JPWO2018061409A1 - Sensitizing dye, sensitizing dye for photoelectric conversion, photoelectric conversion device using the same, and dye-sensitized solar cell - Google Patents

Abstract

Provided is a sensitizing dye represented by the following general formula (1). [Wherein, R 1 to R 6 may be the same or different, and each independently represent a hydrogen atom, a halogen atom, a specific alkyl group, or a specific alkoxy group, and R 7 and R 8 may be the same or different] And may represent a particular alkyl group, a particular cycloalkyl group, a particular alkenyl group, a particular aralkyl group, or a particular aryl group, and R.sup.7 and R.sup.8 may combine with each other to form a ring. X represents a monovalent group. ]

Description

  The present invention relates to a sensitizing dye used for a dye-sensitized photoelectric conversion device, a photoelectric conversion device using the sensitizing dye, 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. With global energy consumption increasing with population growth, there is concern that global environmental destruction will further progress. Under these circumstances, unlike fossil fuels, utilization of renewable energy that is less likely to run out is being energetically studied. The use of solar energy, mainly solar power, is important as a next-generation major renewable energy generation system that can contribute to the prevention of global warming, instead of thermal power and nuclear power that consume fossil fuels. Is growing more and more. Developments and applications are progressing in a variety of fields, from generation and charging of watches and portable small electronic devices to homes that can save on energy costs, and small-scale power generation facilities in buildings and fallow lands.

  As a means of solar power generation, a photoelectric conversion element that converts the energy of sunlight into electric energy is used in a solar cell. As solar cells, inorganic solar cells such as single crystal, polycrystalline, amorphous silicon, compound semiconductors such as gallium arsenide, cadmium sulfide, indium copper selenide, and the like are mainly studied, and now homes and small-scale power generation facilities Are widely implemented. However, these inorganic solar cells have problems such as high manufacturing cost and difficulty in securing raw materials.

  On the other hand, although the photoelectric conversion efficiency and the durability are much lower than 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. ing. Organic solar cells are said to be more advantageous than inorganic solar cells in terms of production cost, large area, light weight, thin film, translucency, widening of absorption wavelength, flexibility, securing of raw materials, etc. .

  Among them, the dye-sensitized solar cell proposed by Gretzel et al. (See Non-Patent Document 1) is a thin film electrode made of porous titanium oxide as a semiconductor, and a ruthenium complex dye adsorbed on the semiconductor surface to widen the photosensitive wavelength range. It is a wet solar cell comprised from the electrolyte solution containing an iodine, and the high photoelectric conversion efficiency comparable to an amorphous silicon solar cell is anticipated. In addition, dye-sensitized solar cells are attracting attention as next-generation solar cells because they have a simple element structure compared to other solar cells and can be manufactured without large-sized manufacturing equipment.

  From the viewpoint of photoelectric conversion efficiency, a ruthenium complex is considered to be the most superior as a sensitizing dye used for a dye-sensitized solar cell. However, since ruthenium is a noble metal, it is disadvantageous in terms of manufacturing cost, and resource limitations also become a problem when it is put into practical use and a large amount of ruthenium complex is required. 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 containing no 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) reference). In recent years, compounds having a benzopyran structure, a naphthalimide structure, a fluorene structure, a fluorenone structure, and a dibenzothiophene structure have been reported as sensitizing dyes (see, for example, Patent Documents 3 to 7).

  Further, a compound having an indanone structure has also been proposed as an electron attracting portion for adsorbing to the surface of semiconductor particles such as titanium oxide and efficiently transporting excited electrons generated in the sensitizing dye to the semiconductor (for example, See Patent Documents 8 to 10). However, although these organic dyes have the advantages of being inexpensive, having a large absorption coefficient, and being able to control the absorption characteristics due to the diversity of structures, the required characteristics are sufficiently satisfied 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 Application Laid-Open No. 11-214730 Japanese Patent Application Laid-Open No. 11-238905 Japanese Patent Application Laid-Open No. 2003-17146 Japanese Patent Application Laid-Open No. 2004-227825 Japan JP 2009-266633 Japan JP 2009-277527 Japanese Patent Laid-Open Publication No. 2015-191934 Japan JP 2011-207784 Japanese Patent Laid-Open Publication No. 2012-51854 Japanese Patent Application Laid-Open No. 2016-6811

"Nature", (UK), 1991, Vol. 353, p. 737-740

  The problem to be solved by the present invention is to provide a sensitizing dye of a novel structure which can expand the photosensitive wavelength range, and further to use the sensitizing dye as a sensitizing dye for photoelectric conversion which can efficiently extract current. It is an object of the present invention to provide a photoelectric conversion element and a dye-sensitized solar cell which are excellent in photoelectric conversion.

  In order to solve the above problems, the inventors of the present invention have intensively studied the improvement of the photoelectric conversion characteristics of the sensitizing dye. As a result, by using the sensitizing dye having a specific structure as a sensitizing dye for photoelectric conversion, high efficiency and high durability are obtained. It has been found that a photoelectric conversion element of high quality can be obtained. That is, the present invention is configured as follows.

1. The sensitizing dye represented by following General formula (1).

[Wherein, R ^{1 to} R ⁶ may be the same or different and each independently represent a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms] 6 straight or branched alkoxy groups,
R ⁷ and R ⁸ may be the same or different, and may have a substituent, a linear or branched alkyl group having 1 to 20 carbon atoms, carbon which may have a substituent A cycloalkyl group having 3 to 20 atoms, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, and 7 to 7 carbon atoms which may have a substituent 26 represents an aralkyl group of 26 or an aryl group having 6 to 30 carbon atoms which may have a substituent, and R ⁷ and R ⁸ may be bonded to each other to form a ring.
X represents a monovalent group. ]

2. A sensitizing dye in which X is a monovalent group represented by the following Formula (X1), (X2) or (X3) in the Formula (1).

[Wherein, R ⁹ represents an acidic group. ]

[Wherein, L and M may be the same or different, and are a linear or branched alkyl group having 1 to 6 carbon atoms having one or two acidic groups as a substituent, or an unsubstituted one It represents a linear or branched alkyl group having 1 to 6 carbon atoms. However, at least any one of L and M is a linear or branched alkyl group having 1 to 6 carbon atoms having one or two acidic groups as a substituent. p represents an integer of 0 to 2, and when p is 2, a plurality of L may be the same as or different from each other. ]

[Wherein, R ¹¹ and R ¹² represent a hydrogen atom or an acidic group, and at least one of R ¹¹ or R ¹² is an acidic group.
R ¹³ and R ¹⁴ may be the same or different, and a hydrogen atom,
A linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent,
A linear or branched alkoxy group having 1 to 18 carbon atoms which may have a substituent,
Or a linear or branched alkenyl group having 2 to 18 carbon atoms which may have a substituent, or
R ¹³ and R ¹⁴ may be bonded to each other to form a ring.
r represents an integer of 0 to 4, when r is an integer of 2 to 4, ^{R 13} and ^{R 14} there are a plurality, the ^{R 13 together, R 14} themselves may be the same or different from each other. ]

3. A sensitizing dye in which all of R ^{1 to} R ⁶ in the general formula (1) are hydrogen atoms.

4. In the above general formula (1), R ⁷ and R ⁸ each represent a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent, or 6 to 6 carbon atoms which may have a substituent. 4. The sensitizing dye as described in 3 above, which is any of 30 aryl groups, and R ⁷ and R ⁸ may be bonded to each other to form a ring.

