coating material 13 was used as the light-scattering layer-forming coating material during the manufacture of the semiconductor electrode. Among them, the content rate of the rod-shaped TiO ₂ particles 8 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(photoelectrochemical cell 10)

The photoelectrochemical cell 10 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the semiconductor layer-forming coating material and the coating material 14 was used as the light-scattering layer-forming coating material during the manufacture of the semiconductor electrode. Among them, the content rate of the rod-shaped TiO ₂ particles 9 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

(Photoelectrochemical Cell 11)

In the manufacture of the semiconductor electrode, the photoelectrochemical cell 1 was fabricated according to the same procedure as that of the photoelectrochemical cell 1, except that the semiconductor electrode formed only of the semiconductor layer (light-receiving surface area: 10 mm × 10 mm, layer thickness: 10 μm) was fabricated using only the paint 2. battery11.

(photoelectrochemical cell 12)

The photoelectrochemical cell 12 was produced in the same procedure as the photoelectrochemical cell 1 except that the coating material 2 was used as the semiconductor layer-forming coating material and the coating material 7 was used as the light-scattering layer-forming coating material during the manufacture of the semiconductor electrode. Among them, the content rate of the rod-shaped TiO ₂ particles 2 contained in the light scattering layer of the semiconductor electrode: 30% by mass.

[Test and evaluation of characteristics]

The photoelectrochemical cells 1 to 12 were irradiated with 1000 W/m ² similar to the sun from a xenon lamp through an AM1.5 filter using a solar simulator (manufactured by WACOM, WXS-85H (trade name)). Light. The current-voltage characteristics were measured by IV test to obtain the initial value of the conversion efficiency. The above results are shown in Table 6.

The conversion efficiency above 2.5% is indicated by ◎, the one above 1% and less than 2.5% is indicated by ○, the one above 0.3% and less than 1% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were rated as ×, the above results are shown in Table 6. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

Table 6

Sample number photoelectrochemical cell pigment conversion efficiency Durability Remark 6-1 Photoelectrochemical Cell 1 S-15 ○ ○ this invention 6-2 Photoelectrochemical cell 2 S-15 ◎ ○ this invention 6-3 Photoelectrochemical Cell 3 S-15 ◎ ○ this invention 6-4 Photoelectrochemical Cell 4 S-15 ◎ ◎ this invention 6-5 Photoelectrochemical cell 5 S-15 ○ ◎ this invention 6-6 Photoelectrochemical cell 6 S-15 ○ ○ this invention 6-7 Photoelectrochemical Cell 7 S-15 ◎ ○ this invention 6-8 Photoelectrochemical Cell 8 S-15 ◎ ◎ this invention 6-9 Photoelectrochemical Cell 9 S-15 ◎ ○ this invention 6-10 Photoelectrochemical Cell 10 S-15 ◎ ◎ this invention 6-11 Photoelectrochemical Cell 1 T-6 ○ ◎ this invention 6-12 Photoelectrochemical cell 2 T-6 ◎ ◎ this invention 6-13 Photoelectrochemical Cell 3 T-6 ◎ ◎ this invention 6-14 Photoelectrochemical Cell 4 T-6 ◎ ◎ this invention 6-15 Photoelectrochemical cell 5 T-6 ○ ◎ this invention 6-16 Photoelectrochemical cell 6 T-6 ○ ◎ this invention 6-17 Photoelectrochemical Cell 7 T-6 ◎ ◎ this invention 6-18 Photoelectrochemical Cell 8 T-6 ◎ ◎ this invention 6-19 Photoelectrochemical Cell 9 T-6 ◎ ◎ this invention 6-20 Photoelectrochemical Cell 10 T-6 ◎ ◎ this invention 6-21 Photoelectrochemical Cell 1 A-1 ○ △ comparative example 6-22 Photoelectrochemical cell 2 A-1 ○ △ comparative example 6-23 Photoelectrochemical Cell 3 A-1 ◎ △ comparative example 6-24 Photoelectrochemical Cell 4 A-1 ◎ △ comparative example 6-25 Photoelectrochemical cell 5 A-1 ○ △ comparative example 6-26 Photoelectrochemical cell 6 A-1 ○ △ comparative example 6-27 Photoelectrochemical Cell 7 A-1 ◎× comparative example 6-28 Photoelectrochemical Cell 8 A-1 ◎ △ comparative example 6-29 Photoelectrochemical Cell 9 A-1 ◎ △ comparative example 6-30 Photoelectrochemical Cell 10 A-1 ◎ △ comparative example 6-31 Photoelectrochemical Cell 11 A-1 △× comparative example 6-32 Photoelectrochemical Cell 12 A-1 △× comparative example

As can be seen from Table 6, the photoelectrochemical cell using the pigment of the present invention has an initial value of conversion efficiency of more than 1%, and the conversion efficiency after 500 hours is more than 60% of the initial value, and shows excellent durability.

