JP6111552B2 - Photoelectric conversion element and method for manufacturing photoelectric conversion element - Google Patents

Description

  The present invention relates to a method for manufacturing a photoelectric conversion element.

  In recent years, the importance of Taiyo Batteries 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, research and development of various low-cost solar cells are underway, and among them, dye-sensitized solar cells announced by Graetzel et al. Of Lausanne University of Technology in Switzerland are expected to be put into practical use (for example, (See Patent Literature 1, Non-Patent Literature 1, and Non-Patent Literature 2). This solar cell has a structure in which a porous metal oxide semiconductor is provided on a transparent conductive glass substrate, a dye adsorbed on the surface thereof, an electrolyte having a redox pair, 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.
Further, since the printing method can be applied to the element manufacturing method, it is expected that the manufacturing cost can be reduced because an expensive manufacturing facility is not required. However, this solar cell contains iodine and a volatile solvent, and has problems such as a decrease in power generation efficiency due to deterioration of the iodine redox system, and volatilization and leakage of the electrolyte.

In order to compensate for this drawback, the following completely solid dye-sensitized solar cell has been announced.
1) Using an inorganic semiconductor (for example, see Non-Patent Document 3 and Non-Patent Document 4)
2) A material using a low-molecular organic hole transport material (see, for example, Patent Document 2, Non-Patent Document 5, and Non-Patent Document 6)
3) Using conductive polymer (for example, see Patent Document 3 and Non-Patent Document 7)

  In the solar cell described in Non-Patent Document 3, copper iodide is used as a constituent material of the p-type semiconductor layer. It is known that a relatively good photoelectric conversion efficiency immediately after fabrication is halved in a few hours due to deterioration due to an increase in copper iodide crystal grains and the like. Therefore, in the solar cell described in Non-Patent Document 4, the crystallization of copper iodide is suppressed by adding imidazolinium thiocyanate, but this is not sufficient.

  A solid type solar cell using the organic hole transport material described in Non-Patent Document 5 has been reported by Hagen et al. And improved by Graetzel et al. (Non-Patent Document 6). In a solid-state solar cell using a triphenylamine compound described in Patent Document 2, a charge transport layer is formed by vacuum deposition of a triphenylamine compound. Therefore, the triphenylamine compound cannot reach the internal pores of the porous semiconductor, and only low conversion efficiency is obtained. In the example described in Non-Patent Document 6, a spiro-type hole transport material is dissolved in an organic solvent, and a composite of nanotitania particles and a hole transport material is obtained using spin coating. However, the optimum value of the nanotitania particle thickness in this solar cell is about 2 μm, which is very thin as compared with 10 to 20 μm when the element electrolyte is used. Therefore, the amount of the dye adsorbed on the titanium oxide is small, and it is difficult to perform sufficient light absorption and carrier generation, which does not reach the characteristics when using the electrolytic solution. The reason why the film thickness of the nanotitania particles remains at 2 μm is that the penetration of the hole transport material becomes insufficient as the film thickness increases.

In addition, as a solid-type solar cell using a conductive polymer, Osaka University Yanagida et al. Reported using polypyrrole (see Non-Patent Document 7). Also in these solar cells, the conversion efficiency is low, and the solid-type solar cell using the polythiophene derivative described in Patent Document 3 is a charge transfer layer using an electrolytic polymerization method on a porous titanium oxide electrode adsorbing a dye. However, there is a problem that the pigment is desorbed from titanium oxide or the pigment is decomposed. Further, the polythiophene derivative has a very problem in durability.
As a method for producing a titanium oxide layer in a dye-sensitized solar cell, a method of pressing a titanium oxide film has been reported from Hagfeld of Uppsala University or Arakawa of Tokyo University of Science. (See Non-Patent Document 8 and Patent Document 4). This is because the titanium oxide is pressed to generate necking between the particles, and the electron conduction can be performed smoothly without firing at a high temperature, both of which are film types using an iodine-based electrolyte. The solar cell was proposed for use.
As described above, none of the perfect solid-state photoelectric conversion elements that have been studied so far have been obtained with satisfactory characteristics.

  An object of the present invention is to solve the above-described problems, and to provide a complete solid-state photoelectric conversion element that is superior in long-term stability and excellent in productivity as compared with the prior art.

As a result of intensive studies to solve the above problems, it has been found that a high-performance photoelectric conversion element can be provided, and the present invention has been achieved.
The said subject is solved by this invention including the "photoelectric conversion element" and the "manufacturing method of a photoelectric conversion element" as described in the following (1)-(13) of this invention.
(1) “a first electrode coated with an electron transporting material; a second electrode facing the electron transporting material of the first electrode; an electron transporting material of the first electrode; and the second electrode A photoelectric conversion device comprising a hole transporting layer made of a hole transporting material in between, wherein the hole transporting material contains at least a compound represented by the following general formula (1).

(In the formula, X ₁ represents an oxygen atom, a sulfur atom, a selenium atom, or an alkylene group, and X ₂ represents an aryl ring group selected from the group consisting of an aromatic hydrocarbon or an unsaturated heterocyclic ring. D ₁ , D ₂ is an alkenyl group having 2 to 4 carbon atoms and an alkynyl group having 2 to 4 carbon atoms, which may have a substituent selected from the group consisting of an alkyl group, an alkoxy group, and an amino group , An aryl group selected from the group consisting of a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted unsaturated heterocyclic group, or 1 to 4 carbon atoms substituted with the aryl group Represents an alkyl group, an alkenyl group, or an alkynyl group, which may be target or asymmetric.