5. The sensitizing dye for photoelectric conversion which consists of said sensitizing dye.

6. The photoelectric conversion element using the said sensitizing dye for photoelectric conversion.

7. The dye-sensitized solar cell using the said photoelectric conversion element.

  According to the sensitizing dye of the present invention, it is possible to obtain a sensitizing dye for photoelectric conversion which can efficiently extract a current. In addition, by using the sensitizing dye for photoelectric conversion, a photoelectric conversion element and a dye-sensitized solar cell with high efficiency and high durability can be obtained.

It is a schematic sectional drawing showing the structure of the photoelectric conversion element of this invention Example and a comparative example.

  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 formed by adsorbing a dye on a semiconductor layer on a conductive support and a counter electrode are disposed opposite to each other through an electrolyte layer.

  Although the sensitizing dye represented by the said General formula (1) is concretely demonstrated below, this invention is not limited to these.

In the general formula (1), "halogen atom" represented by R ¹ to R ⁶ are, specifically, fluorine atom, chlorine atom, bromine atom, and the like iodine atom.

Specific examples of “a linear or branched alkyl group having 1 to 6 carbon atoms” represented by R ^{1 to} R ⁶ in the general formula (1) include a methyl group, an ethyl group and an n-propyl group And isopropyl, n-butyl, s-butyl, t-butyl, n-pentyl, n-hexyl, isohexyl and the like.

Specific examples of “a linear or branched alkoxy group having 1 to 6 carbon atoms” represented by R ^{1 to} R ⁶ in the general formula (1) include a methoxy group, an ethoxy group, a propoxy group and an iso group. A propoxy group, n-butoxy group, s-butoxy group, t-butoxy group, n-pentyloxy group, n-hexyloxy group, isohexyloxy group etc. can be mentioned.

In the general formula (1), R ^{1 to} R ⁶ are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and a hydrogen atom for reasons such as the availability of raw materials Is more preferred.

"C1-C20 1-20" in "C1-C20 linear or branched alkyl group optionally having substituent (s)" represented by R ⁷ or R ⁸ in General Formula (1) Specific examples of the linear or branched alkyl group of “(1)” include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group and n-hexyl group. Groups and isohexyl groups.

As the “substituent” in the “C1-C20 linear or branched alkyl group optionally having substituent (s)” represented by R ⁷ or R ⁸ in the general formula (1), Specifically, a halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; 1 to 19 carbon atoms such as methoxy group, ethoxy group, propoxy group, t-butoxy group, pentyloxy group and hexyloxy group Linear or branched alkoxy group; aryl group having 6 to 19 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group and the like; dimethylamino group, diethylamino group, ethylmethylamino group, methylpropyl group A linear or branched alkyl group having 1 to 18 carbon atoms, such as amino group, di-t-butylamino group, diphenylamino group, etc. Or a disubstituted amino group having a substituent selected from an aryl group having 6 to 18 carbon atoms; a hydroxyl group; a carboxyl group; a carboxylic acid ester group such as a methyl ester group or an ethyl ester group; a cyano group etc. Can. One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

As the “C 3-20 cycloalkyl group” in the “C 3-20 cycloalkyl group optionally having substituent (s)” represented by R ⁷ or R ⁸ in the general formula (1) Specific examples thereof include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, cyclododecyl group and the like.

As the “substituent” in the “C 3-20 cycloalkyl group optionally having substituent (s)” represented by R ⁷ or R ⁸ in the general formula (1), specifically, a fluorine atom Halogen atoms such as chlorine atom, bromine atom and iodine atom; straight-chain having 1 to 17 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group and hexyl group A linear or branched alkyl group; a linear or branched alkoxy group having 1 to 17 carbon atoms such as methoxy group, ethoxy group, propoxy group, t-butoxy group, pentyloxy group, hexyloxy group; phenyl Aryl group having 6 to 17 carbon atoms such as naphthyl group, anthryl group, phenanthryl group, pyrenyl group, etc .; dimethylamino group, diethylamino group, ethylmethylamino Selected from linear or branched alkyl groups having 1 to 16 carbon atoms such as methylpropylamino, di-t-butylamino, diphenylamino and the like, or aryls having 6 to 16 carbon atoms Substituted amino group; hydroxyl group; carboxyl group; carboxylic acid ester group such as methyl ester group and ethyl ester group; ethenyl group such as vinyl group, vinylene group, phenylethenyl group and diphenylethenyl group; cyano It is possible to raise a group. One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

"C2-20 carbon atoms" in "C2-C20 linear or branched alkenyl group optionally having substituent (s)" represented by R ⁷ or R ⁸ in General Formula (1) As the linear or branched alkenyl group of the above, specifically, a vinyl group, an allyl group, an isopropenyl group, a 2-butenyl group, a 1-hexenyl group, or a linear group in which a plurality of these alkenyl groups are bonded Alternatively, branched groups can be mentioned.

As the “substituent” in the “C2-20 linear or branched alkenyl group optionally having substituent (s), which is represented by R ⁷ or R ⁸ in the general formula (1), Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; Carbon atoms such as methoxy group, ethoxy group, propoxy group, t-butoxy group, n-pentyloxy group and n-hexyloxy group 1 to 18 linear or branched alkoxy group; aryl group having 6 to 18 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group and the like; dimethylamino group, diethylamino group, ethylmethylamino A straight or branched chain having 1 to 17 carbon atoms, such as methylpropylamino, di-t-butylamino or diphenylamino A disubstituted amino group having a substituent selected from the group consisting of a methyl group or an aryl group having 6 to 17 carbon atoms; a hydroxyl group; a carboxyl group; a carboxylic acid ester group such as a methyl ester group and an ethyl ester group; You can raise it. One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

Specific examples of the "C7-C26 aralkyl group" in the "C7-C26 aralkyl group optionally having substituent (s)" represented by R ⁷ or R ⁸ in General Formula (1) Specific examples thereof include benzyl, phenethyl, 3-phenylpropyl, benzhydryl, trityl, 1-naphthylmethyl, 2-naphthylmethyl, 2-naphthylethyl and 2-pyrenylethyl groups.

The “substituent” in the “optionally substituted aralkyl group having 7 to 26 carbon atoms” represented by R ⁷ or R ⁸ in the general formula (1) is specifically a fluorine atom, Halogen atoms such as chlorine atom, bromine atom and iodine atom; straight chain having 1 to 19 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group and hexyl group Or branched alkyl group; linear or branched alkoxy having 1 to 19 carbon atoms such as methoxy, ethoxy, propoxy, t-butoxy, n-pentyloxy, n-hexyloxy and the like Group having 1 to 18 carbon atoms, such as dimethylamino, diethylamino, ethylmethylamino, methylpropylamino, di-t-butylamino, diphenylamino and the like; Or substituted alkyl group or disubstituted amino group having a substituent selected from an aryl group having 6 to 19 carbon atoms; hydroxyl group; carboxyl group; carboxylic acid ester group such as methyl ester group and ethyl ester group And ethenyl groups such as vinyl, vinylene, phenylethenyl and diphenylethenyl; cyano; and the like. One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

As the "C6-C30 aryl group" in the "C6-C30 aryl group optionally having substituent (s)" represented by R ⁷ or R ⁸ in the general formula (1) Specific examples thereof include phenyl group, naphthyl group, biphenyl group, anthryl group, phenanthryl group, pyrenyl group, triphenylenyl group, indenyl group, fluorenyl group and the like. Here, in the present invention, the "aryl group" represents an aromatic hydrocarbon group and a fused polycyclic aromatic group. Among these, a phenyl group or a naphthyl group is preferable, and a phenyl group is more preferable.