On the other hand, in the case of using the comparative dye, it was found that the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

[Experiment 7]

A paste-like material in which metal alkoxide is added to metal oxide particles is coated on a conductive substrate, and then subjected to UV ozone irradiation, UV irradiation or drying to produce an electrode. Next, a photoelectrochemical cell was produced, and the conversion efficiency was measured.

(metal oxide fine particles)

Titanium oxide is used as the metal oxide fine particles. As titanium oxide, P25 powder (manufactured by Degussa, trade name) having a mass ratio of 30% rutile type and 70% anatase type and an average particle diameter of 25 nm was used.

(Pretreatment of metal oxide fine particle powder)

The organic matter and moisture on the surface are removed by pre-heating the metal oxide particles. In the case of titanium oxide fine particles, it was heated in an oven at 450°C for 30 minutes in the atmosphere.

(Measurement of water content in metal oxide fine particles)

The amount of moisture contained in titanium oxide and P25 powder (manufactured by Degussa, trade name) stored in an environment with a temperature of 26°C and a humidity of 72% can be measured by thermogravimetric measurement of weight loss and heating at 300°C Quantify the amount of water removed by Karl Fischer titration.

When titanium oxide and P25 powder (manufactured by Degussa Corporation, trade name) were dehydrated by Karl Fischer titration to quantify the amount of water removed by heating at 300°C, 0.1033 g of titanium oxide fine powder contained 0.253 mg of water. That is, the titanium oxide fine powder contains about 2.5% by mass of water. After heat treatment for 30 minutes and cooling, it was stored in a desiccator for use.

(Preparation of metal alkoxide paint)

Metal alkoxides that have the effect of binding metal oxide fine particles use tetraisopropoxide titanium (IV) (titanium (IV) tetraisopropoxide, TTIP) as a titanium raw material, tetra-n-propoxide zirconium (IV) (zirconium (IV) tetra n-propoxide) as a zirconium raw material and niobium (V) pentaethoxide as a niobium raw material (all are manufactured by Aldrich).

The molar concentration ratio of the metal oxide fine particles to the metal alkoxide is determined according to the diameter of the metal oxide fine particles so that the amorphous layer produced by the hydrolysis of the metal alkoxide is not too thick and the bonding between the particles is sufficiently advanced. And make appropriate adjustments. In addition, all metal alkoxides were used as 0.1 M ethanol solutions. When mixing titanium oxide fine particles and titanium (IV) tetraisopropylate (TTIP), 3.55 g of 0.1M TTIP solution was mixed with 1 g of titanium oxide fine particles. At this time, the concentration of titanium oxide in the obtained paint was about 22% by mass, which was an appropriate viscosity for coating. In addition, the mass ratio of titanium oxide, TTIP, and ethanol at this time was 1:0.127:3.42, and the molar ratio was 1:0.036:5.92.

Similarly, the mixed paint of titanium oxide fine particles and alkoxides other than TTIP was prepared so that the fine particle concentration was 22% by mass. The paint using zinc oxide and tin oxide is 16% by mass. In the case of zinc oxide and tin oxide, they are mixed in a ratio of 5.25 g of the metal alkoxide solution per 1 g of the metal oxide fine particles.

Next, the metal oxide microparticles and the metal alkoxide solution were placed in an airtight container and stirred for 2 hours with a magnetic stirrer to obtain a uniform coating. The method of coating the paint on the conductive substrate can be doctor blade method, screen printing method, spray coating method, etc. The appropriate viscosity of the paint is selected according to the coating method. Here, a simple glass rod coating method (similar to the doctor blade film-forming method) is used. In this case, the concentration of the metal oxide fine particles to give an appropriate paint viscosity is approximately in the range of 5% by mass to 30% by mass.

The thickness of the amorphous metal oxide produced by decomposing the metal alkoxide was in the range of about 0.1 nm to 0.6 nm in this experiment, and this is a suitable thickness range.

(coating and air-drying of paint on conductive substrates)

On a polyethylene terephthalate (PET) film substrate (20Ω/cm ² ) with an indium tin oxide (ITO) conductive film, or a glass substrate with a fluorine-doped tin oxide (FTO) conductive film ( 10 Ω/cm ² ), two adhesive tapes as spacers were pasted in parallel at a constant interval, and then the paint prepared by the above-mentioned method was uniformly applied using a glass rod.

After the paint was applied and before the dye was adsorbed, the conditions regarding the presence or absence of UV ozone treatment, UV irradiation treatment, or drying treatment were changed to produce a porous membrane.

(dry treatment)

The film coated on the conductive substrate was air-dried in the air at room temperature for about two minutes. During this process, the metal alkoxides in the paint are hydrolyzed due to moisture in the atmosphere, and amorphous titanium oxide, zirconium oxide, and niobium oxide.

The generated amorphous metal oxide serves to bond the metal oxide fine particles and the film to the conductive substrate, so a porous film excellent in mechanical strength and adhesion can be obtained only by air drying.

