JP2015002001A - Photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a complete solid state dye sensitized solar cell having high conversion efficiency and excellent productivity.SOLUTION: A photoelectric conversion element includes: a first electrode; an electron transport layer; a hole transport layer; and a second electrode. The hole transport layer has a polymer derived from a vinyl compound expressed by the following general formula (1). (where, Ar represents an aryl group which may have a substituent). The hole transport layer includes ion liquid containing an imidazolium compound. The electron transport layer contains at least one selected from a group of TiO, ZnO, NbO, and a tin oxide.

Description

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

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, 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 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.

  In addition, since the printing method can be applied to the device manufacturing method, it is expected that the manufacturing cost can be reduced because expensive manufacturing equipment 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 Documents 3 and 4)
(2) A material using a low-molecular organic hole transport material (see, for example, Patent Document 2, Non-Patent Documents 5 and 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 of (1), 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 dye-sensitized solar cell using the organic hole transport material described in Non-Patent Document 5 of (2) has been reported by Hagen et al. And improved by Graetzel et al. (Non-Patent Document 6). In a solid-state dye-sensitized solar cell using a triphenylamine compound described in Patent Document 2, a triphenylamine compound is vacuum-deposited to form a charge transport layer. 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 compared to 10 to 20 μm when using an iodine electrolyte. 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, and the characteristics when using the electrolytic solution are not achieved. 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-state solar cell of the type (3) 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 dye-sensitized solar cell using the polythiophene derivative described in Patent Document 3 uses an electrolytic polymerization method on a porous titanium oxide electrode adsorbing the dye. Although the charge transfer layer is provided, there is a problem that the dye is desorbed from titanium oxide or the dye is decomposed. Further, the polythiophene derivative has a very problem in durability.

In addition to dye-sensitized solar cells, organic thin-film solar cells have been actively studied in recent years as solar cells using organic semiconductor materials. This organic thin film solar cell is a pn junction solar cell using a p-type organic semiconductor and an n-type organic semiconductor. This solar cell is based on the principle of generating power by transporting carriers generated at the interface between the p-type organic semiconductor and the n-type organic semiconductor by light irradiation, transporting holes by the p-type organic semiconductor and transporting electrons by the n-type organic semiconductor. is there.
As the p-type organic semiconductor, phthalocyanine or polythiophene is used, and as the n-type semiconductor, fullerene is used. However, if the p-type and n-type do not have high carrier generation and carrier transport performance, good conversion efficiency can be produced. I can't.

  On the other hand, the dye-sensitized solar cell generates power by a photochemical reaction. The sensitizing dye is excited by light irradiation, electrons are injected into titanium oxide, the dye receives electrons from the hole transport layer, and iodine receives electrons from the electrode to generate electricity. Therefore, the p-type organic semiconductor (hole transport material) used in the dye-sensitized solar cell is different from the organic thin-film solar cell and only needs to consider the carrier transport performance.

  As described above, none of the perfect solid-state photoelectric conversion elements studied so far has been obtained with satisfactory characteristics.

  An object of the present invention is to solve the above-described problems, and to provide a completely solid dye-sensitized solar cell having high conversion efficiency and excellent productivity.

The said subject is solved by following (1)-(7) of this invention.
(1) “It has a first electrode, an electron transport layer, a hole transport layer, and a second electrode, and the hole transport layer is derived from a vinyl compound represented by the following general formula (1). A photoelectric conversion element having a polymer;

（式中、Ａｒは置換基を有してもよいアリール基を表す。）」、
（２）「前記一般式（１）で表される化合物が下記構造式Ａで表される化合物を含む前記第（１）項に記載の光電変換素子；

(In the formula, Ar represents an aryl group which may have a substituent.) "
(2) "The photoelectric conversion element according to (1), wherein the compound represented by the general formula (1) includes a compound represented by the following structural formula A;

（３）「前記一般式（１）で表される化合物が下記構造式Ｂで表される化合物を含む前記第（１）項または第（２）項に記載の光電変換素子；

(3) The photoelectric conversion element according to (1) or (2), wherein the compound represented by the general formula (1) includes a compound represented by the following structural formula B;

（４）「前記電子輸送層は、酸化チタン、酸化亜鉛、酸化スズ及び酸化ニオブの群から選択される少なくとも１つの材料を含む、前記第（１）項乃至第（３）項のいずれか一項に記載の光電変換素子」、
（５）「前記ホール輸送層は、イオン液体を含む前記第（１）項１乃至第（４）項のいずれか一項に記載の光電変換素子」、
（６）「前記イオン液体は、イミダゾリウム化合物を含む、前記第（５）項に記載の光電変換素子」、
（７）「前記ホール輸送層と前記第２の電極との間に第２のホール輸送層を有し、該第２のホール輸送層は、ホール輸送性の高分子材料を含むことを特徴とする前記第（１）項乃至第（６）項のいずれか一項に記載の光電変換素子」。

(4) Any one of the above items (1) to (3), wherein the electron transport layer includes at least one material selected from the group consisting of titanium oxide, zinc oxide, tin oxide, and niobium oxide. The photoelectric conversion element according to the item ",
(5) "The photoelectric conversion element according to any one of (1) to 1 (4), wherein the hole transport layer contains an ionic liquid",
(6) "The photoelectric conversion element according to (5), wherein the ionic liquid contains an imidazolium compound",
(7) “having a second hole transport layer between the hole transport layer and the second electrode, and the second hole transport layer includes a hole transporting polymer material, The photoelectric conversion element according to any one of (1) to (6).