As the "substituent" in the "optionally substituted aryl group having 6 to 30 carbon atoms" represented by R ⁷ or R ⁸ in the general formula (1), specifically, a fluorine atom , Halogen atoms such as chlorine atom, bromine atom and iodine atom; carbons such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, n-hexyl group and t-octyl group Linear or branched alkyl group having 1 to 24 atoms; having 1 to 24 carbon atoms such as methoxy, ethoxy, propoxy, t-butoxy, n-pentyloxy, n-hexyloxy and the like Linear or branched alkoxy group; aryl group having 6 to 24 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group and the like; dimethylamino group, diethylamine Group, a linear or branched alkyl group having 1 to 23 carbon atoms, such as ethylmethylamino, methylpropylamino, di-t-butylamino and diphenylamino, or 6 to 23 carbon atoms Disubstituted amino group having a substituent selected from the aryl group of: hydroxyl group; carboxyl group; carboxylic acid ester group such as methyl ester group and ethyl ester group; vinyl group, vinylene group, phenylethenyl group, diphenylethenyl group Etc .; and a cyano group. One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

In the general formula (1), R ⁷ and R ⁸ each represent a linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent, carbon which may have a substituent A cycloalkyl group having 3 to 20 atoms or an aryl group having 6 to 30 carbon atoms which may have a substituent is preferable, and a cycloalkyl having 3 to 20 carbon atoms which may have a substituent is preferable. An aryl group having 6 to 30 carbon atoms which may have a group or a substituent is more preferable.

In the general formula (1), R ⁷ and R ⁸ represent the substituents as described above, but R ⁷ and R ⁸ are a single bond (R ⁷ -R ⁸ ) or a bond via an oxygen atom ( They may be combined with each other to form a ring by R ⁷ —O—R ⁸ ) or a bond (R ⁷ —S—R ⁸ ) via a sulfur atom.

  In the general formula (1), X represents a monovalent group and is preferably a monovalent group represented by the general formula (X1), (X2) or (X3). X is more preferably a monovalent group represented by Formula (X1) or (X3), and particularly preferably a monovalent group represented by Formula (X3).

Specific examples of the "acidic group" represented by R ⁹ in General Formula (X1) 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 It is possible to raise a group. Among these, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable.

  “C1-C6 linear or branched alkyl group having one or two acidic groups as a substituent,” represented by L or M in General Formula (X2), or “unsubstituted As the “C1-C6 linear or branched alkyl group” in the C1-C6 linear or branched alkyl group of “(1) carbon atoms” is specifically methyl group, ethyl group, n And -propyl, isopropyl, n-butyl, t-butyl, n-hexyl, isohexyl and the like. Among these, a linear or branched alkyl group having 1 to 3 carbon atoms is preferable, and a methyl group or an ethyl group is more preferable.

  As an "acidic group" in "a C1-C6 linear or branched alkyl group having one or two acidic groups as a substituent" represented by L or M in General Formula (X2) Specific examples thereof include carboxyl group, sulfonic acid group, phosphoric acid group, hydroxamic acid group, phosphonic acid group, boric acid group, phosphinic acid group and silanol group. Among these, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable. When the number of “acidic groups” is one, the substitution position of the “acidic group” is preferably at the end of the alkyl group, and when the number of “acidic groups” is two, the two “positions” It is preferable that the substituted position of at least any one "acid group" among the "acid groups" is the terminal of an alkyl group.

  The “C1-C6 linear or branched alkyl group having one or two acidic groups as a substituent”, which is represented by L or M in the general formula (X2), is a carboxyl group or A linear or branched alkyl group having 1 to 3 carbon atoms having one or two acidic groups selected from phosphonic acid groups as a substituent is preferable, and one or two carboxyl groups as a substituent Methyl or ethyl is more preferred.

  In General Formula (X2), at least one of L and M is “a C 1-6 linear or branched alkyl group having one or two acidic groups as a substituent”. . Here, p represents an integer of 0 to 2, and when p is 0, since L is absent, M is preferably selected from the group having 1 to 6 carbon atoms having one or two acidic groups as a substituent. It becomes a linear or branched alkyl group ". In addition, when p is 2, at least any one of two L or M having two or more L represents a “linear group having 1 to 6 carbon atoms having one or two acidic groups as a substituent group. Or a branched alkyl group ".

Specifically as the "acidic group" in the "hydrogen atom or acidic group" represented by R ¹¹ and R ¹² in the general formula (X3), specifically, 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, a silanol group etc. can be mentioned. Among these, a carboxyl group or a phosphonic acid group is preferable, and a carboxyl group is more preferable.

In the general formula (X3), "one carbon atom" in "a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent," represented by R ¹³ and R ¹⁴ As specific examples of the "~ 18 linear or branched alkyl group", methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like can be mentioned Examples thereof include linear alkyl groups; branched alkyl groups such as isopropyl group, isobutyl group, s-butyl group, t-butyl group and isooctyl group.

In the general formula (X3), "one carbon atom" in "a linear or branched alkoxy group having 1 to 18 carbon atoms which may have a substituent," represented by R ¹³ and R ¹⁴ Specifically, the linear or branched alkoxy group of to 18 is a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, Linear alkoxy groups such as decyloxy group; branched alkoxy groups such as isopropoxy group, isobutoxy group, s-butoxy group, t-butoxy group, isooctyloxy group and the like.

In the general formula (X3), "2 carbon atoms" in "a linear or branched alkenyl group having 2 to 18 carbon atoms which may have a substituent," represented by R ¹³ and R ¹⁴ Specifically, the linear or branched alkenyl group of to 18 may be an alkenyl group such as a vinyl group, an allyl group, an isopropenyl group, a 2-butenyl group, a 1-hexenyl group, or an alkenyl group of these A plurality of linked linear or branched alkenyl groups can be mentioned.

In the general formula (X3), “a linear or branched alkyl group having 1 to 18 carbon atoms having a substituent” represented by R ¹³ and R ¹⁴ ,
"Substituent" in "C1-C18 linear or branched alkoxy group having substituent (s)" or "linear- or branched alkenyl group having 2 to 18 carbon atoms having substituent (s)" as,
Specifically, 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 cycloalkyl group having 3 to 16 carbon atoms, such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group and the like;
A linear alkoxy group having 1 to 16 carbon atoms, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy and the like;
A branched alkoxy group having 3 to 16 carbon atoms such as isopropoxy group, isobutoxy group, s-butoxy group, t-butoxy group, isooctyloxy group;
Cycloalkoxy groups having 3 to 16 carbon atoms such as cyclopropoxy, cyclobutoxy, cyclopentyloxy and cyclohexyloxy;
An aryl group having 6 to 16 carbon atoms, such as phenyl, naphthyl, biphenyl, anthryl, phenanthryl, pyrenyl, indenyl and fluorenyl;
Unsubstituted amino group; substituents having 1 to 16 carbon atoms such as methylamino, dimethylamino, diethylamino, ethylmethylamino, methylpropylamino, di-t-butylamino, diphenylamino and the like An amino group having;
Examples thereof include carboxyl groups; carboxylic acid ester groups such as methyl ester groups and ethyl ester groups; One or more of these “substituents” may be contained, or two or more of these “substituents” may be contained in the same or different groups. Moreover, these "substituents" may further have the substituents exemplified above.

In General Formula (X3), R ¹³ and R ¹⁴ are preferably a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent, and a hydrogen atom is more preferable. .

In the general formula (X3), R ¹³ and R ¹⁴ may be bonded to each other to form a ring, and the ring is a single bond or an atom of either a nitrogen atom, an oxygen atom or a sulfur atom The bonds may be combined with each other to form a ring.

