JP2012051854A - Indanone derivative and use thereof as color material for dye-sensitized solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensitizing dye for photoelectric conversion for a dye-sensitized photoelectric conversion cell which is stable and has high conversion efficiency of solar energy without using any raw material with exhaustibility, such as ruthenium.SOLUTION: There is provided an indanone derivative represented by formula (in formula, Rto Rmutually independently represent a hydrogen atom or an electron-attracting group; and Rto Rmutually independently represent a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, and so on).

Description

  The present invention relates to a photoelectric conversion material. Moreover, this invention relates to the photoelectric conversion element using this photoelectric conversion material, and the solar cell using the same.

  As for photovoltaic power generation, single crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells, and compound solar cells such as cadmium telluride and indium copper selenide have been put into practical use or research and development. In order to further spread these solar cells, it is necessary to overcome problems related to manufacturing costs, raw materials, energy payback time, and the like. On the other hand, a large number of solar cells using organic materials aimed at increasing the area and price have been proposed so far, but these cells have a problem of low conversion efficiency and durability.

  Under such circumstances, a photoelectric conversion electrode and a photoelectric conversion cell using a semiconductor microporous material sensitized with a dye, and a material and a manufacturing technique for producing the photoelectric conversion electrode are disclosed (Non-Patent Document 1, 2 and Patent Document 1). The disclosed battery is a dye-sensitized photoelectric conversion cell comprising a porous titanium oxide layer spectrally sensitized with a ruthenium complex dye as a working electrode, an electrolyte layer mainly composed of iodine, and a counter electrode. The first advantage of this method is that an inexpensive photoelectric conversion element can be provided because an inexpensive oxide semiconductor such as titanium oxide is used. The second advantage is that a relatively high conversion efficiency can be obtained because the ruthenium complex dye used has a wide absorption in the visible region.

  On the other hand, one of the problems of such a dye-sensitized photoelectric conversion cell is that ruthenium is used as a raw material for the dye. Ruthenium has a relatively low Clark number of 0.01 ppm, and a small amount is present on the earth comparable to platinum and palladium. Therefore, there is a risk of depletion when used in large quantities. Furthermore, since ruthenium complex dyes are expensive, they hinder further spread of photoelectric conversion cells.

  Recently, researches on dyes other than ruthenium complexes have been actively conducted as sensitizing dyes in dye-sensitized solar cells. Examples thereof include phenylxanthene dyes, phthalocyanine dyes, coumarin dyes, cyanine dyes, porphyrin dyes, azo dyes, and the like. These organic dyes are expected to exhibit high photoelectric conversion efficiency because they have a larger extinction coefficient and a higher degree of freedom in molecular design than ruthenium complexes. However, organic sensitizing dyes with good performance have not yet been found because the light absorption region of the dye is narrow and charge injection into titanium oxide is inefficient.

  In order to solve these problems, it has been disclosed that a sensitizing dye having a substituted acrylic acid moiety has a relatively high conversion efficiency as a sensitizing dye imparted with a feature at the adsorption end with titanium oxide (Patent Document). 3 and 4). The feature of these sensitizing dyes is that the electron-withdrawing effect at the acrylic acid terminal is increased by replacing the carbon atom to which the carboxylic acid group at the acrylic acid terminal is bonded with an electron-withdrawing group such as a cyano group. is there. The sensitizing dye is bonded to the surface of an inorganic oxide semiconductor such as titanium oxide at the terminal carboxy group, and through this carboxy group, excited electrons generated by light absorption of the sensitizing dye are injected into the inorganic oxide semiconductor side. ing. Therefore, the electron injecting effect at this part is strengthened to promote the electron injecting effect, and as a result, high conversion efficiency is realized. As a representative example, a sensitizing dye combining a coumarin skeleton and an acrylic acid terminal having a cyano group achieves a high conversion efficiency of 5% or more. (See Non-Patent Document 3) In addition, a high conversion efficiency of 5% or more is similarly achieved in a sensitizing dye in which a similar acrylate end is introduced into a chromophore in which a polyene structure and an amino group are combined (Non-patent Document 3). Reference 4).

  However, since the absorption wavelength region such as a coumarin skeleton is biased to a relatively short wavelength side in the visible light region, a long-chain double bond site is required to increase the absorption wavelength based on this skeleton. (Polyene structure) must be introduced. A long double bond site is easily oxidized to active oxygen or the like, and has low thermal stability, and therefore has low durability. For the same reason, it is expected that the sensitizing dye having the polyene structure described in Non-Patent Document 3 also has a problem in durability. In addition, cyanine dyes that function as sensitizing dyes also have long-chain double bond sites, and thus are examples of dyes with low durability.

  For the above reasons, regardless of the introduction of sites with low durability such as long-chain double bond sites, etc., it has a highly durable skeleton structure, and further uses raw materials that are not subject to depletion. A sensitizing dye capable of providing a photoelectric conversion cell having high conversion efficiency has been demanded.

