JP6182046B2 - Sensitizing dye for photoelectric conversion, photoelectric conversion element using the same, and dye-sensitized solar cell - Google Patents

Description

  The present invention relates to a sensitizing dye used for a dye-sensitized photoelectric conversion element, a photoelectric conversion element using the same, and a dye-sensitized solar cell.

In recent years, carbon dioxide generated from fossil fuels such as coal, oil, and natural gas has caused global warming as a greenhouse gas and environmental destruction due to global warming. There is a concern that the destruction of the environment on a global scale will continue to progress. Under such circumstances, the use of solar energy, which is unlikely to be depleted unlike fossil fuels, has been energetically studied. Since solar power generation can be expected to prevent global warming and save energy costs, solar energy is being developed and used rapidly, especially in Europe and Japan.

As a means for photovoltaic power generation, a solar cell using a photoelectric conversion element that converts sunlight energy into electric energy has attracted attention. As solar cells, inorganic solar cells such as single crystal, polycrystal, amorphous silicon, gallium arsenide, cadmium sulfide, indium copper selenide and other compound semiconductors have been mainly studied, some of which are for residential use. Have been put to practical use. However, these inorganic solar cells have problems such as high manufacturing costs and difficulty in securing raw materials.

On the other hand, organic solar cells using organic materials are said to be advantageous in terms of manufacturing cost, increase in area, and securing raw materials. As an organic solar cell, a Schottky junction type organic solar cell using generation of electromotive force at a contact interface between an organic semiconductor and a metal has been known, but it is recognized that there is a limit in improving photoelectric conversion efficiency. It came to be. Therefore, a pn heterojunction organic solar cell using a contact interface between two organic semiconductors or a contact interface between an organic semiconductor and an inorganic semiconductor has been expected. However, the photoelectric conversion efficiency of these organic solar cells is significantly lower than that of inorganic solar cells, and there is a problem that durability is poor.

Under such circumstances, a dye-sensitized solar cell exhibiting high photoelectric conversion efficiency has been reported by Professor Gretzel et al. Of Lausanne University of Technology in Switzerland (for example, Non-Patent Document 1). The proposed dye-sensitized solar cell is a wet solar cell composed of a titanium oxide porous thin film electrode, a ruthenium complex dye, and an electrolytic solution. Dye-sensitized solar cells have a simpler device structure than other solar cells, and can be manufactured without large-scale manufacturing facilities, and are comparable to amorphous silicon solar cells already in practical use. In recent years, it has attracted attention as a next-generation solar cell because high photoelectric conversion efficiency is expected.

As the sensitizing dye used in the dye-sensitized solar cell, from the point of photoelectric conversion efficiency, ruthenium complex is considered to be the most dominant, but ruthenium is a noble metal, which is disadvantageous in terms of production cost, and When practical use requires a large amount of ruthenium complex, resource constraints also become a problem. Therefore, research on dye-sensitized solar cells using organic dyes that do not contain noble metals such as ruthenium as sensitizing dyes has been actively conducted. As organic dyes not containing a noble metal, coumarin dyes, cyanine dyes, merocyanine dyes, rhodacyanine dyes, phthalocyanine dyes, porphyrin dyes, xanthene dyes and the like have been reported (for example, Patent Documents 1 and 2). ).

In recent years, compounds having an enamine structure and a fluorene structure have been reported as sensitizing dyes (for example, Patent Documents 3 to 6). However, these organic dyes have the advantages that they are inexpensive, have a large extinction coefficient, and can control the absorption characteristics due to the variety of structures. However, they have sufficient characteristics required in terms of photoelectric conversion efficiency and stability over time. The present condition is that the thing which is satisfied is not obtained.

Japanese Patent Laid-Open No. 11-214730 JP 11-238905 A JP 2006-73375 A JP 2008-226582 A JP 2009-266633 A JP 2010-116561 A

Nature (Vol. 353, 737-740, 1991)

The problem to be solved by the present invention is to provide a sensitizing dye having a novel structure capable of efficiently taking out an electric current, and further using the sensitizing dye, a photoelectric conversion element having good photoelectric conversion and a dye sensitization It is to provide a solar cell.

In order to solve the above problems, the inventors have intensively studied on improving the photoelectric conversion characteristics of a sensitizing dye, and as a result, by using a sensitizing dye having a specific structure, a highly efficient and highly durable photoelectric conversion element is obtained. I found out that That is, the present invention has the following contents.

1. A sensitizing dye for photoelectric conversion represented by the following general formula (1).

(In the formula, R _{1 to} R ₃ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or an aryl group. R ₄ has 1 to 6 carbon atoms. R ₅ and R ₆ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an aryl group, R ₅ and R ₆ may combine with each other to form a ring, and R ₇ and R ₈ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, n is 1 to 4 represents an integer. here, when n is 2 to 4, _{R 7} and _{R 8} there are a plurality, that _{R 7} together may be each other _{R 8} is not the same as or different from each other to each other .A the following general 1 represented by formula (2) or (3) It represents a group.)

(In the formula, R ₉ represents an acidic group.)

(In the formula, X represents a monovalent group represented by the following general formula (4), Y represents a monovalent group represented by the following general formula (5), p represents an integer of 0 to 2, and p represents In the case of 2, a plurality of Xs may be the same or different.

(In the formula, R ₁₀ and R ₁₁ may be the same or different and each represents a hydrogen atom or an acidic group. Q represents an integer of 0 to 2, and r represents an integer of 0 to 3. Here, when in the general formula (3) p is 2, _R 10 there are a _{plurality, R} 11, q, r, the _{R 10 together, R 11} together, q each other, even if r each other mutually the same or different, respectively Good.)

_{(Wherein, R 12} and _{R 13} may be the same or different, .v represents a hydrogen atom or an acidic group is an integer of 0 to 2, w is an integer of 0 to 3.)
However, when p is 0, at least one of R ₁₂ or R ₁₃ in the general formula (5) is an acidic group, and when p is 1 or 2, the general formula (4) or the general formula At least one of R ₁₀ , R ₁₁ , R ₁₂ or R ₁₃ in (5) is an acidic group. )

2. 2. The sensitizing dye for photoelectric conversion as described in 1 above, wherein in general formula (1), R ₅ and R ₆ are a hydrogen atom, an alkyl group having 1 or 2 carbon atoms, or an aryl group.

3. 3. The sensitizing dye for photoelectric conversion as described in 1 or 2 above, wherein in the general formula (1), at least one of R _{7 and} R ₈ is an alkyl group having 5 to 12 carbon atoms.

4). In the said General formula (1), A is a monovalent group shown by the said General formula (2), The sensitizing dye for photoelectric conversion as described in any one of said 1-3 characterized by the above-mentioned.