  In general formula (X3), r represents the number of thiophene groups. Here, the thiophene group has a role of a linking group which transports (transfers) the electrons excited in the dye portion to the indanone group which is an electron attracting portion. r represents the integer of 0-4, 0-2 are preferable.

  Among the sensitizing dyes of the present invention represented by the general formula (1), a 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, so It leads to the further improvement of the photoelectric conversion characteristic of the photoelectric conversion element using a sensitizing dye.

The sensitizing dye of the present invention represented by the general formula (1) is intended to include all stereoisomers that can be generated. Any isomer can be suitably used as a sensitizing dye in the present invention. For example, the sensitizing dye of the present invention in which R ^{1 to} R ⁶ are a hydrogen atom and X is a monovalent group represented by the above general formula (X1) in the above general formula (1) is a compound represented by the following general formula (2) And compounds represented by (3) are included.

  Specific examples of the sensitizing dye of the present invention represented by the general formula (1) are shown in the following formulas (A-1) to (A-51), but the present invention is not limited thereto. The following exemplified compounds are examples of possible stereoisomers and include all other stereoisomers. Moreover, each may be a mixture of two or more stereoisomers.

The sensitizing dye of the present invention represented by the general formula (1) can be synthesized using a known method. In the general formula (1), when all of R ^{1 to} R ⁶ are hydrogen atoms, they can be synthesized, for example, as follows. An intermediate represented by the following formula (6) by performing Buchwald-Hartwig reaction between 3,7-dibromodibenzothiophene represented by the following formula (4) and an amine compound represented by the following formula (5) Certain monobromo forms can be obtained. Furthermore, a formyl group (a bromo group (—Br) of the general formula (6) is subjected to a cross coupling reaction such as a Suzuki coupling with a boronic acid having a corresponding substituent or according to a conventional method By conversion to —CHO), a formyl form which is an intermediate represented by the following general formula (7) is obtained. However, in the following general formulas (5) to (7), R ⁷ , R ⁸ , R ¹³ and R ¹⁴ have the same meanings as the symbols in the general formula (1), and similarly, r is 0 to 4 Represents an integer of

  The formyl form (r = 0) represented by the following general formula (7) is, for example, an aryllithium obtained by metal halogen exchange of the bromo form represented by the general formula (6) with butyl lithium and the like, It can be synthesized by capturing with N, N-dimethylformamide (DMF).

  The synthesis of a formyl form (r = 1 to 4) represented by the following general formula (7) is, for example, 5-formyl-2-thiopheneboronic acid or 5'-formyl-2,2'-bithiophene-5-boron A formyl form represented by the general formula (7) can be synthesized by cross-coupling reaction using a boronic acid having a formyl group and a thiophene ring having a corresponding substituent, such as an acid.

  The sensitizing dye in the general formula (1) of the present invention, in which X is a monovalent group represented by the general formula (X1), (X2) or (X3), depends on the target X1 to X3. It can synthesize | combine by performing the condensation reaction of the intermediate body (formyl form) of General formula (7), and a suitable compound, respectively. Specifically, cyanoacetic acid etc. (when X is the general formula (X1)), rhodanine compounds such as rhodanine 3-acetic acid (when X is the general formula (X2)), or the following formula (8) It can synthesize | combine by performing condensation reaction with an indenone compound (when X is the said general formula (X3)) as it represents.

  In addition, about said Formula (4) or (5) used as a starting material, a commercially available thing may be used and what was synthesize | combined by the well-known method may be used. The indenone compound represented by the above general formula (8) can be easily synthesized by the method described in Patent Documents 8 to 10 described above.

When R ^{1 to} R ⁶ are a substituent other than a hydrogen atom, they are represented by the general formula (1) by carrying out the same reaction as described above using the corresponding dibromodibenzothiophene derivatives and the like. The sensitizing dyes of the present invention can be synthesized.

  As a purification method of the compound of the sensitizing dye of the present invention represented by the general formula (1), purification by column chromatography; adsorption purification by silica gel, activated carbon, activated clay or the like; recrystallization by crystallization, crystallization method, etc. There are known methods. In addition, identification of these compounds can be performed by nuclear magnetic resonance analysis (NMR) or the like.

  The sensitizing dyes of the present invention may be used alone or in combination of two or more. In addition, the sensitizing dyes 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 ruthenium complexes, coumarin dyes, cyanine dyes, merocyanine dyes, rhodacyanine dyes, phthalocyanine dyes, porphyrin dyes, xanthene dyes, etc. Mention may be made of sensitizing dyes other than those represented. When the sensitizing dye of the present invention is used in combination with these other sensitizing dyes, the amount of the other sensitizing dye to the sensitizing dye of the present invention is preferably 10 to 200% by weight, 20 It is more preferable that the amount be 100% by weight.

  The sensitizing dye of the present invention can be applied as a photosensitive material for various imaging materials such as silver halide, zinc oxide, titanium oxide, etc., as a spectral sensitizing dye such as a photocatalyst, a photofunctional material, etc. The present invention can also be applied as a sensitizing dye for photoelectric conversion used in devices and the like. In addition, light such as next-generation solar cells such as organic thin film solar cells and perovskite solar cells fabricated by combining the energy excited by the sensitizing dye of the present invention with other photoelectric conversion elements, and next generation storage batteries It is possible to apply to energy (electricity, heat, information, etc.) conversion elements. For example, the method for producing a dye-sensitized photoelectric conversion element in the present invention is not particularly limited, but a semiconductor layer is formed on a conductive support (electrode), and the increase in the photoelectric conversion of the present invention is performed on the semiconductor layer. A method of producing a photoelectrode by adsorbing (supporting) a dyestuff is preferred (see FIG. 1). As a method of 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 for photoelectric conversion of the present invention are used in combination, or when the sensitizing dyes for photoelectric conversion of the present invention are used in combination with other sensitizing dyes, a mixed solution of all the dyes to be used is prepared. The semiconductor layer may be dipped, or separate solutions may be prepared for each dye, and the semiconductor layer may be dipped in each solution in turn.

  In the present invention, 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 in addition to the metal plate. 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 complex oxide, and carbon. Preferably, a glass substrate coated with a fluorine-doped tin oxide thin film is used.

  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, yttrium oxide and the like Oxides; metal sulfides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, silver sulfide; titanium selenide, zirconium selenide, indium selenide, tungsten selenide And other elemental semiconductors such as silicon and germanium. These semiconductors may be used alone or in combination of two or more. In the present invention, it is preferable to use one or more selected from titanium oxide, zinc oxide and tin oxide as the semiconductor.

  Although the aspect of the semiconductor layer in this invention is not specifically limited, The thin film which has a porous structure which consists of microparticles | fine-particles is preferable. When the substantial surface area of the semiconductor layer is increased due to the porous structure or the like and the dye adsorption amount to the semiconductor layer is increased, a highly efficient photoelectric conversion element can be obtained. 5-500 nm is preferable and, as for a semiconductor particle diameter, 10-100 nm is more preferable. The film thickness of the semiconductor layer is usually 2 to 100 μm, preferably 5 to 20 μm. As a method of forming a semiconductor layer, a paste containing semiconductor fine particles is applied on a conductive substrate by a wet coating method such as spin coating method, doctor blade method, squeegee method, screen printing method, etc. There may be mentioned a method of forming a film by removing and a method of 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 it is not limited thereto.

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

  In the present invention, the semiconductor fine powder may be dispersed in a solvent by grinding in 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 to prevent aggregation of the semiconductor fine particles, and to thicken it, it is preferable to add a thickener such as polyethylene glycol.

