JP2008105967A - Compound, photoelectric transducer and photoelectrochemical cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound, a photoelectric transducer and a photoelectrochemical cell. <P>SOLUTION: A complex compound (I), obtained by causing a compound represented by formula (II) [abbreviated as compound (II)] to co-ordinate to a metal atom, is provided. In the formula, R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>and R<SP>4</SP>are each a salt of an acidic group, an acidic group, a hydrogen atom or a substituent group, and at least one of them is an acidic group or a salt thereof; R<SP>3</SP>and R<SP>4</SP>may be linked together; A is a group containing a nitrogen atom, an oxygen atom, a carbon atom, a silicon atom, a sulfur atom or a selenium atom; m is an integer of 1 or 2; a, b, c and d are each independently an integer of 0-2; and a+b+c+d≥1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compound, a photosensitizing dye containing the compound, a photoelectric conversion element containing the dye, and a photoelectrochemical cell such as a solar battery containing the photoelectric conversion element.

In recent years, in order to prevent global warming, reduction of CO ₂ released into the atmosphere has been demanded. As an effective means for reducing CO ₂ , for example, switching to a solar system using a photoelectrochemical cell such as a pn junction type silicon solar cell on the roof of a house has been proposed. However, single crystal, polycrystalline and amorphous silicon used in the silicon-based photoelectrochemical cell have a problem that they are expensive because high temperature and high vacuum conditions are required in the production process.
On the other hand, Patent Document 1 proposes a photoelectrochemical cell including a photoelectric conversion element in which a photosensitizing dye that is easy to produce is adsorbed on the surface of semiconductor fine particles such as titanium oxide. It has been reported that the compound represented by the formula shows excellent photoelectric conversion efficiency.

JP 7-500630 A, Application Example A

When the present inventors examined the photoelectrochemical cell containing a photosensitizing dye (1), it is clear that the photoelectric conversion efficiency is not sufficient from the visible light region to the long wavelength region, particularly in the long wavelength region of 750 nm or more. became.
An object of the present invention is to provide a compound that provides a photoelectric conversion element with high photoelectric conversion efficiency in a wide region from the visible light region to a long wavelength region, a dye for a photoelectric conversion device containing the compound, a photoelectric conversion device containing the dye, and It is to provide a photoelectrochemical cell including the element.

［式中、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴は、それぞれ独立に、酸性基の塩、酸性基、水素原子、叉は置換基を表し、少なくとも一つは酸性基叉はその塩を表す。Ｒ³及びＲ⁴は互いに結合していてもよく、Ａは、窒素原子、酸素原子、炭素原子、ケイ素原子、硫黄原子、又はセレン原子を含む基を表し、ｍは１〜２の整数であり、ａ、ｂ、ｃ及びｄは、それぞれ独立に、０〜２の整数を表し、ａ＋ｂ＋ｃ＋ｄ≧１である。］ The present invention is abbreviated as a compound represented by formula (II) [compound (II). ] A complex compound (I) obtained by coordinating a metal atom; a photosensitizing dye containing the complex compound (I); a photoelectric conversion element containing the dye; and a photoelectrochemical cell containing the element.

[Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents an acidic group salt, an acidic group, a hydrogen atom, or a substituent, and at least one of the acidic group or its salt represents To express. R ³ and R ⁴ may be bonded to each other, A represents a group containing a nitrogen atom, an oxygen atom, a carbon atom, a silicon atom, a sulfur atom, or a selenium atom, and m is an integer of 1 to 2. , A, b, c and d each independently represents an integer of 0 to 2, and a + b + c + d ≧ 1. ]

  The complex compound (I) of the present invention is a compound that provides a photoelectric conversion element having high photoelectric conversion efficiency in the visible light region to the long wavelength region. Especially, it is remarkably excellent in the photoelectric conversion efficiency in a long wavelength region of 750 nm or more. Further, such a complex compound is easy to produce and can be suitably used for a photoelectric conversion element for a photoelectrochemical cell.

The present invention will be described in detail below.
The present invention is a complex compound (I) comprising a metal atom and a compound represented by the formula (II).
Metal atoms include Group 4 Ti, Zr, Group 8 Fe, Ru, Os, Group 9 Co, Rh, Ir, Group 10 Ni, Pd, Pt, Group 11 Cu, Group 11 Zn of group 12 and the like can be mentioned, and a metal atom of group 8 is preferable, and Ru is more preferable.

塩としては、有機塩基との塩が挙げられ、具体的にはテトラアルキルアンモニウム塩、イミダゾリウム塩、ピリジニウム塩などが挙げられる。 In the formulas (I) and (II), R ¹ , R ² , R ³ and R ⁴ each independently represents an acid group salt, an acid group, a hydrogen atom, or a substituent, at least one of which is acidic Represents a group or a salt thereof. Examples of the acidic group include a carboxyl group, a sulfonic acid group (—SO 3 H), a squaric acid group, a phosphoric acid group (—PO 3 H 2), a boric acid group (—B (OH) 2), and a silicic acid group (—Si (OH). ) 2) etc. A carboxyl group is particularly preferable.

Examples of the salt include salts with organic bases, and specific examples include tetraalkylammonium salts, imidazolium salts, and pyridinium salts.

a, b, c and d each independently represent an integer of 0 to 2, and a + b + c + d ≧ 1. Particularly preferably, R ¹ and R ² contain at least one acidic group or a salt thereof.

