CN113321942A

CN113321942A - Sensitizing dye, sensitizing dye composition for photoelectric conversion, photoelectric conversion element, and dye-sensitized solar cell

Info

Publication number: CN113321942A
Application number: CN202110218770.3A
Authority: CN
Inventors: 冈地诚; 桦泽直朗; 佐藤洋
Original assignee: Hodogaya Chemical Co Ltd
Current assignee: Hodogaya Chemical Co Ltd
Priority date: 2020-02-28
Filing date: 2021-02-26
Publication date: 2021-08-31
Also published as: TW202140468A; JP2021138935A; KR20210110229A

Abstract

Disclosed are a sensitizing dye, a sensitizing dye composition for photoelectric conversion, a photoelectric conversion element, and a dye-sensitized solar cell. Provided are a sensitizing dye having a novel structure capable of expanding a photosensitive wavelength band, and a photoelectric conversion element and a dye-sensitized solar cell having excellent photoelectric conversion characteristics, which use the sensitizing dye as a sensitizing dye composition for photoelectric conversion capable of efficiently extracting current. The sensitizing dye is represented by the following general formula (1). [ formula 1]

Description

Sensitizing dye, sensitizing dye composition for photoelectric conversion, photoelectric conversion element, and dye-sensitized solar cell

Technical Field

The present invention relates to a sensitizing dye, a sensitizing dye composition for photoelectric conversion, a photoelectric conversion element, and a dye-sensitized solar cell.

Background

In recent years, carbon dioxide generated from fossil fuels such as coal, oil, and natural gas causes global warming as a greenhouse gas, and environmental destruction is caused by global warming, and there is concern that global environmental destruction will be developed due to an increase in energy consumption in the world as a result of an increase in population. In response to this situation, studies are actively being made on the use of renewable energy sources that are less dangerous to be exhausted unlike fossil fuels. As a power generation system based on the next generation of main renewable energy sources that can contribute to prevention of global warming, instead of thermal power generation or atomic power generation that consumes fossil fuels, solar energy utilization mainly based on solar photovoltaic power generation has been increasing in importance. The use of solar energy has been progressing in various fields, from the power generation and charging of watches and portable small electronic devices, to small-scale power generation facilities in houses and buildings, and leisure areas where lighting and heating costs can be saved.

As a solar photovoltaic power generation means, a photoelectric conversion element for converting solar energy into electric energy is used for a solar cell, and as a solar cell, inorganic solar cells such as compound semiconductors of single crystal, polycrystal, amorphous silicon, gallium arsenide, cadmium sulfide, indium copper selenide and the like are mainly studied, and are now widely used in houses and small-scale power generation facilities. However, such inorganic solar cells have problems such as high production cost and difficulty in securing raw materials.

On the other hand, although the photoelectric conversion rate and durability are significantly lower than those of inorganic solar cells, organic solar cells such as organic thin-film solar cells and dye-sensitized solar cells using various organic materials have been developed. Organic solar cells are considered to be more advantageous than inorganic solar cells in terms of manufacturing cost, large area, light weight, thin film, light transmittance, wide absorption wavelength range, flexibility, material conservation, and the like.

Among them, the dye-sensitized solar cell proposed by Gretzel et al (see non-patent document 1) is a wet solar cell composed of a thin-film electrode composed of porous titanium oxide as a semiconductor, a ruthenium complex dye adsorbed on the surface of the semiconductor for expanding the light-sensitive wavelength band, and an electrolyte containing iodine, and is expected to have high photoelectric conversion efficiency matching that of an amorphous silicon solar cell. The dye-sensitized solar cell has a simple device structure and can be manufactured without a large manufacturing facility as compared with other solar cells, and thus is attracting attention as a next-generation solar cell.

Ruthenium complexes are considered to be the most suitable sensitizing dyes for dye-sensitized solar cells from the viewpoint of photoelectric conversion efficiency, but ruthenium is a noble metal and therefore disadvantageous in terms of production cost, and also there is a problem of resource restrictions when a large amount of ruthenium complexes are required for practical use. Therefore, studies on dye-sensitized solar cells using an organic dye containing no noble metal such as ruthenium as a sensitizing dye have been actively conducted. As the organic dye containing no noble metal, coumarin dyes, cyanine dyes, merocyanine dyes, rhodanine dyes, phthalocyanine dyes, porphyrin dyes, x-ton dyes, and the like are disclosed (for example, see patent documents 1 to 3). The present inventors have also proposed a compound having a 9, 10-dihydroacridine (acridine) skeleton, a phenothiazine (phenothiazine) skeleton, or the like as an organic dye having an excellent sensitizing effect (see patent document 4).

Further, as an electron attracting portion for adsorbing on the surface of a semiconductor particle such as titanium oxide and efficiently transporting excited electrons generated in a sensitizing dye to a semiconductor, a compound having an indanone structure has been proposed (for example, see patent documents 6 to 7).

However, although these organic dyes have advantages such as low cost, large absorption coefficient, and controllable absorption characteristics due to their diversified structures, they do not satisfy the required characteristics sufficiently in terms of photoelectric conversion efficiency and stability over time, and thus are currently available.

Patent document

Patent document 1: japanese laid-open patent publication No. 11-214730

Patent document 2: japanese laid-open patent publication No. 11-238905

Patent document 3: japanese patent laid-open publication No. 2011-26376

Patent document 4: japanese patent laid-open publication No. 2013-60581

Patent document 5: japanese patent laid-open publication No. 2011-207784

Patent document 6: japanese laid-open patent publication No. 2012-51854

Patent document 7: japanese patent laid-open publication No. 2016-6811

Non-patent document

Non-patent document 1: "Nature", UK, 1991, 353 rd, 737-

Disclosure of Invention

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a sensitizing dye having a novel structure capable of expanding a photosensitive wavelength band, and further to provide a photoelectric conversion element and a dye-sensitized solar cell having excellent photoelectric conversion characteristics, which use the sensitizing dye as a sensitizing dye composition for photoelectric conversion capable of efficiently extracting an electric current.

In order to solve the above problems, the inventors of the present invention have conducted extensive studies to improve the photoelectric conversion characteristics of a sensitizing dye, and have found that a highly efficient and highly durable photoelectric conversion element can be obtained by using a sensitizing dye having a specific structure as a sensitizing dye for photoelectric conversion. That is, the present invention is constituted as follows.