  The adsorption of the sensitizing dye for photoelectric conversion of the present invention onto the surface of the semiconductor layer is carried out by immersing the semiconductor layer in the dye solution and leaving it for 30 minutes to 100 hours at room temperature or for 10 minutes to 24 hours under heating conditions. 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 for adsorbing the sensitizing dye for photoelectric conversion of the present invention on the surface of the semiconductor layer include alcohol solvents such as methanol, ethanol, isopropyl alcohol and t-butyl alcohol; acetone, methyl ethyl ketone, 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-based solvents such as dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone; nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile; dichloromethane, chloroform, bromoform, o-dichlorobenzene Halogenated hydrocarbon solvents; n-hexane, cyclohexane, benzene, may be mentioned hydrocarbon solvents such as toluene, and the like. These solvents are used alone or as a mixture of two or more. Among these solvents, it is preferable to use one or more selected from methanol, ethanol, t-butyl alcohol, acetone, methyl ethyl ketone, tetrahydrofuran and acetonitrile.

  When the sensitizing dye for photoelectric conversion of the present invention is adsorbed onto the surface of the semiconductor layer, a cholic acid or a cholic acid derivative such as deoxycholic acid, chenodeoxycholic acid, lithocholic acid or dehydrocholic acid is dissolved in a dye solution, It may be co-adsorbed with the dye. By using cholic acid or cholic acid derivative, association of the dyes is suppressed, and electrons can be efficiently injected from the dye to 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 0.1 to 100 mM, 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 has conductivity, but a conductive material having a catalytic ability is used to promote the redox reaction of redox ions. It is preferable to do. 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 thin film of platinum formed on a conductive support. In addition, as a method of forming a conductive thin film, a paste containing a conductive material is applied on a conductive substrate by a wet coating method such as spin coating method, doctor blade method, squeegee method or screen printing method, and then fired. Although the method to form into a film by removing a solvent and an additive and the method to form into a film by sputtering method, a vapor deposition method, an electrodeposition method, the electrodeposition method, a microwave irradiation method etc. can be mentioned, It is not limited to these.

  In the photoelectric conversion element of the present invention, an electrolyte is filled between a pair of opposing electrodes to form an electrolyte layer. As an electrolyte to be used, a redox electrolyte is preferable. Examples of the redox electrolyte include, but 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, etc. and iodine is used. In the present invention, it is preferable to use an electrolytic solution obtained by dissolving these electrolytes in a solvent. 0.05-5 M is preferable and, as for the density | concentration of the electrolyte in electrolyte solution, 0.2-1 M is more preferable.

  As a solvent for dissolving the electrolyte, nitrile solvents such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, benzonitrile, etc .; ether solvents such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, etc. 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 mixture of two or more. Among these solvents, nitrile solvents are preferred.

  In the present invention, an amine compound may be contained in the electrolytic solution to further improve the open circuit voltage and fill factor of the dye-sensitized photoelectric conversion device. Examples of amine compounds include 4-t-butylpyridine, 4-methylpyridine, 2-vinylpyridine, N, N-dimethyl-4-aminopyridine, N, N-dimethylaniline, and N-methylbenzimidazole. Can. 0.05-5 M is preferable and, as for the density | concentration of the amine compound in electrolyte solution, 0.2-1 M is more preferable.

  A gelled electrolyte obtained by adding a gelling agent, a polymer or the like as the electrolyte in the photoelectric conversion element of the present invention, or a solid electrolyte using a polymer such as polyethylene oxide derivative may be used. By using a gel electrolyte or a solid electrolyte, the 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 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 transport materials such as copper iodide, copper bromide and copper thiocyanate, polypyrrole, polythiophene, poly-p-phenylenevinylene, polyvinylcarbazole, polyaniline, oxadiazole derivative, tri Examples include organic hole transport materials such as phenylamine derivatives, pyrazoline derivatives, fluorenone derivatives, hydrazone compounds and stilbene compounds, but are not limited thereto. The solid charge transport layer may contain a lithium compound such as lithium bis (trifluoromethanesulfonyl) imide or lithium diisopropylimide, a basic amine compound such as 4-t-butylpyridine or 2-amylpyridine as an additive preferable. Further, in order to improve the conductivity, an oxidizing agent may be added to convert a part of the organic hole transporting substance into a radical cation. Examples of the oxidizing agent include cobalt complexes such as tris (2- (1H-pyrazol-1-yl) -4-t-butylpyridine) cobalt (III) tris (bis (trifluoromethylsulfonyl) imide).

  When forming a solid charge transport layer using an organic hole transport material in the present invention, a film-forming binder resin may be used 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. Not limited to these. These resins may be used alone or in combination of one or more as a copolymer. 20-1000 weight% is preferable and, as for the usage-amount with respect to the organic hole transport material of these binder resin, 50-500 weight% is more preferable.

  In the photoelectric conversion element of the present invention, the electrode (photoelectrode) provided with the semiconductor layer to which the sensitizing dye for photoelectric conversion is adsorbed is a cathode, and the counter electrode is an anode. The light such as sunlight may be irradiated from either the photoelectrode side or the counter electrode side, but it is preferable to irradiate from the photoelectrode side. By irradiation with sunlight or the like, the dye absorbs light and is excited to emit electrons. The electrons flow to the outside through the semiconductor layer and move to the counter electrode. On the other hand, the dye in the oxidized state by emitting electrons returns to the ground state by receiving the electrons supplied from the counter electrode via the 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, the short circuit current, the open circuit voltage, the fill factor, and the 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 shorted, 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 product of the maximum output (the product of current and voltage) by the product of the short circuit current and the open circuit voltage, mainly depending on the internal resistance. The photoelectric conversion efficiency is obtained as a value expressed as a percentage 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 light sensors, and the like. In the dye-sensitized solar cell of the present invention, a photoelectric conversion element containing a sensitizing dye for photoelectric conversion comprising the sensitizing dye represented by the general formula (1) is a cell, and the required number of cells is arranged to be a module And by providing predetermined electrical wiring.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples. For identification of the compounds in Synthesis Examples ^were carried out by 1 H-NMR analysis (JEOL Ltd. nuclear magnetic resonance apparatus, JNM-ECA-600 or JNM-EX270).

Synthesis Example 1 Synthesis of Sensitizing Dye (A-5) In a nitrogen-substituted reaction vessel, 165 mL of toluene, 8.00 g of 3,7-dibromodibenzothiophene, 10.12 g of bis (4-t-octylphenyl) amine C., 3.37 g of sodium-t-butoxide, 1.07 g of tris (dibenzylideneacetone) dipalladium (0), and 2.36 mL of tri-t-butylphosphine / toluene solution having a concentration of 0.2 mg / mL, The mixture was stirred for 2 hours. The reaction mixture was allowed to cool to 25 ° C., and then 380 mL of water and 380 mL of ethyl acetate were added and the mixture was stirred to extract an organic layer. The organic layer was washed with saturated brine, dried over sodium sulfate and dried under reduced pressure to give a crude product. The crude product is purified by column chromatography (carrier: silica gel, solvent (n-hexane)) and dried under reduced pressure to obtain a white solid (5.96 g) of a monobromo compound represented by the following formula (9) The

  In a nitrogen-substituted reaction vessel, 1.20 g of the monobromo compound represented by the above formula (9) and 16 mL of dehydrated tetrahydrofuran are placed, and 1.5 mL of a 1.6 M n-butyllithium hexane solution is stirred at -72 ° C. Were added dropwise, and after reaction for 1 hour, 0.3 mL of dehydrated dimethyl formaldehyde was added dropwise to carry out reaction for 2 hours. Thereafter, the reaction solution was poured into ice water, and the organic layer was extracted with methylene chloride. The organic layer was washed with water, separated, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by chromatography (carrier: silica gel, solvent: hexane / toluene = 9/1 (volume ratio)) to obtain a white solid (0.78 g) of a formyl compound represented by the following formula (10) .