(UV ozone treatment)

The UV ozone treatment is to use the NL-UV253UV ozone cleaning device manufactured by Japan Laser (laser) Electronics Company. The UV light source is equipped with three 4.5W mercury lamps with 185nm and 254nm glow lines, and the sample is placed horizontally at a distance of about 6.5cm from the light source. Ozone is then generated by introducing a stream of oxygen in a chamber. In this example, UV ozone treatment was carried out for 2 hours. However, no decrease in the conductivity of the ITO film and the FTO film by the above-mentioned UV ozone treatment was observed.

(UV treatment)

The treatment was performed for 2 hours in the same manner as the above-mentioned UV ozone treatment except that the chamber was replaced with nitrogen gas. None of the reductions in the electrical conductivity of the ITO film and the FTO film by the above-mentioned UV treatment was observed.

(pigment adsorption)

The dyes described in Table 7 were used, and 0.5 mM ethanol solutions of each dye were prepared. In this experiment, the porous membrane produced by the above process was dried in an oven at 100°C for 1 hour, then immersed in a solution of sensitizing dye, and then left at room temperature for 50 minutes to adsorb the dye on the surface of titanium oxide. The sample after dye adsorption was washed with ethanol and air-dried.

(Fabrication of Photoelectrochemical Cells and Evaluation of Cell Characteristics)

A conductive substrate formed with a porous film after dye adsorption is used as a photoelectrode, and it is placed opposite to an ITO/PET film or FTO/glass counter-electrode decorated with platinum particles by sputtering to test photoelectrochemical Battery. The effective area of the photoelectrode is about 0.2 cm ² . The electrolyte solution is 3-methoxypropionitrile containing 0.5M LiI, 0.05M I ₂ and 0.5M tert-butylpyridine, and is introduced into the gap between the two electrodes by capillary phenomenon.

The battery performance was evaluated based on photocurrent action spectrum measurement under irradiation with a certain number of photons (10 ¹⁶ cm ² ), and IV measurement under irradiation with AM1.5 similar to sunlight (100mW/cm ² ). The above-mentioned measurement was performed using a CEP-2000 spectroscopic sensitivity measuring device manufactured by Spectrometer Co., Ltd., and the obtained conversion efficiencies are shown in Table 7.

The conversion efficiency above 2.0% is indicated by ◎, the one above 0.8% and less than 2.0% is indicated by ○, the one above 0.3% and less than 0.8% is indicated by △, and the conversion efficiency of less than 0.3% is indicated by ×, and the conversion efficiency is More than 0.3% are qualified, less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were evaluated as ×, and the above results are shown in Table 7 as durability. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

Table 7

In Table 7, the columns of "UV ozone", "UV", and "drying" respectively indicate the presence or absence of UV ozone treatment, UV irradiation treatment, and drying treatment after the formation of the porous membrane and before the adsorption of the sensitizing dye. . Those who have been processed are marked as "○", and those that have not been processed are marked as "×".

The column of "TiO ₂ pretreatment" in Table 7 indicates the presence or absence of pretreatment of titanium oxide fine particles (heat treatment in an oven at 450° C. for 30 minutes). Samples 6, 14, and 22 are samples using a paint with a high TTIP concentration (the molar ratio of titanium oxide:TTIP is 1:0.356), while the other samples (samples 1 to 5, 7 to 13, 23, 24) All are coatings using titanium oxide:TTIP=1:0.0356.

As can be seen from Table 7, the photoelectrochemical cell using the dye of the present invention, after the formation of the porous membrane, before the adsorption of the sensitizing dye, regardless of whether there is UV ozone treatment, UV irradiation treatment, or drying treatment, compared with the photoelectrochemical cell using the above-mentioned dye alone In general, the conversion efficiency of photoelectrochemical cells is high, and the conversion efficiency of qualified standards can be obtained. Furthermore, the conversion efficiency after 500 hours was 60% or more of the initial value, and excellent durability was shown.

On the other hand, in the case of using the comparative dye, it was found that the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

[Experiment 8]

Using acetonitrile as a solvent, 0.1 mol/L of lithium iodide, 0.05 mol/L of iodine, and 0.62 mol/L of dimethylpropylimidazolium iodide were dissolved to prepare an electrolytic solution. Here, polybenzimidazole-based compounds of No. 1 to No. 8 shown below were individually added and dissolved so that the concentrations thereof became 0.5 mol/L, respectively.

[chem 48]

The polybenzimidazole-based compound electrolytes of No. 1 to No. 8 were dropped onto the porous titanium oxide semiconductor thin film (thickness 15 μm) carrying the pigment described in Table 8 on the conductive glass. Then, a frame-type spacer (25 μm in thickness) made of polyethylene film was mounted thereon, and then a platinum counter electrode was covered to fabricate a photoelectric conversion element.

Table 8 shows the open voltage and photoelectric conversion efficiency obtained by irradiating the obtained photoelectric conversion element with light having an intensity of 100 mW/cm ² using a xenon lamp as a light source.