[式中、Ａｒは置換基を有していてもよいアリール基を表し、Ｑ^１及びＱ^２が、それぞれ独立に、水素原子、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、炭素数６〜２０のアリール基、叉はシアノ基を表し、ｐは１〜３の整数を表す。] In the formulas (I) and (II), R ¹ , R ² , R ³ and R ⁴ each independently represents an acidic group salt, acidic group, hydrogen atom, or substituent, and at least one of the acidic group or Represents the salt. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, and an aryl having 7 to 20 carbon atoms. Alkyloxy group, aryloxyalkyl group having 7-20 carbon atoms, alkylthio group having 1-20 carbon atoms, alkylthioalkyl group having 2-20 carbon atoms, arylthio group having 6-20 carbon atoms, aryl having 7-20 carbon atoms Alkylthio group, arylthioalkyl group having 7 to 20 carbon atoms, alkylsulfonyl group having 1 to 20 carbon atoms, arylsulfonyl group having 6 to 20 carbon atoms, alkyl group having 1 to 20 carbon atoms, or aryl having 6 to 20 carbon atoms And at least one group selected from the group consisting of an amino group disubstituted by a group, a cyano group, and groups represented by formula (III) and formula (IV).

[In the formula, Ar represents an aryl group which may have a substituent, and Q ¹ and Q ² are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents a group, an aryl group having 6 to 20 carbon atoms, or a cyano group, and p represents an integer of 1 to 3. ]

In formula (III) or formula (IV), Ar represents an aromatic group shown below.
A specific example of Ar is shown by the following formula. In addition, the following illustration represents that two hydrogen atoms become a coupling | bonding site | part among the hydrogen atoms substituted on a carbon atom.

In formula (III) or formula (IV), p represents an integer of 1 to 3, preferably p = 1.
Either E body or Z body may be used, and a mixture of E body and Z body may be used.
In the group represented by formula (III) or formula (IV), the Ar binding site may be bonded to a substituent or an unsaturated hydrocarbon group.
* Represents a bonding site with a substituent or an unsaturated hydrocarbon group. In the case of Ar containing a hetero atom, it is bonded to the substituent at a site close to the hetero atom (a sulfur atom and an oxygen atom are preferred over a nitrogen atom) or a site having a hetero atom on both sides.
Examples of the substituent for Ar include an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, and 7 to 20 carbon atoms. Arylalkyloxy group, C7-20 aryloxyalkyl group, C1-20 alkylthio group, C2-20 alkylthioalkyl group, C6-20 arylthio group, C7-20 Arylalkylthio group, C7-20 arylthioalkyl group, C1-C20 alkylsulfonyl group, C6-C20 arylsulfonyl group, C1-C20 alkyl group or C6-C20 And an amino group and a cyano group that are disubstituted by the aryl group.

The alkyl group has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. Specific examples include linear alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, n-pentyl group, n-octyl group and n-nonyl group; i- Examples thereof include branched alkyl groups such as propyl group, t-butyl group and 2-ethyl-hexyl group; and alicyclic alkyl groups such as cyclopropyl group and cyclohexyl group.
The aryl group has 6 to 20 carbon atoms, and specific examples thereof include a phenyl group and a naphthyl group.
The carbon atom contained in the alkyl group or aryl group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom.

  Examples of the amino group disubstituted by an alkyl group or an aryl group include, for example, a linear or branched dimethylamino group, a diethylamino group, a dipropylamino group, a methylethylamino group, a methylhexylamino group, a methyloctylamino group, and the like. And diarylamino groups such as dialkylamino groups, diphenylamino groups and dinaphthylamino groups containing a branched alkyl group.

R ³ and R ⁴ may be bonded to each other. For example, in the case of c = 2 (or d = 2), R ³ may be bonded (or R ⁴ may be bonded).
c and d each independently represents an integer of 0 to 2.
When R ¹ , R ² , R ³ and R ⁴ are substituents, among them, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a group represented by formula (III) are particularly preferable. , An alkyl group having 1 to 20 carbon atoms and a group represented by the formula (III) are preferable.
More preferably, at least one of R ³ and R ⁴ preferably has the above group.

In the formulas (I) and (II), A represents a group containing a nitrogen atom, an oxygen atom, a carbon atom, a silicon atom, a sulfur atom, or a selenium atom.
m is an integer of 1 to 2, and preferably m = 1.
Specific examples of-(A) _m- include -N (Y ¹ )-, -O-, -C (Y ¹ ) (Y ² )-, -Si (Y ¹ ) (Y ² )-[where Y ¹ and Y ² each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. ]), - S -, - SO -, - SO 2 -, - Se- , and the like, and preferably -S- is.
Specific examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, n-pentyl group, n-octyl group and n-nonyl group. Linear alkyl groups such as i-propyl group, t-butyl group, 2-ethyl-hexyl group and the like; and alicyclic alkyl groups such as cyclopropyl group and cyclohexyl group.
Specific examples of the aryl group having 6 to 20 carbon atoms include a phenyl group and a naphthyl group.

As a method for producing compound (II), when A is a sulfur atom, one of the halogen atoms is substituted with SH and reacted in the presence of a base, whereby the target compound (m = 1, 2, sometimes referred to as S-crosslinked product) (in the case of compound (II), it can be represented by the following formula of formula (2)). Further, when A is SO or SO ₂ , it can be obtained by oxidizing the S crosslinked product with m-chloroperbenzoic acid or the like.

  In the production method of compound (II), when the acidic group is a carboxyl group, it is protected with an ester (eg, methyl ester, ethyl ester, propyl ester, butyl ester), etc., and then subjected to a coupling reaction, followed by hydrolysis. Then, it may be returned to the carboxyl group.

Specific examples of compound (II) include compounds (II-1) to (II-62) represented by the following formula and Table 1.