  25 mL of acetic acid, 0.362 g of a formyl compound represented by the above formula (10), 0.297 g of cyanoacetic acid, and 0.027 g of ammonium acetate were added to a reaction vessel purged with nitrogen, and the mixture was heated and stirred at 110 ° C. for 21 hours. The reaction solution was allowed to cool to 25 ° C., and then 125 mL of water was added and stirred to extract the organic layer. The organic layer was washed successively with water and saturated brine, and the obtained organic layer was dried to give the desired sensitizing dye as a red solid (0.333 g, yield 86%).

  NMR analysis was performed on the obtained red solid, and the following 49 hydrogen signals were detected and identified as a structure represented by the following formula (A-5) (hydrogen of carboxyl group was not observed).

¹ H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 0.66 to 0.88 (18 H), 1.24 to 1.40 (12 H), 1.60 to 1.80 (4 H), 6 .95-7.10 (4H), 7.14-7.18 (1H), 7.22-7.34 (4H), 7.35-7.40 (1H), 7.94-8.00 (1H), 8.02-8.12 (2H), 8.36-8.41 (1H), 8.42-8.48 (1H).

Synthesis Example 2 Synthesis of Sensitizing Dye (A-22) In a nitrogen-substituted reaction vessel, 10.7 mL of a mixed solution of acetic acid / toluene = 5/2 (volume ratio), the formula obtained in Synthesis Example 1 ( 0.247 g of a formyl compound represented by 10) and 0.117 g of an indanone compound represented by the following formula (11) were added and stirred at 90 ° C. for 3 hours. The reaction solution was allowed to cool to 25 ° C., 50 mL of water was added and stirred, and the organic layer was extracted. The organic layer was washed successively with water and brine, and dried to give the desired sensitizing dye as a reddish-brown solid (0.283 g, 93% yield).

  The NMR analysis of the obtained reddish brown solid was performed, and the following 52 hydrogen signals were detected and identified as a structure represented by the following formula (A-22) (hydrogen of carboxyl group was not observed).

¹ H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 0.64-0.85 (18 H), 1.22-1. 45 (12 H), 1. 70-1.91 (4 H), 6 .95-7.00 (1H), 7.01-7.05 (4H), 7.22-7.30 (1H), 7.35-7.40 (4H), 7.90-8.00 (1H), 8.04-8.07 (1H), 8.20-8.24 (1H), 8.27-8.33 (1H), 8.34-8.38 (1H), 8. 39-8.41 (1 H), 8.54-8.59 (1 H), 9.10-9.15 (1 H).

Synthesis Example 3 Synthesis of Sensitizing Dye (A-28) In a nitrogen-substituted reaction vessel, 200 mL of toluene, 10.78 g of 3,7-dibromodibenzothiophene, and an amine compound represented by the following formula (12). 27 g, sodium-t-butoxide 4.54 g, tris (dibenzylideneacetone) dipalladium (0) 1.44 g, a concentration of 0.2 mg / mL tri-t-butylphosphine / toluene solution 2.6 mL, 85 ° C. The mixture was stirred for 2 hours. The reaction mixture was allowed to cool to 25 ° C., 150 mL of water and 500 mL of ethyl acetate were added and the mixture was stirred to extract an organic layer. The organic layer was washed with saturated brine, and the obtained organic layer was dried over sodium sulfate and concentrated under reduced pressure to give a crude product. The crude product was purified by column chromatography (carrier: silica gel, solvent: n-hexane) and dried to give a white solid (5.32 g) of a monobromo compound represented by the following formula (13).

  In a reaction vessel purged with nitrogen, 34.5 mL of N, N-dimethylformamide, 2.30 g of a monobromo compound of the above formula (13), and 1.01 g of phosphorus oxychloride are added, and stirred at 25 ° C. for 90 minutes. Stir for hours. The reaction solution was poured into 175 mL of ice water, and 175 mL of ethyl acetate was added to extract the organic layer. Extraction with ethyl acetate was performed three times. The organic layer was dried over magnesium sulfate and the solvent was evaporated to give a crude product. The obtained crude product was purified by column chromatography (carrier: silica gel, solvent: toluene) to obtain a brown solid of 2.25 g (yield 91%) of a compound represented by the following formula (14).

  35 mL of N, N-dimethylformamide, 2.23 g of a compound represented by the above formula (14), 1.97 g of diethyl diphenylmethylphosphonate and 1.00 g of potassium t-butoxide are put in a nitrogen-substituted reaction vessel, and Stir for hours. After the reaction was stopped by adding 90 mL of water, the reaction was washed with water / methanol = 1/1 (volume ratio). The obtained crude product is purified by column chromatography (carrier: silica gel, solvent: hexane / toluene = 5/1 (volume ratio)), and 2.89 g of a monobromo compound represented by the following formula (15) Yield 97%) of a yellow solid.

  In a nitrogen-substituted reaction vessel, 0.500 g of the monobromo compound represented by the above formula (15) and 10 mL of dehydrated tetrahydrofuran are charged, and 0.71 mL of a 1.6 M n-butyllithium / hexane solution is stirred at -72 ° C. Was added dropwise and the reaction was carried out for 2 hours. After the reaction, 0.3 mL of dehydrated dimethyl formaldehyde was added dropwise to the reaction solution to carry out a reaction for 2 hours. Thereafter, the reaction solution was poured into ice water, and methylene chloride was added to extract the organic layer. The organic layer was washed with water, separated, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by chromatography (carrier: silica gel, solvent: hexane / toluene = 9/1 (volume ratio)) to obtain a yellow solid (0.196 g) of a formyl compound represented by the following formula (16) .

  In a reaction vessel purged with nitrogen, 8.5 mL of a mixed solution of acetic acid / toluene = 5/2 (volume ratio), 0.188 g of a formyl compound represented by the above formula (16), an indanone represented by the above formula (11) 0.102 g of the compound was added and stirred at 90 ° C. for 5 hours. The reaction solution was allowed to cool to 25 ° C., 17 mL of methanol was added and stirred, and the reaction product was filtered. The reaction product was washed with methanol, and the obtained organic layer was dried to obtain the desired sensitizing dye as a black solid (0.242 g, yield 98%).

  The obtained black solid was subjected to NMR analysis to detect signals of the following 32 hydrogens, and identified as a structure represented by the following formula (A-28) (hydrogen of carboxyl group was not observed).

¹ H-NMR (600 MHz, CDCl ₃ ): δ (ppm) = 1.25 to 1.28 (1 H), 1.47 to 1.49 (1 H), 1.55 to 1.60 (1 H), 1 .72-1.76 (1 H), 1.80 -1.89 (1 H), 1.90 -1.96 (3 H), 6.60-6.70 (1 H), 6.80-6.95 (1H), 7.00-7.10 (2H), 7.15-7.21 (2H), 7.24-7.35 (5H), 7.40-7.50 (4H), 7. 80-7.90 (1H), 7.95-7.97 (1H), 8.00-8.09 (1H), 8.30-8.43 (4H), 8.58-8.62 1 H), 9.10-9.21 (1 H).