  According to the present invention, it is possible to provide a completely solid photoelectric conversion element having excellent photoelectric characteristics, high conversion efficiency, and excellent productivity.

It is the schematic of the cross section of an example of the photoelectric conversion element of this embodiment. It is the schematic of the cross section of the other example of the photoelectric conversion element of this embodiment. 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 infrared absorption spectrum figure of the synthesis example 3 compound of this embodiment. It is an infrared absorption spectrum figure of the synthesis example 4 compound of this embodiment. It is an infrared absorption spectrum figure of the synthesis example 5 compound of this embodiment. It is an infrared absorption spectrum figure of the synthesis example 6 compound of this embodiment.

Hereinafter, this embodiment will be described with reference to the drawings.
Generally, a photoelectric conversion element includes an electron collector electrode, an electron acceptor / electron transport layer (hereinafter referred to as an electron transport layer), and an electron donor / hole transport layer (hereinafter referred to as a hole transport layer). And a hole collecting electrode.

In FIG. 1, the schematic of the cross section of an example of the photoelectric conversion element of this embodiment is shown. FIG. 2 shows a schematic cross-sectional view of another example of the photoelectric conversion element of the present embodiment.
As shown in FIG. 1, the photoelectric conversion element 100 a according to this embodiment includes a first electrode 3, which is an electron collector electrode, a first electron transport layer 6, and a second electron transport, on a first substrate 1. An electron transport layer 5 including a layer 7, a hole transport layer 8 including a first hole transport layer 9 and a second hole transport layer 10, a metal oxide layer 11, a second electrode 4 serving as a hole collector electrode, a second electrode 4 Two substrates 2 are sequentially provided.
Moreover, the photoelectric conversion element 100b of FIG. 2 has the same configuration as the photoelectric conversion element 100a except that the metal oxide layer 11 is not provided.
Hereinafter, each component will be described in detail.

<Board>
The 1st board | substrate 1 and the 2nd board | substrate 2 are provided in order to hold | maintain fixed hardness, and if it is a transparent material with respect to visible light, it will not specifically limit. Specific examples include glass, a transparent plastic plate, a transparent plastic film, and an inorganic transparent crystal.

(Electronic current collecting electrode)
The electron collecting electrode of the first electrode 3 is not particularly limited as long as it is a conductive material transparent to visible light, and an electrode used in a known photoelectric conversion element or liquid crystal panel is used. Can do.
Specific examples of the electron collector electrode include indium tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), indium / zinc oxide, niobium / titanium oxide, and graphene. Can be mentioned. These may be used alone or in combination of two or more.
In addition, as the electron collector electrode, for example, an FTO-coated glass, ITO-coated glass, zinc oxide: aluminum-coated glass, FTO-coated transparent plastic film, ITO-coated transparent plastic film, or the like integrated with the substrate is used. May be.
Furthermore, a transparent electrode obtained by doping tin oxide or indium oxide with a cation or an anion having a different valence, a metal electrode having a configuration capable of transmitting light, such as a mesh shape or a stripe shape, is provided on the above-described substrate. You may use things. These may be used alone or in combination of two or more.

  The thickness of the electron collecting electrode is preferably in the range of 5 nm to 100 μm, and more preferably in the range of 50 nm to 10 μm.

In addition, for the purpose of reducing the resistance of the first substrate 1 and the second substrate 2, as shown in FIGS. 1 and 2, a first lead wire 13 and a second lead wire 14 may be disposed, respectively. good.
Examples of the material of the first lead wire 13 and the second lead wire 14 include metals such as copper, silver, gold, platinum, and nickel. In addition, the method of providing these electrodes on the board | substrates 1 and 2 by vapor deposition, sputtering, pressure bonding, etc., and providing the electrode mentioned above on it is mentioned.

<Electron transport layer>
As described above, the photoelectric conversion element 100 of the present embodiment has the electron transport layer 5 formed on the first electrode 3 from semiconductor fine particles to be described later.

The configuration of the electron transport layer 5 is preferably a configuration having a dense first electron transport layer 6 and a porous second electron transport layer 7 on the first electrode 3.
Here, “dense” means that the packing density of the semiconductor fine particles in the first electron transport layer 6 is higher than the packing density of the semiconductor fine particles in the second electron transport layer 7. .