(2) “The compound represented by the general formula (1) is represented by the following general formula (2),” The photoelectric conversion element as described in the above item (1),

(In the formula, X ₁ represents an oxygen atom, a sulfur atom, a selenium atom, or an alkylene group, and X ₂ represents an aryl ring group selected from the group consisting of an aromatic hydrocarbon or an unsaturated heterocyclic ring. D ₁ , D ₂ is an alkenyl group having 2 to 4 carbon atoms and an alkynyl group having 2 to 4 carbon atoms, which may have a substituent selected from the group consisting of an alkyl group, an alkoxy group, and an amino group , An aryl group selected from the group consisting of a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted unsaturated heterocyclic group, or 1 to 4 carbon atoms substituted with the aryl group Represents an alkyl group, an alkenyl group, or an alkynyl group, which may be target or asymmetric.

(3) “The photoelectric conversion element according to (1) or (2) above, wherein the electron transporting material is an n-type oxide semiconductor”.
(4) Any one of the items (1) to (3), wherein the oxide semiconductor is selected from at least one of titanium oxide, zinc oxide, tin oxide, and niobium oxide. The photoelectric conversion element as described. "
(5) "The photoelectric conversion element according to any one of (1) to (4), wherein the hole transport layer contains at least one of a metal compound and an ionic liquid."
(6) “The photoelectric conversion element according to (5), wherein the ionic liquid is an imidazolinium compound-containing liquid.”
(7) Any of the above (1) to (6), wherein the hole transport layer is laminated with materials having different molecular weights, and the hole transport material close to the second electrode side is a polymer material The photoelectric conversion element according to the above. "
(8) “The photoelectric conversion element according to any one of (1) to (7), wherein the electron transporting compound is coated with a photosensitizer”.
(9) "The photoelectric conversion element according to any one of (1) to (8) above, wherein a metal oxide is present between the hole transport layer and the second electrode."
(10) The method according to (10), wherein the hole transporting material is provided on the first electrode coated with the electron transporting material, and then is subjected to a pressing process. The photoelectric conversion element according to any one of items 1) to (9). "
The present invention also includes the following “photoelectric conversion element” and “photoelectric conversion element manufacturing method”.
(11) “The photoelectric conversion element according to (9), wherein the metal oxide layer contains molybdenum oxide.”
(12) “The metal compound is one or more of a metal halide, a metal thiocyanide, and an amidated metal, or any one of the above (5) to (9), or (11 ) The photoelectric conversion element according to the item.
(13) “a first electrode coated with an electron transporting material, a second electrode facing the electron transporting material of the first electrode, an electron transporting material of the first electrode, and the second electrode In the method of manufacturing a photoelectric conversion element having a hole transport layer made of a hole transport material between the hole transport compound, the hole transport compound contains at least a compound represented by the following general formula (1), and the electron transport: A process for producing a photoelectric conversion element comprising a step of pressing a hole transporting material after the hole transporting material is provided on the first electrode coated with the conductive material:

(In the formula, X ₁ represents an oxygen atom, a sulfur atom, a selenium atom, or an alkylene group, and X ₂ represents an aryl ring group selected from the group consisting of an aromatic hydrocarbon or an unsaturated heterocyclic ring. D ₁ , D ₂ is an alkenyl group having 2 to 4 carbon atoms and an alkynyl group having 2 to 4 carbon atoms, which may have a substituent selected from the group consisting of an alkyl group, an alkoxy group, and an amino group , An aryl group selected from the group consisting of a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted unsaturated heterocyclic group, or 1 to 4 carbon atoms substituted with the aryl group Represents an alkyl group, an alkenyl group, or an alkynyl group, which may be target or asymmetric.

According to the present invention, by providing a specific hole transport material on the first electrode, it is possible to provide a complete solid-state photoelectric conversion element having excellent long-term stability and excellent productivity. Furthermore, it is possible to obtain a photoelectric conversion element having good characteristics by performing a press treatment after providing the specific hole transport material.
That is, more specifically, the photoelectric conversion element having excellent cost performance and good conversion efficiency is provided by the configurations (1) to (2) and (8) to (11) of the present invention. According to the configurations of (5) to (7) and (12), the hole transport of the hole transport layer becomes efficient, and a photoelectric conversion element exhibiting further excellent conversion efficiency is provided. (3), (4) With this configuration, by using an n-type oxide semiconductor in the electron transport layer, electron transfer becomes efficient, and a photoelectric conversion element that exhibits further excellent conversion efficiency is provided.

It is the schematic of an example showing the structure of the photoelectric conversion element which concerns on this invention. It is the schematic of another example showing the structure of the photoelectric conversion element which concerns on this invention. 4 is a graph showing an IR spectrum of an exemplary compound (A-03) in Synthesis Example 1. FIG. 4 is a graph showing an IR spectrum of an exemplary compound (A-04) in Synthesis Example 1. FIG. 6 is a graph showing an IR spectrum of an exemplary compound (A-06) in Synthesis Example 1. FIG. 4 is a graph showing an IR spectrum of an exemplary compound (A-21) in Synthesis Example 1. FIG.