The complex compound (I) of the present invention is obtained by coordinating the compound represented by the formula (II) to a metal atom.
The complex compound (I) of the present invention is a compound in which the central atom is a metal atom and one of the ligands is represented by the formula (II).
An auxiliary ligand other than the compound represented by the formula (II) may be coordinated, and examples of the auxiliary ligand contained in the complex compound (I) include isothiocyanate (-N = C = S, hereinafter referred to as NCS), thiocyanate (—S—C≡N, hereinafter referred to as SCN), diketonate, chloro, bromo, iodo, cyano, hydroxyl group, etc., preferably NCS or SCN It is. With counter anions such as halogen anions

In some cases, the charge is neutralized.
Below, the case where a metal atom is Ru is demonstrated as an example as a manufacturing method of complex compound (I).
It is obtained by dissolving Ru reagent in N, N-dimethylformamide or an alcohol solvent, mixing compound (II) at about 40 to 180 ° C., and then, if necessary, mixing a salt that gives an auxiliary ligand. And a method obtained by purification from the reaction solution by recrystallization, chromatography or the like. Here, as the Ru reagent, divalent and trivalent Ru reagents are used, and specific examples include RuCl _3, [RuCl ₂ (p-cymene)] _2, and RuCl ₂ (DMSO) _4. . Specific examples of the complex compound (I) include compounds (I-1) to (I-159) represented by the following formulas, Table 2, Table 3, Table 4, and Table 5.

The photosensitizing dye of the present invention is a dye containing the complex compound (I). As a pigment | dye, even if it is only complex compound (I), the compound of the kind different from complex compound (I) may contain.
Examples of the dye that may be mixed with the complex compound (I) include metal complexes and organic dyes having absorption in the vicinity of a wavelength of 300 to 700 nm.
Specific examples of metal complexes that may be mixed include metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine, chlorophyll, hemin, ruthenium, osmium, iron described in JP-A-1-220380 and JP-A-5-504023, Examples include zinc complexes.
More detailed examples of ruthenium complexes include cis-bis (isothiocyanate) bis (2,2'-bipyridyl-4,4'-dicarboxylate) -ruthenium (II) bis-tetrabutylammonium, cis-bis (iso Thiocyanate) bis (2,2'-bipyridyl-4,4'-dicarboxylate) -ruthenium (II), tris (isothiocyanate) -ruthenium (II) -2,2 ': 6', 2 "-thepyridine- Tris-tetrabutylammonium 4,4 ', 4 "-tricarboxylate, cis-bis (isothiocyanate) (2,2'-bipyridyl-4,4'-dicarboxylate) (2,2'-bipyridyl-4, 4'-dinonyl) ruthenium (II) and the like.

Examples of organic dyes include metal-free phthalocyanine, cyanine dyes, merocyanine dyes, xanthene dyes, triphenylmethane dyes, coumarin dyes, indoline-based organic dyes, squarylium dyes, and the like.
Specific examples of cyanine dyes include NK1194 and NK3422 (both manufactured by Nippon Photosensitive Dye Research Laboratories).
Specific examples of merocyanine dyes include NK2426 and NK2501 (both manufactured by Nippon Photosensitivity Laboratories).
Examples of xanthene dyes include uranin, eosin, rose bengal, rhodamine B, dibromofluorescein and the like.
Examples of the triphenylmethane dye include malachite green and crystal violet.
Examples of the coumarin dye include compounds containing the following structural sites such as NKX-2777 (manufactured by Hayashibara Biochemical Laboratories).
Specific examples of indoline-based organic dyes include compounds containing the structural sites shown below.
Specific examples of organic dyes such as squarylium-based dyes include compounds containing the structural sites shown below.

  Here, the primary particle size of the semiconductor fine particles used in the photoelectric conversion element is usually about 1 to 5000 nm, preferably about 5 to 300 nm. For the purpose of improving photoelectric conversion efficiency by reflection, semiconductor fine particles having different primary particle diameters may be mixed. Tubes and hollow fine particles may be used.

  Here, the primary particle size of the semiconductor fine particles used in the photoelectric conversion element is usually about 1 to 5000 nm, preferably about 5 to 300 nm. For the purpose of improving photoelectric conversion efficiency by reflection, semiconductor particles having different primary particle diameters may be mixed. Tubes and hollow fine particles may be used.

Examples of the material compound constituting the semiconductor fine particles include titanium oxide, tin oxide, zinc oxide, iron oxide, tungsten oxide, zirconium oxide, hafnium oxide, strontium oxide, indium oxide, cerium oxide, yttrium oxide, lanthanum oxide, and vanadium oxide. Metal oxides such as niobium oxide, tantalum oxide, gallium oxide, nickel oxide, strontium titanate, barium titanate, potassium niobate, sodium tantalate;
Metal halides such as silver iodide, silver bromide, copper iodide, copper bromide;
Metal sulfides such as zinc sulfide, titanium sulfide, indium sulfide, bismuth sulfide, cadmium sulfide, zirconium sulfide, tantalum sulfide, molybdenum sulfide, silver sulfide, copper sulfide, tin sulfide, tungsten sulfide, and antimony sulfide;
Metal selenides such as cadmium selenide, zirconium selenide, zinc selenide, titanium selenide, indium selenide, tungsten selenide, molybdenum selenide, bismuth selenide, lead selenide;
Metal tellurides such as cadmium telluride, tungsten telluride, molybdenum telluride, zinc telluride, bismuth telluride;
Metal phosphides such as zinc phosphide, gallium phosphide, indium phosphide, cadmium phosphide;
Examples of the material compound include gallium arsenide, copper-indium-selenide, copper-indium-sulfide, silicon, and germanium.
Further, it may be a mixture of two or more material compounds such as zinc oxide / tin oxide and tin oxide / titanium oxide.