  The dense first electron transport layer 6 is formed to prevent electronic contact (contact) between the first electrode 3 and a hole transport layer 8 described later. Therefore, if the first electrode 3 and the hole transport layer 8 are not in physical contact, pinholes, cracks, or the like may be formed.

  Although it does not restrict | limit especially as a film thickness of the 1st electron carrying layer 6, It is preferable to exist in the range of 10 nm-1 micrometer, and it is more preferable to exist in the range of 20 nm-700 nm.

The second electron transport layer 7 is a granular (hereinafter sometimes referred to as a porous) electron transport layer, and is formed on the first electron transport layer 6.
The second electron transport layer 7 may be a single layer or a multilayer. The second electron transport layer 7 is formed by a coating method or the like, but is formed by multilayer coating when the film thickness formed by one coating is insufficient.

  When the second electron transport layer 7 is a multilayer, it may be formed by multilayer coating of semiconductor fine particle dispersions having different particle diameters, or different types of semiconductors, resins, additives, etc. The coating liquid may be formed by multilayer coating.

The film thickness of the second electron transport layer 7 is preferably in the range of 100 nm to 100 μm.
As the film thickness of the second electron transport layer 7 increases, the amount of supported photosensitizing compound per unit projected area increases, so the light capture rate increases, but the diffusion distance of injected electrons also increases. Loss due to charge recombination also increases. Therefore, the film thickness of the second electron transport layer 7 is preferably in the range of 100 nm to 100 μm.

  The material for the electron transport layer is not particularly limited as long as it is a semiconductor material, and examples thereof include single semiconductors such as silicon and germanium, compound semiconductors typified by metal chalcogenides, and compounds having a perovskite structure.

Examples of the metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc, lead, silver, antimony, Bismuth sulfide, cadmium, lead selenide, cadmium telluride and the like.
Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium, gallium arsenide, copper-indium-selenide, and copper-indium-sulfide.

Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
The above-mentioned materials may be used alone or in combination of two or more. The crystal form of the semiconductor described above may be single crystal, polycrystalline, or amorphous.
Among the materials described above, it is preferable to use an N-type oxide semiconductor, and it is particularly preferable to use titanium oxide, zinc oxide, tin oxide, or niobium oxide.

The primary particle size of the semiconductor fine particles described above is preferably in the range of 1 to 100 nm, and more preferably in the range of 5 to 50 nm.
Moreover, photoelectric characteristics can be improved by mixing or laminating semiconductor fine particles having a larger average particle diameter to scatter incident light. In this case, it is preferable to use semiconductor fine particles having an average particle diameter of 50 to 500 nm.

  There is no restriction | limiting in particular as a formation method of an electron carrying layer, The method of forming a thin film in vacuum, such as sputtering, a wet film-forming method etc. can be used. From the viewpoint of production cost, it is preferable to use a wet film forming method, and a method of preparing a paste or dispersion in which a semiconductor fine particle powder or sol is dispersed and applying the paste or dispersion onto an electron collector electrode substrate is used. Is more preferable.

When using the wet film formation method, the method for applying the paste or dispersion is not particularly limited, and examples thereof include a dipping method, a spray method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, and a gravure coating. Or printing methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen can be used.
In the case of producing a dispersion liquid, the semiconductor fine particles can be dispersed alone or in a mixture with a resin in a solvent described later using mechanical pulverization or a mill.
Examples of the resin include polymers or copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicon resins, phenoxy resins, polysulfone resins, polyvinylidyl butyral resins, polyvinyl formal resins, polyester resins, and cellulose. Examples include ester resins, cellulose ether resins, urethane resins, phenol resins, epoxy resins, polycarbonate resins, polyarylate resins, polyamide resins, and polyimide resins.

  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-butyl acetate. Ester solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane or dioxane, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone, Dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenze Or halogenated hydrocarbon solvents 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. One of these may be used alone, or two or more may be used in combination.

  The semiconductor fine particle paste obtained by a dispersion of semiconductor fine particles or a sol-gel method is used to prevent re-aggregation of the particles. It is preferable to add an activator, a chelating agent such as acetylacetone, 2-aminoethanol, and ethylenediamine. Moreover, you may add a thickener for the purpose of improving film formability. Examples of the thickener include polymers such as polyethylene glycol and polyvinyl alcohol, and thickeners such as ethyl cellulose.

  Semiconductor fine particles are baked, microwave-irradiated, electron-beam irradiated, laser-irradiated or pressed in order to contact the particles electronically after coating, improve the film strength, and improve the adhesion to the substrate. It is preferable to process. These treatments may be performed alone or in combination of two or more.