Nature (Vol. 353, 737-740, 1991) J. Am. Chem. Soc. (Vol. 115, 6382-6390, 1993) Chem. Commun. (569-570, 2001) Chem. Commun. (Pages 252-253, 2003) US Pat. No. 4,927,721 JP 2002-164089 A WO02 / 11213 pamphlet

  An object of the present invention is to provide a sensitizing dye for a dye-sensitized photoelectric conversion cell that has a highly durable skeleton structure and is inexpensive and has high conversion efficiency. Furthermore, a photoelectric conversion material in which this sensitizing dye is connected to the surface of the inorganic semiconductor porous body, a photoelectric conversion electrode formed by laminating the photoelectric conversion material on the conductive surface of a transparent substrate having a conductive surface, and An object of the present invention is to provide a photoelectric conversion cell in which a photoelectric conversion electrode is combined with a conductive counter electrode via an electrolyte layer.

  As a result of intensive studies to solve the above problems, the present inventors have obtained a photoelectric property exhibiting good characteristics by linking a specific sensitizing dye to the surface of an inorganic oxide semiconductor laminated on a transparent conductive substrate. The inventors have found that a conversion cell can be produced and have reached the present invention.

That is, the present invention relates to an optical functional material represented by the following general formula (1).
General formula (1)

[Wherein, R ^{1 to} R ³ each independently represents a hydrogen atom or an electron-withdrawing group. R ^{4 to} R ²¹ each independently have a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkylthio group, an unsubstituted or substituted group Represents an aryl group. N represents an integer of 0 to 3. ]

  The present invention also relates to a sensitizing dye for photoelectric conversion comprising the optical functional material.

  The present invention also relates to a photoelectric conversion material obtained by connecting the sensitizing dye and an inorganic semiconductor porous body.

  Moreover, this invention relates to the photoelectric conversion electrode formed by laminating | stacking the said photoelectric conversion material on a transparent electrode.

  The present invention also relates to a photoelectric conversion cell comprising the photoelectric conversion electrode, an electrolyte layer, and a conductive counter electrode.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the photoelectric conversion cell which has high photoelectric conversion efficiency with the material which does not have a possibility of exhaustion. In addition, by combining the sensitizing dye of the present invention with another sensitizing dye, a photoelectric conversion material, a photoelectric conversion electrode, and a photoelectric conversion cell that exhibit a highly efficient photoelectric conversion function in a wide wavelength range with respect to sunlight. Can be manufactured. Furthermore, since the dye does not have a polyene structure, it is possible to provide a highly stable battery without deterioration due to light, heat, or the like.

FIG. 1 represents a photoelectric conversion cell test sample.

  Hereinafter, the present invention will be described in detail. In the present invention, the photoelectric conversion material is a material that exhibits a function of generating electricity by absorbing light, that is, a function of converting light into electric energy.

  In this specification, since the compound represented by the general formula (1) is used as a sensitizing dye for photoelectric conversion, this material is referred to as a sensitizing dye for photoelectric conversion or a sensitizing dye.

  The operation mechanism of the dye-sensitized solar cell consists of the following processes. That is, the process in which electrons are injected from the excited sensitizing dye into the conduction band of an inorganic semiconductor such as titanium oxide after photosensitizing the sunlight-absorbing dye, and the oxidation by injecting electrons into the inorganic semiconductor The sensitizing dye is reduced by electron injection from a redox system such as iodine.

  Therefore, functions necessary for the sensitizing dye for photoelectric conversion include that the dye has a wide light absorption region and can efficiently absorb sunlight, and that charges can be efficiently injected into an inorganic semiconductor such as titanium oxide. .

  Since the sensitizing dye represented by the general formula (1) has a specific structure, the absorption region of the sensitizing dye can be adjusted and broadened by the site in the structure. In conventional cyanine dyes and dyes described in Chemical Communications, pages 252-253, 2003, the absorption region of the dye is broadened by using a polyene structure. When this method is used, the polyene structure tends to undergo oxidation by active oxygen, and thus tends to cause photodegradation. There is also a drawback that the thermal stability is low. Since the sensitizing dye represented by the general formula (1) does not have a polyene structure, these problems can be avoided.

Moreover, since the sensitizing dye represented by the general formula (1) has at least one acidic functional group, it has an ester bond or the like generated by interaction with a hydroxyl group on the surface of an inorganic semiconductor such as titanium oxide. Chemisorption is possible. As a result, electrons are efficiently injected from the sensitizing dye into an inorganic semiconductor such as titanium oxide.
In addition, when at least one electron-withdrawing group is substituted on the aromatic ring to which the acidic functional group of the sensitizing dye represented by the general formula (1) is bonded, electron acceptance of the aromatic ring to which the acidic functional group is bonded Therefore, excited electrons are efficiently injected into an inorganic semiconductor such as titanium oxide via a π-conjugated system.