  Among them, titanium oxide, tin oxide, zinc oxide, iron oxide, tungsten oxide, zirconium oxide, hafnium oxide, strontium oxide, indium oxide, cerium oxide, yttrium oxide, lanthanum oxide, vanadium oxide, niobium oxide, tantalum oxide, gallium oxide, Metal oxides such as nickel oxide, strontium titanate, barium titanate, potassium niobate, sodium tantalate, zinc oxide / tin oxide, tin oxide / titanium oxide are relatively inexpensive and readily available, and are also dyed in pigments. Titanium oxide is particularly preferable because it is easy.

As the conductive substrate (8 and 9 in FIG. 1) used in the photoelectric conversion element of the present invention, a conductive substance itself, or a substrate in which a conductive substance is stacked can be used. As the conductive material, platinum, gold, silver, copper, aluminum, rhodium, indium, titanium, palladium, iron, or other metals, alloys of these metals, indium-tin composite oxides, tin oxide doped with fluorine Examples thereof include conductive metal oxides such as carbon, conductive polymers such as carbon, polyethylenedioxythiophene (PEDOT), and polyaniline. The conductive polymer may be doped with, for example, paratoluene sulfonic acid.
In order to confine incident light and use it effectively, the conductive substrate preferably has a texture structure on its surface. The conductive layer (2 and 6 in FIG. 1) should have a lower resistance, and preferably has a high transmittance (at a wavelength longer than 350 nm, the transmittance is 80% or more). As the conductive substrates (in FIG. 1) 8 and 9, a glass or plastic coated with a conductive metal oxide is preferable. Among these, conductive glass in which conductive layers made of tin dioxide doped with fluorine are laminated is particularly preferable. When plastic substrates are used, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC), polypropylene (PP), polyimide (PI), triacetylcellulose (TAC), syndiotactic Cycpolystyrene (SPS), polyarylate (PAR); cyclic polyolefins such as Arton (registered trademark of JSR), Zeonoa (registered trademark of Nippon Zeon), Apel (registered trademark of Mitsui Chemicals) and Topas (registered trademark of Ticona) (COP): Polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSF), polyamide (PA) and the like are used.
Among these, conductive PET in which a conductive layer made of indium-tin composite oxide is deposited is particularly preferable because of its low resistance, good permeability, and easy availability.

As a method for forming a semiconductor fine particle layer on a conductive substrate, a method in which semiconductor fine particles are directly formed as a thin film on a conductive substrate by spraying or the like; a semiconductor fine particle thin film is electrically deposited using a conductive substrate as an electrode Method: A method in which a slurry of semiconductor fine particles is applied on a conductive substrate and then dried, cured, or baked is exemplified.
Examples of the method for applying the semiconductor fine particle slurry onto the conductive substrate include a doctor blade, squeegee, spin coating, dip coating, and screen printing. In the case of this method, the average particle diameter in the dispersed state of the semiconductor fine particles in the slurry is preferably 0.01 μm to 100 μm. The dispersion medium for dispersing the slurry may be any medium that can disperse the semiconductor fine particles, and water or an alcohol solvent such as ethanol, isopropanol, t-butanol or terpineol; an organic solvent such as a ketone solvent such as acetone is used. These water and organic solvent may be a mixture. The dispersion may contain a polymer such as polyethylene glycol; a surfactant such as Triton-X; an organic acid or inorganic acid such as acetic acid, formic acid, nitric acid or hydrochloric acid; and a chelating agent such as acetylacetone.
The conductive substrate coated with the slurry is fired, but the firing temperature is lower than the melting point (or softening point) of the base material such as a thermoplastic resin. Usually, the upper limit of the firing temperature is 900 ° C., preferably It is below 600 ° C. The firing time is usually within 10 hours. The thickness of the semiconductor fine particle layer on the conductive substrate is usually 1 to 200 μm, preferably 5 to 50 μm.

  As a method for forming a semiconductor fine particle layer on a conductive substrate at a relatively low temperature, a hydrothermal method in which a porous semiconductor fine particle layer is formed by hydrothermal treatment (dye-sensitized photoelectrochemical cell for practical use, second lecture) (Hideki Kajiura) pp. 63-65, published by NTS (2003)), electrophoretic electrodeposition method (T. Miyasaka et al., Chem. Lett., 1250) of electrodepositing a dispersion of dispersed semiconductor particles on a substrate. (2002)), a method in which a semiconductor paste is applied to a substrate and pressed after drying (dye-sensitized photoelectrochemical cell for practical use, 12th lecture (Takehiko Tsuji), pages 312 to 313, issued by NTS (2003) ) And the like.

The surface of the semiconductor fine particle layer may be subjected to chemical plating using a titanium tetrachloride aqueous solution or electrochemical plating using a titanium trichloride aqueous solution. This increases the surface area of the semiconductor fine particles, increases the purity in the vicinity of the semiconductor fine particles, masks impurities such as iron existing on the surface of the semiconductor fine particles, or improves the connectivity and bonding properties of the semiconductor fine particles. can do.
The semiconductor fine particles preferably have a large surface area so that many photosensitizing dyes can be adsorbed. For this reason, the surface area of the semiconductor fine particle layer applied on the substrate is preferably 10 times or more, more preferably 100 times or more the projected area. This upper limit is usually about 1000 times.
The semiconductor fine particle layer is not limited to a single fine particle layer, and a plurality of layers having different particle diameters may be stacked.