  In the case of firing, the range of the firing temperature is not particularly limited, but is preferably in the range of 30 to 700 ° C, and more preferably in the range of 100 to 600 ° C. When the firing temperature exceeds 700 ° C., the resistance of the substrate may increase. Also, the substrate may melt. The firing time is not particularly limited, but is preferably within a range of 10 minutes to 10 hours.

  After firing, chemical plating using, for example, an aqueous solution of titanium tetrachloride or a mixed solution with an organic solvent for the purpose of increasing the surface area of the semiconductor fine particles and / or increasing the efficiency of electron injection from the photosensitizing compound into the semiconductor fine particles. Alternatively, an electrochemical plating process using a titanium trichloride aqueous solution may be performed.

  Moreover, when irradiating a microwave, you may irradiate from the electron carrying layer formation side, and may irradiate from the back side. Although there is no restriction | limiting in particular as irradiation time, It is preferable to carry out within 1 hour.

When the press treatment is employed, the press pressure is preferably 100 kg / cm ² or more, and more preferably 1000 kg / cm ² or more. The time for performing the press treatment is not particularly limited, but is preferably within 1 hour. Note that heat may be applied during the pressing process.

  The roughness factor of the electron transport layer is preferably 20 or more. The roughness factor is a numerical value representing the actual area inside the porous with respect to the area of the semiconductor fine particles applied to the substrate. Usually, a film in which semiconductor fine particles having a diameter of several tens of nanometers are laminated by sintering or the like forms a nanoporous state and has a high surface area.

In order to improve the light conversion efficiency, it is preferable to adsorb the photosensitizing compound to the second electron transport layer 7. A photosensitizing compound is a compound that is photoexcited by the excitation light used.
Specifically, the metals described in JP 7-500630 A, JP 10-233238 A, JP 2000-26487 A, JP 2000-323191 A, JP 2001-59062 A, and the like. Complex compounds, JP-A-10-93118, JP-A-2002-164089, JP-A-2004-95450, J. Org. Phys. Chem. C, 7224, Vol. 111 (2007), etc., JP-A-2004-95450, Chem. Commun. , 4887 (2007), etc., JP-A No. 2003-264010, JP-A No. 2004-63274, JP-A No. 2004-115636, JP-A No. 2004-200068, JP-A No. 2004-235052. J. et al. Am. Chem. Soc. , 12218, Vol. 126 (2004), Chem. Commun. , 3036 (2003), Angew. Chem. Int. Ed. , 1923, Vol. 47 (2008), etc .; Am. Chem. Soc. 16701, Vol. 128 (2006), J.M. Am. Chem. Soc. , 14256, Vol. 128 (2006), JP-A-11-86916, JP-A-11-214730, JP-A-2000-106224, JP-A-2001-76773, JP-A-2003-7359. And the merocyanine dyes described in JP-A-11-214731, JP-A-11-238905, JP-A-2001-52766, JP-A-2001-76775, JP-A-2003-7360, etc. 9-arylxanthene compounds described in JP-A-10-92477, JP-A-11-273754, JP-A-11-273755, JP-A-2003-3273, etc., JP-A-10-93118, Triarylmethane compounds described in Japanese Unexamined Patent Publication No. 2003-31273, JP-A-9- 99744, JP-A No. 10-233238, JP-A No. 11-204821, JP-A No. 11-265738, J. Phys. Chem. , 2342, Vol. 91 (1987), J. MoI. Phys. Chem. B, 6272, Vol. 97 (1993), Electroanaly. Chem. , 31, Vol. 537 (2002), JP-A-2006-032260, J. Pat. Porphyrins Phthalocyanines, 230, Vol. 3 (1999), Angew. Chem. Int. Ed. , 373, Vol. 46 (2007), Langmuir, 5436, Vol. Photosensitizing compounds such as phthalocyanine compounds and porphyrin compounds described in No. 24 (2008) can be used. Among these compounds, it is preferable to use metal complex compounds, coumarin compounds, polyene compounds, indoline compounds, and thiophene compounds.

As a method for adsorbing the photosensitizing compound in the second electron transport layer 7, a method of immersing the electron integrated electrode 1 having semiconductor fine particles in a photosensitizing compound solution or a photosensitizing compound dispersion, or Examples thereof include a method in which a photosensitizing compound solution or a photosensitizing compound dispersion is applied to and adsorbed on an electron transport layer.
In the former case, specific examples include dipping method, dipping method, roller method, air knife method, etc. In the latter case, wire bar method, slide hopper method, extrusion method, curtain method, spin method, spray Law. Further, a method of adsorbing in a supercritical fluid using carbon dioxide or the like may be employed.
When adsorbing the photosensitizing compound, a condensing agent may be used in combination. The condensing agent is one that catalyzes a reaction that physically or chemically bonds a photosensitizing compound and an electron transport compound to the surface of an inorganic substance, or one that acts stoichiometrically and moves chemical equilibrium advantageously. Can be used.
Moreover, you may add a thiol and a hydroxy compound as a condensation adjuvant.