  Further, the sensitizing dye represented by the general formula (1) has a wide light absorption region due to a chemical structure having an electron-donating amino group at one end and an electron-withdrawing substituent at the other end. The efficiency of electron injection into an inorganic semiconductor such as titanium oxide can be expected.

  Furthermore, as a structural feature of the sensitizing dye represented by the general formula (1), a chemical structure in which an electron-accepting site and an electron-donating site are separated by a double bond and connected by a π-conjugated system. I'm taking it. Such a characteristic chemical structure tends to localize electrons to an electron-donating site in the ground state and localize electrons to an electron-accepting site in the excited state. Electron injection into an inorganic semiconductor such as can be performed very efficiently.

  That is, it can be said that the chemical structure of the sensitizing dye represented by the general formula (1) is a structure that can achieve high photoelectric conversion efficiency and high stability.

Next, each substituent in the sensitizing dye represented by the general formula (1) will be described.
R ^{1 to} R ³ in the sensitizing dye represented by the general formula (1) each independently represents a hydrogen atom or an electron-withdrawing group.

The electron-withdrawing group in the present invention represents a functional group having a Hammett's substituent constant σ greater than 0. These functional groups are not particularly limited, but are cyano group, carboxyl group, nitro group, acyl group, alkyloxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, perfluoroalkyl group, perfluoroalkylcarbonyl. Group, halogen atom and the like.

  Among the electron withdrawing groups, examples of the acyl group include an acetyl group, a thioacetyl group, a benzoyl group, and a thiobenzoyl group.

  Examples of the alkyloxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a propyloxycarbonyl group, a butoxycarbonyl group, a pentyloxycarbonyl group, a hexyloxycarbonyl group, a heptyloxycarbonyl group, and an octyloxycarbonyl group.

  Examples of the aryloxycarbonyl group include a phenoxycarbonyl group, a 1-naphthyloxycarbonyl group, and a 2-naphthyloxycarbonyl group.

    Examples of the alkylsulfonyl group include a mesyl group, an ethylsulfonyl group, and a propylsulfonyl group.

  Examples of the arylsulfonyl group include a benzenesulfonyl group and a toluenesulfonyl group.

  Examples of the perfluoroalkyl group include a trifluoromethyl group and a pentafluoroethyl group.

  Examples of the perfluoroalkylcarbonyl group include a trifluoroacetyl group and a pentafluoroethylcarbonyl group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Of the electron-withdrawing groups listed above, preferred are a cyano group, a carboxyl group, and a perfluoroalkylcarbonyl group.

R ^{4 to} R ²¹ are each independently a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkylthio group, an unsubstituted or substituted group. Represents an aryl group having

  As the alkyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, Examples include isohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, and nonadecyl group.

  Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, hexyloxy, isopentyloxy, isohexyloxy Group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group, tridecyloxy group, tetradecyloxy group, pentadecyloxy group, hexadecyloxy group, heptadecyloxy group, There are an octadecyloxy group, a nonadecyloxy group, and the like.

  As the alkylthio group, methylthio group, ethylthio group, propylthio group, butylthio group, isopropylthio group, isobutylthio group, sec-butylthio group, tert-butylthio group, pentylthio group, hexylthio group, isopentylthio group, isohexylthio group , Heptylthio group, octylthio group, nonylthio group, decylthio group, undecylthio group, dodecylthio group, tridecylthio group, tetradecylthio group, pentadecylthio group, hexadecylthio group, heptadecylthio group, octadecylthio group, nonadecylthio group and the like.

  As the aryl group, phenyl group, biphenylyl group, terphenylyl group, quarterphenylyl group, pentarenyl group, indenyl group, naphthyl group, binaphthalenyl group, tarnaphthalenyl group, quarternaphthalenyl group, azulenyl group, heptalenyl group, biphenylenyl group, indacenyl Group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, phenalenyl group, fluorenyl group, anthryl group, bianthracenyl group, teranthracenyl group, quarteranthracenyl group, anthraquinolyl group, phenanthryl group, triphenylenyl Group, pyrenyl group, chrycenyl group, naphthacenyl group, preadenyl group, picenyl group, perylenyl group, pentaphenyl group, pentacenyl group, tetraphenylenyl group, hexaphenyl group, hexyl group Seniru group, rubicenyl group, coronenyl groups, trinaphthylenyl groups, heptacenyl groups, pyranthrenyl groups, there is ovalenyl group.

  These alkyl group, alkoxy group, alkylthio group, and aryl group may have a substituent.

  In this case, examples of the substituent include an alkyl group, an alkoxy group, an alkylthio group, and an aryl group.

Specific examples in which the alkyl group, alkoxy group, alkylthio group, and aryl group in R ^{4 to} R ¹⁷ have a substituent are shown below.