A sensitizing dye is represented by the following general formula (1),

[ solution 1]

In the formula, R⁰Represents a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, or an aryl group having 6 to 36 carbon atoms which may have a substituent,

R¹～R⁴the same or different and represent a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, a nitro group, a nitroso group, a thiol group, a,

A linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent,

A cycloalkyl group having 3 to 36 carbon atoms which may have a substituent,

A linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent,

A cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent,

A linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent,

An aryl group having 6 to 36 carbon atoms which may have a substituent,

Or an amino group having 0 to 36 carbon atoms which may have a substituent,

R¹～R⁴capable of bonding to each other between adjacent groups to form a ring,

x represents a sulfur atom, an oxygen atom or CR⁵R⁶，R⁵、R⁶The same or different, and represents a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, or an aryl group having 6 to 36 carbon atoms which may have a substituent,

y represents a sulfur atom, an oxygen atom, CR⁷R⁸Or NR⁹，R⁷～R⁹The same or different, and represents a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, a linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent, or a C6 to 3 carbon atoms which may have a substituent6 of a group consisting of an aryl group,

a represents a monovalent group, and B represents a divalent group or a single bond.

A sensitizing dye composition for photoelectric conversion comprising a sensitizing dye represented by the general formula (1).

A photoelectric conversion element using the sensitizing dye composition for photoelectric conversion.

A dye-sensitized solar cell uses the photoelectric conversion element.

According to the sensitizing dye of the present invention, a sensitizing dye composition for photoelectric conversion capable of efficiently extracting an electric current can be obtained. Further, by using the sensitizing dye composition for photoelectric conversion, a photoelectric conversion element and a dye-sensitized solar cell having high efficiency and high durability can be obtained.

Drawings

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

(description of reference numerals)

1 a conductive support; 2 a dye carrying semiconductor layer; 3 an electrolyte layer; 4. a counter electrode; 5 an electrically conductive support.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. First, this embodiment will be described with reference to examples thereof.

1. A sensitizing dye is represented by the following general formula (1),

[ solution 1]

A cycloalkyl group having 3 to 36 carbon atoms which may have a substituent,

A cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent,

An aryl group having 6 to 36 carbon atoms which may have a substituent,

Or an amino group having 0 to 36 carbon atoms which may have a substituent,

y represents a sulfur atom, an oxygen atom, CR⁷R⁸Or NR⁹，R⁷～R⁹The same or different alkyl groups may be substituted by a linear or branched alkyl group having 1 to 36 carbon atoms, a substituted linear or branched alkoxy group having 1 to 36 carbon atoms, or a substituted aryl group having 6 to 36 carbon atoms,

2. A sensitizing dye, wherein,

in the above general formula (1), A is a 1-valent group represented by any one of the following general formulae (2) to (4),

[ solution 2]

In the formula, R²⁰And R²¹Represents a hydrogen atom or an acidic group, and R²⁰And R²¹At least one of which is an acidic group, R²²And R²⁴Represents an acidic group, R²³And R²⁵Represents a hydrogen atom or an electron-withdrawing group.

3. A sensitizing dye, wherein,

in the above general formula (1), B is a 2-valent bond or a single bond represented by the following general formula (5),

[ solution 3]

Wherein Z represents a carbon atom or a silicon atom,

R³⁰and R³¹Are the same or different and represent a hydrogen atom,

Or an aryl group having 6 to 36 carbon atoms which may have a substituent,

R³²to R³⁷Are the same or different and represent a hydrogen atom,

Or a linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent,

R³²and R³³，R³⁴And R³⁵And R³⁶And R³⁷Each of which is the same or different and each of which is bonded to each other to form a ring,

p, q and r represent 0 or 1.

4. A sensitizing dye, wherein,

in the general formula (1), R⁰Is a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 26 carbon atoms which may have a substituent, R¹～R⁴Is a hydrogen atom,

An aryl group having 6 to 36 carbon atoms which may have a substituent,

Or an amino group having 0 to 36 carbon atoms which may have a substituent,

x is CR⁵R⁶Or a sulfur atom,

y is a sulfur atom, CR⁷R⁸Or NR⁹。

5. A sensitizing dye composition for photoelectric conversion comprises the sensitizing dye.

6. A photoelectric conversion element using the sensitizing dye composition for photoelectric conversion.

7. A dye-sensitized solar cell uses the photoelectric conversion element.

The sensitizing dye composition for photoelectric conversion comprising the sensitizing dye of the present invention is used as a sensitizing agent in a dye-sensitized photoelectric conversion element. In addition, in the specification of the present application, "sensitizing dye" means a compound represented by general formula (1), and "sensitizing dye composition for photoelectric conversion" means a composition comprising one or two or more compounds represented by general formula (1) and optionally comprising other sensitizing dyes not belonging to the present invention. The "photoelectric conversion element" of the present invention is typically such that a photoelectrode in which a dye is adsorbed to a semiconductor layer on a conductive support and a counter electrode are arranged to face each other with an electrolyte layer interposed therebetween.

Hereinafter, the sensitizing dye represented by the above general formula (1) will be specifically described, but the present invention is not limited thereto.

In the general formula (1), as represented by R⁰The "linear or branched alkyl group having 1 to 36 carbon atoms" in the "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" includes, specifically, a linear alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and the like; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl and isooctyl.

In the general formula (1), as represented by R⁰The "aryl group having 6 to 36 carbon atoms" in the "aryl group having 6 to 36 carbon atoms which may have a substituent" includes, specifically, aryl groups such as phenyl, naphthyl, biphenyl, anthracenyl, phenanthrolinyl, pyrenyl, triethylene, indenyl, and fluorenyl. The "aryl group" in the present invention means an aromatic hydroxyl group and a condensed polycyclic aryl group, and among them, a phenyl group, a naphthyl group and a biphenyl group are preferable.

In the general formula (1), as represented by R⁰The "substituent" in the "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" and the "aryl group having 6 to 36 carbon atoms which may have a substituent" shown,

specifically, there may be mentioned: halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom;

a cyano group; a hydroxyl group; a nitro group; a nitroso group; a thiol group;

cycloalkyl groups having 3 to 34 carbon atoms such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclooctyl group;

a straight-chain alkoxy group having 1 to 34 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, a hexoxy group, a heptoxy group, an octoxy group, a nonoxy group, a decyloxy group, and the like;

a branched alkoxy group having 3 to 34 carbon atoms such as an isopropoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, and an isooctoxy group;

a cycloalkoxy group having 3 to 34 carbon atoms such as a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, etc.;

aryl groups having 6 to 34 carbon atoms such as phenyl, naphthyl, biphenyl, anthryl, phenanthryl, pyrenyl, triphenylene, indenyl, and fluorenyl;

an unsubstituted amino group; an amino group having a substituent having 1 to 34 carbon atoms, such as a methylamino group, dimethylamino group, diethylamino group, ethylmethylamino group, methylpropylamino group, di-t-butylamino group, or diphenylamino group;

a carboxyl group; carboxylic acid ester groups such as methyl ester group and ethyl ester group, and the like. These "substituents" may include one or more, and when a plurality of such substituents are included, they may be the same as or different from each other. In addition, these "substituents" may further have the substituents exemplified above.