(evaluation of results)

(i) Those whose open voltage is above 7.0V are represented by ◎, those between 6.5V and below 7.0V are represented by ○, those between 6.0V and below 6.5V are represented by △, those below 6.0V are represented by ×, and Those above 6.5V are qualified.

(ii) A conversion efficiency of 2.0% or more is indicated by ◎, a conversion efficiency of 0.8% to less than 2.0% is indicated by ○, a conversion efficiency of 0.3% to less than 0.8% is indicated by △, and less than 0.3% is indicated by ×, and Those with a conversion efficiency of 0.3% or more are qualified, and those with a conversion efficiency of less than 0.3% are unqualified. In addition, with respect to the initial value of the conversion efficiency, the conversion efficiency after 500 hours was evaluated as ◎ if it was 90% or more, ○ if it was 60% or more and less than 90%, and △ if it was 40% or more and less than 60%. , less than 40% were evaluated as ×, and the above-mentioned values are shown in Table 8 as durability. The conversion efficiency after 500 hours was 60% or higher than the initial value of the conversion efficiency, and the conversion efficiency was less than 60%.

In addition, Table 8 also shows the results of a photoelectric conversion element using an electrolytic solution in which no polybenzimidazole-based compound was added.

Table 8

As can be seen from Table 8, the photoelectrochemical cell using the pigment of the present invention is that the initial values of open voltage and conversion efficiency are all qualified standards, and the conversion efficiency after 500 hours is more than 60% of the initial value, and shows excellent durability.

On the other hand, in the case of using a comparative dye, the initial values of open voltage and conversion efficiency are acceptable standards, but there is a problem in durability.

[Experiment 9]

(Photoelectrochemical Cell 1)

According to the procedure shown below, a photoelectrode having the same structure as the photoelectrode 10 shown in FIG. In addition to this photoelectrode, a photoelectrochemical cell having the same structure as the dye-sensitized solar cell 20 shown in FIG. 1 of JP-A-2004-152613 (the area of the light-receiving surface F2 of the semiconductor electrode 2: 1 cm ² ) was fabricated. Among the layers of the semiconductor electrode 2 having this two-layer structure, the layer arranged on the side close to the transparent electrode 1 is referred to as the "first layer", and the layer arranged on the side close to the porous layer PS is referred to as "the first layer". Layer 2".

First, using P25 powder (manufactured by Degussa Corporation, trade name) with an average particle diameter of 25 nm, titanium oxide particles different from the particle diameter, and P200 powder (average particle diameter of 200 nm, manufactured by Degussa Corporation, trade name), and The total content of P25 and P200 is 15%, and the mass ratio of P25 and P200 is P25:P200=30:70, adding acetylacetone (acetylacetone), ion-exchanged water, surfactant (manufactured by Tokyo Chemical Industry Co., Ltd. , trade name: "Triton-X"), and kneaded to prepare a slurry for forming the second layer (hereinafter referred to as "slurry 1").

Next, except that P200 was not used and only P25 was used, the slurry for forming the first layer was prepared in the same preparation procedure as the above-mentioned slurry 1 (content of P1: 15%, hereinafter referred to as "slurry 2") ).

On the other hand, a transparent electrode (thickness: 1.1 mm) in which a fluorine-doped SnO ₂ conductive film (film thickness: 700 nm) was formed on a glass substrate (transparent conductive glass) was prepared. Next, the above-mentioned slurry 2 was coated on the SnO ₂ conductive film by a bar coating method, and then dried. Thereafter, calcination was performed in air at 450° C. for 30 minutes. As described above, the first layer of the semiconductor electrode 2 is formed on the transparent electrode.

Then, using the slurry 1, the second layer was formed on the first layer by repeating the same coating and firing as above. As mentioned above, the semiconductor electrode 2 is formed on the SnO ₂ conductive film (the area of the light-receiving surface: 1.0cm ² , the total thickness of the first layer and the second layer: 10μm (the thickness of the first layer: 3μm, the thickness of the second layer: 7 μm)), and then fabricate a photoelectrode 10 that does not contain a sensitizing pigment.

Thereafter, ethanol solutions of dyes listed in Table 9 were prepared as dyes (concentration of each sensitizing dye: 3×10 ^-4 mol/L). Then, the photoelectrode 10 was immersed in the above solution and left at 80°C for 20 hours, whereby about 1.0×10 ^-7 mol/cm ² of sensitizing dye was adsorbed inside the semiconductor electrode.

Next, a counter electrode CE having the same shape and size as the aforementioned photoelectrode was produced. First, drop the isopropanol solution of chloroplatinic acid hexahydrate on the transparent conductive glass, dry it in the air, and then calcine it at 450°C for 30 minutes to obtain platinum sintering. Opposite pole CE. In addition, a hole (diameter: 1 mm) for injection of the electrolyte E is provided in advance in the above-mentioned counter electrode CE.