  Solvents for dissolving or dispersing the photosensitizing compound include water, alcohol solvents such as methanol, ethanol or isopropyl alcohol, ketone solvents such as acetone, methyl ethyl ketone or methyl isobutyl ketone, ethyl formate, ethyl acetate or n-butyl acetate. Ester solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, and amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone , Dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene or 1- Halogenated hydrocarbon solvents such as lolonaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p -Hydrocarbon solvents such as xylene, ethylbenzene or cumene. These may be used alone or in combination of two or more.

Depending on the photosensitizing compound to be used, there are those that exhibit functions more effectively by suppressing aggregation between the compounds. Therefore, an aggregation dissociator may be used in combination.
As the aggregation / dissociation agent, it is preferable to use a steroid compound such as cholic acid or chenodeoxycholic acid, a long-chain alkyl carboxylic acid, or a long-chain alkyl phosphonic acid.
The addition amount of the aggregating and dissociating agent is preferably in the range of 0.01 to 500 parts by mass, more preferably in the range of 0.1 to 100 parts by mass with respect to 1 part by mass of the dye described later. .

The temperature for adsorbing the photosensitizing compound or the photosensitizing compound and the aggregation / dissociation agent is preferably −50 ° C. or more and 200 ° C. or less. Adsorption may be carried out in a stationary state or with stirring. When carrying out with stirring, the stirring method is not limited, and examples thereof include a stirrer, ball mill, paint conditioner, sand mill, attritor, disperser, and ultrasonic dispersion.
The adsorption treatment time is preferably 5 seconds to 1000 hours, more preferably 10 seconds to 500 hours, and even more preferably 1 minute to 150 hours.
Note that the adsorption treatment is preferably performed in a dark place.

<Hole transport layer>
The hole transport layer 8 in this embodiment may be only the first hole transport layer 9, but the first hole transport layer 9 and the second hole transport layer 10 are laminated from the first electrode side. It may have a structure. The second hole transport layer 10 includes a polymer material. By including a polymer material excellent in film formability, the surface of the porous second electron transporting layer can be made more smooth, and the photoelectric conversion characteristics can be improved.
In addition, since it is difficult for the polymer material to penetrate into the porous electron transport layer, the polymer material has excellent coverage on the surface of the porous second electron transport layer, and prevents short circuit when the electrode is installed. Also effective.

In the present embodiment, the hole transporting compound used for the first hole transporting layer 9 on the first electrode 3 side is a polymer in which a vinyl compound represented by the following general formula (1) is formed by a thermal reaction. Including.
As a specific example, an aromatic compound represented by the general formula (1) can be used.
Specific exemplary compounds of the present invention represented by the general formula (1) are shown in Table 1 below, but are not limited thereto.

（式中、Ａｒは置換基を有してもよいアリール基を表す。）

(In the formula, Ar represents an aryl group which may have a substituent.)

  The hole transporting compound containing a polymer in which the vinyl compound represented by the general formula (1) is formed by a thermal reaction has a specific low resistance and an improved hole transporting property.

The polymer material used in the second hole transport layer 10 on the second electrode 4 side is not particularly limited as long as it is a known hole transport polymer material. For example, poly (3-n-hexylthiophene) , Poly (3-n-octyloxythiophene), poly (9,9′-dioctyl-fluorene-co-bithiophene), poly (3,3 ′ ″-didodecyl-quarterthiophene), poly (3,6-dioctyl) Thieno [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 (3,6-dioctylthieno [3, 2 -B] thiophene-co-thiophene), poly (3.6-dioctylthieno [3,2-b] thiophene-co-bithiophene) and other polythiophene compounds, poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene], poly [2-methoxy-5- (3,7-dimethyloctyloxy) -1,4-phenylene vinylene], poly [(2-methoxy-5- (2-ethylphenyl) Oxy) -1,4-phenylenevinylene) -co- (4,4′-biphenylene-vinylene)] and the like, 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-dihexyloxy) benzene)] and the like Fluorene compounds, poly [2,5-dioctyloxy-1,4-phenylene], poly [2,5-di (2-ethylhexyloxy-1,4-phenylene] and other polyphenylene compounds, poly [(9,9- Dioctylfluorenyl-2,7-diyl) -alt-co- (N, N′-diphenyl) -N, N′-di (p-hexylphenyl) -1,4-diaminobenzene], poly [(9 , 9-Dioctyl Fluorenyl-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-phenylene vinylene-2,5-di (2-ethylhexyloxy) -1,4-phenylene vinylene-1,4-phenylene], poly [4- (2-ethylhexyloxy) phenyl ester Poly-1,4biphenylene], poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (1,4-benzo (2,1 ′, 3) thiadiazole], and polythiadiazole compounds such as poly (3,4-didecylthiophene-co- (1,4-benzo (2,1 ′, 3) thiadiazole). Among these compounds, polythiophene compounds and polyarylamine compounds are preferably used from the viewpoint of carrier mobility, ionization potential, and the like.
In addition, the compound mentioned above may be used individually by 1 type, and may be used in combination of 2 or more types.