The present invention will be described in detail below.
The structure of the photoelectric conversion element will be described with reference to FIGS.
1 and 2 are cross-sectional views of the photoelectric conversion element.
In the embodiment shown in FIG. 1, an electrode (3) is provided on a substrate (1), an electron transport layer (5) comprising a dense electron transport layer (6), a granular electron transport layer (7), and then the first A hole transport layer (8) composed of one hole transport material layer (9) and a second hole transport material layer (10) which is a polymer material is laminated, and a metal oxide layer (11), an electrode (3), The substrate (1) is sequentially provided.
In the embodiment shown in FIG. 2, the first electrode (3) is provided on the first substrate (1), and the electron transport layer comprises a dense electron transport layer (6) and a granular electron transport layer (7). (5) Next, a hole transport layer (8) comprising a first hole transport material layer (9) and a second hole transport material layer (10) which is a polymer is laminated, and an electrode (3) and a substrate (1) Are sequentially provided.
A photoelectric conversion element generally comprises an electron collector electrode, an electron acceptor / electron transport layer (hereinafter simply referred to as an electron transport layer), an electron donor / hole transport layer (hereinafter simply referred to as a hole transport layer), and a hole current collector electrode. Is done.

<Electronic current collecting electrode>
The first electrode used in the present invention, that is, the electron collecting electrode (3) is not particularly limited as long as it is a conductive material transparent to visible light, and is a normal photoelectric conversion element or liquid crystal. The well-known thing used for a panel etc. 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 electron collector electrode is preferably 5 nm to 100 μm, more preferably 50 nm to 10 μm.
In addition, the electron collector 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. .
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 used. Is 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, a metal lead wire or the like may be used for the purpose of reducing the resistance of the substrate (1).
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>
The photoelectric conversion element of this invention forms the thin film which consists of semiconductors as an electron carrying layer (5) on said electron current collection electrode (3).
The electron transport layer (5) is a laminate in which a dense electron transport layer (6) is formed on the electron collecting electrode (3), and further a granular and porous electron transport layer (7) is formed thereon. A structure is preferred.
The dense electron transport layer (6) is formed for the purpose of preventing electronic contact between the electron collecting electrode (3) and the hole transport layer (8). Therefore, if the electron current collecting electrode and the hole transport layer 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, 10 nm-1 micrometer are preferable and 20 nm-700 nm are more preferable.
The “dense” of the electron transport layer (6) 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 (7).
The porous electron transport layer (7) formed on the dense electron transport layer (6) 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, acetic acid, polyoxyethylene (10) octylphenyl ether, etc. 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 order to further improve the light conversion efficiency, it is preferable to adsorb the photosensitizing compound (12) on the electron transport layer.
The photosensitizing compound (12) is not particularly limited as long as it is a compound that is photoexcited by the excitation light used, and specific examples thereof include the following compounds.
The metal complex compounds described in JP 7-500630 A, JP 10-233238 A, JP 2000-26487 A, JP 2000-323191 A, JP 2001-59062 A, etc. 10-93118, JP-A No. 2002-164089, JP-A No. 2004-95450, J. Phys. Chem. C, 7224, Vol. 111 (2007), and the like. No. 95450, Chem. Commun., 4887 (2007), etc., JP 2003-264010 A, JP 2004-63274 A, JP 2004-115636 A, JP 2004-200068 A. J. Am. Chem. Soc., 12218, Vol. 126 (2004), Chem. Commun., 3036 (2003), Angew. Chem. Int. Ed., 1923, Vol. 47 (2008) etc. Compounds, J. Am. Chem. Soc., 16701, Vol. 128 (2006), thiophene compounds described in J. Am. Chem. Soc., 14256, Vol. 128 (2006), etc., JP-A-11-86916 Cyanine dyes described in JP-A-11-214730, JP-A-2000-106224, JP-A-2001-76773, JP-A-2003-7359, etc., JP-A-11-214731, Merocyanine dyes described in Kaihei 11-238905, JP-A-2001-52766, JP-A-2001-76775, JP-A-2003-7360, etc., JP-A-10-92477, JP-A-11-273754 , 9-arylxanthene compounds described in JP-A-11-273755, JP-A-2003-3273, etc., JP-A-10-93118, JP-A-2003-31273, etc. The described triarylmethane compounds, JP-A-9-199744, JP-A-10-233238, JP-A-11-204821, JP-A-11-265738, J. Phys. Chem., 2342, Vol.91 (1987), J. Phys. Chem. B, 6272, Vol. 97 (1993), Electroanal. Chem., 31, Vol. 537 (2002), JP 2006-032260, J. Porphyrins Phthalocyanines, 230, Examples include phthalocyanine compounds and porphyrin compounds described in Vol. 3 (1999), Angew. Chem. Int. Ed., 373, Vol. 46 (2007), Langmuir, 5436, Vol. 24 (2008), etc. .
Among these, it is particularly preferable to use metal complex compounds, coumarin compounds, polyene compounds, indoline compounds, and thiophene compounds.

As a method of adsorbing the photosensitizing compound (12) to the electron transport layer (7), a method of immersing an electron current collecting electrode containing semiconductor fine particles in a photosensitizing compound solution or dispersion, solution or dispersion Can be applied to the electron transport layer and adsorbed onto the electron transport layer.
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.
Further, it may be adsorbed in a supercritical fluid using carbon dioxide or the like.

When adsorbing the photosensitizing compound, a condensing agent may be used in combination.
The condensing agent has a catalytic action that seems to physically or chemically bond the photosensitizing compound and the electron transport compound to the inorganic surface, or acts stoichiometrically to favorably shift the chemical equilibrium. Either may be sufficient.
Furthermore, a thiol or a hydroxy compound may be added as a condensation aid.
Solvents for dissolving or dispersing the photosensitizing compound are water, methanol, ethanol, alcohol solvents such as isopropyl alcohol, ketone solvents such as acetone, methyl ethyl ketone, or methyl isobutyl ketone, ethyl formate, ethyl acetate, or acetic acid. Ester solvents such as n-butyl, ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone Amido solvents, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromoben Halogenated hydrocarbon solvents such as ethylene, iodobenzene or 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o Examples include hydrocarbon solvents such as -xylene, m-xylene, p-xylene, ethylbenzene, and cumene, and these can be used alone or as a mixture of two or more.