Next, prepare a liquid electrolyte (zinc iodide concentration: 10mmol/L, concentration of dimethylpropylimidazolium iodide: 0.6mol/L, concentration of iodine: 0.05mol/L, concentration of 4-tert-butylpyridine: 1mol/L).

Then, a spacer S (trade name: "Hi-milan", ethylene/methacrylic acid random copolymerization ionomer film) manufactured by Mitsui DuPont Polymer Chemicals (DUPONT-MITSUI POLYCHEMICALS) Co. ), as shown in Figure 1 of Japanese Patent Application Laid-Open No. 2004-152613, the photoelectrode and the counter are arranged oppositely through the spacer, and they are bonded together by thermal welding to obtain the body of the battery (not filled with electrolyte) .

Next, after the liquid electrolyte is injected into the body from the hole of the counter electrode, the hole is plugged with a member of the same material as the spacer, and the above member is thermally welded to the hole of the counter electrode to seal the hole to complete the photoelectrochemical cell 1 .

(Photoelectrochemical Cell 2)

The photoelectrochemical cell 2 was produced in the same procedure and conditions as the photoelectrochemical cell 1 except that the concentration of zinc iodide in the liquid electrolyte was 50 mmol/L.

(Photoelectrochemical Cell 3)

Except that lithium iodide is added instead of zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte is 20 mmol/L, with the same order and conditions as the photoelectrochemical cell 1, a comparative photoelectrochemical cell 1 is produced.

(Compare Photoelectrochemical Cell 4)

Except that lithium iodide is added instead of zinc iodide in the liquid electrolyte, and the concentration of lithium iodide in the liquid electrolyte is 100 mmol/L, with the same sequence and conditions as the photoelectrochemical cell 1, a comparative photoelectrochemical cell 4 is produced.

(test and evaluation)

The conversion efficiencies of the samples used in the photoelectrochemical cells 1 to 4 were measured according to the following procedure.

The battery characteristic evaluation test was to use a solar simulator (manufactured by WACOM, trade name: "WXS-85H type"), under the light similar to sunlight from a xenon lamp light source passing through an AM filter (AM1.5). Irradiation conditions were set to 100 mW/cm ² (irradiation conditions of so-called "1 Sun").

With regard to each photoelectrochemical cell, the current-voltage characteristic was measured at room temperature using an I-V test, and the conversion efficiency was obtained therefrom. The results obtained above are shown in the "initial value" of Table 9A (irradiation conditions of 1Sun). In addition, the results of the conversion efficiency after 300 hours of conversion efficiency under the operating condition of 10Ω load under 60° C. and 1 Sun irradiation are also shown in Table 9A. The initial value of the conversion efficiency was 2.4% or more, and the case of less than 2.4% was unacceptable. In addition, compared with the initial value, the reduction rate of the conversion efficiency after lapse of 300 hours was 20% or less, and it was not acceptable if it exceeded 20%.

In addition, evaluation was performed in the same manner except that the conversion efficiency after 500 hours had passed was measured. The above results are shown in Table 9B.

Table 9A

Table 9B

As can be seen from Tables 9A and 9B, the photoelectrochemical cell using the pigment of the present invention is that the initial value of the conversion efficiency is a qualified standard, and the reduction rate of the conversion efficiency after 300 hours is 20% or less, and shows excellent durability sex.

On the other hand, in the case of using the comparative dye, it was found that the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

[Experiment 10]

1. Preparation of titanium dioxide dispersion

In a stainless steel container with an internal volume of 200 ml coated with fluororesin on the inside, 15 g of titanium dioxide microparticles (manufactured by Japan Aerosil Co., Ltd., Degussa P-25), 45 g of water, and a dispersant (manufactured by Japan Aldrich Co., Ltd.) , Triron X-100) 1 g, 30 g of zirconia beads (manufactured by Nikkato) with a diameter of 0.5 mm, and then use a sand mill (manufactured by Aimex) to carry out dispersion treatment at 1500 rpm 2 Hour. From the resulting dispersion, the zirconia beads were filtered. The average particle diameter of the titanium dioxide fine particles in the obtained dispersion liquid was 2.5 μm. However, the particle size was measured with a Mastersizer (trade name) manufactured by Malvern Corporation.