    Examples of the alkyl group having a substituent include a benzyl group, 4-biphenylylmethyl group, 4- (p-terphenylyl) methyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 9-phenanthrylmethyl group, 9 -Anthrylmethyl group, 2-phenethyl group, 2- (4-biphenylyl) ethyl group, 2- {4- (p-terphenylyl)} ethyl group, 2- (1-naphthyl) ethyl group, 2- (2- Naphthyl) ethyl group, 2- (9-phenanthryl) ethyl group, 2- (9-anthryl) ethyl group, 3-phenylpropyl group, 3- (4-biphenylyl) propyl group, 3- {4- (p-terphenylyl) )} Propyl group, 3- (1-naphthyl) propyl group, 3- (2-naphthyl) propyl group, 3- (9-phenanthryl) propyl group, 3- (9-anthryl) propyl , Methoxymethyl group, ethoxymethyl group, propoxymethyl group, butoxymethyl group, pentyloxymethyl group, hexyloxymethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-propoxyethyl group, 2-butoxyethyl group 2-pentyloxyethyl group, 2-hexyloxyethyl group, 3-methoxypropyl group, 3-ethoxypropyl group, 3-propoxypropyl group, 3-butoxypropyl group, 3-pentyloxypropyl group, 3-hexyloxy Propyl group, 4-methoxybutyl group, 4-ethoxybutyl group, 4-propoxybutyl group, 4-butoxybutyl group, 4-pentyloxybutyl group, 4-hexyloxybutyl group, methylthiomethyl group, ethylthiomethyl group, Propylthiomethyl group, butylthiomethyl group, pentyl Omethyl group, hexylthiomethyl group, 2- (methylthio) ethyl group, 2- (ethylthio) ethyl group, 2- (propylthio) ethyl group, 2- (butylthio) ethyl group, 2- (pentylthio) ethyl group, 2- (Hexylthio) ethyl group and the like can be mentioned.

  Examples of the alkoxy group having a substituent include benzyloxy group, 4-biphenylylmethyloxy group, 4- (p-terphenylyl) methyloxy group, 1-naphthylmethyloxy group, 2-naphthylmethyloxy group, and 9-phenane. Tolylmethyloxy group, 9-anthrylmethyloxy group, methylthiomethoxy group, ethylthiomethoxy group, 2-methylthioethoxy group, 2-ethylthioethoxy group, phenethyloxy group, 2- (4-biphenylyl) ethyloxy group, 2 -{4- (p-terphenylyl)} ethyloxy group, 2- (1-naphthyl) ethyloxy group, 2- (2-naphthyl) ethyloxy group, 2- (9-phenanthryl) ethyloxy group, 2- (9-anthryl) An ethyloxy group etc. are mentioned.

  As the alkylthio group having a substituent, benzylthio group, 4-biphenylylmethylthio group, 1-naphthylmethylthio group, 2-naphthylmethylthio group, 9-phenanthrylmethylthio group, 9-anthrylmethylthio group, phenethylthio group, 2- (4-biphenylyl) ethylthio group, 2- (1-naphthyl) ethylthio group, 2- (2-naphthyl) ethylthio group, 2- (9-phenanthri) ethylthio group, 2- (9-anthryl) ethylthio group, Methoxymethylthio group, ethoxymethylthio group, 2-methoxyethylthio group, 2-ethoxyethylthio group, (methylthio) methylthio group, (ethylthio) methylthio group, (2-methylthio) ethylthio group, (2-ethylthio) ethylthio group, etc. Is mentioned.

  Examples of the aryl group having a substituent include o-, m- and p-tolyl groups, xylyl groups, mesityl groups, o-, m- and p-ethylphenyl groups, o-, m- and p-cumenyl groups, 4 -(4'-methyl) biphenylyl group, 4- (4'-ethyl) biphenylyl group, 1- (5-methyl) naphthyl group, 1- (5-ethyl) naphthyl group, 2- (5-methyl) naphthyl group 2- (5-ethyl) naphthyl group, 9- (3-methyl) phenanthryl group, 9- (3-ethyl) phenanthryl group, 9- (10-methyl) anthryl group, 9- (10-ethyl) anthryl group O-, m- and p-methoxyphenyl groups, o-, m- and p-ethoxyphenyl groups, 2-methylthiophenyl groups, 2-ethylthiophenyl groups, 2-propylthiophenyl groups, 2-butylthiophenyl groups Group, - (methylthio) phenyl group, 4- (ethylthio) phenyl, 4- (propylthio) phenyl group, 4- (butylthio) phenyl group.

  Now, since the compound of this invention has a double bond, it can take various structural isomers, such as a cis body and a trans body. Any of these can be used favorably as a sensitizing dye for photoelectric conversion. Further, the same can be said when a substituent has a double bond.

  The compound represented by the general formula (1) can be produced, for example, by a synthetic route as shown in the following formula (1).

Formula (1)

  The following Table 1 shows typical compounds that can be used as the sensitizing dye for photoelectric conversion of the present invention, but the present invention is not limited to these examples.