As a method for adsorbing the photosensitizing dye of the present invention to semiconductor fine particles, a method of immersing well-dried semiconductor fine particles in the photosensitizing dye solution of the present invention for about 1 minute to 24 hours is used. The adsorption of the photosensitizing dye may be performed at room temperature or under heating and reflux. The adsorption of the photosensitizing dye may be performed before or after the application of the semiconductor fine particles, or the semiconductor fine particles and the photosensitizing dye may be simultaneously applied and adsorbed. More preferably, a photosensitizing dye is adsorbed on the film. The photosensitizing dye adsorption when the semiconductor fine particle layer is heat-treated is preferably performed after the heat treatment, and a method of quickly adsorbing the photosensitizing dye after the heat treatment and before water is adsorbed on the surface of the fine particle layer is particularly preferred. .
In order to suppress the reduction of the sensitizing effect due to floating of the photosensitizing dye not attached to the semiconductor fine particles, it is desirable to remove the unadsorbed photosensitizing dye by washing.
The photosensitizing dye to be adsorbed may be one kind or a mixture of several kinds. When the application is a photoelectrochemical cell, it is preferable to select a photosensitizing dye to be mixed so that the wavelength range of photoelectric conversion of irradiation light such as sunlight is as wide as possible. Further, the adsorption amount of the photosensitizing dye to the semiconductor fine particles is preferably 0.01 to 1 mmol with respect to 1 g of the semiconductor fine particles. Such a dye amount is preferable because the sensitizing effect in the semiconductor fine particles can be sufficiently obtained and the reduction of the sensitizing effect due to floating of the photosensitizing dye not attached to the semiconductor fine particles tends to be suppressed. .

  A colorless compound may be co-adsorbed for the purpose of suppressing interaction such as association and aggregation between photosensitizing dyes. Examples of the hydrophobic compound to be co-adsorbed include steroid compounds having a carboxyl group (for example, chenodeoxycholic acid). For the purpose of promoting the removal of excess photosensitizing dye, the surface of the semiconductor fine particles may be treated with amines after adsorbing the dye. Preferable amines include pyridine, 4-tert-butylpyridine and polyvinylpyridine. When these are liquids, they may be used as they are, or when they are solids, they may be dissolved in an organic solvent.

The photoelectrochemical cell of the present invention includes a photoelectric conversion element, a charge transfer layer, and a counter electrode, and can convert light into electricity. In a photoelectrochemical cell, a photoelectric conversion element, a charge transfer layer, and a counter electrode are sequentially stacked, and a conductive substrate and a counter electrode of the photoelectric conversion element are connected to move charges, that is, generate electric power.
Other photoelectrochemical cells include, for example, a photoelectrochemical cell having a plurality of stacked portions composed of photoelectric conversion elements and charge transfer layers and one counter electrode, for example, a plurality of photoelectric conversion elements, one charge transfer layer, and 1 Examples include a photoelectrochemical cell in which two counter electrodes are stacked.
Photoelectrochemical cells are roughly classified into wet photoelectrochemical cells and dry photoelectrochemical cells. In the wet photoelectrochemical cell, the charge transfer layer included is a layer composed of an electrolytic solution, and the charge transfer layer is usually filled with an electrolytic solution between the photoelectric conversion element and the counter electrode.
Examples of the dry photoelectrochemical battery include a battery in which the charge transfer layer between the photoelectric conversion element and the counter electrode is a solid hole transport material.

One embodiment of the photoelectrochemical cell is shown in FIG. A conductive substrate 8, a counter electrode (conductive substrate) 9 facing the conductive substrate 8, and the semiconductor fine particle layer 3 on which the photoelectric conversion element dye 4 is adsorbed exist between these. In the case of a wet photoelectric conversion element, the semiconductor particle layer 3 is filled with the electrolytic solution 5 and sealed with the sealing material 10.
The conductive substrate 8 includes a substrate 1 and a conductive layer 2 in order from the top. The counter electrode 9 includes a substrate 7 and a conductive layer 6 in order from the bottom.

When the photoelectrochemical cell of the present invention is a wet photoelectrochemical cell, examples of the electrolyte used in the electrolyte contained in the wet photoelectrochemical cell include a combination of I ₂ and various iodides, Br ₂ and various types of electrolytes. Combinations of bromides, ferrocyanate-ferricyanate metal complexes, ferrocene-ferricinium ion metal complexes, alkylthiol-alkyldisulfide sulfur compounds, alkylviologens and their reduced forms Combinations, combinations of polyhydroxybenzenes and their oxidants, and the like can be mentioned.
Here, examples of the iodide that can be combined with I ₂ include metal iodides such as LiI, NaI, KI, CsI, and CaI ₂ ; 1-propyl-3-methylimidazolium iodide, 1-propyl-2,3 -Iodine salts of tetravalent imidazolium compounds such as dimethylimidazolium idide; iodine salts of tetravalent pyridinium compounds; iodine salts of tetraalkylammonium compounds.
Examples of bromides that can be combined with Br ₂ include metal bromides such as LiBr, NaBr, KBr, CsBr, and CaBr ₂ ; and bromine salts of tetravalent ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide.
Examples of alkyl viologen include methyl viologen chloride, hexyl viologen bromide, and benzyl viologen tetrafluoroborate. Examples of polyhydroxybenzenes include hydroquinone and naphthohydroquinone.
Among electrolytes, at least one iodide selected from the group consisting of metal iodides, iodine salts of tetravalent imidazolium compounds, iodine salts of tetravalent pyridinium compounds, and iodine salts of tetraalkylammonium compounds, and I A combination with ₂ is preferred.

  Examples of the organic solvent used in the above electrolyte include nitrile solvents such as acetonitrile, methoxyacetonitrile, and propionitrile; carbonate solvents such as ethylene carbonate and propylene carbonate; 1-methyl-3-propylimidazolium iodide, 1- Examples thereof include ionic liquids such as methyl-3-hexylimidazolium iodide; 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonic acid) imide. Also, lactone solvents such as γ-butyrolactone; amide solvents such as N, N-dimethylformamide, and the like can be given. These solvents may be gelated with polyacrylonitrile, polyvinylidene fluoride, poly-4-vinylpyridine, or a low molecular gelling agent shown in Chemistry Letters, 1241 (1998).