5. In the said General formula (1), R < ₁ > and R < ₂ > is an aryl group, The sensitizing dye for photoelectric conversion as described in any one of said 1-4 characterized by the above-mentioned.

6). In Formula (1), characterized in that R ₄ is an aryl group, a photoelectric conversion sensitizing dye according to any one of the 1-5.

7). In the general formula (1), any one of the above 1 to 6, wherein R ₇ is a hydrogen atom, and R ₈ is a hydrogen atom or an alkyl group having 5 to 12 carbon atoms. The sensitizing dye for photoelectric conversion as described.

8). In the general formula (1), R ₇ is a hydrogen atom, and wherein the R ₈ is a hydrogen atom or n- hexyl group, a photoelectric conversion according to any one of the 7 Sensitizing dye.

9. In the dye-sensitized photoelectric conversion element in which at least a semiconductor layer and an electrolyte layer are provided between a pair of opposing electrodes, the photoelectric conversion sensitizing dye according to any one of 1 to 8 is the semiconductor. A photoelectric conversion element supported on a layer.

10. 10. The photoelectric conversion element as described in 9 above, wherein the electrolyte layer contains 4-tert-butylpyridine.

11. A dye-sensitized solar cell having a photoelectric conversion element, which is obtained by modularizing the photoelectric conversion element described in 9 or 10 above and providing predetermined electric wiring.

  According to the present invention, it is possible to obtain a sensitizing dye for photoelectric conversion capable of efficiently taking out current. Moreover, by using the sensitizing dye for photoelectric conversion, a highly efficient and highly durable photoelectric conversion element and a dye-sensitized solar cell can be obtained.

It is a schematic sectional drawing showing the structure of the photoelectric conversion element produced in this invention Examples 1-10 and Comparative Examples 1-4.

  Hereinafter, embodiments of the present invention will be described in detail. The sensitizing dye for photoelectric conversion of the present invention is used as a sensitizer in a dye-sensitized photoelectric conversion element. In the photoelectric conversion element of the present invention, a photoelectrode obtained by adsorbing a dye to a semiconductor layer on a conductive support and a counter electrode are arranged to face each other with an electrolyte layer interposed therebetween.

  Although the sensitizing dye for photoelectric conversion represented by the general formula (1) will be specifically described below, the present invention is not limited to these.

Specific examples of the “alkyl group having 1 to 6 carbon atoms” represented by R _{1 to} R ₄ in the general formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and n-butyl. Examples thereof include straight-chain or branched alkyl groups having 1 to 6 carbon atoms such as a group, t-butyl group and n-hexyl group. Among these, a linear alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 or 2 carbon atoms (methyl group or ethyl group) is more preferable.

The “alkyl group having 1 to 6 carbon atoms” represented by R _{1 to} R ₄ in the general formula (1) may have a substituent, specifically, a fluorine atom, a chlorine atom, a bromine atom, etc. A halogen atom of 1 to 6 linear or branched alkoxy group having 1 to 6 carbon atoms such as methoxy group, ethoxy group, propoxy group, t-butoxy group, pentyloxy group; phenyl group, naphthyl group, anthryl group, phenanthryl Group, aryl group such as pyrenyl group; straight chain having 1 to 6 carbon atoms such as dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, diphenylamino group Or a disubstituted amino group having a substituent selected from a branched alkyl group or an aryl group having 6 to 20 carbon atoms; a hydroxyl group; a carboxyl group; Chiruesuteru group, a carboxylic acid ester group such as an ethyl ester group; and a cyano group may be mentioned. Although the number of these substituents may be one or more, R _{1 to} R ₄ are preferably groups having no substituent.

Specific examples of the “aralkyl group” represented by R _{1 to} R ₄ in the general formula (1) include benzyl group, phenethyl group, 3-phenylpropyl group, benzhydryl group, trityl group, naphthylmethyl group, 2- Examples thereof include aralkyl groups having 7 to 26 carbon atoms such as naphthylethyl group. Among these, a benzyl group or a phenethyl group is preferable, and a benzyl group is more preferable.

The “aralkyl group” represented by R _{1 to} R ₄ in the general formula (1) may have a substituent, specifically, a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom; A linear or branched alkyl group having 1 to 6 carbon atoms such as ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, hexyl group; methoxy group, ethoxy group, propoxy A straight-chain or branched alkoxy group having 1 to 6 carbon atoms such as a group, t-butoxy group, pentyloxy group; dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t- A substituent selected from a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms, such as a butylamino group and a diphenylamino group; A hydroxyl group; a carboxyl group; a carboxylic acid ester group such as a methyl ester group or an ethyl ester group; a linear or branched alkoxy group having 1 to 6 carbon atoms substituted with a carboxyl group; phenyl An ethenyl group such as an ethenyl group and a diphenylethenyl group; a cyano group and the like can be mentioned. The number of these substituents may be one or more. The substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkoxy group having 1 to 6 carbon atoms, and a straight chain having 1 to 6 carbon atoms. A chain alkyl group or a linear alkoxy group having 1 to 6 carbon atoms is particularly preferred.

Specific examples of the “aryl group” represented by R _{1 to} R ₄ in the general formula (1) include aryl having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. You can raise a group. Here, in the present invention, the aryl group represents an aromatic hydrocarbon group and a condensed polycyclic aromatic group. Among these, a phenyl group or a naphthyl group is preferable, and a phenyl group is more preferable.

In the general formula (1), the “aryl group” represented by R _{1 to} R ₄ may have a substituent, specifically, a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom; A linear or branched alkyl group having 1 to 6 carbon atoms such as ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, hexyl group; methoxy group, ethoxy group, propoxy group A linear or branched alkoxy group having 1 to 6 carbon atoms such as t-butoxy group and pentyloxy group; 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group and pyrenyl group The number of carbon atoms such as dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, diphenylamino group, etc. A disubstituted amino group having a substituent selected from a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 20 carbon atoms; hydroxyl group; carboxyl group; methyl ester group, ethyl ester group, etc. A carboxylic acid ester group; a linear or branched alkoxy group having 1 to 6 carbon atoms substituted by a carboxyl group; an ethenyl group such as a phenylethenyl group or a diphenylethenyl group; a cyano group; it can. The number of these substituents may be one or more. The substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkoxy group having 1 to 6 carbon atoms, and a straight chain having 1 to 6 carbon atoms. A chain alkyl group or a linear alkoxy group having 1 to 6 carbon atoms is particularly preferred.