Synthesis Example 4 Synthesis of Sensitizing Dye (A-32) In a nitrogen-substituted reaction vessel, 41 mL of toluene, 2.2 g of 3,7-dibromodibenzothiophene and an amine compound represented by the following formula (17). 68 g, sodium-t-butoxide 0.93 g, tris (dibenzylideneacetone) dipalladium (0) 0.29 g, 0.37 mL of tri-t-butylphosphine / toluene solution with a concentration of 0.2 mg / mL, 80 ° C. Stir for 5 hours. The reaction mixture was allowed to cool to 25 ° C., 30 mL of water and 80 mL of ethyl acetate were added and the mixture was stirred to extract an organic layer. The organic layer was washed with brine, dried over sodium sulfate and concentrated under reduced pressure to give a crude product. The crude product is purified by column chromatography (carrier: silica gel, mixed solvent: n-hexane / toluene), dried and white yellow solid (1.08 g) of monobromo compound represented by the following formula (18) I got

  In a nitrogen-replaced reaction vessel, 1.00 g of the monobromo compound represented by the above formula (18) and 20 mL of dehydrated tetrahydrofuran are charged, and a 1.6 M n-butyllithium / hexane solution is added while stirring at -72 ° C. 4 mL was added dropwise and reacted for 3 hours. After the reaction, 0.4 mL of dehydrated dimethyl formaldehyde was added dropwise to the reaction solution to carry out a reaction for 2 hours. Thereafter, the reaction solution was poured into ice water, and methylene chloride was added to extract the organic layer. The organic layer was washed with water, separated, dried over magnesium sulfate and concentrated under reduced pressure. The residue was purified by chromatography (carrier: silica gel, solvent: hexane / toluene = 9/1 (volume ratio)) to obtain a yellow solid (0.56 g) of a formyl compound represented by the following formula (19) .

  In a nitrogen-purged reaction vessel, 11 mL of acetic acid, 0.160 g of a formyl compound represented by the above formula (19), 0.168 g of cyanoacetic acid, and 0.015 g of ammonium acetate were added, and stirred at 105 ° C. for 7 hours. The reaction solution was allowed to cool to 25 ° C., 65 mL of water was added and the mixture was stirred to extract an organic layer. The organic layer was washed successively with water and saturated brine and dried to give the desired sensitizing dye as a red solid (0.155 g, 89% yield).

  NMR analysis of the obtained red solid was performed, and the following 25 hydrogen signals were detected and identified as a structure represented by the following formula (A-32) (hydrogen of carboxyl group was not observed).

¹ H-NMR (270 MHz, dimethyl sulfoxide (DMSO) -d ₆ ): δ (ppm) = 1.90-2.06 (4H), 2.30-2.40 (4H), 3.90-4. 00 (1 H), 4.90-5.10 (1 H), 7.29-7.60 (8 H), 7.89-8.00 (1 H), 8.10-8.22 (1 H), 8 .30-8.50 (4H), 8.51-8.65 (1 H).

Synthesis Example 5 Synthesis of Sensitizing Dye (A-33) In a nitrogen-substituted reaction vessel, 7.2 mL of a mixed solution of acetic acid / toluene = 5/2 (volume ratio), formyl represented by the above formula (19) 0.160 g of a bulk compound and 0.078 g of the indanone compound represented by the above formula (11) were added and stirred at 90 ° C. for 6 hours. The reaction solution was allowed to cool to 25 ° C., 15 mL of toluene was added and stirred, and the reaction product was filtered. The reaction was washed with methanol and dried to give the desired sensitizing dye as a black solid (0.133 g, 68% yield).

  The obtained black solid was subjected to NMR analysis to detect signals of the following 28 hydrogens, and identified as a structure represented by the following formula (A-33) (hydrogen of carboxyl group was not observed).

¹ H-NMR (270 MHz, DMSO-d ₆ ): δ (ppm) = 1.39-1.41 (1 H), 1.64-1.67 (1 H), 1.83-1.92 (2 H) , 2.00-2.11 (2H), 2.23-2.35 (3H), 3.89-4.00 (1H), 4.93-4.96 (1H), 7.20-7. .61 (8 H), 7.80-7.99 (2 H), 8.00-8.1 1 (1 H), 8.31-8.43 (4 H), 8. 50-8.63 (1 H), 9.18-9.21 (1 H).

Synthesis Example 6 Synthesis of Sensitizing Dye (A-34) In a nitrogen-substituted reaction vessel, 100 mL of dimethyl sulfoxide, 2.86 g of the monobromo compound represented by the above formula (9), 5'-formyl-2,2 '-Bithiophene-5-boronic acid 1.25 g, potassium carbonate 0.515 g, palladium (II) acetate 0.049 g, di (1-adamantyl) -n-butyl phosphine 0.157 g, stirred at 80 ° C. for 3 hours did. The reaction mixture was allowed to cool to 25 ° C., 460 mL of water and 460 mL of ethyl acetate were added and the mixture was stirred to extract an organic layer. The organic layer was washed with brine, dried over sodium sulfate and concentrated under reduced pressure to give a crude product. The crude product is purified by column chromatography (carrier: silica gel, solvent: hexane / toluene = 1/2 (volume ratio)), dried, and yellowish brown solid of formyl compound represented by the following formula (20) Obtained (2.86 g).

  In a reaction vessel purged with nitrogen, 35 mL of a mixed solution of acetic acid / toluene = 5/2 (volume ratio), 0.770 g of a formyl compound represented by the above formula (20), an indanone compound 0 represented by the above formula (11) Add .300 g and stir at 90 ° C. for 7 hours. The reaction mixture was allowed to cool to 25 ° C., and the reaction mixture was concentrated under reduced pressure to give a crude product. The crude product was purified by column chromatography (carrier: silica gel, solvent: chloroform / methanol = 5/2 (volume ratio)) to obtain the desired sensitizing dye as a black solid (0.730 g, yield 78%) ).

  The obtained black solid was subjected to NMR analysis to detect signals of the following 56 hydrogens and identified as a structure represented by the following formula (A-34) (hydrogen of carboxyl group was not observed).

¹ H-NMR (600 MHz, DMSO-d ₆ ): δ (ppm) = 1.00 to 1.04 (18 H), 1.59 to 1.63 (12 H), 1.93 to 2.02 (4 H) , 7.25-7.37 (5H), 7.53-7.59 (4H), 7.61-7.67 (2H), 7.74-7.81 (2H), 7.92-7. .97 (1 H), 8.11-8.41 (6 H), 8.57-8.70 (2 H).

Synthesis Example 7 Synthesis of Sensitizing Dye (A-35) In a nitrogen-substituted reaction vessel, 46 mL of dimethyl sulfoxide, 1.30 g of the monobromo compound represented by the above formula (13), 5-formyl-2-thiophene boron 0.579 g of acid, 0.364 g of potassium carbonate, 0.035 g of palladium (II) acetate and 0.111 g of di (1-adamantyl) -n-butylphosphine were added, and the mixture was stirred at 85 ° C. for 2 hours. The reaction mixture was allowed to cool to 25 ° C., 200 mL of water and 200 mL of chloroform were added and the mixture was stirred to extract an organic layer. The organic layer was washed with saturated brine, dried over sodium sulfate and dried under reduced pressure to give a crude product. The crude product is purified by column chromatography (carrier: silica gel, solvent: hexane / toluene = 1/2 (volume ratio)), dried, and yellowish brown solid of formyl compound represented by the following formula (21) Obtained (1.33 g).

  In a reaction vessel purged with nitrogen, 20 mL of a mixed solution of acetic acid / toluene = 1/3 (volume ratio), 0.270 g of a formyl compound represented by the above formula (21), an indanone compound 0 represented by the above formula (11) Add .193g and stir at 90 ° C for 8 hours. The reaction solution was allowed to cool to 25 ° C., and then the reaction solution was dried under reduced pressure to obtain a crude product. The crude product was purified by column chromatography (Carrier: silica gel, solvent: chloroform / methanol = 5/1 (volume ratio)) to obtain the desired sensitizing dye as a reddish brown solid (0.280 g, yield 75%) ).