  The sensitizing dye for photoelectric conversion used in the present invention may be used in combination with other sensitizing dyes in order to supplement sunlight absorption in a region where the sensitizing dye represented by the general formula (1) cannot absorb. it can. Other sensitizing dyes here include azo dyes, quinacridone dyes, diketopyrrolopyrrole dyes, squarylium dyes, cyanine dyes, merocyanine dyes, triphenylmethane dyes, xanthene dyes, porphyrin dyes, Examples thereof include chlorophyll dyes, ruthenium complex dyes, indigo dyes, perylene dyes, dioxazine dyes, anthraquinone dyes, phthalocyanine dyes, naphthalocyanine dyes, and derivatives thereof. These sensitizing dyes preferably have a functional group capable of being linked to the surface of the inorganic semiconductor porous body in the chemical structure. The reason is that the excited electrons of the photoexcited dye can be quickly transmitted to the conduction band of the inorganic semiconductor porous body. The functional group mentioned here includes the above-mentioned acidic functional group, etc., but a sensitizing dye is connected to the surface of the inorganic semiconductor porous body, and the excited electrons of the dye are quickly transmitted to the conduction band of the inorganic semiconductor porous body. Any substituent may be used as long as it has a function to obtain.

  Hereinafter, materials other than the sensitizing dye for photoelectric conversion used in the present invention will be described.

(Inorganic oxide)
The photoelectric conversion sensitizing dye used in the present invention forms a photoelectric conversion material in which the inorganic semiconductor porous body is sensitized by connecting to the surface of the inorganic semiconductor porous body through a linking group. Inorganic semiconductors generally have a photoelectric conversion function for light in a certain region, but photoelectric conversion to the visible light and / or near infrared light region by connecting a sensitizing dye to this surface. Is possible. As the inorganic semiconductor porous body, an inorganic oxide is mainly used. However, the inorganic semiconductor porous body is not limited to this as long as it has a photoelectric conversion function by connecting a sensitizing dye. Examples of inorganic semiconductors include silicon, germanium, III-V group semiconductors, metal chalcogenides, and the like. Examples of the inorganic oxide semiconductor porous material used in the present invention include titanium oxide, tin oxide, tungsten oxide, zinc oxide, indium oxide, niobium oxide, iron oxide, nickel oxide, cobalt oxide, strontium oxide, tantalum oxide, and antimony oxide. , Lanthanoid oxides, yttrium oxides, vanadium oxides, and the like, but these surfaces can be combined with sensitizing dyes to enable visible and / or near-infrared photoelectric conversion. If it becomes, it will not be limited to these. In order for the surface of the inorganic oxide semiconductor porous body to be sensitized by the sensitizing dye, it is desirable that the conduction band of the inorganic oxide exists at a level at which electrons are easily accepted from the photoexcitation order of the sensitizing dye. For this reason, titanium oxide, tin oxide, zinc oxide, niobium oxide and the like are particularly used among the inorganic oxide semiconductor porous bodies. Furthermore, titanium oxide is particularly used from the viewpoint of price and environmental hygiene. In the present invention, one or more types can be selected and combined from the inorganic oxide semiconductor porous body.

(Porous inorganic oxide)
The inorganic semiconductor porous body has a large surface area by making it porous for the purpose of linking a large amount of sensitizing dye to the surface thereof and expressing a highly efficient photoelectric conversion capability. As a porous method, a method of sintering inorganic oxide particles such as titanium oxide having a particle diameter of several to several tens of nanometers after pasting into a paste is widely known. If it is a method to obtain, it will not restrict to this.

(Photoelectric conversion electrode)
The photoelectric conversion material used in this invention forms a photoelectric conversion electrode by laminating | stacking on the conductive surface of the transparent base material which has an electroconductive surface.

(Conductive surface)
The conductive surface used in the present invention is not particularly limited as long as it is a conductive material that absorbs little light from the visible region of the sunlight to the near infrared region. However, ITO (indium-tin oxide) or tin oxide ( Metal oxides having good electrical conductivity such as zinc oxide are preferable.

(Transparent substrate)
The transparent substrate used is not particularly limited as long as it is a material that absorbs little light from the visible region of sunlight to the near infrared region. Glass substrates such as quartz, ordinary glass, BK7, lead glass, polyethylene terephthalate, polyethylene naphthalate, polyimide, polyester, polyethylene, polycarbonate, polyvinyl butyrate, polypropylene, tetraacetylcellulose, syndiocta polystyrene, polyphenylene sulfide, polyarylate Resin base materials such as polysulfone, polyester sulfone, polyetherimide, cyclic polyolefin, brominated phenoxy, and vinyl chloride can be used.

