JP2015065061A - Interface complex-type organic solar battery, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an interface complex-type organic solar battery having a high efficiency.SOLUTION: An interface complex-type organic solar battery is a photoelectric conversion element comprising: a first electrode covered with an interface complex formed from dicyanomethylene expressed by the general formula (1) below, and a titanium oxide; and a second electrode opposed to the first electrode; and an electrolytic layer between the first and second electrodes. The interface complex is formed under supercritical carbon dioxide fluid in a pressure range of 10-60 MPa and in a temperature range of 35-150°C. (In the formula, X represents a substituted or unsubstituted divalent organic group.)

Description

  The present invention relates to an interface complex organic solar cell and a method for producing the same.

In recent years, the importance of solar cells has been increasing as an alternative energy to fossil fuels and as a countermeasure against global warming. However, current solar cells typified by silicon-based solar cells are expensive at present and are factors that hinder their spread.
Therefore, various low-cost solar cells are being researched and developed, and among them, dye-sensitized solar cells announced by Graetzel et al. Of Lausanne University of Technology in Switzerland are expected to be put to practical use (for example, patents). Reference 1, Non-Patent Documents 1 and 2). This solar cell has a porous metal oxide semiconductor provided on a transparent conductive glass substrate, and is composed of a sensitizing dye adsorbed on the surface thereof, an electrolyte having a redox couple, and a counter electrode. Graetzel et al. Significantly improved the photoelectric conversion efficiency by making a metal oxide semiconductor electrode such as titanium oxide porous to increase the surface area, and by adsorbing a ruthenium complex as a dye on a single molecule basis.

  However, the ruthenium complex used for the sensitizing dye is a rare metal and has resource limitations. Therefore, there is a demand for the development of organic dyes that are less resource-constrained. As sensitizing dyes already proposed, xanthene dyes such as eosin Y (see Non-patent Document 3), perylene dyes (see Non-Patent Document 4), cyanine dyes (see Patent Document 2), merocyanine dyes (patents) Reference 3), coumarin dye (see Non-patent document 5), polyene dye (see Non-patent document 6), porphyrin dye (see Non-patent document 7), phthalocyanine dye (see Non-patent document 8) and the like have been reported. .

  Xanthene dyes and perylene dyes such as eosin Y have an absorption wavelength region of only about 600 nm, and have a disadvantage of low conversion efficiency. Since cyanine dyes, merocyanine dyes, polyene dyes, coumarin dyes and the like have many conjugated double bonds, cis-trans isomerization is likely to occur due to light irradiation, and their durability is very low. Porphyrin dyes and phthalocyanine dyes are disadvantageous in that they have low solubility and low adsorption power to titanium oxide, and are easily desorbed from titanium oxide. Also, it is difficult for phthalocyanine dyes to match the energy level with titanium oxide.

  In recent years, a push-pull type porphyrin complex containing a hole transporting compound (see Non-Patent Document 9) has been reported to have a very high conversion efficiency, but the absorption wavelength region is about 750 nm, and further long wavelength absorption is achieved. There is a need for higher conversion efficiency through conversion.

  Further, since the Ru metal complex used in the Gretzel type dye-sensitized solar cell contains Ru, which is a rare metal, development of a dye having high performance and low cost has been desired. In general, since a method of chemically adsorbing a dye using OH groups on the surface of a metal oxide such as titanium oxide is used, it is necessary to introduce a functional group such as a COOH group or a POOH group to the dye. In some cases, this increases the cost of synthesis.

  In addition, there is a solar cell using a composite material of a dicyanomethylene compound and a metal oxide (see Patent Documents 4 and 5), but it takes a long time to adsorb the metal oxide to the dicyanomethylene compound solution. Furthermore, for higher efficiency, combined adsorption with an aggregation inhibitor is necessary, the amount of dye adsorption is small, and the thickness of the metal oxide layer needs to be increased, leading to an increase in the cost of device fabrication.

Use supercritical carbon dioxide to adsorb specific dyes having COOH groups, —P (O) (OH) ₂ groups, —OP (O) (OH) ₂ groups, etc. as particularly preferred bonding groups to the surface of the semiconductor fine particles. There are reports of shortening the adsorption time and increasing the adsorption amount (see Patent Document 6). However, it does not disclose supercritical conditions for quickly adsorbing a dicyanomethylene compound without decomposing it.
As described above, none of the sensitizing dyes of dye-sensitized solar cells that have been studied so far has been obtained with satisfactory characteristics.

  An object of the present invention is to provide a highly efficient interface complex type organic solar cell in order to solve the above-mentioned problems.

As a result of intensive research, the present inventors have not only adsorbed an interface complex composed of an organic molecule having a dicyanomethylene group and a metal oxide by conventional solution immersion, but also in supercritical carbon dioxide, It was found that an interfacial complex was formed.
Further, in a compound having a triarylamine group and having a bulky steric structure, an interface complex cannot be formed by conventional solution immersion, but an interface complex can be obtained in the supercritical carbon dioxide. By having a triarylamine group, the extinction coefficient was increased, and photoelectric conversion characteristics could be improved.