  The resulting reddish brown solid was subjected to NMR analysis, and the signals of the following 24 hydrogens were detected and identified as a structure represented by the following formula (A-35) (hydrogen of carboxyl group was not observed).

¹ H-NMR (600 MHz, DMSO-d ₆ ): δ (ppm) = 1.06-1.19 (1 H), 1.31-1.35 (1 H), 1.55-1.59 (1 H) , 1.72-1.76 (1H), 1.91-2.02 (2H), 3.78-3.82 (1H), 4.78-4.82 (1H), 6.69-6. .73 (1 H), 7.00-7.12 (3 H), 7.37-7.41 (1 H), 7.75-8.39 (11 H).

Example 1
On a glass substrate coated with a fluorine-doped tin oxide thin film, a titanium oxide paste (PST-18NR manufactured by JGC Co., Ltd.) was applied by a squeegee method. After drying at 110 ° C. for 1 hour, baking was carried out at 450 ° C. for 30 minutes to obtain a titanium oxide thin film having a thickness of 7 μm. Next, for the sensitizing dye (A-5) and deoxycholic acid obtained in Synthesis Example 1, acetonitrile / t-butyl alcohol = 1/1 (volume ratio) so that the concentrations would be 100 μM and 1 mM, respectively. Dissolve in a mixed solvent to prepare 50 mL of a solution, and immerse a glass substrate coated with titanium oxide in this solution for 15 hours at room temperature to adsorb the sensitizing dye as a sensitizing dye for photoelectric conversion, It was a photoelectrode.

  On a glass substrate coated with a fluorine-doped tin oxide thin film, a platinum thin film with a film thickness of 15 nm was formed by sputtering using an auto-fine coater (JFC-1600 manufactured by JEOL Ltd.) to form a counter electrode.

  Next, a spacer (heat fusion film) with a thickness of 60 μm is sandwiched between the photo electrode and the counter electrode, and bonded by heat fusion, and the electrolyte is injected from the hole formed in advance in the counter electrode, and then the hole is sealed. And produced a photoelectric conversion element. As an electrolytic solution, a 3-methoxypropionitrile solution of lithium iodide 0.1 M, dimethylpropyl imidazolium iodide 0.6 M, iodine 0.05 M, 4-t-butylpyridine 0.5 M was used.

From the photoelectrode side of the photoelectric conversion element, light generated by a simulated solar light irradiation device (OTENTO-SUN III type manufactured by Spectrometer Co., Ltd.) is irradiated to obtain a source meter (Model 2400 General-Purpose SourceMeter manufactured by KEITHLEY). The current-voltage characteristics were measured using this. The light intensity was adjusted to 100 mW / cm ² . The photoelectric conversion efficiency was also measured after irradiation with light for 20 hours to evaluate the change in characteristics. The measurement results are summarized in Table 1 and shown.

[Examples 2 to 9]
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 instead of (A-5) as the sensitizing dye for photoelectric conversion, and the current-voltage characteristics were measured. . The photoelectric conversion efficiency was also measured after irradiation with light for 20 hours to evaluate the change in characteristics. The measurement results are summarized in Table 1 and shown.

[Comparative Example 1 to Comparative Example 4]
As a sensitizing dye for photoelectric conversion, in place of (A-5), the following formulas (B-1) to (B) which do not belong to the present invention and which are disclosed in the prior art (patent documents 4 to 6) The photoelectric conversion element was produced similarly to Example 1 except having used the sensitizing dye shown to -4), and the current-voltage characteristic was measured. The photoelectric conversion efficiency was also measured after irradiation with light for 20 hours to evaluate the change in characteristics. The measurement results are summarized in Table 1 and shown.

  From the results shown in Table 1, photoelectric conversion efficiency is high by using the sensitizing dye for photoelectric conversion comprising the sensitizing dye of the present invention, and photoelectric conversion in which high photoelectric conversion efficiency is maintained even if light irradiation is continued for a long time It turned out that an element could be obtained. On the other hand, the photoelectric conversion efficiency of the photoelectric conversion element using the sensitizing dye for photoelectric conversion of a comparative example was inadequate.

Although the present invention has been described in detail with reference to particular embodiments, it will be 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.
The present application is based on the Japanese Patent Application (Japanese Patent Application No. 2016-188633) filed on September 27, 2016, which is incorporated by reference in its entirety. Also, all references cited herein are taken as a whole.

  The sensitizing dye for photoelectric conversion which consists of a sensitizing dye of the present invention is useful as a highly efficient and highly durable photoelectric conversion element and a dye-sensitized solar cell, and a solar cell capable of efficiently converting sunlight energy into electric energy As a clean energy can be provided.

1 conductive support 2 dye-supporting semiconductor layer 3 electrolyte layer 4 counter electrode 5 conductive support

Claims (7)

The sensitizing dye represented by following General formula (1).

[Wherein, R ^{1 to} R ⁶ may be the same or different and each independently represent a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or 1 to 6 carbon atoms] 6 straight or branched alkoxy groups,
R ⁷ and R ⁸ may be the same or different, and may have a substituent, a linear or branched alkyl group having 1 to 20 carbon atoms, carbon which may have a substituent A cycloalkyl group having 3 to 20 atoms, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, and 7 to 7 carbon atoms which may have a substituent 26 represents an aralkyl group of 26 or an aryl group having 6 to 30 carbon atoms which may have a substituent, and R ⁷ and R ⁸ may be bonded to each other to form a ring.
X represents a monovalent group. ] The sensitizing dye according to claim 1, wherein in the general formula (1), X is a monovalent group represented by the following general formula (X1), (X2) or (X3).

[Wherein, R ⁹ represents an acidic group. ]

[Wherein, L and M may be the same or different, and are a linear or branched alkyl group having 1 to 6 carbon atoms having one or two acidic groups as a substituent, or an unsubstituted one It represents a linear or branched alkyl group having 1 to 6 carbon atoms. However, at least any one of L and M is a linear or branched alkyl group having 1 to 6 carbon atoms having one or two acidic groups as a substituent. p represents an integer of 0 to 2, and when p is 2, a plurality of L may be the same as or different from each other. ]

[Wherein, R ¹¹ and R ¹² represent a hydrogen atom or an acidic group, and at least one of R ¹¹ or R ¹² is an acidic group. R ¹³ and R ¹⁴ may be the same or different, and have a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent, or a substituent R ¹³ represents a linear or branched alkoxy group having 1 to 18 carbon atoms, or a linear or branched alkenyl group having 2 to 18 carbon atoms which may have a substituent, and R ¹³ And R ¹⁴ may be bonded to each other to form a ring. r represents an integer of 0 to 4, when r is an integer of 2 to 4, ^{R 13} and ^{R 14} there are a plurality, the ^{R 13 together, R 14} themselves may be the same or different from each other. ] The sensitizing dye according to claim 1 or 2, wherein in the general formula (1), all of R ^{1 to} R ⁶ are hydrogen atoms. In the above general formula (1), R ⁷ and R ⁸ each represent a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent, or 6 to 6 carbon atoms which may have a substituent. The sensitizing dye according to claim 3, which is any of 30 aryl groups, and R ⁷ and R ⁸ may be bonded to each other to form a ring.   The sensitizing dye for photoelectric conversion which consists of a sensitizing dye as described in any one of Claims 1-4.   A photoelectric conversion device using the sensitizing dye for photoelectric conversion according to claim 5. The dye-sensitized solar cell using the photoelectric conversion element of Claim 6.

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