(Lamination method)
As a method of laminating the photoelectric conversion material used in the present invention on the conductive surface of a transparent substrate having a conductive surface, it is possible to apply inorganic oxide particles pasted on the conductive surface and then dry or sinter the inorganic surface. Forming an oxide semiconductor porous body and immersing it in a solution in which the sensitizing dye is dissolved together with the transparent substrate, and thereby sensitizing using the affinity between the inorganic porous surface and the linking group of the sensitizing dye A method of bonding the dye to the inorganic porous surface is common, but is not limited to this method. In order to paste the inorganic oxide particles, the inorganic oxide particles are dispersed in water or a suitable organic solvent. It is important to make a paste with good dispersibility for lamination as an inorganic porous surface having a large surface area, and if necessary, a dispersant such as an acid such as nitric acid or acetylacetone, polyethylene glycol, or Triton X-100. Is mixed with the paste component and made into a paste using a paint shaker or the like. As a method for applying the paste to the conductive surface of the transparent substrate, an application method using a spin coater, a screen printing method, an application method using a squeegee, a dipping method, a spraying method, a roller method, or the like is used. After the applied inorganic oxide paste is dried or baked, volatile components in the paste are removed, and an inorganic oxide semiconductor porous body is formed on the conductive surface of the transparent substrate. As a condition for drying or firing, for example, a method of applying a thermal energy of about 30 minutes to 1 hour at a temperature of 400 ° C. to 500 ° C. is generally used. It is not limited to this as long as it is a drying or firing method that provides a good electromotive force during light irradiation.

  Solvents used when preparing a solution in which a sensitizing dye is dissolved include alcohol solvents such as ethanol and benzyl alcohol, nitrile solvents such as acetonitrile and propionitrile, halogen solvents such as chloroform, dichloromethane and chlorobenzene, Ether solvents such as diethyl ether and tetrahydrofuran; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone; carbonate solvents such as diethyl carbonate and propylene carbonate; hexane, octane, benzene, Hydrocarbon solvents such as toluene, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, 1,3-dimethylimidazolinone, N-methylpyrrolidone, water and the like can be used, but are not limited thereto.

  The film thickness of the inorganic oxide semiconductor porous body formed on the conductive surface of the transparent substrate is desirably 0.5 μm to 200 μm. When the film thickness is less than this range, good conversion efficiency cannot be obtained. If the film thickness is thicker than this range, not only is it difficult to produce such as cracking or peeling during film formation, but also the charge generated due to the longer distance between the surface of the inorganic oxide semiconductor porous body and the conductive surface. Cannot be effectively transmitted to the conductive surface, making it difficult to obtain good conversion efficiency.

(Photoelectric conversion cell)
The photoelectric conversion electrode used in the present invention forms a photoelectric conversion cell by combining a conductive counter electrode through an electrolyte layer.

(Electrolyte layer)
The electrolyte layer used in the present invention is preferably composed of an electrolyte, a medium, and an additive. The electrolyte of the present invention contains iodine and iodide (for example, lithium iodide, sodium iodide, potassium iodide, cesium iodide, magnesium iodide, calcium iodide, cuprous iodide, tetraalkylammonium iodide, pyridinium iodide). A mixture of bromine and bromide (for example, lithium bromide), a molten salt described in Inorganic Chemistry, 35, 1168-1178 (1996), and the like can be used. However, this is not the case. Among them, an electrolyte in which lithium iodide, pyridinium iodide, imidazolium iodide, or the like is mixed as a combination of iodine and iodide is preferable in the present invention, but is not limited to this combination. Preferred electrolyte concentrations are 0.01M to 0.5M iodine in the medium and 0.1M to 15M iodide mixture.

  The medium used for the electrolyte layer in the present invention is desirably a compound that can exhibit good ionic conductivity. Solution media include ether compounds such as dioxane and diethyl ether, chain ethers such as ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, and polypropylene glycol dialkyl ether, methanol, ethanol, and ethylene glycol monoalkyl. Alcohols such as ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, polyhydric alcohols such as ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, acetonitrile, glutarodinitrile, Methoxyacetonitrile, propioni Lil, nitrile compounds such as benzonitrile, ethylene carbonate, carbonate compounds such as propylene carbonate, 3-methyl-2-oxazolidinone heterocyclic compounds such as dimethyl sulfoxide, can be used aprotic polar substances such as sulfolane, water, and the like.

  Further, for the purpose of using a solid (including gel) medium, a polymer may be included. In this case, a polymer such as polyacrylonitrile or polyvinylidene fluoride is added to the solution-like medium, or a polyfunctional monomer having an ethylenically unsaturated group is polymerized in the solution-like medium to make the medium solid. To do.

  As the electrolyte layer, an electrolyte that does not require CuI or CuSCN medium, and 2,2 ′, 7,7′-tetrakis (N, N-dioxy) described in Nature, Vol. 395, pages 583 to 585 (1998) can be used. Hole transport materials such as -p-methoxyphenyl-amine) 9,9'-spirobifluorene can be used.