In the above general formula (1), R⁰The alkyl group is preferably a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 26 carbon atoms which may have a substituent, more preferably an aryl group having 6 to 16 carbon atoms which may have a substituent, and most preferably an aryl group having 6 to 12 carbon atoms. In addition, in R⁰The "substituent" is preferably a linear alkoxy group having 1 to 30 carbon atoms, a linear or branched alkenyl group having 2 to 30 carbon atoms which may have a substituent, or an aryl group having 6 to 30 carbon atoms which may have a substituent, more preferably a linear alkoxy group having 1 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 6 carbon atoms which may have a substituent, or an aryl group having 6 to 16 carbon atoms which may have a substituent, most preferably a linear or branched alkenyl group having 2 to 6 carbon atoms which is substituted with a linear alkoxy group having 1 to 10 carbon atoms, an allyl group having 6 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms.

In the general formula (1), as represented by R¹～R⁴The "halogen atom" may specifically include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

In the general formula (1), as represented by R¹～R⁴The "alkyl group having 1 to 36 carbon atoms" in the "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" includesFrom R in the general formula (1)⁰The "alkyl group having 1 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (1), as represented by R¹～R⁴The "cycloalkyl group having 3 to 36 carbon atoms" in the "cycloalkyl group having 3 to 36 carbon atoms which may have a substituent" includes, specifically, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl and the like.

In the general formula (1), as represented by R¹～R⁴The "linear or branched alkoxy group having 1 to 36 carbon atoms" in the "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" includes, specifically, a linear alkoxy group such as methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy, and decyloxy; a branched alkoxy group such as an isopropoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, and an isooctoxy group.

In the general formula (1), as represented by R¹～R⁴The "cycloalkoxy group having 3 to 36 carbon atoms" in the "cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent" includes, specifically, a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, a cyclohexyloxy group and the like.

In the general formula (1), as represented by R¹～R⁴The "linear or branched alkenyl group having 2 to 36 carbon atoms" in the "linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent(s)" may specifically include an alkenyl group such as a vinyl group, a propenyl group, an isopropenyl group, a 2-butenyl group, and a 1-hexenyl group, or a linear or branched alkenyl group having a plurality of these alkenyl groups bonded thereto.

In the general formula (1), as represented by R¹～R⁴The "aryl group having 6 to 36 carbon atoms" in the "aryl group having 6 to 36 carbon atoms which may have a substituent" may be the same as R in the general formula (1)⁰The "aryl group having 6 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (1)In (1) as represented by R¹～R⁴The "amino group having 0 to 36 carbon atoms" in the "amino group having 0 to 36 carbon atoms which may have a substituent" includes, specifically: an unsubstituted amino group; methylamino, dimethylamino, diethylamino, ethylmethylamino, methylpropylamino, di-t-butylamino, diphenylamino, and the like.

In the general formula (1), as represented by R¹～R⁴The "substituent" in the "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent", "cycloalkyl group having 3 to 36 carbon atoms which may have a substituent", "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent", "cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent", "linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent", "aryl group having 6 to 36 carbon atoms which may have a substituent" or "amino group having 0 to 36 carbon atoms which may have a substituent" represented by the formula (1) may be mentioned as the substituent⁰The "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" and the "aryl group having 6 to 36 carbon atoms which may have a substituent" are the same as the "substituent" described above.

In the general formula (1), R¹～R⁴The alkyl group may be the same or different, and is preferably a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms which may have a substituent, an aryl group having 6 to 24 carbon atoms which may have a substituent, or an amino group having 0 to 24 carbon atoms which may have a substituent, and more preferably an aryl group having 6 to 24 carbon atoms which may have a hydrogen atom or a substituent.

In the general formula (1), R¹～R⁴The substituents described above are represented, but adjacent groups may be bonded to each other to form a ring, and these rings may be bonded to each other by a single bond, a nitrogen atom, an oxygen atom, or a sulfur atom to form a ring.

In the above general formula (1), R¹～R⁴Preferably a hydrogen atom, a linear or branched chain having 1 to 36 carbon atoms which may have a substituentAn alkyl group, a linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent, an aryl group having 6 to 36 carbon atoms which may have a substituent, or an amino group having 0 to 36 carbon atoms which may have a substituent, more preferably a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, or an amino group having 0 to 20 carbon atoms which may have a substituent. In addition, in R¹～R⁴In, R¹、R²And R⁴May be a hydrogen atom, R³The alkyl group may be a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, or an amino group having 0 to 20 carbon atoms which may have a substituent. In addition, in R¹～R⁴In, R¹、R²And R⁴May be a hydrogen atom, R³The aryl group may have 6 to 20 carbon atoms.

In the general formula (1), X represents CR⁵R⁶Sulfur atom or oxygen atom, in CR⁵R⁶In the formula (II) is represented by R⁵And R⁶The "alkyl group having 1 to 36 carbon atoms which may have a substituent" may be represented by the formula (1) wherein R is⁰The "alkyl group having 1 to 36 carbon atoms which may have a substituent" is the same as R⁵And R⁶The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" represented by the formula (1) includes¹～R⁴The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" represented by the formula (I) is represented by R⁵And R⁶The "aryl group having 6 to 36 carbon atoms which may have a substituent" may be represented by the formula (1) wherein R is⁰The expression "can have substituentsAryl groups having 6 to 36 carbon atoms are' same, R is⁵And R⁶May be the same or different. In the present invention, X is preferably CR⁵R⁶Or a sulfur atom, more preferably CR⁵R⁶。

In the general formula (1), X is CR⁵R⁶In the case of (1), R⁵And R⁶The alkyl group is preferably a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, or an aryl group having 6 to 36 carbon atoms which may have a substituent, more preferably an aryl group having 6 to 36 carbon atoms which may have a substituent, and most preferably an aryl group having 6 to 20 carbon atoms. When aryl is a phenyl ring, part of the specification is labeled Ph.

In the general formula (1), Y represents a sulfur atom, an oxygen atom, CR⁷R⁸Or NR⁹At CR⁷R⁸Or NR⁹In (1) as represented by R⁷～R⁹The "alkyl group having 1 to 36 carbon atoms which may have a substituent" may be represented by the formula (1) wherein R is⁰The "alkyl group having 1 to 36 carbon atoms which may have a substituent" is the same as R⁷～R⁹The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" represented by the formula (1) includes¹～R⁴The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" represented by R⁷～R⁹The "aryl group having 6 to 36 carbon atoms which may have a substituent" may be represented by the formula (1) wherein R is⁰The "aryl group having 6 to 36 carbon atoms which may have a substituent" is the same as R⁷～R⁹May be the same or different. In the present invention, Y is preferably a sulfur atom or CR⁷R⁸Or NR⁹More preferably a sulfur atom or CR⁷R⁸。

In the general formula (1), Y is CR⁷R⁸In the case of (1), R⁷And R⁸Preferably a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, or may have a substituentThe aryl group having 6 to 36 carbon atoms is more preferably a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, and most preferably a linear or branched alkyl group having 1 to 16 carbon atoms.