2. Fabrication of titanium oxide particle layer (electrode A) that adsorbs pigment

Prepare a 20mm×20mm conductive glass plate (manufactured by Asahi Glass (AGC) Co., Ltd., TCO glass-U, surface resistance: about 30Ω/m ² ) covered with fluorine-doped tin oxide, and the two sides of the conductive layer side After affixing an adhesive tape for a spacer to the end (a part having a width of 3 mm from the end), the above-mentioned dispersion liquid was applied on the conductive layer using a glass rod. After the application of the dispersion liquid, the adhesive tape was peeled off, and air-dried at room temperature for one day. Next, the above-mentioned semiconductor-coated glass plate was placed in an electric furnace (muffle furnace FP-32 manufactured by Yamato Scientific Co., Ltd.) and fired at 450° C. for 30 minutes. The semiconductor-coated glass plate was taken out, cooled, and immersed in ethanol solutions of the dyes shown in Table 10 (concentration: 3×10 ^-4 mol/L) for 3 hours. The dye-adsorbed semiconductor-coated glass plate was dipped in 4-tert-butylpyridine for 15 minutes, washed with ethanol, and naturally dried to obtain a dye-adsorbed titanium oxide fine particle layer (electrode A). The thickness of the dye-sensitized titanium oxide fine particle layer of the electrode A was 10 μm, and the coating amount of the titanium oxide fine particle was 20 g/m ² . In addition, the adsorption amount of the dye is within the range of 0.1 mmol/m ² to 10 mmol/m ² depending on the kind of the dye.

3. Fabrication of photoelectrochemical cell a

The solvent is a mixture of acetonitrile and 3-methyl-2-oxazolinone at a volume ratio of 90/10. Iodine and 1-methyl-3-hexylimidazolium iodide salt as an electrolyte salt were added to the above solvent to prepare a solution containing 0.5 mol/L of electrolyte and 0.05 mol/L of iodine. In the above solution, 10 parts by mass of the nitrogen-containing polymer compound (α) was added to 100 parts by mass of (solvent+nitrogen-containing polymer compound+salt). Furthermore, 0.1 mole of the electrophile (β) was mixed with respect to the reactive nitrogen atom of the nitrogen-containing polymer compound so as to form a uniform reaction solution.

On the other hand, on the dye-sensitized titanium oxide fine particle layer of the above-mentioned electrode A, the platinum thin film side of the opposite electrode including the platinum-deposited glass plate was provided through a spacer, and the conductive glass plate and the platinum-deposited glass plate were fixed. The open end of the obtained assembly was dipped in the above electrolytic solution, and the reaction solution was permeated into the dye-sensitized titanium oxide fine particle layer by capillarity.

Next, it was heated at 80° C. for 30 minutes to perform a crosslinking reaction. In the above manner, on the conductive layer 12 of the conductive glass plate 10 shown in FIG. 2 of Japanese Patent Application Laid-Open No. 2000-323190, a dye-sensitized titanium oxide microparticle layer 20 and an electrolyte layer 30 are sequentially laminated. And the photoelectrochemical cell a-1 (sample number 10-1) of the present invention comprising the counter electrode 40 of the platinum thin film 42 and the glass plate 41.

In addition, in addition to changing the composition of the pigment and the electrolyte composition as shown in Table 10, by repeating the above process, photoelectrochemical cells a-2 (sample Number 10-4).

4. Fabrication of photoelectrochemical cells b and c

(1) Photoelectrochemical cell b

Electrode A (20 mm x 20 mm) including a titanium oxide fine particle layer sensitized with the dye of the present invention was superimposed on a platinum-deposited glass plate of the same size through a spacer as described above. Then, utilize capillary phenomenon, make between the slit of two glass plates by electrolytic solution (with the mixture of acetonitrile and 3-methyl-2-oxazolinone volume ratio 90/10 as the iodine 0.05mol/L of solvent, iodine Lithium chloride 0.5mol/L solution) soaked, to make photoelectrochemical cell b-1. In addition, except that the pigment was changed to those shown in Table 10, the above-mentioned process was repeated to obtain a photoelectrochemical cell b-2 (sample number 10-5).

(2) Photoelectrochemical cell c (electrolyte described in Japanese Patent Laid-Open No. 9-27352)

In the above-mentioned manner, an impregnation electrolyte solution was applied on the electrode A (20 mm×20 mm) including the titanium oxide fine particle layer sensitized with the dye of the present invention. Wherein, the electrolytic solution is 2- Hydroxy-2-methyl-1-phenyl-propane-1-one (2-hydroxy-2-methyl-1-phenylpropane-1-one) (manufactured by Ciba-Geigy Co., Ltd., Japan, DAROCUR 1173) 20 mg of the mixed solution, dissolved lithium iodide 500 mg, and obtained by vacuum degassing for 10 minutes. Next, by placing the porous titanium oxide layer impregnated with the above mixed solution under reduced pressure, thereby removing air bubbles in the porous titanium oxide layer and promoting the infiltration of the monomer, the porous titanium oxide layer in the micropores of the porous titanium oxide layer is A homogeneous sol filled with a polymer compound polymerized by ultraviolet light irradiation. The article obtained in the above manner was exposed to an iodine environment for 30 minutes to diffuse iodine in the polymer compound, and then the platinum vapor-deposited glass plates were stacked to obtain a photoelectrochemical cell c-1. In addition, except that the pigment was changed to those shown in Table 10, the above process was repeated to obtain a photoelectrochemical cell c-2 (sample number 10-6).

5. Determination of photoelectric conversion efficiency

By passing the light of a 500W xenon lamp (manufactured by Ushio) through an AM1.5 filter (manufactured by Oriel) and a sharp cut-off filter (Kenko L-42), as a UV-free Simulate sunlight. The light intensity was 89 mW/cm ² .