The present inventors have found that a highly efficient interface complex organic solar cell can be provided, and have reached the present invention. That is, the inventors have found that the above problems can be solved by the invention described in [1] below, and have reached the present invention.
[1]: “A first electrode covered with an interface complex formed of dicyanomethylene and titanium oxide represented by the following general formula (1); a second electrode facing the first electrode; In the interfacial complex type organic solar cell which is a photoelectric conversion element having an electrolyte layer between the electrode and the second electrode, the interfacial complex is supercritical dioxide in a pressure range of 10 to 60 MPa and a temperature range of 35 to 150 ° C. An interfacial complex organic solar cell formed under a carbon fluid;

（式中、Ｘは置換又は無置換の２価有機基を表す。）」

(In the formula, X represents a substituted or unsubstituted divalent organic group.)

  As will be understood from the following detailed and specific description, according to the present invention, an extremely excellent effect of providing a highly efficient interface complex organic solar cell is exhibited.

It is an example of sectional drawing showing the structure of the dye-sensitized solar cell which concerns on this invention. It is an infrared absorption spectrum figure of the synthesis example 1 compound of this embodiment. It is an infrared absorption spectrum figure of the synthesis example 2 compound of this embodiment. It is an absorption spectrum figure.

As described above, the present invention relates to the “interface complex organic solar cell” described in [1]. The “interface complex organic solar cell” includes the following [2] to [6]. It includes “interface complex organic solar cells” as described. The present invention also provides “a method for producing an interface complex organic solar cell” as described in the following [7] to [12].
[2]: “The absorption spectrum observed from the ultraviolet to the near-infrared region indicated by the interface complex is observed in a wavelength region different from the absorption spectrum of dicyanomethylene represented by the general formula (1)” The interface complex organic solar cell according to [1] above.
[3]: “The dicyanomethylene represented by the general formula (1) is composed of one or more dicyanomethylenes of the following structural formulas (2) to (7): [1] or an interface complex organic solar cell according to any one of [2];

[4]: “The interface complex organic solar cell according to [3], wherein the dicyanomethylene represented by the general formula (7) is represented by the following general formula (8): ;

（式中、Ａｒ２は、炭素数が６から１８の芳香族炭化水素基を表す。Ａｒ３は、アルキル基を置換基として有しても良い炭素数が６から２０の芳香族炭化水素基を表す。）」

(In the formula, Ar2 represents an aromatic hydrocarbon group having 6 to 18 carbon atoms. Ar3 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have an alkyl group as a substituent. .) "

[5]: “The interface complex organic solar cell according to the above [4], wherein the dicyanomethylene represented by the general formula (8) is represented by the following general formula (9): ;

（式中、Ａｒ４は、フェニル基、ビフェニル基を表す。）」

(In the formula, Ar4 represents a phenyl group or a biphenyl group.)

[6]: The interface according to any one of [3] to [5], wherein the dicyanomethylene compound represented by the general formula (7) is represented by the following general formula (10): Complex organic solar cells;

（式中、ｎは０、１、２のいずれかであり、Ｒはアルキル基を表す）」

(In the formula, n is 0, 1, or 2, and R represents an alkyl group) "

[7]: “A method for producing an interfacial complex organic solar cell, wherein the organic solar cell is coated with an interfacial complex formed from dicyanomethylene and titanium oxide represented by the following general formula (1): A photoelectric conversion element comprising an electrode, a second electrode facing the first electrode, and an electrolyte layer between the first electrode and the second electrode, and having a pressure range of 10 to 60 MPa and a temperature of 35 to 150 ° C. A method for producing an interfacial complex organic solar cell, comprising a step of forming the interfacial complex compound under a supercritical carbon dioxide fluid in a temperature range;

（式中、Ｘは置換又は無置換の２価有機基を表す。）」

(In the formula, X represents a substituted or unsubstituted divalent organic group.)

[8]: “The absorption spectrum observed from the ultraviolet to the near-infrared region indicated by the interface complex is observed in a wavelength region different from the absorption spectrum of dicyanomethylene represented by the general formula (1)” The interfacial complex type organic solar cell according to [7].
[9]: “The dicyanomethylene represented by the general formula (1) is composed of one or more dicyanomethylenes of the following structural formulas (2) to (7): [7] or a method for producing an interface complex organic solar cell according to any one of [8];

[10]: “The interface complex organic solar cell according to [9], wherein the dicyanomethylene represented by the general formula (7) is represented by the following general formula (8): Manufacturing method of

（式中、Ａｒ２は、炭素数が６から１８の芳香族炭化水素基を表す。Ａｒ３は、アルキル基を置換基として有しても良い炭素数が６から２０の芳香族炭化水素基を表す。）」

(In the formula, Ar2 represents an aromatic hydrocarbon group having 6 to 18 carbon atoms. Ar3 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have an alkyl group as a substituent. .) "

[11]: “The interface complex organic solar cell according to [10], wherein the dicyanomethylene represented by the general formula (8) is represented by the following general formula (9): Manufacturing method of

（式中、Ａｒ４は、フェニル基、ビフェニル基を表す。）」

(In the formula, Ar4 represents a phenyl group or a biphenyl group.)