Specific examples of the “alkyl group having 1 to 18 carbon atoms” represented by R _{5 to} R ₈ in the general formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and n-butyl. Straight chain having 1 to 18 carbon atoms such as a group, t-butyl group, n-hexyl group, n-octyl group, isooctyl group, n-decyl group, n-dodecyl group, n-pentadecyl group, n-octadecyl group, etc. And a branched or branched alkyl group. R ₅ and R ₆ may combine with each other to form a ring, and examples of such a ring include a cyclopentyl ring and a cyclohexane ring. The “alkyl group having 1 to 18 carbon atoms” represented by R ₅ or R ₆ is preferably a linear alkyl group having 1 to 18 carbon atoms, more preferably a methyl group or an ethyl group, and a methyl group. Is particularly preferred. In addition, as the “alkyl group having 1 to 18 carbon atoms” represented by R ₇ or R ₈ , a linear alkyl group having 1 to 12 carbon atoms is preferable, and a linear chain having 5 to 12 carbon atoms is preferable. An alkyl group is more preferable, and an n-hexyl group is particularly preferable.

The “alkyl group having 1 to 18 carbon atoms” represented by R ₅ or R ₆ in the general formula (1) may have a substituent, and specifically includes a fluorine atom, a chlorine atom, a bromine atom. A halogen atom such as dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, diphenylamino group, etc. A disubstituted amino group having a substituent selected from an alkyl group or an aryl group having 6 to 20 carbon atoms; a carboxyl group; a linear or branched alkoxy having 1 to 6 carbon atoms substituted with a carboxyl group Group. Although the number of these substituents may be one or more, R ₅ or R ₆ is preferably a group having no substituent.

The “alkyl group having 1 to 18 carbon atoms” represented by R ₇ or R ₈ in the general formula (1) may have a substituent, specifically, a fluorine atom, a chlorine atom, or a bromine atom. A halogen atom such as methoxy group, ethoxy group, propoxy group, t-butoxy group, pentyloxy group, etc., linear or branched alkoxy group having 1 to 6 carbon atoms; phenyl group, naphthyl group, anthryl group, Aryl group such as phenanthryl group and pyrenyl group; straight chain having 1 to 6 carbon atoms such as dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, diphenylamino group A disubstituted amino group having a substituent selected from a linear or branched alkyl group or an aryl group having 6 to 20 carbon atoms; a hydroxyl group; Groups; methyl ester group, a carboxylic acid ester group such as an ethyl ester group; and a cyano group may be mentioned. Although the number of these substituents may be one or more, R ₇ or R ₈ is preferably a group having no substituent.

The “aryl group” represented by R ₅ or R ₆ in the general formula (1) is specifically an aryl having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, or a pyrenyl group. You can raise a group. Among these, a phenyl group or a naphthyl group is preferable.

The “aryl group” represented by R ₅ or R ₆ in the general formula (1) may have a substituent, specifically, a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom; a methyl group, A linear or branched alkyl group having 1 to 6 carbon atoms such as ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, hexyl group; methoxy group, ethoxy group, propoxy group A linear or branched alkoxy group having 1 to 6 carbon atoms such as t-butoxy group and pentyloxy group; 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group and pyrenyl group Aryl groups such as dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, diphenylamino group, etc. A disubstituted amino group having a substituent selected from a linear or branched alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms; a hydroxyl group; a carboxyl group; a methyl ester group, an ethyl ester group Carboxylic acid ester groups such as: linear or branched alkoxy groups having 1 to 6 carbon atoms substituted with carboxyl groups; ethenyl groups such as phenylethenyl groups and diphenylethenyl groups; cyano groups and the like Can do. The number of these substituents may be one or more. The substituent is preferably a linear or branched alkyl group having 1 to 6 carbon atoms, or a linear or branched alkoxy group having 1 to 6 carbon atoms, and a straight chain having 1 to 6 carbon atoms. A chain alkyl group or a linear alkoxy group having 1 to 6 carbon atoms is particularly preferred.

In the general formula (2), (4) or (5), the “acidic group” represented by R ₉ , R ₁₀ or R ₁₁ , or R ₁₂ or R ₁₃ is specifically a carboxyl group or a sulfonic acid group. And phosphoric acid group, hydroxamic acid group, phosphonic acid group, boric acid group, phosphinic acid group, silanol group and the like. Among these, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable.

In the general formula (1), R ₁ , R ₂ and R ₄ are preferably an aryl group, more preferably a phenyl group, and an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as a substituent. Particularly preferred is a phenyl group having an alkyl group or an unsubstituted phenyl group. Moreover, it is preferable that R ₁ and R ₂ are both aryl groups, and it is more preferable that R ₁ , R ₂ and R ₄ are all aryl groups.
R ₃ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl group having 1 to 6 carbon atoms or a carbon atom as a substituent. A phenyl group having an alkoxy group of 1 to 6 or an unsubstituted phenyl group is more preferable.
R ₅ and R ₆ are preferably a hydrogen atom, a methyl group or an ethyl group, or an aryl group, more preferably an unsubstituted methyl group or an unsubstituted ethyl group, and particularly preferably an unsubstituted methyl group.

R ₇ is preferably a hydrogen atom or an alkyl group having 5 to 12 carbon atoms, more preferably a hydrogen atom or a linear alkyl group having 5 to 12 carbon atoms, still more preferably a hydrogen atom or an n-hexyl group, A hydrogen atom is particularly preferred. R ₈ is preferably a hydrogen atom or an alkyl group having 5 to 12 carbon atoms, more preferably a hydrogen atom or a linear alkyl group having 5 to 12 carbon atoms, and a linear alkyl group having 5 to 12 carbon atoms. An alkyl group is more preferable, and an n-hexyl group is particularly preferable.
In addition, at least one of R _{7 and} R ₈ is an alkyl group having 5 to 12 carbon atoms (provided that when n is an integer of 2 to 4, among a plurality of R ₇ and R ₈ , At least one of them may be an alkyl group having 5 to 12 carbon atoms), and at least one of R _{7 and} R ₈ is a linear alkyl group having 5 to 12 carbon atoms ( However, when n is an integer of 2 to 4, at least one of R ₇ and R ₈ present in plural may be a linear alkyl group having 5 to 12 carbon atoms) more preferably, R 7 _(if R ₇ there are multiple said all R ₇₎ are hydrogen atom, and a hydrogen atom or a carbon atom _(the all R ₈ if R ₈ there are a _plurality) R ₈ A straight chain of 5 to 12 More preferably a kill group, R 7 _(if R ₇ there are multiple said all R ₇₎ are hydrogen atom, and R _{8 (the} all R ₈ if R ₈ there are a plurality) Is particularly preferably a hydrogen atom or an n-hexyl group.