Alligator clips were respectively connected to the conductive glass plate 10 and the platinum vapor deposition glass plate 40 of the above-mentioned photoelectrochemical cell, and each crocodile clip was connected to a current and voltage measuring device (Keithley SMU238 type (trade name)). Here, simulated sunlight was irradiated from the side of the conductive glass plate 10, and the generated electricity was measured using an amperometric voltage measuring device. Table 10 shows the initial value of the conversion efficiency of the photoelectrochemical cell obtained in this way, and the decrease rate of the conversion efficiency at the time of continuous irradiation for 300 hours. The initial value of the conversion efficiency was 2.7% or more, and those with less than 2.7% were unacceptable. In addition, the reduction rate of the conversion efficiency after 300 hours passed was 20% or less and the thing exceeding 20% was unacceptable.

Table 10

(Remark)

(1) The symbols of the dyes are as described herein.

(2) Nitrogen-containing polymer α and electrophile β are represented by the following compounds.

[chem 49]

[chemical 50]

As can be seen from Table 10, the initial value of the conversion efficiency of the photoelectrochemical cell using the pigment of the present invention is a pass standard, and the reduction rate of the conversion efficiency after 300 hours is 15% or less, and shows excellent durability.

On the other hand, in the case of using the comparative dye, it was found that the initial value of the conversion efficiency is a pass standard, but there is a problem in durability.

Although the present invention has been described together with its implementation forms, the inventor believes that unless otherwise specified, the present invention is not limited to any details of the description, without violating the spirit and spirit of the invention shown in the appended claims. interpretation can be extended.

This application is based on the Japanese patent application No. 2010-124020 filed with the Japan Intellectual Property Office on May 31, 2010, and the Japanese patent application No. 2010-124020 filed with the Japan Intellectual Property Office on December 24, 2010. Priority is claimed for Japanese Patent Application No. 2010-287040 and Japanese Patent Application No. 2011-059911 filed with the Japan Intellectual Property Office on March 17, 2011, and the contents of these patent applications are hereby incorporated by reference as part of the description in this manual.

Description of main component symbols:

1: Conductive support

2: Photoreceptor layer

21: Pigment

22: Semiconductor microparticles

3: Charge moving body layer

4: opposite pole

5: Light-receiving electrode

6: circuit

10: Photoelectric conversion element

100: photoelectrochemical cell

Claims (18)

1. A photoelectric conversion element, characterized in that it includes a photoreceptor layer equipped with a dye represented by the following general formula (1) and semiconductor fine particles, wherein the dye includes an aliphatic group having 5 to 18 carbon atoms in the following formula: The pigment of the compound represented by general formula (1), [chemical 1]

General formula (1) [In the above general formula (1), Q is represented as a tetravalent aromatic group; X ¹ and X ² are independently represented as sulfur atom, oxygen atom or CR ¹ R ² , wherein R ¹ and R ² are independently represented as hydrogen Atoms, aliphatic groups, aromatic groups, heterocyclic groups bonded by carbon atoms, and R ¹ and R ² can also be substituted; R and R' are independently represented by aliphatic groups, aromatic groups, carbon atoms A bonded heterocyclic group, and R and R' can also be substituted; P ¹ and P ² are independently represented as pigment residues; W ¹ represents the counter ion necessary to neutralize the charge. ] 2. The photoelectric conversion element according to claim 1, wherein the aliphatic group having 5 to 18 carbon atoms is a branched alkyl group. 3. The photoelectric conversion element according to claim 1 or 2, characterized in that Q in the above general formula (1) represents a benzene ring or a naphthalene ring. 4. The photoelectric conversion element according to any one of claims 1-3, characterized in that ^P1 and ^P2 in the above-mentioned general formula (1) are respectively independently represented by the following general formula (2) or the following general formula (3) said, [Chem 2]

General formula (2) [Chem 3]

General formula (3) [In the above-mentioned general formula (2) or general formula (3), V ¹ represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, V ¹ may be the same or different, or may be mutually Bond to form a ring; Y represents S, NR ⁹ or CR ¹⁰ R ¹¹ , wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, and R ¹⁰ and R ¹¹ represent a hydrogen atom, aliphatic group An aromatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, R ¹⁰ and R ¹¹ may be the same or different, and may also be bonded to each other to form a ring; Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, and Z may also have a substituent; R ³ to R ⁶ and R ⁸ are each independently represented as a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and R ³ to R ⁶ and R ⁸ may also have substituents; R ⁷ is an oxygen atom or a carbon atom having two substituents, and the sum of σ _p in Hammett's law of the two substituents is a positive number. ] 5. The photoelectric conversion element according to claim 1, characterized in that P ¹ and P ² in the above general formula (1) are independently represented by general formula (4) or general formula (5), [chemical 4]