In addition, depending on the type of photosensitizing compound, there are compounds that work more effectively when aggregation between the compounds is suppressed, and therefore, an aggregation dissociator may be used in combination.
The aggregating / dissociating agent is preferably a steroid compound such as cholic acid or chenodeoxycholic acid, a long-chain alkyl carboxylic acid or a long-chain alkyl phosphonic acid, and is appropriately selected according to the dye used. The addition amount of these aggregating and dissociating agents is preferably 0.01 to 500 parts by mass, more preferably 0.1 to 100 parts by mass with respect to 1 part by mass of the dye.
The temperature at which these are used to adsorb the photosensitizing compound or the photosensitizing compound and the aggregation / dissociation agent is preferably −50 ° C. or more and 200 ° C. or less.
Moreover, this adsorption may be carried out while standing or stirring.
Examples of the stirring method include, but are not limited to, a stirrer, a ball mill, a paint conditioner, a sand mill, an attritor, a disperser, and ultrasonic dispersion.
The time required for adsorption is preferably 5 seconds or more and 1000 hours or less, more preferably 10 seconds or more and 500 hours or less, and further preferably 1 minute or more and 150 hours.
Adsorption is preferably performed in a dark place.

<Hole transport layer>
The hole transport layer (8) in the present invention preferably contains at least the compound represented by the general formula (1). A single layer structure made of a single material or a laminated structure made of a plurality of types of materials may be used. In the case of a laminated structure, at least the compound represented by the general formula (1) is used for the hole transport material layer (9) close to the first electrode (3), and the hole transport material layer close to the second electrode (4) It is preferable to use a polymer material for (10). By using a polymer material excellent in film forming property, the porous (granular) electron transport layer (7) and the hole transport material layer (9) contact surface (generated in the electron transport layer (7) and collected. The contact portion with the hole transport material layer (9) can be further smoothed without reducing the area of the pn junction for excitons (excitons) to be divided into electrons and holes, and the photoelectric conversion characteristics can be improved. It is because it can improve. In addition, since it is difficult for the polymer to penetrate into the porous electron transport layer, it is excellent in covering the surface of the porous electron transport layer, and also effective in preventing a short circuit when an electrode is provided. As a result, higher performance can be obtained.

As the hole transport material in the present invention, the compound represented by the general formula (1) is used as described above. In the general formula (1), X ₁ represents an oxygen atom, a sulfur atom, a selenium atom or an alkylene group, and X ₂ represents an aromatic hydrocarbon or a heterocyclic ring. The aromatic hydrocarbon or heterocycle is preferably a 5- to 6-membered ring. The heterocycle is preferably an unsaturated heterocycle (in other words, the aromatic hydrocarbon or heterocycle is an aryl ring).
D ₁ and D ₂ are each a C2-C4 alkenyl group or alkynyl group optionally substituted with any of an alkyl group, an alkoxy group, and an amino group, an aromatic hydrocarbon or a heterocyclic ring, preferably an unsaturated heterocyclic ring (that is, , An aromatic hydrocarbon or a heterocycle is preferably an aryl group), a C1-C4 alkyl group, an alkenyl group or an alkynyl group substituted with the aryl group, which may be target or asymmetric.
Specific examples of X ₁ include an oxygen atom, a sulfur atom, a selenium atom, an alkylene group such as 1,2-ethylene and 2,3-butylene, and specific examples of X ₂ include a thiophene ring and a furan ring. A hetero 5-membered ring such as a hetero 6-membered ring such as a pyridine ring, and an aromatic hydrocarbon such as a benzene ring. Specific examples of D ₁ and D ₂ include aromatic hydrocarbon ring groups such as benzene ring and naphthalene ring, aralkyl groups such as benzyl group and styryl group, hetero rings such as thiophene ring and thionothiophene ring. And may have a substituent. Specific examples of the substituent are vinylene, acetylene, methyl group, ethyl group, isopropyl group, alkyl group such as n-hexyl group, alkoxy group such as methoxy group and 2-ethylhexyloxy group, dimethylamino group, diethylamino group And amino groups such as a diphenylamino group.

  Although the specific exemplary compound of this invention shown to General formula (1) below is described, it is not limited to these at all.

These 4,7-diaryl-substituted-benzo-2,1,3-thiadiazoles as some examples of the compound of the general formula (1) used in the present invention are described in the following documents, for example. (1) Adv. Mater., Vol.18, pp.2884 (2006). (2) Adv. Funct. Mater., Vol.16, pp.667-674 (2006).
Further, it may be synthesized by a synthesis method as described below [J. Am. Chem. Soc., Vol.130, pp.732-742 (2008)] (not limited to these). it can.