In General formula (1), n represents the integer of 1-4. when n is 2 to 4, _{R 7} and _{R 8} there are a plurality, that _{R 7} together, each other _{R 8} may be the same or different from each other. A represents a monovalent group represented by the general formula (2) or (3).

In the general formula (3), X represents a monovalent group represented by the general formula (4), and Y represents a monovalent group represented by the general formula (5). p represents an integer of 0 to 2, and when p is 2, a plurality of Xs may be the same or different. In General formula (4), q represents the integer of 0-2 and r represents the integer of 0-3. Moreover, in General formula (5), v represents the integer of 0-2 and w represents the integer of 0-3. When in the general formula (3) p is 2, _R 10 there are a _{plurality, R} 11, q, r, the _{R 10 together, R 11} together, q each other, even if r each other mutually the same or different, respectively Good.

In the general formula (3), when p is 0, at least one of R ₁₂ or R ₁₃ is an acidic group, and when p is 1 or 2, the general formula (4) or the general formula ( At least one of R ₁₀ , R ₁₁ , R ₁₂ or R ₁₃ in 5) is an acidic group. That is, when p is 1, at least one of R ₁₀ , R ₁₁ , R ₁₂ , or R ₁₃ may be an acidic group, and when p is 2, two R ₁₀ , Of the two R ₁₁ , R ₁₂ or R ₁₃ , at least one may be an acidic group.

Among the sensitizing dyes for photoelectric conversion of the present invention represented by the general formula (1), when a sensitizing dye for photoelectric conversion in which R ₁ , R ₂ and R ₄ are phenyl groups is used, the efficiency is particularly high. Since a high photoelectric conversion element is obtained, it is preferable. Among the photoelectric conversion dye of the present invention represented by the general formula (1), R ₇ is a hydrogen atom and R ₈ is n- hexyl group (R ₈ there are a plurality of at least one R ₈ Is a n-hexyl group), it is possible to efficiently suppress the association and aggregation of sensitizing dyes, and further by containing a carboxyl group or a phosphonic acid group. The sensitizing dye can be easily adsorbed on the surface of the semiconductor layer, leading to improvement in photoelectric conversion characteristics.

The sensitizing dye for photoelectric conversion of the present invention represented by the general formula (1) includes all possible stereoisomers. Any isomer can be suitably used as a sensitizing dye for photoelectric conversion in the present invention. For example, in the general formula (1), the sensitizing dye for photoelectric conversion of the present invention in which A is a monovalent group represented by the general formula (2) is represented by the following general formula (6) or (7). It is intended to include compounds. In the general formula (1), the sensitizing dye for photoelectric conversion of the present invention in which A is a monovalent group represented by the general formula (3) and p is 0 is represented by the following general formula (8). Or the compound represented by (9) shall be included. In addition, it may be a mixture of two or more selected from these stereoisomers.

  Specific examples of the sensitizing dye for photoelectric conversion of the present invention represented by the general formula (1) are shown below, but the present invention is not limited thereto. The following exemplary compounds show examples of possible stereoisomers, and include all other stereoisomers. Moreover, each may be a mixture of two or more stereoisomers.

The sensitizing dye for photoelectric conversion of the present invention represented by the general formula (1) can be synthesized using a known method. For example, in the general formula (1), when n is 1, it can be synthesized as follows. After protecting aldehyde (B-2) obtained by formylating bromo compound (B-1) as acetal (B-3) using ethylene glycol, reaction using butyllithium and bis (pinacolato) diboron, etc. Thus, the boronic acid ester (B-4) can be obtained. On the other hand, the bromo compound (B-8) can be obtained by deacetylating (B-7) obtained by the Ullmann reaction between the fluorene compound (B-5) and the amide compound (B-6). it can. And amine (B-9) can be obtained by performing cross-coupling reactions, such as Suzuki coupling, using the obtained boronic acid ester (B-4) and a bromo body (B-8). Subsequently, Buchwald-Hartwig reaction between amine (B-9) and bromo compound (B-10) is performed to obtain (B-11), and then aldehyde (B-12) obtained by deprotecting the acetal. ) And cyanoacetic acid or rhodanine-3-acetic acid or the like, the sensitizing dye for photoelectric conversion of the present invention can be synthesized.
Moreover, when n is 2-4 in General formula (1), it is compoundable as follows. After obtaining aldehyde (B-14) by performing cross-coupling reaction such as Suzuki coupling using bromo compound (B-1) and boronic acid (B-13) having an aldehyde group, the boronic acid ester In the same manner as the synthesis method of (B-4), acetal (B-15) and boronic acid ester (B-16) were synthesized in sequence, and cross coupling such as Suzuki coupling with bromo compound (B-8). By carrying out the reaction, amine (B-17) can be obtained. Subsequently, Buchwald-Hartwig reaction between amine (B-17) and the bromo compound (B-10) was performed to obtain (B-18), and then the aldehyde (B The sensitizing dye for photoelectric conversion of the present invention can be synthesized by performing a condensation reaction of -19) with cyanoacetic acid, rhodanine-3-acetic acid or the like.

Purification of the compound of the sensitizing dye for photoelectric conversion of the present invention represented by the general formula (1) includes purification by column chromatography, adsorption purification by silica gel, activated carbon, activated clay, etc., recrystallization or crystallization by a solvent, etc. It can carry out using the well-known method of these. Further, these compounds can be identified by NMR analysis or the like.

  The sensitizing dye for photoelectric conversion of the present invention may be used alone or in combination of two or more. The sensitizing dye for photoelectric conversion of the present invention can be used in combination with other sensitizing dyes not belonging to the present invention. Specific examples of other sensitizing dyes include those represented by the general formula (1) such as ruthenium complexes, coumarin dyes, cyanine dyes, merocyanine dyes, rhodacyanine dyes, phthalocyanine dyes, porphyrin dyes, and xanthene dyes. Sensitizing dyes other than the sensitizing dyes for photoelectric conversion represented can be mentioned. When the sensitizing dye for photoelectric conversion of the present invention and these other sensitizing dyes are used in combination, the amount of the other sensitizing dye used for the sensitizing dye for photoelectric conversion of the present invention is 10 to 200% by mass. It is preferable to set it to 20 to 100% by mass.

  In the present invention, a method for producing a dye-sensitized photoelectric conversion element is not particularly limited. A semiconductor layer is formed on a conductive support (electrode), and the photoelectric conversion sensitizing dye of the present invention is formed on the semiconductor layer. A method of adsorption is preferred. As a method for adsorbing the dye, a method of immersing the semiconductor layer in a solution obtained by dissolving the dye in a solvent is generally used. When using two or more types of the sensitizing dye for photoelectric conversion of the present invention in combination, or when using the sensitizing dye for photoelectric conversion of the present invention in combination with other sensitizing dyes, prepare a mixed solution of all the dyes to be used. The semiconductor layer may be immersed, or a separate solution may be prepared for each dye, and the semiconductor layer may be sequentially immersed in each solution.