In the photoelectrochemical cell of the present invention, a solid hole transport material can be used instead of the electrolytic solution.
Examples of the hole transport material include p-type inorganic semiconductors containing monovalent copper such as CuI and CuSCN, and arylamines as shown by Synthetic Metal, 89, 215 (1997) and Nature, 395, 583 (1998); Examples include polythiophene and derivatives thereof; polypyrrole and derivatives thereof; polyaniline and derivatives thereof; poly (p-phenylene) and derivatives thereof; and conductive polymers such as poly (p-phenylene vinylene) and derivatives thereof.

The counter electrode constituting the photoelectric conversion element of the present invention is an electrode having conductivity, and a substrate similar to the above-described conductive substrate may be used in order to maintain strength or improve hermeticity.
Since light reaches the semiconductor fine particle layer on which the photosensitizing dye is adsorbed, at least one of the conductive substrate and the counter electrode is usually substantially transparent. In the photoelectric conversion element of the present invention, it is preferable that the conductive substrate having the semiconductor fine particle layer is transparent and the irradiation light is incident from the conductive substrate side. In this case, it is more preferable that the counter electrode 9 has a property of reflecting light.
As the counter electrode 9 of the photoelectric conversion element, for example, glass or plastic on which metal, carbon, conductive oxide or the like is deposited can be used. Alternatively, the conductive layer can be formed by a method such as vapor deposition or sputtering so as to have a thickness of 1 mm or less, preferably 5 nm to 100 μm. In the present invention, it is preferable to use a glass in which platinum or carbon is vapor-deposited or a counter electrode in which a conductive layer is formed by vapor deposition or sputtering.

  In order to prevent leakage and transpiration of the electrolytic solution, sealing may be performed using a sealing material. Examples of the sealing material include ionomer resins such as Himiran (Mitsui DuPont Polychemical); glass frit; hot-melt adhesives such as SX1170 (Solaronix); adhesives such as Amosil 4 (Solaronix); BYNEL (DuPont) Can be used.

  EXAMPLES Next, although an Example etc. are given and this invention is demonstrated further in detail, this invention is not limited by these examples.

(Example 1)
<Production Example 1: Production Example of Compound (I-1)>
Q-1 (25.0 g, 145 mmol) was dissolved in 112 mL of N, N-dimethylformamide (hereinafter DMF). To this, potassium t-butoxide (16.3 g, 145 mmol) was added under ice cooling, an ice-cooled bath was taken, and the reaction was allowed to proceed at room temperature for 1 hour. On the other hand, 56.2 g of magnesium sulfate was added to a DMF 112 mL solution of p-methoxybenzaldehyde (19.7 g, 145 mmol) prepared separately, and the anion solution of Q-1 was added dropwise with stirring under ice cooling. Next, the ice bath was removed and the reaction was allowed to proceed at room temperature for 22 hours. After the reaction, water was poured and extracted with ethyl acetate, and the extracted ethyl acetate layer was washed successively with water and saturated brine, and dried over magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by column chromatography to obtain 10.8 g of Q-2 having a HPLC purity of 91.9% in a yield of 25.7%.
Subsequently, the obtained Q-2 was reacted with sodium sulfide by a conventional method to obtain Q-3 in a yield of 30.5%. Then
Q-3 (150.2 mg, 0.62 mmol) and Q-4 (157.6 mg, 0.67 mmol) were dissolved in 70 ml of N, N-dimethyl sulfoxide (hereinafter DMSO) and charged with potassium carbonate (394.4 mg, 2.85 mmol). Heated to 120 ° C. After 30 minutes, it was confirmed that almost all the raw materials had disappeared, and the mixture was poured into 150 ml of ice water, extracted with ethyl acetate, and the extracted ethyl acetate layer was washed successively with water and saturated brine, and dried over magnesium sulfate. After evaporating the solvent under reduced pressure, the residue was purified by column chromatography to obtain Q-5 (88.6 mg) having a HPLC purity of 98.0% in a yield of 32.6%.
The same reaction was carried out, and Q-5 (150.2 mg, 0.38 mmol) obtained was dissolved in tetrahydrofuran (hereinafter referred to as THF) and cooled to -78 ° C. Separately, hexabutyl varnish (1196.1 mg, 2.06 mmol) was dissolved in THF, cooled to −10 ° C., and 1.6M n-butyllithium hexane solution (2.08 ml, 1.30 mmol) was added dropwise over about 1 minute. . The obtained tin lithium reagent was added dropwise to a THF solution of Q-5 in 4 portions at -78 ° C while keeping the temperature at -10 ° C. When the mixture was stirred at −78 ° C., the raw material disappeared immediately, and after spontaneous heating, it was quenched into 100 ml of water and extracted with ethyl acetate. The extracted ethyl acetate layer was washed successively with saturated aqueous ammonium chloride solution and saturated brine, and dried over magnesium sulfate. After the solvent was distilled off under reduced pressure, the residue was purified by column chromatography to obtain Q-6 (53.8 mg) having an HPLC purity of 84.1% in a yield of 31.0%.
Next, Q-6 (42.7 mg, 70.1 μmol) obtained and Q-7 (25.6 mg, 67.5 μmol) synthesized by a known method were dissolved in 25 ml of toluene, and tetrakistriphenylphosphine palladium (18.4 mg, 15.9 μmol) Then, the mixture was stirred under reflux conditions for 7.5 hours. After cooling, the solvent was distilled off under reduced pressure and purified by column chromatography to obtain Q-9 (17.0 mg) in a yield of 39.0%.
Next, Q-9 (12.7 mg, 20.5 μmol) obtained was dissolved in 10 ml of ethanol, lithium hydroxide (15.2 mg, 634.7 μmol) and 2 ml of water were added, and the mixture was stirred at room temperature for 1 hour. After confirming the completion of the reaction,
II-1 was obtained by neutralization with 2N hydrochloric acid and azeotropic dehydration with ethanol. The obtained solid was confirmed to be the target compound (II-1, molecular weight 563) by ESI-MS.
Compound (II-1) ESI-MS (m / z)
m / z = 564 [M + H] +
Ethanol was added to the obtained II-1, and further 5.2 mg (19.9 μmol) of ruthenium chloride trihydrate was added, stirred under reflux conditions for 2 hours, allowed to cool, and then concentrated under reduced pressure to obtain black purple crystals. The obtained crystal was dissolved in 10 ml of DMF, potassium thiocyanate (34.3 mg, 353.0 μmol) and 1 ml of water were added, and the mixture was heated and stirred at 150 ° C. for 4.5 hours. The reaction solution was concentrated with an evaporator, and the main component was separated from the concentrated residue by high performance liquid chromatography to obtain a purple solid. The obtained solid was confirmed to be the target compound (I-1, molecular weight 780) by ESI-MS.
Compound (I-1) ESI-MS (m / z)
m / z = 780 [M] +
m / z = 722 [M-NCS] ⁺ de-NCS body