In the general formula (1), Y is NR⁹In the case of (1), R⁹More preferably a linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent, or an aryl group having 6 to 36 carbon atoms which may have a substituent, and most preferably a linear or branched alkyl group having 1 to 16 carbon atoms.

In the general formula (1), a is preferably represented by any of the 1-valent groups in the general formulae (2) to (4).

In the general formula (2), R²⁰And R²¹Represents a hydrogen atom or an acidic group, R²⁰Or R²¹At least one of which is an acidic group. Specific examples of the "acidic group" include a carboxyl group, a sulfonic acid group, a phosphoric acid group, a hydroxamic acid group, a phosphonic acid group, a boric acid group, a phosphinic acid group, and a silanol group. Among them, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable. Since the sensitizing dye containing a carboxyl group or a phosphonic acid group as an acidic group can be easily adsorbed on the surface of the semiconductor layer, the photoelectric conversion characteristics of the photoelectric conversion element using the sensitizing dye will be further improved.

In the general formula (3) by R²²The "acidic group" and R in the general formula (4)²⁴Examples of the "acidic group" include the same ones as those in the general formula (2).

In the general formula (4), R²³And R²⁵Represents a hydrogen atom or an electron-attracting group, and specific examples of the "electron-attracting group" include:

halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom;

a cyano group; a hydroxyl group; a nitro group; a nitroso group; a carboxyl group; a formyl group; ester group, trifluoromethyl, and the like. Among them, cyano, nitro, trifluoromethyl, carboxyl and the like are preferable.

In the general formula (1), specifically, B is preferably a 2-valent group or a single bond represented by the general formula (5).

In the general formula (5), from R³⁰And R³¹The "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" may be represented by the formula (1) wherein R is⁰The "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (5), from R³⁰And R³¹Among the "linear or branched alkoxy group having 1 to 36 carbon atoms" in the "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent(s)", there may be mentioned the group represented by R in the general formula (1)¹～R⁴The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (5), from R³⁰And R³¹Examples of the "aryl group having 6 to 36 carbon atoms" in the "aryl group having 6 to 36 carbon atoms which may have a substituent(s)" represented by the formula (1) include⁰The "aryl group having 6 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (5), from R³²～R³⁷The "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" may be represented by the formula (1)⁰The "linear or branched alkyl group having 1 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (5), from R³²～R³⁷Among the "linear or branched alkoxy group having 1 to 36 carbon atoms" in the "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent(s)", there may be mentioned the group represented by the formula (1) wherein R represents¹～R⁴The "linear or branched alkoxy group having 1 to 36 carbon atoms which may have a substituent" is the same.

In the general formula (5), from R³²～R³⁷Among the "linear or branched alkenyl group having 2 to 36 carbon atoms which may have a substituent(s)", the "linear or branched alkenyl group having 2 to 36 carbon atoms"may be mentioned the group consisting of R in the general formula (1)¹～R⁴The "linear or branched alkenyl group having 2 to 36 carbon atoms" are the same.

In the general formula (5), R³²And R³³，R³⁴And R³⁵And R³⁶And R³⁷The substituents may be the same or different and each represent the same as described above, but adjacent groups may be bonded to each other to form a ring, and these rings may be bonded to each other by a single bond or a bond of any one atom of a nitrogen atom, a carbon atom and a sulfur atom to form a ring.

In the general formula (5) above,

p, q and r can be respectively 0, 0 and 0, p, q and r can be respectively 1, 0 and 0, p, q and r can be respectively 0, 1 and 0, p, q and r can be respectively 0, 0 and 1, p, q and r can be respectively 1, 1 and 0, p, q and r can be respectively 1, 0 and 1, p, q and r can be respectively 0, 1 and 1, p, q and r can be respectively 1, 1 and 1, and p, q and r can be respectively 1, 1 and 1.

In the present invention, the sensitizing dye represented by the general formula (1) contains all stereoisomers which may be present. Any stereoisomer may be suitable for use as the sensitizing dye of the present invention. For example, in the general formula (1), when B is a 2-valent group or a single bond represented by the general formula (5), A is a 1-valent group represented by the general formula (2), p is 0, q is 0, R is 0, R is²⁰Is a hydrogen atom, and R²¹In the case of a carboxyl group, the sensitizing dye of the present invention comprises compounds represented by the following general formulae (6) and (7). Further, a mixture of 2 or more kinds selected from these stereoisomers may be used.

[ solution 4]

Specific examples of the sensitizing dye compound of the present invention represented by the general formula (1) are represented by the following formula, but the present invention is not limited thereto.

In addition, the following exemplary compounds show one example of stereoisomers that may be present, including all other stereoisomers. Further, each may be a mixture of two or more stereoisomers.

[ solution 5]

[ solution 6]

[ solution 7]

[ solution 8]

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[ solution 48]

The sensitizing dye of the present invention represented by the general formula (1) can be synthesized by a known method. In the general formula (1), Y is a sulfur atom, B is a 2-valent group represented by the general formula (5) or a single bond, A is a 1-valent group represented by the general formula (2), p is 0, q is 1, R is 0, R is³²、R³³、R³⁴And R³⁵Examples of the synthesis in the case of hydrogen atoms.

The bromine compound represented by the general formula (9) can be synthesized by performing a cross-coupling reaction such as suzuki-miyaura coupling of the borate compound represented by the general formula (8) having a corresponding substituent and 4-bromo-2, 1, 3-benzothiazole, and further performing a bromination reaction.

[ solution 49]

Then, the formyl compound represented by the general formula (10) can be synthesized by performing a cross-coupling reaction of the bromine compound represented by the general formula (9) with 4-formylphenylboronic acid.

[ solution 50]

Then, the sensitizing dye represented by the general formula (1) of the present invention can be synthesized by carrying out a condensation reaction of the formyl compound represented by the general formula (10) obtained as described above and the indanone compound represented by the general formula (11).

In the general formula (11), R²⁰And R²¹Represents a hydrogen atom or an acidic group, R²⁰And R²¹At least one of which is an acidic group.

In the above synthesis examples, R in the general formulae (8) to (11)⁰～R⁴、R²⁰And R²¹And R in the general formula (1) of the present invention⁰～R⁴And all-in-oneR in the formula (2)²⁰、R²¹Are meant to be the same.

Further, the above general formula (8) and the like as starting materials may be commercially available or synthesized by a known method. The indanone compound represented by the above general formula (11) can be easily synthesized by the methods described in the aforementioned patent documents 6 to 7.