[12]: The interface according to any one of [9] to [11], wherein the dicyanomethylene compound represented by the general formula (7) is represented by the following general formula (10): A method for producing a complex organic solar cell;

（式中、ｎは０、１、２のいずれかであり、Ｒはアルキル基を表す）」

(In the formula, n is 0, 1, or 2, and R represents an alkyl group) "

The present invention will be described in detail below.
The configuration of the interface type organic solar cell will be described with reference to FIG. In addition, FIG. 1 is sectional drawing of an interface type organic solar cell.
In the embodiment shown in FIG. 1, a first electrode (2) is provided on a substrate (1), an electron transport layer (3) made of a granular electron transport material, and a photosensitizer (4) on the electron transport material. Is adsorbed and the charge transfer layer (5) is sandwiched between the second electrode (6).

<First electrode>
The first electrode (2) used in the present invention is not particularly limited as long as it is a conductive material that is transparent to visible light, and is a known one used in ordinary photoelectric conversion elements or liquid crystal panels. Things can be used.
For example, indium / tin oxide (hereinafter referred to as ITO), fluorine-doped tin oxide (hereinafter referred to as FTO), antimony-doped tin oxide (hereinafter referred to as ATO), indium / zinc oxide, niobium / titanium oxide , Graphene and the like, and these may be used alone or in a plurality of layers.
The thickness of the first electrode is preferably 5 nm to 100 μm, and more preferably 50 nm to 10 μm.
The first electrode is preferably provided on a substrate made of a material transparent to visible light in order to maintain a certain hardness. For example, glass, a transparent plastic plate, a transparent plastic film, an inorganic transparent crystal, or the like is used.

A known one in which the first electrode and the substrate are integrated can also be used, for example, FTO coated glass, ITO coated glass, zinc oxide: aluminum coated glass, FTO coated transparent plastic film, ITO coated transparent plastic film, etc. Can be mentioned.
In addition, a transparent electrode obtained by doping cations or anions with different valences into tin oxide or indium oxide, or a metal electrode having a structure capable of transmitting light, such as a mesh shape or a stripe shape, provided on a substrate such as a glass substrate Good. These may be used singly or as a mixture of two or more kinds or laminated ones. Further, for the purpose of reducing the resistance, a metal lead wire or the like may be used in combination.
Examples of the material of the metal lead wire include metals such as aluminum, copper, silver, gold, platinum, and nickel. For example, the metal lead wire may be provided on the substrate by vapor deposition, sputtering, pressure bonding, or the like, and ITO or FTO may be provided thereon.

<Electron transport layer>
In the dye-sensitized solar cell of the present invention, a thin film made of a semiconductor is formed as the electron transport layer (3) on the first electrode (2).
The electron transport layer (3) has a laminated structure in which a dense electron transport layer is formed on the first electrode (2) and a porous electron transport layer (3) is further formed thereon. I do not care.
This dense electron transport layer is formed for the purpose of preventing electronic contact between the first electrode (2) and the charge transfer layer (5). Therefore, if the first electrode (2) and the charge transfer layer (5) are not in physical contact, pinholes, cracks, or the like may be formed.
Moreover, although there is no restriction | limiting in the film thickness of this precise | minute electron carrying layer (3), 10 nm-1 micrometer are preferable and 20 nm-700 nm are more preferable.
The “dense” of the electron transport layer (3) means that the inorganic oxide semiconductor is filled at a higher density than the packing density of the semiconductor fine particles in the electron transport layer.
The porous electron transport layer (3) formed on the dense electron transport layer may be a single layer or multiple layers.
In the case of multiple layers, a dispersion of semiconductor fine particles having different particle diameters can be applied in multiple layers, or different types of semiconductors, and application layers having different compositions of resins and additives can be applied in multiple layers.
Multi-layer coating is an effective means when the film thickness is insufficient with a single coating.

  In general, as the film thickness of the electron transport layer increases, the amount of the photosensitized compound carried per unit projected area increases, so that the light capture rate increases. Loss due to coupling also increases. Therefore, the film thickness of the electron transport layer is preferably 100 nm to 100 μm.

The semiconductor is not particularly limited, and a known semiconductor can be used.
Specifically, a single semiconductor such as silicon or germanium, a compound semiconductor typified by a metal chalcogenide, a compound having a perovskite structure, or the like can be given.
Metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, or tantalum oxides, cadmium, zinc, lead, silver, antimony, bismuth. Sulfide, cadmium, lead selenide, cadmium telluride and the like.
Other compound semiconductors are preferably phosphides such as zinc, gallium, indium, cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like.
As the compound having a perovskite structure, strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate and the like are preferable.
Among these, an oxide semiconductor is preferable, and titanium oxide, zinc oxide, tin oxide, and niobium oxide are particularly preferable, and they may be used alone or in combination of two or more. The crystal type of these semiconductors is not particularly limited, and may be single crystal, polycrystal, or amorphous.

Although there is no restriction | limiting in particular in the size of a semiconductor fine particle, 1-100 nm is preferable and, as for the average particle diameter of a primary particle, 5-50 nm is more preferable.
Further, the efficiency can be improved by the effect of scattering incident light by mixing or laminating semiconductor fine particles having a larger average particle diameter. In this case, the average particle size of the semiconductor is preferably 50 to 500 nm.