<Preparation of photoelectrochemical cell containing compound (I-1)>
Ti-Nanoxide T / SP (trade name, Solaronix Co., Ltd.), a titanium oxide dispersion, on the conductive surface of a conductive glass with a tin oxide film doped with fluorine (manufactured by Nippon Sheet Glass, 10Ω / □), which is a conductive substrate. Manufactured) was applied using a screen printer, and then fired at 500 ° C., the glass was cooled, and a semiconductor particle layer was laminated on the conductive substrate. Subsequently, it is immersed in a solution of the compound (I-1) (concentration is 0.0003 mol / liter, the solvent is N, N-dimethylacetamide, and chenodeoxycholic acid is added at 0.12 mol / liter) for 16 hours and taken out from the solution. After that, after washing with acetonitrile, it was naturally dried to obtain a laminate of semiconductor fine particle layers adsorbing the conductive substrate and the photosensitizing dye (the area of the titanium oxide electrode was 24 mm ² ). Next, a polyethylene terephthalate film having a thickness of 25 μm was placed around the layer as a spacer, and then an electrolytic solution (solvent was acetonitrile; the iodine concentration in the solvent was 0.05 mol / liter, and the lithium iodide concentration was 0.1 mol / liter, similarly 4-t-butylpyridine concentration was 0.5 mol / liter, and 1-propyl-2,3-dimethylimidazolium iodide concentration was 0.6 mol / liter). . Finally, the platinum-deposited glass as the counter electrode is overlaid, and the conductive substrate, the semiconductor fine particle layer adsorbing the photosensitizing dye, and the counter electrode of the conductive substrate are laminated, and electrolysis is performed between the conductive substrate and the counter electrode. A photoelectrochemical cell impregnated with the liquid was obtained. About the photoelectrochemical cell produced in this way, IPCE was measured using an IPCE (incident photon-to-current efficiency) measuring device (manufactured by Spectrometer). The results are shown in Table 6.

ＩＰＣＥを実施例１と同様にして測定した。
下記比較例１で得た光電気化学電池について、実施例２で得た光電変換素子のＩＰＣＥを表６に示す。 (Example 2)
<Synthesis Example of Compound (I-43)>
Using Q-8 instead of Q-2 in Example 1 and reacting in the same manner as shown in the following reaction formula, II-43 was obtained.
Compound (II-43) ESI-MS (m / z)
m / z = 445 [M + H] +
Using the obtained II-43, the reaction was carried out in the same manner as in Example 1 to obtain I-43.
Compound (I-43) ESI-MS (m / z)
m / z = 662 [M] +
m / z = 604 [M-NCS] ⁺ de-NCS body

IPCE was measured as in Example 1.
Table 6 shows the IPCE of the photoelectric conversion element obtained in Example 2 for the photoelectrochemical cell obtained in Comparative Example 1 below.

(Comparative Example 1)
As a photosensitizing dye, cis-bis (isothiocyanate) bis (2,2′-bipyridyl-4,4′-dicarboxylate) -ruthenium (II) (compound (1)) is used, and ethanol is used as a dissolving solvent. A photoelectrochemical cell was obtained in the same manner as in Example 1 except that it was used. Next, IPCE was measured in the same manner as in Example 1. The results are summarized in Table 6.

The complex compound of the present invention is excellent in photoelectric conversion characteristics not only in visible light but also in a long wavelength region of 750 nm or more, and is suitably used as a photosensitizing dye. Moreover, since the photoelectric conversion element containing this complex compound is excellent in photoelectric conversion efficiency, it can be used for the solar cell by sunlight, the photoelectrochemical cell by artificial light in a tunnel or indoor. The photoelectric conversion element can also be used as an optical sensor because current flows when irradiated with light.

It is a cross-sectional schematic diagram of the photoelectrochemical cell of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductive layer 3 Semiconductor particle layer 4 Photosensitizing dye 5 Electrolytic solution 6 Conductive layer 7 Substrate 8 Conductive substrate 9 Counter electrode (conductive substrate)
10 Sealant

Claims (20)

Compound represented by formula (II) [abbreviated as compound (II). ] Is a complex compound (I) obtained by coordinating to a metal atom.