General formula (4) [chemical 5] General formula (5) [In the above general formula (4) or general formula (5), ^V represents a hydrogen atom or a substituent, n represents an integer of 0 to 4, and when n is 2 or more, ^V may be the same or different, or may be mutually Bond to form a ring; Y represents S, NR ⁹ or CR ¹⁰ R ¹¹ , wherein R ⁹ represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, and R ¹⁰ and R ¹¹ represent a hydrogen atom, aliphatic group An aromatic group, an aromatic group or a heterocyclic group bonded to a carbon atom, R ¹⁰ and R ¹¹ may be the same or different, and may also be bonded to each other to form a ring; Z represents an aliphatic group, an aromatic group or a heterocyclic group bonded to carbon atoms, and Z may also have a substituent. ] 6. The photoelectric conversion element according to claim 4 or 5, wherein said V ¹ has an acidic group. 7. The photoelectric conversion element according to any one of claims 4-6, characterized in that above-mentioned ^V is a hydrogen atom, a 5-carboxyl group, a 5-sulfonic acid group, a 5-methyl group or a 4,5-benzene ring condensation. 8. The photoelectric conversion element according to claim 6 or 7, wherein said Z and V ¹ are acidic groups or groups having acidic groups. 9. The photoelectric conversion element according to any one of claims 4,6-8, characterized in that above-mentioned general formula (2) is represented by following general formula (6), and above-mentioned general formula (3) is represented by following general formula (7) said, [chemical 6]

General formula (6) [chemical 7]

General formula (7) In the above general formula (6) and general formula (7), Y, Z, R ³ ~ R ⁸ have the same definitions as Y, Z, R ³ ~ R ⁸ in general formula (2) or general formula (3); V ¹² represents an acidic group; at least one of E ¹¹ to E ¹³ represents an electron-withdrawing group; p is an integer of 2 or more. 10. The photoelectric conversion element according to claim 4, wherein said general formula (2) is represented by the following general formula (8), and said general formula (3) is represented by the following general formula (9), [chemical 8]

General formula (8) [chemical 9] General formula (9) [chemical 10] Type A Type B Type C Type D In the above general formula (8) or general formula (9), Y, Z, R ³ ~ R ⁸ have the same definitions as Y, Z, R ³ ~ R ⁸ of general formula (2) or general formula (3); L is Represented by the above formula A to formula D, m represents an integer of 0 or more than 1, and when m is more than 2, L can also be different respectively; in the above formula A, Xa is expressed as NRe, O, S, and Re is expressed as A hydrogen atom or a substituent; in the above formulas A and C, Ra to Rd represent acidic groups; in the above general formula (8), p represents an integer of 2 or more, and Rx represents an acidic group. 11. The photoelectric conversion element according to any one of claims 4-10, characterized in that said Y is represented by S, NCH ₃ or C(CH ₃ ) ₂ , and Z is represented by an aliphatic group with 5 to 18 carbons . 12. The photoelectric conversion element according to any one of claims 4, 6-11, characterized in that said formula ^R is represented by any one of the following formulas (10) to (13), [chemical 11]

General formula (10) General formula (11) General formula (12) General formula (13) [In the above formulas (10) to (13), Rf represents a hydrogen atom or a substituent. ] 13. The photoelectric conversion element according to any one of claims 4, 6-12, characterized in that above-mentioned R ⁷ is represented by the following general formula (14) or general formula (15), [chemical 12]

General formula (14) General formula (15). 14. The photoelectric conversion element according to any one of claims 1-13, characterized in that in the general formula (1), Q represents a benzene ring, and X ¹ and X ² independently represent a sulfur atom and an oxygen atom respectively Or C(CH ₃ ) ₂ , R and R' are each independently represented as an aliphatic group having 5 to 18 carbon atoms. 15. The photoelectric conversion element according to claim 1, wherein the semiconductor fine particles are titanium oxide fine particles. 16. A photoelectrochemical cell, characterized in that it comprises the photoelectric conversion element according to any one of claims 1-15. 17. A dye for a photoelectric conversion element, comprising a compound represented by the following general formula (1) having an aliphatic group having 5 to 18 carbon atoms, [chemical 13]

General formula (1) [In the above general formula (1), Q is represented as a tetravalent aromatic group; X ¹ and X ² are independently represented as sulfur atom, oxygen atom or CR ¹ R ² , wherein R ¹ and R ² are independently represented as hydrogen Atoms, aliphatic groups, aromatic groups, heterocyclic groups bonded by carbon atoms, and R ¹ and R ² can also be substituted; R and R' are independently represented by aliphatic groups, aromatic groups, carbon atoms A bonded heterocyclic group, and R and R' can also be substituted; P ¹ and P ² are independently represented as pigment residues; W ¹ represents the counter ion necessary to neutralize the charge. ] 18. A dye solution for photoelectric conversion elements, characterized by comprising: the dye for photoelectric conversion elements according to claim 17 is contained and dissolved in an organic solvent.

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