There is no restriction | limiting in particular in the preparation methods of an electron carrying layer, The method of forming a thin film in vacuum, such as sputtering, and the wet film forming method are mentioned.
In view of the manufacturing cost and the like, a wet film forming method is particularly preferable, and a method in which a paste in which semiconductor fine particle powder or sol is dispersed is prepared and applied onto an electron collecting electrode substrate is preferable.
When this wet film-forming method is used, the coating method is not particularly limited, and can be performed according to a known method.
For example, dip method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, and wet printing methods such as relief printing, offset, gravure, intaglio printing, rubber printing, screen printing, etc. Can be used.
When a dispersion is prepared by mechanical pulverization or using a mill, it is formed by dispersing at least semiconductor fine particles alone or a mixture of semiconductor fine particles and a resin in water or an organic solvent.

  As the resin used at this time, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid ester, methacrylic acid ester, silicon resin, phenoxy resin, polysulfone resin, polyvinyl butyral resin, polyvinyl formal resin, Examples include polyester resin, cellulose ester resin, cellulose ether resin, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin, polyamide resin, polyimide resin, and the like.

  Solvents for dispersing the semiconductor fine particles include water, alcohol solvents such as methanol, ethanol, isopropyl alcohol, and α-terpineol, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethyl formate, ethyl acetate, and n acetate. Ester solvents such as butyl, ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone Amide solvents, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromo Halogenated hydrocarbon solvents such as benzene, iodobenzene or 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o Examples thereof include hydrocarbon solvents such as xylene, m-xylene, p-xylene, ethylbenzene, and cumene. These can be used alone or as a mixed solvent of two or more.

  In order to prevent re-aggregation of particles, a paste of semiconductor fine particles obtained by a dispersion of semiconductor fine particles or a sol-gel method is used, such as acids such as hydrochloric acid, nitric acid and acetic acid, Surfactants, chelating agents such as acetylacetone, 2-aminoethanol, and ethylenediamine can be added.

It is also an effective means to add a thickener for the purpose of improving the film forming property.
Examples of the thickener added at this time include polymers such as polyethylene glycol and polyvinyl alcohol, and thickeners such as ethyl cellulose.

The semiconductor fine particles are preferably subjected to firing, microwave irradiation, electron beam irradiation, or laser beam irradiation in order to bring the particles into electronic contact with each other after coating and to improve film strength and adhesion to the substrate. . These processes may be performed alone or in combination of two or more.
When firing, the range of the firing temperature is not particularly limited, but if the temperature is raised too much, the resistance of the substrate may be increased or the substrate may be melted, so 30 to 700 ° C is preferable, and 100 to 600 ° C is more preferable. Moreover, although there is no restriction | limiting in particular also in baking time, 10 minutes-10 hours are preferable.
For the purpose of increasing the surface area of the semiconductor fine particles after firing and increasing the efficiency of electron injection from the photosensitizing compound to the semiconductor fine particles, for example, chemical plating using titanium tetrachloride aqueous solution or mixed solution with organic solvent, titanium trichloride Electrochemical plating using an aqueous solution may be performed.

Microwave irradiation may be performed from the electron transport layer forming side or from the back side. Although there is no restriction | limiting in particular in irradiation time, It is preferable to carry out within 1 hour. A film in which semiconductor fine particles having a diameter of several tens of nanometers are stacked by sintering or the like forms a porous state.
This nanoporous structure has a very high surface area, which can be expressed using a roughness factor. The roughness factor is a numerical value representing the actual area inside the porous body relative to the area of the semiconductor fine particles applied to the substrate. Accordingly, the roughness factor is preferably as large as possible, but it is also related to the film thickness of the electron transport layer, and is preferably 20 or more in the present invention.

<Photosensitizing compound>
In the present invention, in order to further improve the conversion efficiency, the photosensitizing compound is adsorbed on the surface of the electron transporting semiconductor. As the photosensitizing compound in the present invention, one represented by the general formula (1) is used.
Although the specific exemplary compound in General formula (1) is described below, it is not limited to these at all.

  As a method of adsorbing the photosensitizing compound (4) to the electron transport layer (3), generally, a method of immersing an electron current collecting electrode containing semiconductor fine particles in a photosensitizing compound solution or a dispersion liquid Alternatively, a method in which a solution or dispersion is applied to the electron transport layer and adsorbed can be used. In the former case, dipping method, dipping method, roller method, air knife method, etc. can be used, and in the latter case, wire bar method, slide hopper method, extrusion method, curtain method, spin method, spray method, etc. Can be used.

In the present invention, by adsorbing in a supercritical fluid using carbon dioxide or the like, a steroid compound such as chenodeoxycholic acid or a coadsorbent (aggregation dissociator) such as a long-chain alkyl carboxylic acid or a long-chain alkyl phosphonic acid Aggregation between compounds can be suppressed without using together.
The time for forming the interfacial complex compound formed from the dicyanomethylene compound and titanium oxide using supercritical carbon dioxide is preferably 1 minute to 1000 hours, more preferably 5 minutes to 500 hours, and more preferably 10 minutes to 100 hours. More preferably, the time is less than the time.