In the present invention, in addition to the metal plate, a glass substrate or a plastic substrate provided with a conductive layer having a conductive material on the surface can be used as the conductive support. Specific examples of the conductive material include metals such as gold, silver, copper, aluminum, and platinum, conductive transparent oxide semiconductors such as fluorine-doped tin oxide and indium-tin composite oxide, and carbon. However, it is preferable to use a glass substrate coated with a fluorine-doped tin oxide thin film.

  Specific examples of the semiconductor forming the semiconductor layer in the present invention include metals such as titanium oxide, zinc oxide, tin oxide, indium oxide, zirconium oxide, tungsten oxide, tantalum oxide, iron oxide, gallium oxide, nickel oxide, and yttrium oxide. Oxides: titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, silver sulfide and other metal sulfides; titanium selenide, zirconium selenide, indium selenide, tungsten selenide And metal selenides such as silicon and germanium. These semiconductors can be used alone or in combination of two or more. In the present invention, it is preferable to use titanium oxide, zinc oxide, or tin oxide as the semiconductor.

  Although the aspect of the semiconductor layer in the present invention is not particularly limited, it is preferably a thin film having a porous structure composed of fine particles. When the substantial surface area of the semiconductor layer increases due to the porous structure and the like, and the amount of dye adsorbed on the semiconductor layer increases, a highly efficient photoelectric conversion element can be obtained. The semiconductor particle diameter is preferably 5 to 500 nm, and more preferably 10 to 100 nm. The film thickness of the semiconductor layer is usually 2 to 100 μm, more preferably 5 to 20 μm. As a method for forming a semiconductor layer, a paste containing semiconductor fine particles is applied on a conductive substrate by a wet coating method such as a spin coating method, a doctor blade method, a squeegee method, or a screen printing method, and then a solvent or additive is baked. Examples thereof include, but are not limited to, a method for forming a film by removing the film, and a method for forming a film by sputtering, vapor deposition, electrodeposition, electrodeposition, microwave irradiation, and the like.

  In the present invention, the paste containing semiconductor fine particles may be a commercially available product, or a paste prepared by dispersing a commercially available semiconductor fine powder in a solvent. Specific examples of the solvent used in preparing the paste include alcohol solvents such as water, methanol, ethanol, isopropyl alcohol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, n-hexane, cyclohexane, benzene, Hydrocarbon solvents such as toluene can be mentioned, but are not limited to these. These solvents can be used alone or as a mixed solvent of two or more.

In the present invention, when the semiconductor fine powder is dispersed in a solvent, it may be ground with a mortar or the like, or a dispersing machine such as a ball mill, a paint conditioner, a vertical bead mill, a horizontal bead mill, or an attritor may be used. When preparing the paste, it is preferable to add a surfactant or the like in order to prevent aggregation of the semiconductor fine particles, and it is preferable to add a thickener such as polyethylene glycol to increase the viscosity.

  Adsorption of the sensitizing dye for photoelectric conversion of the present invention onto the surface of the semiconductor layer is performed by immersing the semiconductor layer in the dye solution and leaving it at room temperature for 30 minutes to 100 hours or under heating conditions for 10 minutes to 24 hours. However, it is preferable to leave at room temperature for 10 to 20 hours. The dye concentration in the dye solution is preferably 10 to 2000 μM, more preferably 50 to 500 μM.

  Specific examples of the solvent used when the photoelectric conversion sensitizing dye of the present invention is adsorbed on the surface of the semiconductor layer include alcohol solvents such as methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol, acetone, methyl ethyl ketone, and methyl. Ketone solvents such as isobutyl ketone, ester solvents such as ethyl formate, ethyl acetate and n-butyl acetate, ether solvents such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran and 1,3-dioxolane, N, N -Amide solvents such as dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, dichloromethane, chloroform, bromoform, o-dichlorobenzene, etc. C Gen hydrocarbon solvents, n- hexane, cyclohexane, benzene, may be mentioned hydrocarbon solvents such as toluene, but are not limited to. These solvents are used alone or as a mixed solvent of two or more. Among these solvents, methanol, ethanol, tert-butyl alcohol, acetone, methyl ethyl ketone, tetrahydrofuran and acetonitrile are preferable.

When adsorbing the sensitizing dye for photoelectric conversion of the present invention on the surface of the semiconductor layer, a cholic acid derivative such as cholic acid or deoxycholic acid, chenodeoxycholic acid, lysocholic acid, and dehydrocholic acid is dissolved in the dye solution, It may be co-adsorbed with the dye. By using cholic acid or a cholic acid derivative, association between the dyes is suppressed, and electrons can be efficiently injected from the dye into the semiconductor layer in the photoelectric conversion element. When cholic acid or cholic acid derivatives are used, their concentration in the dye solution is preferably from 0.1 to 100 mM, more preferably from 1 to 10 mM.

  The counter electrode (electrode) used in the photoelectric conversion element of the present invention is not particularly limited as long as it has conductivity, but a conductive material having catalytic ability is used to promote the redox ion oxidation-reduction reaction. It is preferable to do this. Specific examples of the conductive material include, but are not limited to, platinum, rhodium, ruthenium, carbon, and the like. In the present invention, it is particularly preferable to use as a counter electrode a platinum thin film formed on a conductive support. As a method for forming a conductive thin film, a paste containing a conductive material is applied onto a conductive substrate by a wet coating method such as a spin coating method, a doctor blade method, a squeegee method, or a screen printing method, and then fired. Examples thereof include a method for forming a film by removing a solvent and additives, and a method for forming a film by a sputtering method, a vapor deposition method, an electrodeposition method, an electrodeposition method, a microwave irradiation method, and the like, but are not limited thereto.

  In the photoelectric conversion element of the present invention, an electrolyte is filled between a pair of opposed electrodes to form an electrolyte layer. As the electrolyte to be used, a redox electrolyte is preferable. Examples of redox electrolytes include, but are not limited to, redox ion pairs such as iodine, bromine, tin, iron, chromium, and anthraquinone. Among these, iodine-based electrolytes and bromine-based electrolytes are preferable. In the case of an iodine-based electrolyte, for example, a mixture of potassium iodide, lithium iodide, dimethylpropylimidazolium iodide and the like and iodine is used. In the present invention, it is preferable to use an electrolytic solution obtained by dissolving these electrolytes in a solvent. 0.05-5M is preferable and, as for the density | concentration of the electrolyte in electrolyte solution, 0.2-1M is more preferable.