Examples of the method for purifying the sensitizing dye compound of the present invention represented by the general formula (1) include: purification by column chromatography; adsorption purification based on silica gel, activated carbon, activated clay, or the like; known methods such as recrystallization and crystallization using a solvent. Further, identification of these compounds can be performed by nuclear magnetic resonance analysis (NMR) or the like.

The sensitizing dye of the present invention can be used alone, or two or more kinds can be used in combination. In addition, the sensitizing dye of the present invention can be used in combination with other sensitizing dyes not belonging to the present invention. Specific examples of the other sensitizing dyes include sensitizing dyes other than the sensitizing dye represented by the above-mentioned general formula (1), such as ruthenium complexes, coumarin dyes, cyanine dyes, merocyanine dyes, rhodanine dyes, phthalocyanine dyes, porphyrin dyes and x-ton dyes. When the sensitizing dye of the present invention is used as a composition for photoelectric conversion in combination with these other sensitizing dyes, the amount of the other sensitizing dye used for the sensitizing dye of the present invention is preferably 10 to 200% by weight, more preferably 20 to 100% by weight.

The sensitizing dye of the present invention can be applied to spectral sensitizing dyes such as silver halide, zinc oxide, titanium oxide, etc., which are used for photosensitive substances of various image forming materials, photocatalysts, optical functional materials, etc., and can also be applied to sensitizing dye compositions for photoelectric conversion, etc., which are used for dye-sensitized photoelectric conversion elements, etc. The method of manufacturing the dye-sensitized photoelectric conversion element in the present invention is not particularly limited, but the following method is preferred: a semiconductor layer is formed on a conductive support (electrode), and the sensitizing dye composition for photoelectric conversion of the present invention is adsorbed (supported) on the semiconductor layer to produce a photoelectrode (see fig. 1. it is needless to say that the figure is not a real size of an actual element because it is a priority to understand it). 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 for a long time is generally used. When two or more of the sensitizing dyes of the present invention are used in combination, or when the sensitizing dye of the present invention is used in combination with another sensitizing dye, a mixed solution of all the dyes used may be prepared to impregnate the semiconductor layer, or different solutions may be prepared for each dye, and the semiconductor layer may be impregnated in each solution in sequence.

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

In the present invention, specific examples of the semiconductor forming the semiconductor layer include: metal oxides 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; metal sulfides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, and silver sulfide; metal selenides such as titanium selenide, zirconium selenide, indium selenide, tungsten selenide, and the like; and a single semiconductor such as silicon and germanium. These semiconductors may be used alone or in combination of two or more. In the present invention, the semiconductor is preferably one or two or more selected from titanium oxide, zinc oxide, and tin oxide.

The form of the semiconductor layer in the present invention is not particularly limited, but is preferably a thin film having a porous structure made of fine particles. By the porous structure or the like, the actual surface area of the semiconductor layer is increased, and when the amount of dye adsorbed to the semiconductor layer is increased, a high-efficiency photoelectric conversion element can be obtained. The semiconductor particle size is preferably 5 to 500nm, more preferably 10 to 100 nm. The thickness of the semiconductor layer is usually 1 to 100 μm, more preferably 1 to 20 μm. Examples of a method for producing the semiconductor layer include a method in which a slurry containing semiconductor fine particles is applied to a conductive substrate by a wet coating method such as a spin coating method, a doctor blade film forming method, a brush coating method, or a screen printing method, and then the slurry is baked to remove a solvent or an additive to form a film, and a method in which a film is formed by a sputtering method, an evaporation method, an electrodeposition method, or a microwave irradiation method, but the method is not limited thereto.

In the present invention, a slurry containing semiconductor fine particles may be used on the market, or a slurry prepared by dispersing semiconductor fine particles on the market in a solvent may be used. As specific examples of the solvent used in preparing the slurry, water; alcohol solvents such as methanol, ethanol, and isopropanol; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; hydrocarbon solvents such as n-hexane, cyclohexane, benzene, toluene, etc., but are not limited thereto. These solvents may be used alone or as a mixed solvent of two or more.

In the present invention, as a method of dispersing the fine semiconductor powder in the solvent, the powder 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. In preparing the slurry, a surfactant or the like for preventing aggregation of the semiconductor fine particles is preferably added, and a thickener such as polyethylene glycol for thickening is preferably added.

The sensitizing dye composition for photoelectric conversion of the present invention can be applied to the surface of the semiconductor layer by, for example, immersing the semiconductor layer in the dye solution and allowing the semiconductor layer to stand at room temperature for 30 minutes to 100 hours or allowing the semiconductor layer to stand under heating for 10 minutes to 24 hours. In this case, the dye solution is preferably left at room temperature for 10 to 20 hours, and the concentration of the dye in the dye solution is preferably 10 to 2000. mu.M, and more preferably 50 to 500. mu.M.

Specific examples of the solvent used when the sensitizing dye for photoelectric conversion of the present invention is adsorbed on the surface of the semiconductor layer include: alcohol solvents such as methanol, ethanol, isopropanol, and tert-butanol; ketone solvents such as acetone, methyl ethyl ketone, and methyl 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; amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, and N-methyl-2-pyrrolidone; nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, and the like; halogenated hydrocarbon solvents such as dichloromethane, chloroform, bromoform, o-dichlorobenzene, and the like; hydrocarbon solvents such as n-hexane, cyclohexane, benzene, toluene, etc., but not limited thereto. These solvents are used alone or as a mixed solvent of two or more. Among these solvents, one or more selected from methanol, ethanol, t-butanol, acetone, methyl ethyl ketone, tetrahydrofuran, and acetonitrile are preferably used.

When the sensitizing dye composition for photoelectric conversion of the present invention is adsorbed on the surface of the semiconductor layer, cholic acid or cholic acid derivatives such as deoxycholic acid, chenodeoxycholic acid, lithocholic acid, and dehydrocholic acid may be dissolved in a dye solution and co-adsorbed with the dye. By using cholic acid or a cholic acid derivative, polymerization between dyes is suppressed, and electrons can be efficiently injected from the dyes into the semiconductor layer in the photoelectric conversion element. When cholic acid or a cholic acid derivative is used, the concentration thereof in the dye solution is preferably 0.1 to 100mM, more preferably 0.5 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 is a conductive material, but a conductive material having catalytic ability is preferably used in order to promote the redox reaction of the redox ion. Specific examples of the conductive material include platinum, rhodium, ruthenium, carbon, and the like, but are not limited thereto. In the present invention, it is particularly preferable that a platinum thin film is formed on the conductive support as the counter electrode. Further, as a method for producing the conductive thin film, there can be mentioned: a method in which a slurry containing a conductive material is applied to a conductive substrate by a wet coating method such as a spin coating method, a doctor blade film forming method, a brush coating method, or a screen printing method, and then a solvent or an additive is removed by baking to form a film; a method of forming a film by a sputtering method, a vapor deposition method, an electrodeposition method, a microwave irradiation method, or the like, but is not limited thereto.