(Other hole transport layer materials)
As the polymer material used for the hole transport layer (10) close to the second electrode (4) used in the laminated structure, a known hole transport polymer material is used, and specific examples thereof include poly (3- n-hexylthiophene), poly (3-n-octyloxythiophene), poly (9,9′-dioctyl-fluorene-co-bithiophene), poly (3,3 ′ ″-didodecyl-quarterthiophene), poly ( 3,6-dioctylthieno [3,2-b] thiophene), poly (2,5-bis (3-decylthiophen-2-yl) thieno [3,2-b] thiophene), poly (3,4- Didecylthiophene-co-thieno [3,2-b] thiophene), poly (3,6-dioctylthieno [3,2-b] thiophene-co-thieno [3,2-b] thiophene), poly (3 , Polythiophene compounds such as 6-dioctylthieno [3,2-b] thiophene-co-thiophene), poly (3.6-dioctylthieno [3,2-b] thiophene-co-bithiophene), poly [2-methoxy- 5- (2-ethylhexyloxy) -1,4-phenylenevinylene], poly [2-methoxy-5- (3,7-dimethyloctyloxy) -1,4-phenylenevinylene], poly [(2-methoxy- 5- (2-ethylphenyloxy) -1,4-phenylenevinylene) -co- (4,4′-biphenylene-vinylene)] and other polyphenylene vinylene compounds, poly (9,9′-didodecylfluorenyl) -2,7-diyl), poly [(9,9-dioctyl-2,7-divinylenefluorene) -alt-co- (9,10-anthracene)], poly [ 9,9-dioctyl-2,7-divinylenefluorene) -alt-co- (4,4′-biphenylene)], poly [(9,9-dioctyl-2,7-divinylenefluorene) -alt-co -(2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene)], poly [(9,9-dioctyl-2,7-diyl) -co- (1,4- (2,5 -Difluoryloxy) benzene)] and the like, poly [2,5-dioctyloxy-1,4-phenylene], poly [2,5-di (2-ethylhexyloxy-1,4-phenylene] and the like Polyphenylene compound, poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (N, N′-diphenyl) -N, N′-di (p-hexylphenyl) -1, 4-Diaminobenzene] , Poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (N, N′-bis (4-octyloxyphenyl) benzidine-N, N ′-(1,4- Diphenylene)], poly [(N, N′-bis (4-octyloxyphenyl) benzidine-N, N ′-(1,4-diphenylene)], poly [(N, N′-bis (4- (2 -Ethylhexyloxy) phenyl) benzidine-N, N '-(1,4-diphenylene)], poly [phenylimino-1,4-phenylenevinylene-2,5-dioctyloxy-1,4-phenylenevinylene-1, 4-phenylene], poly [p-tolylimino-1,4-phenylenevinylene-2,5-di (2-ethylhexyloxy) -1,4-phenylenevinylene-1,4-phenylene], poly [4- (2 -Echi Hexyloxy) phenylimino-1,4-biphenylene] and other polyarylamine compounds, poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (1,4-benzo (2 , 1 ′, 3) thiadiazole], poly (3,4-didecylthiophene-co- (1,4-benzo (2,1 ′, 3) thiadiazole) and the like. Of these, polythiophene compounds and polyarylamine compounds are particularly preferred in consideration of carrier mobility and ionization potential, and they can be used alone or as a mixture of two or more.

Moreover, in the photoelectric conversion element of this invention, you may add various additives to the hole transport compound shown above.
Additives include iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, silver iodide and other metal iodides, tetraalkylammonium iodide, Quaternary ammonium salts such as pyridinium iodide, metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide and calcium bromide, quaternary ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide Metal chlorides such as bromine salts, copper chloride and silver chloride, metal acetates such as copper acetate, silver acetate and palladium acetate, metal sulfates such as copper sulfate and zinc sulfate, ferrocyanate-ferricyanate, ferrocene -Sulfur compounds such as metal complexes such as ferricinium ions, sodium polysulfide, alkylthiol-alkyl disulfides Viologen dye, hydroquinone, 1,2-dimethyl-3-n-propylimidazolinium iodide, 1-methyl-3-n-hexylimidazolinium iodide, 1,2-dimethyl-3-ethylimidazo 1-methyl-3-butylimidazolium nonafluorobutylsulfonate, 1-methyl-3-ethylimidazolium bis (trifluoromethyl) sulfonylimide, 1-methyl-3-n- Ionic liquids such as hexylimidazolium bis (trifluoromethyl) sulfonylimide, 1-methyl-3-n-hexylimidazolium dicyanamide, basic compounds such as pyridine, 4-t-butylpyridine and benzimidazole, lithium trifluoromethane Sulfonylimide, lithium diisopropylimi Lithium compounds such can be mentioned. Among these, an ionic liquid having a bis (trifluoromethyl) sulfonylimide anion is particularly preferable. These additives can be used alone or as a mixture of two or more.

In the photoelectric conversion element of the present invention, an acceptor material may be further added as necessary in addition to the hole transport compound and various additives described above.
Acceptor materials include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5 , 7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzo Examples include thiophene-5,5-dioxide and diphenoquinone derivatives. These acceptor materials can be used alone or as a mixture of two or more.

Moreover, you may add the oxidizing agent for making a part of hole transport compound into a radical cation for the purpose of improving electroconductivity.
Examples of the oxidizing agent include tris (4-bromophenyl) aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluorate, and silver nitrate.
It is not necessary for all hole transport materials to be oxidized by the addition of the oxidizing agent, and only a part of the hole transporting material needs to be oxidized. The added oxidizing agent may be taken out of the system after the addition or may not be taken out.