  Solvents for dissolving the electrolyte include nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, benzonitrile, ether solvents such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, N Amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide, carbonate solvents such as ethylene carbonate and propylene carbonate, and lactone solvents such as γ-butyrolactone and γ-valerolactone. It is not limited to. These solvents are used alone or as a mixed solvent of two or more. Of these solvents, nitrile solvents are preferred.

In the present invention, 4-tert-butylpyridine, 4-methylpyridine, 2-vinylpyridine, N, N-dimethyl-4-aminopyridine, N, N-dimethylaniline, N-methylbenzimidazole, etc. An amine compound, particularly 4-tert-butylpyridine, may be contained. The concentration of the amine compound in the electrolytic solution is preferably 0.05 to 5M, and more preferably 0.2 to 1M. The inclusion of an amine compound in the electrolytic solution is particularly preferable because the open-circuit voltage and fill factor of the dye-sensitized photoelectric conversion element are increased.

  In the present invention, a gel electrolyte obtained by adding a gelling agent, a polymer or the like to the electrolytic solution may be used. Further, a solid electrolyte using a polymer such as a polyethylene oxide derivative may be used instead of the electrolytic solution containing the redox electrolyte. By using a gel electrolyte or a solid electrolyte, volatilization of the electrolytic solution can be reduced.

  In the photoelectric conversion element of the present invention, a solid charge transport layer may be formed between the pair of opposed electrodes instead of the electrolyte. The charge transport material contained in the solid charge transport layer is preferably a hole transport material. Specific examples of the charge transport material include inorganic hole transport materials such as copper iodide, copper bromide and copper thiocyanide, polypyrrole, polythiophene, poly-p-phenylene vinylene, polyvinyl carbazole, polyaniline, oxadiazole derivatives, tri Organic hole transport materials such as phenylamine derivatives, pyrazoline derivatives, fluorenone derivatives, hydrazone compounds, and stilbene compounds are exemplified, but not limited thereto.

  In the present invention, when forming a solid charge transport layer using an organic hole transport material, it is preferable to use a film-forming binder resin in combination. Specific examples of the film-forming binder resin include polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polysulfone resin, polyester resin, polyphenylene oxide resin, polyarylate resin, alkyd resin, acrylic resin, phenoxy resin, and the like. However, it is not limited to these. These resins can be used alone or as a copolymer in combination of one or more. 20-1000 mass% is preferable and the usage-amount with respect to the organic hole transport material of these binder resin is more preferable 50-500 mass%.

In the photoelectric conversion element of the present invention, the electrode (photoelectrode) provided with the semiconductor layer on which the sensitizing dye is adsorbed serves as a cathode, and the counter electrode serves as an anode. Light such as sunlight may be irradiated from either the photoelectrode side or the counter electrode side, but irradiation from the photoelectrode side is preferable. By irradiation with sunlight or the like, the dye absorbs light and becomes excited to emit electrons. The electrons flow to the outside via the semiconductor layer and move to the counter electrode. On the other hand, the dye that has been in an oxidized state by emitting electrons returns to the ground state by receiving electrons supplied from the counter electrode via ions in the electrolyte. By this cycle, a current flows and functions as a photoelectric conversion element.

When evaluating the characteristics of the photoelectric conversion element of the present invention, short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency are measured. The short circuit current represents the current per 1 cm ² flowing between the two terminals when the output terminal is short-circuited, and the open circuit voltage represents the voltage between the two terminals when the output terminal is opened. The fill factor is a value obtained by dividing the maximum output (product of current and voltage) by the product of the short-circuit current and the open-circuit voltage, and mainly depends on the internal resistance. The photoelectric conversion efficiency is obtained as a percentage value obtained by multiplying the value obtained by dividing the maximum output (W) by the light intensity (W) per 1 cm ² by 100.

  The photoelectric conversion element of the present invention can be applied to a dye-sensitized solar cell, various optical sensors, and the like. In the dye-sensitized solar cell of the present invention, the photoelectric conversion element containing the sensitizing dye represented by the general formula (1) becomes a cell, and the required number of the cells are arranged to be modularized, and predetermined electrical wiring is provided. Can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to a following example.
[Synthesis Example 1] Synthesis of sensitizing dye for photoelectric conversion (A-3) In a nitrogen-substituted reaction vessel, 45 ml of diethyl ether and 4.50 g of 2-bromo-3-hexylthiophene were added, and -74 ° C with dry ice. Then, 12 ml of n-hexane solution (1.58M) of n-butyllithium was added thereto and stirred for 1 hour. Subsequently, 2.1 ml of N, N-dimethylformamide was added, the temperature was raised to room temperature, 90 ml of chloroform was added and stirred, and the organic layer was extracted and washed with water. The obtained organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 4.90 g of an orange oil of the following compound (C-1).

Next, 76 ml of toluene, 4.90 g of the obtained compound (C-1), 5.1 ml of ethylene glycol, and 0.04 g of p-toluenesulfonic acid monohydrate were added to a nitrogen-substituted reaction vessel, and the mixture was heated to 104 ° C. And stirred for 4 hours. After cooling to room temperature, 50 ml of saturated aqueous sodium hydrogen carbonate solution and 76 ml of toluene were added and stirred, and the organic layer was extracted and washed with water. The obtained organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography (carrier: silica gel, eluent: n-hexane / ethyl acetate) and dried under reduced pressure to give 4.05 g (yield 93%) of the following compound (C-2). An orange oil was obtained.

Into a reaction vessel purged with nitrogen, 112 ml of tetrahydrofuran and 3.50 g of the obtained compound (C-2) were added and cooled to -75 ° C. with dry ice, where n-butyllithium in an n-hexane solution (1. 58M) 14 ml was added and stirred for 5 hours. Subsequently, a solution obtained by dissolving 2.98 g of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 14 ml of tetrahydrofuran was added, and the temperature was raised to room temperature. A saturated aqueous ammonium chloride solution (56 ml) and ethyl acetate (112 ml) were added and stirred, and the organic layer was extracted and washed with water. The obtained organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain 5.21 g (yield 98%) of a yellow oil of the following compound (C-3).

In a nitrogen-substituted reaction vessel, 10.0 g of 2,7-dibromo-9,9-dimethylfluorene, 6.35 g of paraacetoluidine, 0.18 g of copper powder, 0.56 g of 1,10-phenanthroline monohydrate, 7.85 g of potassium carbonate, 0.88 g of sodium hydrogen sulfite and 10 ml of nitrobenzene were added and heated, followed by heating and stirring at 225 ° C. for 6 hours. After cooling the reaction solution to room temperature, 200 ml of chloroform was added and stirred, and the organic layer was extracted, washed with water, and washed with saturated brine. The obtained organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography (carrier: silica gel, eluent: n-hexane / ethyl acetate) and dried under reduced pressure to obtain 3.40 g (yield 28%) of the following compound (C-4). A black brown oil was obtained.