In the photoelectric conversion element of the present invention, an electrolyte is filled between a pair of opposing electrodes, thereby forming an electrolyte layer. The electrolyte used is preferably a redox electrolyte. Examples of the redox electrolyte include, but are not limited to, redox ion pairs such as iodine, bromine, tin, iron, chromium, and anthraquinone. Of 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, dimethyl imidazole iodide, etc. and iodine is used. In the present invention, an electrolytic solution obtained by dissolving these electrolytes in a solvent is preferably used. The concentration of the electrolyte in the electrolyte is preferably 0.05 to 5M, and more preferably 0.2 to 1M.

Examples of the solvent for dissolving the electrolyte include: nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, and benzonitrile; ether solvents such as diethyl ether, 1, 2-dimethoxyethane, and tetrahydrofuran; amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide; carbonate solvents such as ethylene carbonate and propylene carbonate; lactone solvents such as γ -butyrolactone and γ -valerolactone, but not limited thereto. These solvents are used alone or as a mixed solvent of two or more. Among these solvents, nitrile solvents are preferable.

In the present invention, in order to further improve the open circuit voltage and the fill factor of the dye-sensitized photoelectric conversion element, an amine compound may be contained in the electrolyte solution. Examples of the amine compound include 4-tert-butylpyridine, 4-methylpyridine, 2-vinylpyridine, N-dimethyl-4-aminopyridine, N-dimethylaniline and N-methylbenzimidazole. The concentration of the amine compound in the electrolyte is preferably 0.05-5M, and more preferably 0.2-1M.

As the electrolyte in the photoelectric conversion element of the present invention, a gel electrolyte obtained by adding a gelling agent, a polymer, or the like, or a solid electrolyte using a polymer such as a polyethylene oxide derivative can be used. 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 a pair of opposing 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-transporting substances such as copper iodide, copper bromide, and copper thiocyanate; organic hole transport materials such as polypyrrole, polythiophene, poly (p-phenylene vinylene), polyvinylcarbazole, polyaniline, oxadiazole derivatives, triphenylamine derivatives, pyrazoline derivatives, fluorenone derivatives, hydrazone compounds, stilbene compounds, and the like, but are not limited thereto.

In the present invention, when the solid charge transport layer is formed using an organic hole transport substance, a film-forming adhesive resin may be used in combination. Specific examples of the film-forming adhesive resin include, but are not limited to, polystyrene resins, polyvinyl acetal resins, polycarbonate resins, polysulfone resins, polyester resins, polyphenylene ether resins, polyarylate resins, alkyd resins, acrylic resins, phenoxy resins, and the like. These resins may be used alone or as a copolymer in combination of one or more. The amount of the organic hole-transporting substance used for the binder resin is preferably 20 to 1000 wt%, more preferably 50 to 500 wt%.

In the photoelectric conversion element of the present invention, the electrode (photoelectrode) provided with the semiconductor layer having the sensitizing dye composition for photoelectric conversion adsorbed thereon serves as a cathode, and the counter electrode serves as an anode. Light such as sunlight may be irradiated from either the side of the photoelectric electrode or the counter electrode, but is preferably irradiated from the side of the photoelectric electrode. Upon irradiation with sunlight or the like, the dye absorbs light to become an excited state, and electrons are released. The electrons flow to the outside via the semiconductor layer, and move to the counter electrode. On the other hand, the dye that has released electrons to become an oxidized state receives electrons supplied from the counter electrode via ions in the electrolyte, and is restored to a ground state. By this circulation, a current flows, functioning as a photoelectric conversion element.

When the performance (characteristics) of the photoelectric conversion element of the present invention was evaluated, a short-circuit current and an open-circuit current were performedAnd measuring the pressure, the filling factor and the photoelectric conversion efficiency. The short-circuit current indicates a current flowing between the output terminals every 1cm when the output terminals are short-circuited²The open circuit voltage represents a voltage between both terminals when the output terminal is opened. In addition, the fill factor refers to a value of a maximum output (a product of a circuit and a voltage) divided by a product of a short-circuit current and an open-circuit voltage, and mainly depends on the internal resistance. Photoelectric conversion efficiency is determined by dividing the maximum output (W) by 1cm per square meter²Is calculated by multiplying the value of the light intensity (W) by 100 to obtain a value expressed as a percentage.

The photoelectric conversion element of the present invention can be applied to a dye-sensitized solar cell, various photosensors, and the like. The dye-sensitized solar cell of the present invention is obtained as follows: a photoelectric conversion element comprising a sensitizing dye composition for photoelectric conversion comprising a sensitizing dye represented by the above general formula (1) is formed into cells, and the cells are arranged in a desired number and modularized to provide a predetermined wiring.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. Furthermore, in the synthetic examples, the compounds were identified by¹H-NMR analysis (JNM-ECZ-400S, a nuclear magnetic resonance apparatus manufactured by Nippon electronics Co., Ltd.).

Synthesis example 1 Synthesis of sensitizing dye (D-20)

In a reaction vessel purged with nitrogen, 7.03g of (4, 4-dihexyl-4H-cyclopentane [1, 2-b:5, 4-b' ] dithiophen-2-yl) trimethylsilan, 4.47g of 4, 7-dibromobenzene [ c ] [1, 2, 5] thiadiazole, and 130mL of toluene were charged, and 0.239g of bis (triphenylphosphine) palladium (type II) dichloride was added to conduct degassing under reduced pressure. The reaction was carried out at 60 ℃ for 6 hours with stirring. After cooling to 40 ℃ and removal of the solvent under reduced pressure, the crude product was purified by column chromatography (carrier: silica gel, eluent: hexane/chloroform 1/1 (volume ratio)) to obtain 3.94g of a red oil represented by the following formula (12).

[ solution 51]

Into a reaction vessel purged with nitrogen, 0.406g of the compound represented by the above formula (12), 0.54g of 10-biphenyl-9, 9-biphenyl-7- (4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborane-2-yl) -2-phenyl-9, 10-dihydroacridine, 0.924g of sodium carbonate, 12mL of ethanol, 24mL of water, and 0.11g of tetrakis (triphenylphosphine) palladium (0) were charged, followed by degassing under reduced pressure. The reaction was carried out at 75 ℃ for 3 hours with stirring. The reaction mixture was cooled to 25 ℃ and then 180mL of chloroform and 60mL of water were added thereto and the mixture was stirred to extract the organic layer. The organic layer was dried over sodium sulfate and concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: hexane/toluene 5/1 (volume ratio)), and 0.972g of red black oil was brominated according to a conventional method to obtain 0.988g of the bromine compound represented by the above formula (13).