The hole transport layer (8) forms the hole transport layer (9, 10) directly on the electron transport layer (7) carrying the photosensitizing compound.
There is no restriction | limiting in particular in the preparation methods of a hole transport layer, The method of forming a thin film in vacuum, such as vacuum deposition, and the wet film forming method are mentioned.
In consideration of the manufacturing cost and the like, a wet film forming method is particularly preferable, and a method of coating on the electron transport layer is preferable. Solvents that dissolve or disperse the hole transporting compound and various additives when using the wet film-forming method include 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 solvent, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, or 1 Halogenated hydrocarbon solvents such as chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p -A hydrocarbon solvent such as xylene, ethylbenzene, or cumene can be used, and these can be used singly or as a mixture of two or more. The coating method in wet film formation is not particularly limited, and is according to a known method. Can be done. 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. Alternatively, the film may be formed in a supercritical fluid or a subcritical fluid.

As a supercritical fluid, it exists as a non-aggregating high-density fluid in a temperature and pressure range that exceeds the limit (critical point) at which gas and liquid can coexist, and does not aggregate even when compressed. The fluid is not particularly limited as long as it is in the above state, and can be appropriately selected according to the purpose. However, a fluid having a low critical temperature is preferable.
This supercritical fluid includes, for example, carbon monoxide, carbon dioxide, ammonia, nitrogen, water, methanol, ethanol, ercol solvents such as n-butanol, ethane, propane, 2,3-dimethylbutane, benzene, toluene and the like. Hydrocarbon solvents, halogen solvents such as methylene chloride and chlorotrifluoromethane, and ether solvents such as dimethyl ether are preferred.
Among these, carbon dioxide is particularly preferable because it has a critical pressure of 7.3 MPa and a critical temperature of 31 ° C., so that it can easily create a supercritical state and is nonflammable and easy to handle.
These fluids may be used alone or in combination of two or more.
The subcritical fluid is not particularly limited as long as it exists as a high-pressure liquid in the temperature and pressure regions near the critical point, and can be appropriately selected according to the purpose.
The compound mentioned as a supercritical fluid mentioned above can be used conveniently also as a subcritical fluid.
The critical temperature and critical pressure of the supercritical fluid are not particularly limited and can be appropriately selected according to the purpose. However, the critical temperature is preferably −273 ° C. or more and 300 ° C. or less, particularly 0 ° C. or more and 200 ° C. or less. preferable.

Furthermore, in addition to the above supercritical fluid and subcritical fluid, an organic solvent or an entrainer can be used in combination.
By adding an organic solvent and an entrainer, the solubility in the supercritical fluid can be adjusted more easily.
Such an organic solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 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 diisopropyl 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, bromobenzene, iodobenzene Is a halogenated hydrocarbon solvent such as 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m- Examples thereof include hydrocarbon solvents such as xylene, p-xylene, ethylbenzene, and cumene.

In the present invention, after the hole transport material is provided on the first electrode provided with the electron transport material coated with the photosensitizing compound, the press treatment step is performed. By performing this press treatment, the hole transport material is more closely attached to the porous electrode, so that the efficiency is improved.
Although there is no restriction | limiting in particular in a press processing method, The roll press method using the press molding method using a flat plate represented by IR tablet shaper, a roller, etc. can be mentioned. The pressure is preferably 10 kgf / cm ² or more, more preferably 30 kgf / cm ² or more. Although there is no restriction | limiting in particular in the time to press-process, It is preferable to carry out within 1 hour. Further, heat may be applied during the pressing process.
Further, a release material may be sandwiched between the press and the electrode. Release materials include polytetrafluoroethylene, polychlorotrifluoride ethylene, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkoxy fluoride resin, polyvinylidene fluoride, ethylene tetrafluoride ethylene copolymer, ethylene chloro Fluorine resins such as ethylene trifluoride copolymer and polyvinyl fluoride can be mentioned.

  In the present invention, the element may be formed by forming the mixed layer of the electron transporting material and the hole transporting material on the first electrode and then performing the above-described press treatment. In the step of forming the mixed layer on the first electrode, the electron transporting compound and the hole transporting compound are dissolved or dispersed in water or an organic solvent and formed by the above-described wet film forming method. At this time, it is preferable to mix the photosensitizing compound in a solution or dispersion of the electron transporting compound and the hole transporting compound.

  After performing the said press processing process, you may provide a metal oxide between a hole transport compound and a 2nd electrode before providing a counter electrode. Examples of the metal oxide that may be provided include molybdenum oxide, tungsten oxide, vanadium oxide, and nickel oxide, and molybdenum oxide is particularly preferable.

<Hall current collector electrode>
There is no restriction | limiting in particular as a method of providing these metal oxides on a hole transport material, The method of forming a thin film in vacuum, such as sputtering and vacuum evaporation, and the wet film-forming method can be mentioned.
In the wet film forming method, it is preferable to prepare a paste in which a metal oxide powder or sol is dispersed and apply the paste onto the hole transport layer.
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. The film thickness is preferably from 0.1 to 50 nm, more preferably from 1 to 10 nm.