  In the electrolyte layer used in the present invention, an additive that functions to improve the electrical output of the photoelectric conversion cell or improve the durability can be added. Examples of additives that improve electrical output include 4-t-butylpyridine, 2-picoline, and 2,6-lutidine. Examples of the additive for improving durability include magnesium iodide.

(Conductive counter electrode)
The conductive counter electrode used in the present invention functions as a positive electrode of the photoelectric conversion cell. Specifically, the conductive material used for the counter electrode is metal (for example, platinum, gold, silver, copper, aluminum, rhodium, indium, etc.), metal oxide, ITO (indium-tin oxide), tin oxide (fluorine, etc.). Including doped ones), zinc oxide and carbon. The thickness of the counter electrode is not particularly limited, but is preferably 5 nm to 10 μm.

(How to assemble)
A photoelectric conversion cell is formed by combining the photoelectric conversion electrode and the conductive counter electrode via an electrolyte layer. In order to prevent leakage and volatilization of the electrolyte layer, sealing is performed around the photoelectric conversion cell as necessary. For sealing, a thermoplastic resin, a photocurable resin, glass frit, or the like can be used as a sealing material. The photoelectric conversion cell is made by connecting small-area photoelectric conversion cells as necessary. The electromotive voltage can be increased by combining the photoelectric conversion cells in series.

  Examples are shown below specifically, but the present invention is not limited to the following examples.

  Synthesis Example: Synthesis of Exemplary Compound 1

  First, compound (1) was synthesized by a reaction represented by the following formula (1).

Formula (1)

Next, the compound (2) was synthesized by the reaction represented by the formula (2).

更に、化合物（２）と次式（３）で表されるアルデヒドから、式（４）に示す反応により本発明の例示化合物１を合成した。 Formula (2)

Furthermore, Exemplified Compound 1 of the present invention was synthesized from Compound (2) and an aldehyde represented by the following Formula (3) by a reaction represented by Formula (4).

Formula (3)

Formula (4)

Synthesis of compound (1)
Methyl acetoacetate (6.01 g, 51.8 mmol) and triethylamine (16.90 g, 167 mmol) were added to an acetic anhydride solution (38 ml) of Trimellitic anhydride (5.10 g, 26.5 mmol), and the mixture was stirred at 100 ° C. for 1.5 hours. Acetic anhydride and excess triethylamine were removed at 100 ° C. under reduced pressure, and 5.95 g of compound (1) was obtained as a black liquid by column chromatography (silica gel, chloroform: methanol = 10: 1).
¹ H NMR (300 MHz, DMSO-d ₆ ) δ 1.13 (t, J = 7.2 Hz, 18H), 2.91 (q, J = 7.2 Hz, 12H), 3.53 (s, 3H), 7.37 (d, J = 7.4 Hz, 1H), 7.83 (s, 1H), 7.99 (d, J = 7.4 Hz, 1H).

Synthesis of Compound (2) Ammonium acetate (1.06 g, 13.8 mmol) was added to a methanol solution (30 mL) of Compound (1) 2.09 g (4.6 mmol), and the mixture was stirred for 3 hours under reflux. The obtained suspension was filtered and washed with methanol to obtain 1.02 g of Compound (2) as a yellow solid.
¹ H NMR (300 MHz, DMSO-d ₆ ) δ 3.51 (s, 3H), 7.27 (d, J = 7.5 Hz, 1H), 7.81 (s, 1H), 7.93 (d, J = 7.3 Hz, 1H) .

Synthesis of Exemplary Compound 1 Compound (2) 0.21 g (0.58 mmol) of aldehyde represented by formula (3) was added to 0.20 g (0.58 mmol) of acetic acid solution (2 mL), and the mixture was stirred at 100 ° C. for 1 hour. The resulting mixture was concentrated under reduced pressure at 70 ° C. and purified by column chromatography (silica gel, chloroform: methanol = 10: 1) to obtain 0.24 g of crystals. It was in agreement with the molecular weight (theoretical value 527.59, measured value 527.81) of exemplary compound 1 by the mass spectrometry by MALDITF-MS (autoflex II by Bruker Daltonics).

Evaluation of Conversion Sensitizing Dye As a method of evaluating the conversion sensitizing dye, FIG. 1 showing a test sample of a photoelectric conversion cell is used for a method of measuring the conversion efficiency of a photoelectric conversion cell assembled using a sensitizing dye. I will explain.

Transparent electrode The glass substrate 3 with a fluorine dope type tin oxide layer (transparent electrode layer) (Asahi Glass Co., Ltd. type U-TCO) was used.

Conductive counter electrode A conductive counter electrode in which a platinum layer (platinum electrode layer) (thickness 150 nm) was laminated by sputtering on the conductive layer of a glass substrate 3 with fluorine-doped tin oxide layer (type U-TCO, manufactured by Asahi Glass Co., Ltd.) 4 was used.