In a reaction vessel purged with nitrogen, 0.066g of 4-formylphenylboronic acid, 0.494g of the bromine compound represented by the above formula (13), 20mL of dioxane, 4mL of water, 0.469g of tripotassium phosphate, and 0.009g of 2-dicyclohexylphosphine-2 ', 6' -dimethoxybiphenyl were charged and stirred, and then, in the reaction vessel, pressure reduction, degassing, and purging with nitrogen were repeated 5 times. Then, 0.005g of palladium acetate was added, and the reaction vessel was repeatedly subjected to pressure reduction, degassing, and nitrogen substitution 5 times. Then, the mixture was stirred at 60 ℃ for 2 hours. The reaction mixture was cooled to 25 ℃ and then 90mL of chloroform and 30mL of water were added thereto and the mixture was stirred to extract the organic layer. The organic layer was dried over sodium sulfate and concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: toluene/hexane 1/1 (volume ratio)), and dried to give a red-black solid (0.299g) of the formyl compound represented by the above formula (14).

Into a reaction vessel purged with nitrogen, 0.149g of the formyl compound represented by the above formula (14), 0.198g of cyanoacetic acid, 13mL of acetic acid, and 0.024g of ammonium acetate were charged, and the mixture was stirred at 100 ℃ for 7 hours. The reaction mixture was cooled to 25 ℃ and 70mL of water was added thereto, followed by stirring to extract the organic layer. The organic layer was washed with water and saturated brine in this order and dried to obtain a crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: chloroform/methanol 10/1 (vol.%)) and dried to give the desired sensitizing dye as a black solid (0.127g, yield 81%).

The obtained black solid was subjected to NMR analysis, and the following 65 hydrogen signals were detected, and identified as a structure represented by the following formula (D-20) (no hydrogen of carboxyl group was observed).

¹H-NMR(400MHz，DMSO-d₆):δ(ppm)＝0.75-0.79(6H)，0.97-1.01(4H)，1.10-1.18(12H)，1.91-1.98(4H)，6.54-6.65(2H)，7.08-7.17(5H)，7.27-7.57(17H)，7.66-7.70(2H)，7.78-7.87(6H)，7.97-8.03(4H)，8.09-8.19(3H)。

[ solution 52]

Synthesis example 2 Synthesis of sensitizing dye (D-19)

In a nitrogen-purged reaction vessel, 0.401g of the formyl compound represented by the above formula (14), 0.094g of the indanone represented by the following formula (15), 5.7mL of acetic acid and 14.5mL of toluene were charged, and the mixture was stirred at 90 ℃ for 8 hours. The reaction mixture was cooled to 25 ℃ and 50mL of toluene was added thereto, followed by stirring to extract the organic layer. The organic layer was washed with water and saturated brine in this order and dried to obtain a crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: chloroform/methanol 10/1 (vol.%)) and dried to give the desired sensitizing dye as a dark purple solid (0.328g, yield 71%).

[ Hua 53]

The obtained black-purple solid was subjected to NMR analysis, and the following 68 hydrogen signals were detected, and identified as a structure represented by the following formula (D-19) (no hydrogen of carboxyl group was observed).

¹H-NMR(400MHz，THF-d₈):δ(ppm)＝0.82-0.90(6H)，1.15-1.27(16H)，2.07-2.15(4H)，6.68-6.77(2H)，7.20-7.30(5H)，7.30-7.42(11H)，7.40-7.48(4H)，7.51-7.59(2H)，7.62-7.68(1H)，7.77-7.83(4H)，7.91-8.01(6H)，8.02-8.08(1H)，8.06-8.17(1H)，8.24-8.28(1H)，8.50-8.56(1H)，8.57-8.65(1H)，8.70-8.76(2H)。

[ solution 54]

Synthesis example 3 Synthesis of sensitizing dye (D-18)

In a reaction vessel purged with nitrogen, 0.319g of the bromine compound represented by the above formula (13), 0.138g of 4-ethynylbenzoic acid, 10mL of super-dehydrated tetrahydrofuran and 1.5mL of dried triethylamine were charged, and decompression, degassing and purging with nitrogen were repeated 5 times in the reaction vessel. Then, 0.053g of tetrakis (triphenylphosphine) palladium (0) and 0.009g of copper iodide were added thereto, and the inside of the reaction vessel was depressurized, degassed, and replaced with nitrogen gas 5 times. Thereafter, the mixture was stirred at 70 ℃ for 3 hours. The reaction solution was cooled to 25 ℃ and then concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: chloroform) and dried to give the desired sensitizing dye as a black-red solid (0.317g, yield 69%).

The obtained black-red solid was subjected to NMR analysis, and the following 64 hydrogen signals were detected, and identified as a structure represented by the following formula (D-18) (no hydrogen of carboxyl group was observed).

¹H-NMR(400MHz，THF-d₈):δ(ppm)＝0.83-0.91(6H)，1.10-1.15(4H)，1.19-1.31(12H)，2.01-2.09(4H)，6.67-6.77(2H)，7.20-7.29(5H)，7.29-7.41(11H)，7.41-7.46(4H)，7.51-7.58(3H)，7.62-7.68(3H)，7.69-7.78(1H)，7.78-7.84(3H)，7.90-8.02(3H)，8.01-8.07(1H)，8.05-8.13(1H)，8.21-8.26(1H)。

[ solution 55]

Synthesis example 4 Synthesis of sensitizing dye (D-26)

To a reaction vessel purged with nitrogen, 0.720g of 10-biphenyl-9, 9-biphenyl-7- (4, 4, 5, 5-tetramethyl-1, 3, 2-dioxaborolan-2-yl) -2-phenyl-9, 10-dihydroacridine, 0.335g of 4, 7-dibromobenzene [ c ] [1, 2, 5] thiadiazole, 1.32g of sodium carbonate, 21mL of ethanol, and 41mL of water were added, and the inside of the reaction vessel was evacuated, degassed, and purged with nitrogen 5 times. 0.141g of tetrakis (triphenylphosphine) palladium (0) was added thereto, and the reaction vessel was again evacuated under reduced pressure, degassed, and replaced with nitrogen 5 times. The reaction was carried out at 75 ℃ for 3 hours with stirring. The reaction mixture was cooled to 25 ℃ and then 30mL of toluene was added thereto, followed by stirring to extract the organic layer. The organic layer was dried over sodium sulfate and concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: hexane/toluene 5/1 (volume ratio)) to give 0.520g of a bromine compound represented by the following formula (16).