The hole collecting electrode is newly applied after the hole transport layer is formed or on the metal oxide.
In addition, the hole collecting electrode can be usually the same as the above-described electron collecting electrode, and the support is not necessarily required in a configuration in which the strength and the sealing performance are sufficiently maintained.
Specific examples of the hole collector electrode material include metals such as platinum, gold, silver, copper, and aluminum, carbon compounds such as graphite, fullerene, carbon nanotube, and graphene, and conductive metal oxides such as ITO, FTO, and ATO. , Conductive polymers such as polythiophene and polyaniline.
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 can be used as long as it has conventionally used a solar cell or a power supply device using the solar cell.
For example, although it may be used for an electronic desk calculator or a solar cell for a wristwatch, examples of utilizing the characteristics of the photoelectric conversion element of the present invention include power supply devices 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 of hole transport material used in the present invention>
[Synthesis Example 1]
(Synthesis of Exemplary Compound (A-03))

  2-n-butyl-5-tributylstannylthiophene (3.21 g), 4,7-dibromo-2,1,3-benzothiodiazole (1.0 g), palladium acetate (1.5 mg), cataCXium- A (5.3 mg) and xylene (30 ml) were placed in a flask and reacted at 120 ° C. under a nitrogen stream. After 1.5 hours, the reaction was stopped and cooled to room temperature. Purification by silica gel column chromatography (solvent: n-hexane / methylene chloride = 5/1) gave 0.88 g of the desired product. Yield 62.9%. Melting point 50.5-52.0 ° C. The IR spectrum of the obtained compound is shown in FIG.

(Synthesis of Exemplary Compound (A-04))

  2-n-hexyl-5-tributylstannylthiophene (3.42 g), 4,7-dibromo-2,1,3-benzothiodiazole (1.0 g), palladium acetate (1.5 mg), cataCXium- A (5.3 mg) and xylene (30 ml) were placed in a flask and reacted at 120 ° C. under a nitrogen stream. After 1.5 hours, the reaction was stopped and cooled to room temperature. Purification by silica gel column chromatography (solvent: n-hexane / methylene chloride = 5/1) gave 1.22 g of the desired product. Yield 76.5%. Melting point 75.0-76.0 ° C. The IR spectrum of the obtained compound is shown in FIG.

(Synthesis of Exemplified Compound (A-06))

  2-n-octyl-5-tributylstannylthiophene (3.65 g), 4,7-dibromo-2,1,3-benzothiodiazole (1.0 g), palladium acetate (1.5 mg), cataCXium- A (5.3 mg) and xylene (30 ml) were placed in a flask and reacted at 120 ° C. under a nitrogen stream. After 1.5 hours, the reaction was stopped and cooled to room temperature. Purification by silica gel column chromatography (solvent: n-hexane / methylene chloride = 5/1) gave 1.15 g of the desired product. Yield 64.6%. Melting point 50.5-52.0 ° C. The IR spectrum of the obtained compound is shown in FIG.

(Synthesis of Exemplary Compound (A-21))

  1-n-hexyl-5-bromoindole (2.88 g), 4,7-bis (4,4,5,5-tetramethyll-1,3,2-dioxaborolan-2-yl) -2,1, 3-Benzothiadiazole (1.33 g), palladium acetate (7.7 mg), Degussa cataCXium-A (27.1 mg), potassium-t-butoxide (0.96 g), xylene (30 ml) were placed in a flask, under a nitrogen stream, The reaction was performed at 120 ° C. After 3 hours, the reaction was stopped and cooled to room temperature. Purification by silica gel column chromatography (solvent: n-hexane / methylene chloride = 5/1) gave 360 mg of the desired product. Yield 19.6%. Amorphous. The IR spectrum of the obtained compound is shown in FIG.

[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.
Bead mill treatment with 3 g of titanium oxide (ST-21 manufactured by Ishihara Sangyo Co., Ltd.), 0.2 g of acetylacetone, and 0.3 g of surfactant (polyoxyethylene octylphenyl ether manufactured by Wako Pure Chemical Industries, Ltd.) together with 5.5 g of water and 1.0 g of ethanol For 12 hours.
1.2 g of polyethylene glycol (# 20,000) was added to the obtained dispersion to prepare a paste.
This paste was applied onto the dense electron transport layer so as to have a film thickness of 2 μm, dried at room temperature, and then baked in air at 500 ° C. for 30 minutes to form a porous electron transport layer.

(Preparation of photoelectric conversion element)
The titanium oxide semiconductor electrode is immersed in D358 (0.5 mM, acetonitrile / t-butanol (volume ratio 1: 1) solution) manufactured by Mitsubishi Paper Industries as a sensitizing dye, and allowed to stand for 1 hour in a dark place. Was adsorbed.
A chlorobenzene (solid content: 10%) solution in which the exemplified compound (A-03) is dissolved on a semiconductor electrode carrying a photosensitizer is added to trifluoromethanesulfonylimide lithium (27 mM), 4-t-butylpyridine (0.11M). ) Was formed on a semiconductor electrode carrying a photosensitizer by spin coating and air-dried.
Furthermore, a solution obtained by adding lithium bis (trifluoromethanesulfonyl) imide (27 mM) to chlorobenzene (2% solids) in which poly (3-n-hexylthiophene) manufactured by Aldrich was dissolved was added to the hole transport layer. About 100 nm was formed by spray coating. Gold was vacuum-deposited thereon with a thickness of 100 nm to produce a photoelectric conversion element.

(Evaluation of photoelectric conversion element)
The photoelectric conversion efficiency of the obtained photoelectric conversion element under simulated sunlight irradiation (AM1.5, 100 mW / cm ² ) was measured. The simulated solar light was measured with a solar simulator SS-80XIL manufactured by Eiko Seiki, and the evaluation equipment was measured with a solar cell evaluation system As-510-PV03 manufactured by NF Circuit Design Block. As a result, the excellent characteristics of an open circuit voltage = 0.92 V, a short-circuit current density of 4.0 mA / cm ² , a form factor = 0.60, and a conversion efficiency = 2.21% were exhibited.

[Example 2]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 3]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 4]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[ Reference Example 5]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 6]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 7]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 8]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 9]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 10]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 11]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 12]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 13]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 14]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

[Example 15]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown in Table 1. The results are shown in Table 2.