  Further, the pressure for forming an interface complex formed from dicyanomethylene and titanium oxide using supercritical carbon dioxide is preferably 10 MPa or more and 60 MPa or less, more preferably 15 MPa or more and 50 MPa or less, and further preferably 20 MPa or more and 40 MPa or less.

  Furthermore, the temperature at which the interface complex formed from dicyanomethylene and titanium oxide is formed using supercritical carbon dioxide is preferably 35 ° C. or higher and 150 ° C. or lower, more preferably 40 ° C. or higher and 135 ° C. or lower, and 50 ° C. or higher and 120 ° C. or lower. More preferably, it is not higher than ° C.

<Electrolytic transfer layer>
As the charge transfer layer of the present invention, an electrolytic solution in which a redox couple is dissolved in an organic solvent, a gel electrolyte in which a liquid in which the redox couple is dissolved in an organic solvent is impregnated in a polymer matrix, a molten salt containing the redox couple, a solid An electrolyte, an inorganic hole transport material, an organic hole transport material, or the like can be used.
The electrolytic solution used in the present invention is preferably composed of an electrolyte, a solvent, and an additive. Preferred electrolytes are metal iodide-iodine combinations such as lithium iodide, sodium iodide, potassium iodide, cesium iodide, and calcium iodide, and quaternary compounds such as tetraalkylammonium iodide, pyridinium iodide, and imidazolium iodide. Iodine salt of ammonium compound-iodine combination, metal bromide-bromine combination such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, calcium bromide, quaternary ammonium such as tetraalkylammonium bromide, pyridinium bromide Bromine-bromine combinations of compounds, metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion, sodium compounds such as polysulfide, alkylthiol-alkyldisulfide, viologen dyes, hydroxy Down - quinones, metal complexes such as cobalt, include the nitroxide radical compounds.
The above electrolytes may be a single combination or a mixture. Further, when an ionic liquid such as imidazolinium iodide is used, it is not particularly necessary to use a solvent.

  The electrolyte concentration in the electrolytic solution is preferably 0.05 to 20M, and more preferably 0.1 to 15M. Solvents used for the electrolyte include carbonate solvents such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether solvents such as dioxane, diethyl ether and ethylene glycol dialkyl ether, methanol, ethanol , Alcohol solvents such as polypropylene glycol monoalkyl ether, nitrile solvents such as acetonitrile and benzonitrile, aprotic polar solvents such as dimethyl sulfoxide and sulfolane, etc. are preferable, and t-butylpyridine, 2-picoline, 2, A basic compound such as 6-lutidine may be used in combination.

  In the present invention, the electrolyte can be gelled by a technique such as addition of a polymer, addition of an oil gelling agent, polymerization including polyfunctional monomers, or a crosslinking reaction of the polymer. Preferable polymers in the case of gelation by polymer addition include polyacrylonitrile, polyvinylidene fluoride and the like. Preferred gelling agents for gelation by adding an oil gelling agent include dibenzylden-D-sorbitol, cholesterol derivatives, amino acid derivatives, alkylamide derivatives of trans- (1R, 2R) -1,2-cyclohexanediamine, alkylureas Derivatives, N-octyl-D-gluconamide benzoate, double-headed amino acid derivatives, quaternary ammonium derivatives and the like can be mentioned.

  Preferred monomers for polymerization with a polyfunctional monomer include divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and the like. be able to. Furthermore, esters and amides derived from acrylic acid such as acrylamide and methyl acrylate and α-alkyl acrylic acid, esters derived from maleic acid and fumaric acid such as dimethyl maleate and diethyl fumarate, butadiene, cyclohexane and the like. Dienes such as pentadiene, aromatic vinyl compounds such as styrene, p-chlorostyrene and sodium styrene sulfonate, vinyl esters, acrylonitrile, methacrylonitrile, vinyl compounds having a nitrogen-containing heterocyclic ring, vinyl having a quaternary ammonium salt A monofunctional monomer such as a compound, N-vinylformamide, vinylsulfonic acid, vinylidene fluoride, vinyl alkyl ethers, N-phenylmaleimide may be contained.

0.5-70 mass% is preferable and the polyfunctional monomer which occupies for the monomer whole quantity has more preferable 1.0-50 mass%.
The above-mentioned monomers can be polymerized by radical polymerization. The monomer for gel electrolyte that can be used in the present invention can be radically polymerized by heating, light, electron beam or electrochemical. The polymerization initiator used when the crosslinked polymer is formed by heating is 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2. Azo initiators such as 2,2′-azobis (2-methylpropionate) and peroxide initiators such as benzoyl peroxide are preferable. The addition amount of these polymerization initiators is preferably 0.01 to 20% by mass and more preferably 0.1 to 10% by mass with respect to the total amount of monomers.

  When the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a reactive group necessary for the crosslinking reaction and a crosslinking agent in combination. Preferable examples of the crosslinkable reactive group include nitrogen-containing heterocycles such as pyridine, imidazole, thiazole, oxazole, triazole, morpholine, piperidine, piperazine, etc. Preferred crosslinking agents include alkyl halides, halogens Bifunctional or higher functional reagents capable of electrophilic reaction with nitrogen atoms such as aralkyl fluoride, sulfonic acid ester, acid anhydride, acid chloride, and isocyanate can be exemplified.