Moreover, you may add an additive to the above-mentioned hole transportable compound. Examples of additives include iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, silver iodide, and other metal iodides,
Quaternary ammonium salts such as tetraalkylammonium iodide, pyridinium iodide, metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, calcium bromide,
Bromine salts of quaternary ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide,
Metal chlorides such as 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,
Metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion,
Sulfur compounds such as sodium polysulfide, alkylthiol-alkyl disulfides, viologen dyes, hydroquinone, etc.
1,2-dimethyl-3-n-propylimidazolinium iodide, 1-methyl-3-n-hexylimidazolinium iodide, 1,2-dimethyl-3-ethylimidazolium trifluoromethanesulfonic acid Salt, 1-methyl-3-butylimidazolium nonafluorobutyl sulfonate, 1-methyl-3-ethylimidazolium bis (trifluoromethyl) sulfonylimide, 1-methyl-3-n-hexylimidazolium bis (tri Fluoromethylsulfonyl) imide, 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide, 1-methyl-3-n-hexylimidazolium dicyanamide, lithium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolinium bis (pen Trifluoroethyl) imide, 1-ethyl-3-methyl imidazolium bis (pentafluoroethyl sulfonyl) imide / lithium bis (trifluoromethanesulfonyl) imide, ionic liquids and the like,
Basic compounds such as pyridine, 4-t-butylpyridine, benzimidazole,
Examples thereof include lithium compounds such as lithium trifluoromethanesulfonylimide and lithium diisopropylimide.
Among these additives, it is preferable to use an ionic liquid having a bis (trifluoromethyl) sulfonylimide anion. In addition, an additive may be used individually by 1 type and may be used in combination of 2 or more types.

Moreover, you may add acceptor material to the above-mentioned hole transportable compound as needed.
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 may be used alone or in combination of two or more.

Moreover, you may add the oxidizing agent for making a part of above-mentioned hole transportable 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.
In addition, it is not necessary to oxidize all the hole transportable compounds by addition of an oxidizing agent, and a part should just be oxidized. Moreover, the added oxidizing agent may be taken out of the system after the addition, or may remain without being taken out.

  The hole transport layer 8 is formed on the electron transport layer 7 carrying a photosensitizing compound. There is no restriction | limiting in particular as a formation method of a hole transport layer, The method of forming a thin film in vacuum, such as vacuum deposition, and methods, such as a wet film-forming method, are employable. From the viewpoint of manufacturing cost, it is preferable to employ a wet film forming method.

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, or methyl isobutyl ketone, ethyl formate, ethyl acetate, or n-butyl acetate. Ester solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone Solvent, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, or 1-chloro Halogenated hydrocarbon solvents such as naphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p- Examples thereof include hydrocarbon solvents such as xylene, ethylbenzene, and cumene.
These may be used alone or in combination of two or more.

  The application method in the wet film formation is not particularly limited. For example, dipping method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, or relief printing, offset, gravure, Printing methods such as intaglio, rubber plate, and screen can be used. Further, 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 the temperature and pressure range that exceeds the criticality (critical point) at which gas and liquid can coexist. As long as the fluid is in the above state, there is no particular limitation, and it can be appropriately selected according to the purpose. However, it is preferable to use a fluid having a low critical temperature. Specifically, hydrocarbons such as carbon monoxide, carbon dioxide, ammonia, nitrogen, water, ercol solvents such as methanol, ethanol, n-butanol, ethane, propane, 2,3-dimethylbutane, benzene, toluene, etc. Solvents, halogen solvents such as methylene chloride and chlorotrifluoromethane, and ether solvents such as dimethyl ether can be preferably used.
Among these, carbon dioxide is preferably used because it has a critical pressure of 7.3 MPa and a critical temperature of 31 ° C., can easily create a supercritical state, and is nonflammable and easy to handle. In addition, the fluid mentioned above may be used individually by 1 type, and may be used in combination of 2 or more types.

The subcritical fluid is not particularly limited as long as it can exist as a high-pressure liquid in a temperature and pressure region near the critical point, and can be appropriately selected according to the purpose.
The compounds mentioned as the supercritical fluid described above can be suitably used as a subcritical fluid.

  The critical temperature and critical pressure of the supercritical fluid are not particularly limited and may be appropriately selected depending on the intended purpose. The critical temperature is preferably −273 ° C. or higher and 300 ° C. or lower, and 0 ° C. or higher and 200 ° C. or lower. Is more preferable.