3.40 g of the compound (C-4) obtained, 6 ml of isoamyl alcohol, 3 ml of toluene, 1.5 ml of purified water and 1.80 g of potassium hydroxide were added to the reaction vessel purged with nitrogen, and the mixture was heated and stirred at 80 ° C. for 15 hours. did. After cooling the reaction solution to room temperature, 50 ml of toluene and 25 ml of purified water were added and stirred, and the organic layer was extracted and washed with water. The obtained organic layer was washed with saturated brine, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography (carrier: silica gel, eluent: n-hexane / ethyl acetate) and dried under reduced pressure to obtain 1.90 g (yield 62%) of the following compound (C-5). A white solid was obtained.

In a nitrogen-substituted reaction vessel, 37 ml of N, N-dimethylformamide and 7.7 ml of purified water were added, and 1.61 g of compound (C-3), 3.20 g of compound (C-5), and triphenylphosphine were added thereto. After adding 0.19 g and 2.42 g of cesium carbonate and stirring, the pressure reduction, deaeration, and nitrogen substitution in the reaction vessel were repeated three times. Next, 0.04 g of palladium acetate was added, and the mixture was heated and stirred at 87 ° C. for 1.5 hours. After cooling the reaction solution to room temperature, 60 ml of hexane, 60 ml of ethyl acetate and 40 ml of water were added to extract the organic layer. The obtained organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a crude product. The crude product was purified by silica gel column chromatography (carrier: silica gel, eluent: n-hexane / ethyl acetate) and dried under reduced pressure to obtain 0.99 g (99% yield) of the following compound (C-6). A yellow-green solid was obtained.

In a nitrogen-substituted reaction vessel, 0.80 g of compound (C-6), 0.55 g of 2-bromo-1,1,2-triphenylethylene, 0.18 g of 1,3-dimethyl-2-imidazolidinone, Copper acetylacetonate 0.06g, potassium carbonate 0.24g and toluene 2.5ml were added, and it heated and stirred at 150 degreeC for 14 hours. The reaction solution was cooled to room temperature, and 25 ml of toluene was added and stirred, followed by filtration. The obtained filtrate was concentrated under reduced pressure, dissolved in chloroform, and further concentrated three times to obtain a brown oily crude product. The crude product was purified by silica gel column chromatography (carrier: silica gel, eluent: n-hexane / ethyl acetate) and dried under reduced pressure to give 0.37 g (yield 20%) of the following compound (C-7) yellow A solid was obtained.

In a reaction vessel purged with nitrogen, 0.10 g of compound (C-7), 3 ml of acetone, and 0.03 g of pyridinium paratoluenesulfonate were added and stirred at room temperature for 1.5 hours. 30 ml of ethyl acetate and 30 ml of purified water were added and stirred, and the organic layer was extracted, washed with water, washed with an aqueous sodium hydrogen carbonate solution and saturated brine successively. The obtained organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure to obtain 0.09 g (yield 95%) of a yellow oil of the following compound (C-8).

Under an argon atmosphere, 15 ml of toluene, 0.10 g of compound (C-8), 0.02 g of cyanoacetic acid, and 0.03 g of piperidine were added to the reaction vessel, and the mixture was heated and stirred at 80 ° C. for 15 hours. After cooling the reaction solution to room temperature, 50 ml of 1M hydrochloric acid and 50 ml of ethyl acetate were added, and the organic layer was extracted, washed with water, and washed with saturated brine in that order. The organic layer was dried over anhydrous sodium acetate and the solvent was distilled off to obtain a crude product. By purifying the crude product by silica gel column chromatography (carrier: silica gel, eluent: chloroform / methanol), 0.08 g (70% yield) of reddish brown powder of the following sensitizing dye for photoelectric conversion (A-3) was obtained. Obtained.

  The structure of the obtained reddish brown powder was identified by NMR analysis.

The following 49 hydrogen signals were detected by 1H-NMR (CDCl ₃ ) (carboxyl group hydrogen was not observed). δ (ppm) = 0.87-0.95 (3H), 1.22-1.44 (12H), 1.63-1.73 (2H), 2.16-2.24 (3H), 2 .78-2.88 (2H), 6.85-7.16 (20H), 7.29-7.38 (3H), 7.50-7.55 (1H), 7.60-7.66 (2H), 8.43-8.52 (1H).

[Synthesis Example 2] Synthesis of sensitizing dye for photoelectric conversion (A-35) In a nitrogen atmosphere, 5 ml of toluene, 0.25 g of compound (C-8), 0.07 g of rhodanine-3-acetic acid, piperidine 0.01 g was added and the mixture was stirred with heating at 90 ° C. for 2 hours. The reaction solution was cooled to room temperature, and extracted by adding 10 ml of 1M hydrochloric acid and 10 ml of toluene. The obtained organic layer was dried over sodium sulfate, the solvent was distilled off under reduced pressure to obtain a crude product, and then dispersed and washed with methanol, whereby the following sensitizing dye for photoelectric conversion (A- 35) 0.25 g (yield 79%) of a red-black solid was obtained.

  The structure of the obtained red-black powder was identified by NMR analysis.

The following 51 hydrogen signals were detected by 1H-NMR (CDCl ₃ ) (carboxyl group hydrogen was not observed). δ (ppm) = 0.87-0.94 (3H), 1.21-1.43 (12H), 1.63-1.73 (2H), 2.15-2.24 (3H), 2 .76-2.87 (2H), 4.91-4.97 (2H), 6.85-7.19 (20H), 7.29-7.39 (3H), 7.50-7.60 (3H), 7.98-8.04 (1H).

[Example 1]
A titanium oxide paste (manufactured by JGC Catalysts & Chemicals, PST-18NR) was applied by a squeegee method on a glass substrate coated with a fluorine-doped tin oxide thin film. After drying at 110 ° C. for 1 hour, baking was performed at 450 ° C. for 30 minutes to obtain a titanium oxide thin film having a thickness of 7 μm. Next, the sensitizing dye for photoelectric conversion (A-3) obtained in Synthesis Example 1 is dissolved in a mixed solvent of acetonitrile / tert-butyl alcohol = 1/1 to prepare 50 ml of a 100 μM concentration solution. Inside, a glass substrate coated with titanium oxide and sintered was immersed for 15 hours at room temperature to adsorb the pigment, thereby obtaining a photoelectrode.