[ solution 56]

In a reaction vessel purged with nitrogen, 0.482g of the bromine compound represented by the above formula (16), 0.085g of 4-ethynylbenzoic acid, 15mL of super-dehydrated tetrahydrofuran, and 2.2mL of dried triethylamine were added, and the inside of the reaction vessel was subjected to vacuum reduction, degassing, and purging with nitrogen 5 times. Then, 0.128g of tetrakis (triphenylphosphine) palladium (0) and 0.021g of copper iodide were added thereto, and the reaction vessel was depressurized, degassed, and replaced with nitrogen gas 5 times. Thereafter, the mixture was stirred at 65 ℃ for 4 hours. The reaction solution was cooled to 25 ℃ and then concentrated under reduced pressure to obtain a crude product. The crude product was purified by column chromatography (carrier: silica gel, eluent: chloroform/methanol 10/1 (vol.%)) and dried to give the desired sensitizing dye as a red solid (0.243g, yield 49%).

The obtained red solid was subjected to NMR analysis, and the following 36 hydrogen signals were detected, and identified as a structure represented by the following formula (D-26) (no hydrogen at the carboxyl group was observed).

¹H-NMR(400MHz，THF-d₈):δ(ppm)＝6.54-6.65(2H)，7.05-7.10(1H)，7.09-7.15(4H)，7.24-7.58(17H)，7.67-7.77(4H)，7.78-7.86(3H)，7.97-8.04(5H)。

[ solution 57]

EXAMPLE 1 evaluation of characteristics

On a glass substrate coated with a fluorine-doped tin oxide thin film, a titanium oxide slurry (PST-18 NR manufactured by Nikkaido chemical Co., Ltd.) was applied by a doctor blade method. After drying at 110 ℃ for 1 hour, the film was baked at 450 ℃ for 30 minutes to obtain a titanium oxide thin film having a film thickness of 6 μm. Next, the sensitizing dye (D-20) obtained in synthesis example 1 was dissolved in a mixed solution of acetonitrile/t-butanol (volume ratio) 1/1 to prepare 50mL of a solution having a concentration of 100 μ M, and the glass substrate coated with sintered titanium oxide was immersed at 25 ± 2 ℃ for 15 hours to adsorb the dye, thereby using the solution as a photoelectrode.

A platinum thin film having a thickness of 15nm was formed by sputtering on a glass substrate coated with a fluorine-doped tin oxide thin film using an automatic fine coater (JFC-1600 manufactured by Nippon electronics Co., Ltd.) and used as a counter electrode.

Then, a spacer (thermal fusion film) having a thickness of 60 μ M was interposed between the photoelectrode and the counter electrode and bonded by thermal fusion, and an electrolytic solution (0.1M lithium iodide, 0.6M dimethylpropyl imidazole iodide, 0.05M iodine, 0.5M 4-t-butylpyridine)/3-methoxypropionitrile solution) was injected from the hole of the counter electrode to seal the hole, thereby producing a photoelectric conversion element.

Light generated by a simulated solar light irradiation device (OTENTO-SUN III type manufactured by spectrometer Co., Ltd.) was irradiated from the photoelectric electrode side of the photoelectric conversion element, and current-voltage characteristics were measured using a source meter (a model 2400 universal source meter manufactured by KEITHLEY). The intensity of light was adjusted to 100mW/cm². The obtained measurement results and initial photoelectric conversion efficiency are shown in table 1.

[ examples 2 and 3]

A photoelectric conversion element was produced in the same manner as in example 1 except that the sensitizing dyes shown in table 1 were used as the sensitizing dyes for photoelectric conversion, respectively, instead of the sensitizing dye (D-20) obtained in synthetic example 1. Table 1 summarizes the current-voltage characteristics, initial photoelectric conversion efficiencies, of the photoelectric conversion elements.

Comparative examples 1 and 2 evaluation of characteristics

A photoelectric conversion element was produced in the same manner as in example 1 except that sensitizing dyes shown in (E-1) and (E-2) below, which do not belong to the present invention, were used instead of (D-20), respectively, as the sensitizing dyes for photoelectric conversion. The measurement results of the current-voltage characteristics of the photoelectric conversion element and the initial photoelectric conversion efficiency are shown in table 1.

[ solution 58]

[ Table 1]

By using the sensitizing dye composition for photoelectric conversion containing the sensitizing dye of the present invention, a photoelectric conversion element having high photoelectric conversion efficiency and capable of maintaining the photoelectric conversion efficiency even when light is irradiated for a long time can be obtained. On the other hand, the photoelectric conversion element using the sensitizing dye for photoelectric conversion of the comparative example had insufficient photoelectric conversion efficiency.

Although the present invention has been described in detail with reference to the specific embodiments, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

Further, the present application is based on the Japanese patent application filed on 28.2.2020 (Japanese patent application No. 2020-33131), the entire contents of which are incorporated herein by reference. Moreover, all references cited herein are incorporated by reference in their entirety.

(availability in industry)

The sensitizing dye and the sensitizing dye composition for photoelectric conversion containing the sensitizing dye according to the present invention are useful for a photoelectric conversion element and a dye-sensitized solar cell having high efficiency and high durability, and can provide clean energy as a solar cell capable of efficiently converting solar energy into electric energy.

Claims

1. A sensitizing dye is represented by the following general formula (1),

[ solution 1]

A cycloalkyl group having 3 to 36 carbon atoms which may have a substituent,

A cycloalkoxy group having 3 to 36 carbon atoms which may have a substituent,

An aryl group having 6 to 36 carbon atoms which may have a substituent,

Or an amino group having 0 to 36 carbon atoms which may have a substituent,

2. The sensitizing dye according to claim 1,

[ solution 2]

3. The sensitizing dye according to claim 1,

in the above general formula (1), B is a 2-valent bonding group or a single bond represented by the following general formula (5),

[ solution 3]

Wherein Z represents a carbon atom or a silicon atom,

R³⁰and R³¹Are the same or different and represent a hydrogen atom,

Or an aryl group having 6 to 36 carbon atoms which may have a substituent,

R³²to R³⁷Are the same or different and represent a hydrogen atom,

p, q and r represent 0 or 1.

4. The sensitizing dye according to claim 2,

[ solution 4]

Wherein Z represents a carbon atom or a silicon atom,

R³⁰and R³¹Are the same or different and represent a hydrogen atom,

Or an aryl group having 6 to 36 carbon atoms which may have a substituent,

R³²to R³⁷Are the same or different and represent a hydrogen atom,

p, q and r represent 0 or 1.

5. The sensitizing dye according to any one of claims 1 to 4,

in the general formula (1), R⁰Is a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 26 carbon atoms which may have a substituent,

R¹～R⁴is a hydrogen atom,

An aryl group having 6 to 36 carbon atoms which may have a substituent,

Or an amino group having 0 to 36 carbon atoms which may have a substituent,

x is CR⁵R⁶Or a sulfur atom,

y is a sulfur atom, CR⁷R⁸Or NR⁹。

6. A sensitizing dye composition for photoelectric conversion comprising the sensitizing dye according to any one of claims 1 to 5.

7. A photoelectric conversion element using the sensitizing dye composition for photoelectric conversion according to claim 6.

8. A dye-sensitized solar cell using the photoelectric conversion element according to claim 7.