<Second electrode>
In the present invention, there are roughly two methods for forming the charge transfer layer.
One is a method in which a counter electrode (second electrode in FIG. 1) is first pasted on a semiconductor fine particle-containing layer carrying a sensitizing dye, and a liquid charge transfer layer is sandwiched between the two, and the other is a semiconductor. In this method, the charge transfer layer is directly provided on the fine particle-containing layer. In the latter case, the counter electrode is newly added thereafter.
In the former case, examples of the method for sandwiching the charge transfer layer include a normal pressure process using a capillary phenomenon due to immersion and a vacuum process in which the gas phase is replaced with a liquid phase at a pressure lower than normal pressure. In the latter case, in the wet charge transfer layer, it is necessary to provide a counter electrode without being dried to prevent liquid leakage at the edge portion. In the case of a gel electrolyte, there is a method in which it is applied in a wet manner and solidified by a method such as polymerization. In that case, you may provide a counter electrode after drying and fixing. In addition to the electrolyte solution, the organic charge transport material solution and the gel electrolyte can be applied in the same manner as the semiconductor fine particle-containing layer and the dye, as in the immersion method, roller method, dipping method, air knife method, and extrusion method. , Slide hopper method, wire bar method, spin method, spray method, casting method, various printing methods, and the like.

As the counter electrode, a support having a conductive layer can be used in the same manner as the conductive support described above, but the support is not necessarily required in a configuration in which the strength and the sealing performance are sufficiently maintained.
Specific examples of the material used for the counter electrode include metals such as platinum, gold, silver, copper, aluminum, rhodium, and indium, and conductive metal oxides such as carbon, ITO, and FTO.
There is no particular limitation on the thickness of the counter electrode.

When an inorganic hole transport material or an organic hole transport material is used for the charge transfer layer, the hole current collecting electrode (second electrode in FIG. 1) is newly applied after the formation of the solid hole transport layer or on the above metal oxide. . As the hole collecting electrode, the same one as the above-described electron collecting electrode (first electrode in FIG. 1) can be usually used, and the support is not necessarily used in a configuration in which the strength and the sealing performance are sufficiently maintained. Not necessary. Specific examples of hole collecting electrode materials include metals such as platinum, gold, silver, copper, and aluminum, carbon compounds such as graphite, fullerene, and carbon nanotubes, conductive metal oxides such as ITO and FTO, polythiophene, and polyaniline. And conductive polymers such as
There is no restriction | limiting in particular in the film thickness of a hole current collection electrode layer, and you may use individually or in mixture of 2 or more types. The hole collecting electrode can be applied by a method such as coating, laminating, vapor deposition, CVD, and bonding on the hole transport layer as appropriate depending on the type of material used and the type of hole transport layer.

In order to operate as a photoelectric conversion element, at least one of the electron collector electrode and the hole collector electrode must be substantially transparent.
In the photoelectric conversion element of the present invention, a method in which the electron collecting electrode side is transparent and sunlight is incident from the electron collecting electrode side is preferable. In this case, it is preferable to use a material that reflects light on the side of the hole collecting electrode, and a metal, glass, plastic, or metal thin film on which a conductive oxide is deposited is preferable.
It is also effective to provide an antireflection layer on the sunlight incident side.

<Application>
The photoelectric conversion element of the present invention can be applied to a solar cell and a power supply device using the solar cell.
As an application example, any device using a conventional solar cell or a power supply device using the solar cell can be used.
For example, although it may be used for an electronic desk calculator or a solar cell for a wristwatch, examples of utilizing the features of the dye-sensitized solar cell of the present invention include a power supply device such as a mobile phone, an electronic notebook, and electronic paper. It can also be used as an auxiliary power source for extending the continuous use time of a rechargeable or dry battery type electric appliance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, embodiment of this invention is not limited to these Examples.

[Synthesis example]
[Synthesis Example 1; Synthesis of Exemplified Compound 6]

2-Bromo-9,10-anthraquinone (0.91 g, 3.1 mmol), [4 ′-[bis (4-methylphenyl) amino] [1,1′-phenyl] -4-yl] -Boronic acid, ( 1.20 g, 3.80 mmol), Pd (PPh 3) 4 (0.28 g, 0.25 mmol), K ₂ CO ₃ aqueous solution (2M, 10 ml), and toluene (10 ml) were refluxed under an argon stream for 5 hours. . After cooling to room temperature, methanol was added to precipitate a precipitate. The precipitate was collected by filtration and washed with methanol to obtain 0.9 g (yield 60.5%) of an intermediate compound as a purple solid.
The intermediate compound (0.50 g, 1.04 mmol), dicyanomethylene (0.30 g, 4.6 mmol), and dichloromethane (10 ml) were stirred at 0 ° C. Titanium tetrachloride (2 ml) was gradually added thereto, and then pyridine (5 ml) was gradually added. After the addition was complete, the mixture was stirred at room temperature for 2 hours. Extraction was performed with toluene, the organic layer was taken out, and the solvent was distilled off under reduced pressure. The product was purified by column chromatography (eluent: toluene), and further purified by size exclusion chromatography to obtain 95 mg of the objective dark green powder (yield 15%). In FIG. 6 shows an infrared absorption spectrum as identification data for No. 6.