As is apparent from Table 2, it can be seen that all the hole transport compounds exhibit good characteristics. Among these, the exemplified compound (A-21) showed particularly good characteristics.

[Comparative Example 1]
A photoelectric conversion element was produced and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown below. The results are shown in Table 3.

[Comparative Example 2]
A photoelectric conversion element was produced and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown below. The results are shown in Table 3.

[Comparative Example 3]
A photoelectric conversion element was produced and evaluated in the same manner as in Example 1 except that the hole transport material in Example 1 was changed to the hole transport material shown below. The results are shown in Table 3.

From Table 3, it is clear that the characteristics are low as compared with the hole transport material of the present invention.

[Example 16]
A photoelectric conversion element was obtained in the same manner as in Example 1 except that lithium bis (trifluoromethanesulfonyl) imide in Example 1 was changed to 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide. Prepared and evaluated. As a result, the excellent characteristics of an open circuit voltage = 0.94 V, a short circuit current density of 3.88 mA / cm ² , a form factor = 0.61, and a conversion efficiency = 2.22% were exhibited.

[Example 17]
A photoelectric conversion element was prepared in the same manner as in Example 1 except that lithium bis (trifluoromethanesulfonyl) imide in Example 1 was changed to 1-ethyl-3-methylimidazolinium bis (pentafluoroethylsulfonyl) imide. ,evaluated. As a result, the excellent characteristics of an open circuit voltage = 0.92 V, a short circuit current density of 4.11 mA / cm ² , a form factor = 0.60, and a conversion efficiency = 2.26% were exhibited.

[Example 18]
Lithium bis (trifluoromethanesulfonyl) imide in Example 1 was changed to 1-ethyl-3-methylimidazolinium bis (pentafluoroethylsulfonyl) imide / lithium bis (trifluoromethanesulfonyl) imide (weight ratio = 1/1). A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except for the change. As a result, the excellent characteristics of an open circuit voltage = 0.92 V, a short circuit current density of 4.14 mA / cm ² , a form factor = 0.63, and a conversion efficiency = 2.40% were exhibited.

[Example 19]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example 1 except that lithium bis (trifluoromethanesulfonyl) imide in Example 1 was changed to lithium perchlorate. As a result, excellent characteristics of an open-circuit voltage = 0.90 V, a short-circuit current density of 3.98 mA / cm ² , a form factor = 0.61, and a conversion efficiency = 2.19% were exhibited.

  As apparent from the above, it can be seen that the photoelectric conversion element of the present invention exhibits excellent photoelectric conversion characteristics.

1 substrate 2 substrate 3 first electrode 4 second electrode 5 electron transport layer 6 dense electron transport layer 7 granular electron transport layer 8 hole transport layer 9 first hole transport layer 10 second hole transport layer (high Molecular)
11 Metal oxide layer 12 Photosensitizing compound 13 Lead line 14 Lead line

Japanese Patent No. 2664194 Japanese Patent Laid-Open No. 11-144773 JP 2000-106223 A WO07 / 100095 publication

Nature, 353 (1991) 737 J. Am. Chem. Soc., 115 (1993) 6382 Semicond. Sci. Technol., 10 (1995) 1689 Electrochemistry, 70 (2002) 432 Synthetic Metals, 89 (1997) 215 Nature, 398 (1998) 583 Chem. Lett., (1997) 471 Nano. Lett., 1 (2001) 97

Claims (10)

A first electrode electron transporting material is coated, a second electrode facing the electron transporting material of the first electrode, between the electron-transporting material and the second electrode of the first electrode in the photoelectric conversion element provided with the hole transport layer comprising a hole transporting material, the hole transporting material, the following structural formulas (a-03), the structural formula (a-04), the structural formula (a-06), Structural formula (A-10), structural formula (A-21), structural formula (A-24), structural formula (A-31), structural formula (A-37), structural formula (A-43), structural formula At least a compound represented by any one of (A-47), structural formula (A-49), structural formula (A-55), structural formula (A-60), and structural formula (A-66) The photoelectric conversion element characterized by the above-mentioned.
The photoelectric conversion element according to claim 1, wherein the hole transporting material contains at least a compound represented by the structural formula (A-21).   The photoelectric conversion element according to claim 1, wherein the electron transporting material is an n-type oxide semiconductor. The photoelectric conversion element according to claim 3 , wherein the n-type oxide semiconductor is selected from at least one of titanium oxide, zinc oxide, tin oxide, and niobium oxide. The hole transport layer, a photoelectric conversion device according to any one of claims 1 to 4, characterized in that it contains at least one of a metal compound or an ionic liquid. The photoelectric conversion element according to claim 5, wherein the ionic liquid is an imidazolinium compound-containing liquid. The said hole transport layer is laminated | stacked by the material from which molecular weight differs, The other hole transport material near the said 2nd electrode side is a polymeric material, The one in any one of Claim 1 thru | or 6 characterized by the above-mentioned. Photoelectric conversion element. The photoelectric conversion element according to claim 1, wherein the electron transporting material is coated with a photosensitizer. The photoelectric conversion element according to any one of claims 1 to 8, wherein a metal oxide is present between the hole transport layer and the second electrode. It is a manufacturing method of the photoelectric conversion element according to any one of claims 1 to 9,
After the hole transporting material in the electron transporting material is coated the over the first electrode is provided, the method of manufacturing the photoelectric conversion element you characterized and this includes the step to be pressing.