A platinum thin film having a thickness of 15 nm was formed on a glass substrate coated with a fluorine-doped tin oxide thin film by a sputtering method using an auto fine coater (JFC-1600 manufactured by JEOL Ltd.) as a counter electrode. Next, a spacer (heat-sealing film) having a thickness of 60 μm is sandwiched between the photoelectrode and the counter electrode, and bonded together by heat sealing. After the electrolyte is injected from the hole previously formed in the counter electrode, the hole is sealed. And the photoelectric conversion element was produced. As the electrolytic solution, a 3-methoxypropionitrile solution of lithium iodide 0.1M, dimethylpropylimidazolium iodide 0.6M, iodine 0.05M, and 4-tert-butylpyridine 0.5M was used.

From the photoelectrode side of the photoelectric conversion element, light generated by a pseudo-sunlight irradiation device (OTENTO-SUN III type manufactured by Spectrometer Co., Ltd.) is irradiated, and a source meter (Model 2400 General-Purpose SourceMeter manufactured by KEITHLEY) is irradiated. Was used to measure current-voltage characteristics. The intensity of light was adjusted to 100 mW / cm ² . In addition, the photoelectric conversion efficiency was measured after 20 hours of irradiation with light, and the change in characteristics was evaluated. The measurement results are summarized in Table 1.

[Examples 2 to 10]
A photoelectric conversion element was prepared in the same manner as in Example 1 except that the sensitizing dye shown in Table 1 was used instead of (A-3) as the sensitizing dye for photoelectric conversion, and the current-voltage characteristics were measured. . In addition, the photoelectric conversion efficiency was measured after 20 hours of irradiation with light, and the change in characteristics was evaluated. The measurement results are summarized in Table 1.

[Comparative Examples 1-4]
As the sensitizing dye for photoelectric conversion, it was carried out except that the sensitizing dye for photoelectric conversion shown in the following (D-1) to (D-4) not belonging to the present invention was used instead of (A-3). A photoelectric conversion element was produced in the same manner as in Example 1, and current-voltage characteristics were measured. In addition, the photoelectric conversion efficiency was measured after 20 hours of irradiation with light, and the change in characteristics was evaluated. The measurement results are summarized in Table 1.

From the results of Table 1, by using the sensitizing dye for photoelectric conversion of the present invention, it is possible to obtain a photoelectric conversion element that has high photoelectric conversion efficiency and maintains high photoelectric conversion efficiency even if light irradiation is continued for a long time. There was found. Among the examples, the photoelectric conversion efficiency of the photoelectric conversion elements obtained in Examples 1 to 3 was particularly excellent. On the other hand, the photoelectric conversion efficiency of the photoelectric conversion element using the sensitizing dye for photoelectric conversion of the comparative example was insufficient.

The solar cell using the sensitizing dye for photoelectric conversion of the present invention is useful as a dye-sensitized solar cell that can efficiently convert sunlight energy into electric energy, and can provide clean energy.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Dye carrying | support semiconductor layer 3 Electrolyte layer 4 Counter electrode 5 Conductive support body

Claims (11)

A sensitizing dye for photoelectric conversion represented by the following general formula (1).

(In the formula, R _{1 to} R ₃ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aralkyl group, or an aryl group. R ₄ has 1 to 6 carbon atoms. R ₅ and R ₆ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an aryl group, R ₅ and R ₆ may combine with each other to form a ring, and R ₇ and R ₈ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, n is 1 to 4 represents an integer. here, when n is 2 to 4, _{R 7} and _{R 8} there are a plurality, that _{R 7} together may be each other _{R 8} is not the same as or different from each other to each other .A the following general 1 represented by formula (2) or (3) It represents a group.)

(In the formula, R ₉ represents an acidic group.)

(In the formula, X represents a monovalent group represented by the following general formula (4), Y represents a monovalent group represented by the following general formula (5), p represents an integer of 0 to 2, and p represents In the case of 2, a plurality of Xs may be the same or different.

(In the formula, R ₁₀ and R ₁₁ may be the same or different and each represents a hydrogen atom or an acidic group. Q represents an integer of 0 to 2, and r represents an integer of 0 to 3. Here, when in the general formula (3) p is 2, _R 10 there are a _{plurality, R} 11, q, r, the _{R 10 together, R 11} together, q each other, even if r each other mutually the same or different, respectively Good.)

_{(Wherein, R 12} and _{R 13} may be the same or different, .v represents a hydrogen atom or an acidic group is an integer of 0 to 2, w is an integer of 0 to 3.)
However, when p is 0, at least one of R ₁₂ or R ₁₃ in the general formula (5) is an acidic group, and when p is 1 or 2, the general formula (4) or the general formula At least one of R ₁₀ , R ₁₁ , R ₁₂ or R ₁₃ in (5) is an acidic group. ) 2. The sensitization for photoelectric conversion according to claim 1, wherein in the general formula (1), R ₅ and R ₆ are a hydrogen atom, an alkyl group having 1 or 2 carbon atoms, or an aryl group. Pigment. In the general formula (1), characterized in that one of at least R ₇ or R ₈ is an alkyl group having 5 to 12 carbon atoms, up photoelectric conversion according to claim 1 or claim 2 Sensitive dye. The sensitization for photoelectric conversion according to any one of claims 1 to 3, wherein in the general formula (1), A is a monovalent group represented by the general formula (2). Pigment. In Formula (1), characterized in that R ₁ and R ₂ is an aryl group, claims 1 to 4 of any one photoelectric conversion sensitizing dyes described. In Formula (1), characterized in that R ₄ is an aryl group, claims 1 to 5 any one photoelectric conversion sensitizing dyes described in. In the general formula (1), R ₇ is a hydrogen atom, and wherein the R ₈ is a hydrogen atom or an alkyl group 5 to 12 carbon atoms, any one of claims 1 to 6 The sensitizing dye for photoelectric conversion according to one item. 8. The general formula (1), wherein R ₇ is a hydrogen atom, and R ₈ is a hydrogen atom or an n-hexyl group, according to claim 1. Sensitizing dye for photoelectric conversion. The dye-sensitized photoelectric conversion element in which at least a semiconductor layer and an electrolyte layer are provided between a pair of opposed electrodes, and the photoelectric conversion sensitizing dye according to any one of claims 1 to 8. Is supported on the semiconductor layer. The photoelectric conversion element according to claim 9, wherein the electrolyte layer contains 4-tert-butylpyridine. A dye-sensitized solar cell having a photoelectric conversion element, which is obtained by modularizing the photoelectric conversion element according to claim 9 or 10 and providing predetermined electric wiring. battery.

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