[Synthesis Example 2; Synthesis of Exemplified Compound 11]

2-bromo-9,10-anthraquinone (0.91 g, 3.1 mmol), [4 ′-[bis (4-methylphenyl) amino] [1,1′-biphenyl] -4-yl] -Boronic acid, ( 1.50 g, 3.80 mmol), Pd (PPh 3) 4 (0.28 g, 0.25 mmol), K ₂ CO ₃ aqueous solution (2M, 10 ml), and toluene (10 ml) were refluxed under an argon stream for 5 hours. After cooling to room temperature, methanol was added to precipitate a precipitate. The precipitate was collected by filtration and washed with methanol to obtain 1.0 g of a purple solid intermediate compound (yield 82%).
The intermediate compound (0.50 g, 0.92 mmol), dicyanomethylene (0.30 g, 4.6 mmol), and dichloromethane (10 ml) were stirred at 0 ° C. Titanium tetrachloride (2 ml) was gradually added thereto, and then pyridine (5 ml) was gradually added. After the addition was complete, the mixture was stirred at room temperature for 2 hours. Extraction was performed with toluene, the organic layer was taken out, and the solvent was distilled off under reduced pressure. Purification by column chromatography (eluent: toluene) and further purification by size exclusion chromatography gave 100 mg of the target dark green powder (yield 16%). In FIG. The infrared absorption spectrum figure as 11 identification data is shown.

[Example 1]
(Production of titanium oxide semiconductor electrode)
Titanium tetra-n-propoxide (2 ml), acetic acid (4 ml), ion exchange water (1 ml), and 2-propanol (40 ml) were mixed, spin-coated on an FTO glass substrate, dried at room temperature, and baked at 450 ° C. for 30 minutes in air. Using the same solution again, it was applied on the obtained electrode by spin coating so as to have a film thickness of 100 nm, and baked in air at 450 ° C. for 30 minutes to form a dense electron transport layer.
A bead mill treatment was performed for 12 hours with 3 g of titanium oxide (P-25 manufactured by Nippon Aerosil Co., Ltd.) and 0.3 g of acetylacetone together with 5.5 g of water and 1.2 g of ethanol.
A paste was prepared by adding 0.3 g of a surfactant (polyoxyethylene octylphenyl ether manufactured by Wako Pure Chemical Industries, Ltd.) and 1.2 g of polyethylene glycol (# 20,000) to the obtained dispersion.
This paste was applied onto the dense electron transport layer so as to have a film thickness of 10 μm, dried at room temperature, and then baked in air at 500 ° C. for 30 minutes to form a porous electron transport layer.
An acetone solution of a photosensitizing compound shown in Exemplified Compound 1 (tetracyanoethylene, manufactured by Tokyo Chemical Industry Co., Ltd.) prepared by adjusting the titanium oxide semiconductor electrode to 3 mM, and a supercritical fluid dye adsorption system (SCF-220, manufactured by ISCO) ) Was allowed to stand under supercritical carbon dioxide at 50 ° C. and 40 MPa for 20 minutes to adsorb the photosensitizing compound and form an interface complex.

(Production and evaluation of dye-sensitized solar cells)
As an electrolytic solution, 0.05M iodine, 0.1M lithium iodide, 0.6M 1,3-dimethyl-2-imidazolinium iodide dissolved in a mixed solution of acetonitrile / valeronitrile = 17/3 used. As the counter electrode, platinum sputtered on FTO was used. A spacer having a thickness of 30 μm was sandwiched between both electrodes, and an electrolyte was injected to prepare a dye-sensitized solar cell. Here, pseudo solar light generated from a solar simulator (AM1.5, 100 mW / cm ² ) was irradiated from the working electrode side to evaluate solar cell characteristics. As a result, an open circuit voltage of 0.53 V, a short-circuit current density of 5.3 mA / cm ² , a form factor of 0.65, and a conversion efficiency of 1.31% were shown.

[Example 2]
Exemplified compound 1 in Example 1 was changed to the exemplified compound shown in Table 2, and a solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed. The results are shown in Table 2. All showed good values.

[Example 3]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 4]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 5]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was produced and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 6]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 7]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 8]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 9]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 10]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 11]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 12]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 13]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 14]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 15]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 16]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 17]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 18]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 19]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 20]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 21]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure, and time under supercritical carbon dioxide were changed as shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 22]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 23]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 24]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Example 25]
Exemplified Compound 1 in Example 1 was replaced with Exemplified Compound No. 1 shown in Table 2. The solar cell was prepared and evaluated in the same manner as in Example 1 except that the temperature, pressure and time under supercritical carbon dioxide were changed to those shown in Table 2. The results are shown in Table 2. Good value was shown.

[Comparative Example 1]
A solar cell was prepared and evaluated in the same manner as in Example 2 except that the temperature and pressure under supercritical carbon dioxide in Example 2 were changed. The results are shown in Table 3.