  In addition to the supercritical fluid and subcritical fluid described above, it is also preferable to use in combination with an organic solvent or entrainer. 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 examples thereof include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl formate, ethyl acetate, and n-butyl acetate, diisopropyl ether, dimethoxyethane, and the like. Ether solvents such as tetrahydrofuran, dioxolane or dioxane, amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide or N-methyl-2-pyrrolidone, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane Halogenated hydrocarbon solvents such as trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene or 1-chloronaphthalene, n-pentane, -Hydrocarbon solvents such as hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, or cumene. It is done.

  In the present embodiment, it is preferable to perform a press treatment after providing the hole transport layer 8 on the first electrode 3 having the second electron transport layer 7 coated with the photosensitizing compound 12. By performing the press treatment, the hole transport layer 8 is more closely attached to the porous electrode, so that it is considered that the photoelectric efficiency is improved.

Although there is no restriction | limiting in particular as a press processing method, The press molding method using the flat plate represented by the tablet molding machine, the roll press method using a roller etc. are mentioned.
The pressure for the press treatment is preferably 10 kgf / cm ² or more, more preferably 30 kgf / cm ² or more.
The time for the press treatment is not particularly limited, but is preferably within 1 hour.
Further, heat may be applied during the pressing process. Moreover, it is preferable to arrange a release material between the pressing means and the first electrode 3. Release materials include polytetrafluoroethylene, polychlorotrifluoride ethylene, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkoxy fluoride resin, polyvinylidene fluoride, ethylene tetrafluoride ethylene copolymer, ethylene chloro Examples thereof include fluorine resins such as ethylene trifluoride copolymer and polyvinyl fluoride.

  After the press treatment, the metal oxide layer 11 may be formed so that the metal oxide layer 11 is disposed between the hole transport layer 8 and a second electrode 4 described later. Examples of the metal oxide of the metal oxide layer 11 include molybdenum oxide, tungsten oxide, vanadium oxide, and nickel oxide. Among these, it is preferable to use molybdenum oxide.

  Although there is no restriction | limiting in particular as a formation method of a metal oxide, The method of forming a thin film in vacuum, such as sputtering and vacuum evaporation, the wet film-forming method, etc. are employable.

  As the wet film forming method, it is preferable to employ a method in which a paste in which a metal oxide powder or sol is dispersed is prepared and applied onto the hole transport layer 8.

  When adopting the wet film formation method, there is no particular limitation as the coating method, for example, dip method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, or letterpress, Examples of the printing method include offset, gravure, intaglio, rubber plate, and screen printing.

  The film thickness of the metal oxide layer 11 is preferably in the range of 0.1 to 50 nm, and more preferably in the range of 1 to 10 nm.

<Hall current collector electrode>
The second electrode 4, which is a hole current collecting electrode, is formed on the hole transport layer 8 or the metal oxide layer 11. As the material of the second electrode 4, the same material as that of the first electrode 3 described above can be used. Further, in the case of a configuration in which the strength and the sealing performance are sufficiently maintained, the support may not be provided.
Specific examples of the material of the second electrode 4 include metals such as platinum, gold, silver, copper, and aluminum, carbon compounds such as graphite, fullerene, carbon nanotube, and graphene, and conductive metals such as ITO, FTO, and ATO. Examples thereof include conductive polymers such as oxide, polythiophene, and polyaniline. One of these materials may be used alone, or two or more of these materials may be used in combination.

  Further, the film thickness of the second electrode 4 is not particularly limited.

  As a method for forming the second electrode 4, techniques such as coating, laminating, vapor deposition, CVD, and bonding can be employed depending on the type of material used and the type of the hole transport layer 8.

When the photoelectric conversion element of the present embodiment is used as a dye-sensitized solar cell, it is sufficient that at least one of the first electrode 3 and the second electrode 4 is transparent. However, in this embodiment, it is preferable to employ a method in which the first electrode 3 side which is an electron current collecting electrode is at least transparent and sunlight is incident from the electron current collecting electrode 3 side.
In this case, it is preferable to use a material that reflects light on the hole collecting electrode side, and it is preferable to use glass, plastic, or metal thin film on which a metal or conductive oxide is deposited.

It is also preferable to provide an antireflection film on the sunlight incident side.
Note that the dye-sensitized solar cell of the present embodiment can also be applied to a solar cell and / or a power supply device using the solar cell. In addition, any device that has conventionally used a solar cell or a power supply using a solar cell can be applied. For example, an electronic desk calculator, a solar cell for a wrist watch, a mobile phone It can be applied to power supply devices such as electronic notebooks and electronic papers. Moreover, it can also be used as an auxiliary power source for extending the continuous use time of rechargeable or dry battery type electric appliances.