Preparation of Titanium Oxide Paste Titanium oxide paste and zirconia beads were mixed according to the following formulation and dispersed using a paint shaker to obtain a titanium oxide paste.
Titanium oxide (Nippon Aerosil Co., Ltd., P25 particle size 21 nm) 6 parts Water (adjusted to pH 2 by addition of nitric acid) 14 parts Acetylacetone 0.6 parts Surfactant (ICN Triton X-100) 0.04 parts PEG- # 500 , 000 0.3 parts

Preparation of porous titanium oxide layer A 60μm thick mending tape is applied to the conductive surface (transparent electrode layer 3) of the transparent electrode, and a mask is made by removing the 1cm square tape. After dropping several drops, excess paste was removed with a squeegee. After air drying, all the masks were removed and baked in an oven at 450 ° C. for 1 hour to obtain a titanium oxide electrode having a titanium oxide porous layer having an effective area of 1 cm ² .

Adsorption of sensitizing dye The sensitizing dye for photoelectric conversion is dissolved in tetrahydrofuran: acetonitrile = 1: 1 (volume ratio) (concentration 0.6 mmol / L), and insoluble matter is removed by a membrane filter. The titanium oxide electrode was immersed and left at room temperature for 24 hours. The immersion time was set so that the conversion efficiency was maximized by actually creating a cell and obtaining the conversion efficiency.
The colored electrode surface was washed with the solvent and alcohol used for dissolution, then immersed in a 2 mol% alcohol solution of 4-t-butylpyridine for 30 minutes, and then dried to form a porous titanium oxide adsorbed with a sensitizing dye. A photoelectric conversion electrode having the layer 1 was obtained.

Preparation of electrolyte solution An electrolyte solution having the following formulation was prepared. Methoxyacetonitrile was used as the solvent.
Lithium iodide 0.1M
Iodine 0.05M
4-t-butylpyridine 0.5M
1-propyl-2,3-dimethylimidazolium iodide 0.6M

Assembly of Photoelectric Conversion Cell As shown in FIG. 1, a test sample of the photoelectric conversion cell was assembled. That is, a transparent electrode (a glass substrate 3 with a fluorine-doped tin oxide layer) on which a titanium oxide porous layer 1 on which a sensitizing dye for photoelectric conversion is adsorbed by the above procedure is formed, and a glass with a fluorine-doped tin oxide layer A conductive counter electrode 4 in which a platinum layer is laminated on a conductive layer of a substrate is fixed with a spacer 6 made of resin film (“High Milan” film (25 μm thickness) made by Mitsui-DuPont Polychemical Co., Ltd.) sandwiched in the gap. The above electrolyte solution was injected to form the electrolyte solution layer 2. Conductive wires 7 for measuring conversion efficiency were fixed to the glass substrate 3 and the platinum counter electrode layer, respectively.

Measurement Method of Conversion Efficiency A solar simulator (# 8116) manufactured by ORIEL Co., Ltd. and an air mass filter were combined and adjusted to a light amount of 100 mW / cm ² with a light meter to obtain a measurement light source. The IV curve characteristic was measured using a KEITHLEY MODEL 2400 source meter while irradiating the test sample of the photoelectric conversion cell with light. The conversion efficiency η was calculated by the following equation using Voc (open circuit voltage value), Isc (short circuit current value) and ff (fill factor value) obtained from the IV curve characteristic measurement.

Example 1-7
The exemplary compounds listed in Table 1 were used as sensitizing dyes, and evaluation was performed using the cell assembled by the above method. The obtained results are shown in Table 2.

  As is apparent from Table 2, the device produced using the compound of the present invention shows almost the same conversion efficiency as that immediately after production even after 24 hours exposure under fluorescent lamps and 100 hours after simulated sunlight irradiation. I understand.

1. Titanium oxide porous layer (adsorbed sensitizing dye for photoelectric conversion)
2. 2. Electrolyte solution layer Transparent electrode layer (fluorine-doped tin oxide)
4). 4. Pt electrode layer 5. Glass substrate 6. Resin film spacer Conversion efficiency measurement lead

Claims (5)

An indanone derivative represented by the following general formula (1).
General formula (1)

[Wherein, R ^{1 to} R ³ each independently represents a hydrogen atom or an electron-withdrawing group. R ^{4 to} R ¹⁷ are each independently a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alkoxy group, an unsubstituted or substituted alkylthio group, an unsubstituted or substituted group. Represents an aryl group having ] A sensitizing dye for photoelectric conversion comprising the indanone derivative according to claim 1. A photoelectric conversion material obtained by linking the sensitizing dye for photoelectric conversion according to claim 2 and an inorganic semiconductor porous body. A photoelectric conversion electrode obtained by laminating the photoelectric conversion material according to claim 3 on a transparent electrode. A photoelectric conversion cell comprising the photoelectric conversion electrode according to claim 4, an electrolyte layer, and a conductive counter electrode.

Images