[Comparative Example 2]
A solar cell was prepared and evaluated in the same manner as in Example 2 except that the temperature and pressure under supercritical carbon dioxide in Example 2 were changed. The results are shown in Table 3.

[Comparative Example 3]
A solar cell was prepared and evaluated in the same manner as in Example 2 except that the temperature and pressure under supercritical carbon dioxide in Example 2 were changed. The results are shown in Table 3.

[Comparative Example 4]
A solar cell was prepared and evaluated in the same manner as in Example 2 except that the temperature and pressure under supercritical carbon dioxide in Example 2 were changed. The results are shown in Table 3.

  All had low conversion efficiency. Comparative Example 1 is below the critical temperature of carbon dioxide, and Comparative Example 2 is below the critical pressure of carbon dioxide, both of which were considered to be factors of low conversion efficiency because sufficient photosensitizers could not be adsorbed. It is done. In Comparative Example 3, peeling of the titanium oxide layer under high pressure is considered to be a factor of low conversion efficiency. In Comparative Example 4, it is considered that deterioration of the photosensitizer at a high temperature is a factor of low conversion efficiency.

[Comparative Example 5]
The titanium oxide semiconductor electrode in Example 2 was allowed to stand in a dark place for 15 hours at room temperature in an acetone solution of the photosensitized compound shown in Exemplary Compound 2 adjusted to 3 mM to adsorb the photosensitized compound. Except for the above, a dye-sensitized solar cell was prepared and evaluated in the same manner as in Example 1. As a result, the open circuit voltage = 0.35V, the short circuit current density 4.8 mA / cm ² , the form factor = 0.62, and the conversion efficiency = 1.04%.

[Comparative Example 6]
The titanium oxide semiconductor electrode in Example 6 was allowed to stand in a dark place at room temperature for 15 hours in an acetone solution of the photosensitized compound shown in Exemplified Compound 6 adjusted to 3 mM to adsorb the photosensitized compound. Except for the above, a dye-sensitized solar cell was prepared and evaluated in the same manner as in Example 1. As a result, the open circuit voltage = 0.39V, the short circuit current density 1.2 mA / cm ² , the form factor = 0.63, and the conversion efficiency = 0.29%.

(Absorption spectrum)
The absorption spectrum of the titanium oxide semiconductor electrode formed with the interface complex of Example 1 in which the film thickness of the titanium oxide semiconductor electrode described in Example 1 was adjusted to 5 μm and the powder of the exemplified compound 2 was measured with UV3100 manufactured by Hitachi, Ltd. As shown in FIG.

Japanese Patent No. 2664194 Japanese Patent Application Laid-Open No. 11-86916 Japanese Patent Laid-Open No. 11-238925 Japanese Patent Application No. 2008-58818 WO200910618 publication JP 2001-223037 A

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Claims (7)

A first electrode coated with an interface complex formed of dicyanomethylene and titanium oxide represented by the following general formula (1); a second electrode facing the first electrode; and the first electrode and the second electrode The interfacial complex type organic solar cell, which is a photoelectric conversion element having an electrolyte layer therebetween, is formed by a supercritical carbon dioxide fluid in a pressure range of 10 to 60 MPa and a temperature range of 35 to 150 ° C. An interfacial complex organic solar cell characterized by being made.

(In the formula, X represents a substituted or unsubstituted divalent organic group.)   The absorption spectrum observed from the ultraviolet region to the near infrared region indicated by the interface complex is observed in a wavelength region different from the absorption spectrum of dicyanomethylene represented by the general formula (1). The interface complex organic solar cell described. The dicyanomethylene represented by the general formula (1) is composed of one or more dicyanomethylenes of the following structural formulas (2) to (7). The interface complex type organic solar cell according to any one of the above.

4. The interface complex organic solar cell according to claim 3, wherein the dicyanomethylene represented by the general formula (7) is represented by the following general formula (8).

(In the formula, Ar2 represents an aromatic hydrocarbon group having 6 to 18 carbon atoms. Ar3 represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have an alkyl group as a substituent. .) The interface complex organic solar cell according to claim 4, wherein the dicyanomethylene represented by the general formula (8) is represented by the following general formula (9).

(In the formula, Ar4 represents a phenyl group or a biphenyl group.) The interface complex organic solar cell according to any one of claims 3 to 5, wherein the dicyanomethylene compound represented by the general formula (7) is represented by the following general formula (10).

(In the formula, n is 0, 1, or 2, and R represents an alkyl group) A method for producing an interfacial complex type organic solar cell, wherein the organic solar cell is a first electrode coated with an interfacial complex formed from dicyanomethylene and titanium oxide represented by the following general formula (1): A photoelectric conversion element comprising a second electrode facing one electrode, and an electrolyte layer between the first electrode and the second electrode, in a pressure range of 10 to 60 MPa and a temperature range of 35 to 150 ° C., The manufacturing method of the interface complex type organic solar cell characterized by including the process of forming the said interface complex compound under a critical carbon dioxide fluid.

(In the formula, X represents a substituted or unsubstituted divalent organic group.)

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