[Wherein, R ¹ , R ² , R ³ and R ⁴ each independently represents a salt of an acidic group, an acidic group, a hydrogen atom or a substituent, and at least one represents an acidic group or a salt thereof. R ³ and R ⁴ may be bonded to each other, A represents a group containing a nitrogen atom, oxygen atom, carbon atom, silicon atom, sulfur atom, or selenium atom, and m is an integer of 1 or 2. , A, b, c and d each independently represents an integer of 0 to 2, and a + b + c + d ≧ 1.
Here, the substituent is an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, or 7 to 7 carbon atoms. 20 arylalkyloxy groups, aryloxyalkyl groups having 7 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylthioalkyl groups having 2 to 20 carbon atoms, arylthio groups having 6 to 20 carbon atoms, 7 to 7 carbon atoms 20 arylalkylthio groups, arylthioalkyl groups having 7 to 20 carbon atoms, alkylsulfonyl groups having 1 to 20 carbon atoms, arylsulfonyl groups having 6 to 20 carbon atoms, alkyl groups having 1 to 20 carbon atoms, or 6 to 6 carbon atoms And at least one group selected from the group consisting of an amino group disubstituted with 20 aryl groups, a cyano group, and groups represented by the following formulas (III) and (IV): .

(In the formula, Ar represents an aryl group which may have a substituent, and Q ¹ and Q ² are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. And represents an aryl group having 6 to 20 carbon atoms or a cyano group, and p represents an integer of 1 to 3)] The complex compound (I) obtained by coordinating the compound represented by the formula (II) according to claim 1 to a metal atom.
[Wherein, R ¹ and R ² each independently represents a salt of an acidic group, an acidic group, a hydrogen atom, or a substituent, at least one of which represents an acidic group or a salt thereof, and R ³ and R ⁴ Each independently represents a hydrogen atom or a substituent, and R ³ and R ⁴ may be bonded to each other. A, m, a, b, c and d represent the same meaning as in claim 1 and a + b ≧ 1. ] A compound represented by the formula (II) according to claim 1.
[Wherein R ¹ , R ² , R ³ , R ⁴ , A, m, a, b, c and d represent the same meaning as in claim 1. ] A compound represented by the formula (II) according to claim 1.
[Wherein R ¹ , R ² , R ³ , R ⁴ , A, m, a, b, c and d represent the same meaning as in claim 2. ] The acidic group is at least one group selected from the group consisting of a carboxyl group, a sulfonic acid group, a squaric acid group, a phosphoric acid group, a boric acid group, and a silicic acid group. Compound (I) or (II). The acidic group is a carboxyl group, Compound (I) or (II) according to any one of claims 1 to 5. The compound (I) or (II) according to any one of claims 1 to 6, wherein the salt of the acidic group is a salt with an organic base. R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms, or an aryloxy having 6 to 20 carbon atoms. Group, arylalkyloxy group having 7 to 20 carbon atoms, aryloxyalkyl group having 7 to 20 carbon atoms, alkylthio group having 1 to 20 carbon atoms, alkylthioalkyl group having 2 to 20 carbon atoms, arylthio group having 6 to 20 carbon atoms Group, arylalkylthio group having 7 to 20 carbon atoms, arylthioalkyl group having 7 to 20 carbon atoms, alkylsulfonyl group having 1 to 20 carbon atoms, arylsulfonyl group having 6 to 20 carbon atoms, alkyl having 1 to 20 carbon atoms The group according to any one of claims 1 to 7, which is at least one group selected from the group consisting of a group or an amino group disubstituted by an aryl group having 6 to 20 carbon atoms and a cyano group. Compound (I) or (II) as described above. R ³ and R ⁴ are each independently a group represented by the following formula (III) or formula (IV), wherein the compound (I) or ( II).

[In the formula, Ar represents an aryl group which may have a substituent, and Q ¹ and Q ² are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. Represents an aryl group having 6 to 20 carbon atoms or a cyano group, and p represents an integer of 1 to 3. ] R < ³ > and R < ⁴ > are respectively independently a hydrogen atom, a C1-C20 alkyl group, and a C1-C20 alkoxy group, The compound (I) in any one of Claims 1-8 or ( II). Q < ¹ > and Q < ² > are hydrogen atoms and Ar is a benzene ring having a substituent, Compound (I) or (II) according to any one of claims 1 to 7 and 9. -(A) m- is -N (Y1)-, -O-, -C (Y1) (Y2)-, -Si (Y1) (Y2)-, -S-, -SO-, -SO2-. The compound (I) or (II) according to any one of claims 1 to 11, which is at least one group selected from the group consisting of -Se-. [However, Y1 and Y2 each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. ] -(A) m- is -S-, Compound (I) or (II) according to any one of claims 1 to 12. The compound (I) or (II) according to any one of claims 1 to 13, wherein a + b = 2. The compound (I) or (II) according to any one of claims 1 to 14, wherein m = 1. R ¹ and R ² are each independently a carboxyl group or a salt thereof, and R ³ and R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or a claim The compound (I) or (II) according to any one of claims 1 to 15, wherein A is -S- in the group represented by formula (III) according to item 9. The compound (I) according to any one of claims 1 to 2 and 5 to 16, wherein the metal atom is Fe, Ru or Os. The photosensitizing dye containing the compound (I) in any one of Claims 1-2 and 5-17. A photoelectric conversion element comprising a conductive substrate and a semiconductor fine particle layer on which the photosensitizing dye according to claim 18 is adsorbed. A photoelectrochemical cell comprising the photoelectric conversion device according to claim 19, a charge transfer layer, and a counter electrode.

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