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

<Synthesis of hole transporting compound in the present invention>
(Synthesis Example 1)
[Synthesis of 4,4 ′, 4 ″ -triformyltriphenylamine]
In a reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel, Tokyo Chemical Industry Co., Ltd .: Tris (4-bromophenyl) amine: 24.1 g, dehydrated tetrahydrofuran: 200 ml were placed at −72 ° C. in an argon gas atmosphere. After stirring, a 2.77 M n-butyllithium hexane solution: 65 ml was added dropwise, followed by reaction for 1 hour.
Thereafter, 16.45 g of dehydrated dimethylformaldehyde was dropped, and the reaction was performed for 2 hours. Thereafter, the reaction solution was poured into ice water and extracted with methylene chloride.
The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (solvent: toluene / ethyl acetate = 9/1) to obtain the desired product (yield: 17.17 g, yellow powder).
The infrared absorption spectrum of the obtained compound is shown in FIG.

(Synthesis Example 2)
[Synthesis of phosphonium salt compounds]
A reactor equipped with a stirrer and a thermometer was charged with Tokyo Chemical Industry Co., Ltd .: 4-chloromethylstyrene: 152.62 g, Tokyo Chemical Industry Co., Ltd .: triphenylphosphine: 262.29 g, toluene: 200 ml, and 3 at 80 ° C. Time reaction was performed.
Thereafter, the mixture was filtered, washed with toluene, and then dried under reduced pressure to obtain the desired product (yield: 376 g, white powder).
The infrared absorption spectrum of the obtained compound is shown in FIG.

(Synthesis Example 3)
[Synthesis of Exemplified Compound 1]
In a reaction vessel equipped with a stirrer and a thermometer, 4,4 ′, 4 ″ -triformyltriphenylamine of Synthesis Example 1: 6.58 g, phosphonium salt compound obtained in Synthesis Example 2: 127.38 g, Dehydrated dimethylformaldehyde: 100 ml was added and stirred under ice cooling.
Thereto was added potassium-tertiary-butoxide: 8.08 g. Then, reaction was performed at room temperature for 3 hours.
After completion of the reaction, the reaction solution was poured into ice water and extracted with methylene chloride. The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (solvent: dichloromethane / cyclohexane = 3/7) to obtain the desired product (yield: 9.88 g, yellow amorphous).
The infrared absorption spectrum of the obtained compound is shown in FIG.

(Synthesis Example 4)
[Synthesis of Exemplified Compound 3]
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, Tokyo Chemical Industry Co., Ltd .: Tris (4-bromophenyl) amine: 2.09 g, Aldrich Co., Ltd .: 4-vinylphenylboronic acid: 2.31 g, potassium carbonate : 2.157 g, ethanol: 5 ml, toluene: 10 ml, ion-exchanged water: 10 ml were added and stirred under an argon atmosphere and at room temperature.
To this, Tokyo Chemical Industry Co., Ltd .: Tetrakistriphenylphosphine palladium: 0.3 g was added and reacted at 70 ° C. for 5 hours. Thereafter, the reaction solution was poured into ice water and extracted with methylene chloride.
The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (solvent: dichloromethane / cyclohexane = 1/1) to obtain the desired product. (Yield: 2.15 g, pale yellowish white powder)
The infrared absorption spectrum of the obtained compound is shown in FIG.

(Synthesis Example 5)
[Synthesis of Tris (3-bromophenyl) amine]
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, Tokyo Chemical Industry Co., Ltd .: 3-bromoaniline: 6.88 g, Tokyo Chemical Industry Co., Ltd .: 3-bromoiodobenzene: 33.95 g, potassium carbonate: 22.11 g Ortho-dichlorobenzene: 40 ml, stirred under reflux in an argon atmosphere, and reacted for 24 hours. Thereafter, the reaction solution was poured into ice water and extracted with methylene chloride.
The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (solvent: dichloromethane / cyclohexane = 1/5) and recrystallized with ethanol to obtain the desired product (yield: 7.02 g, white powder).
The infrared absorption spectrum of the obtained compound is shown in FIG.

(Synthesis Example 6)
[Synthesis of Exemplified Compound 5]
In a reaction vessel equipped with a stirrer, a thermometer, and a cooling tube, tris (3-bromophenyl) amine obtained in Synthesis Example 5: 2.41 g, Aldrich's 4-vinylphenylboronic acid: 2.66 g, Potassium carbonate: 2.48 g, ethanol: 5 ml, toluene: 10 ml, ion-exchanged water: 10 ml were added and stirred under an argon atmosphere and at room temperature.
To this, Tokyo Chemical Industry Co., Ltd .: Tetrakistriphenylphosphine palladium: 0.35 g was added and reacted at 70 ° C. for 5 hours. Thereafter, the reaction solution was poured into ice water and extracted with methylene chloride.
The organic layer was washed with water, separated, dried over magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel chromatography (solvent: dichloromethane / cyclohexane = 1/1) to obtain the desired product (yield: 2.15 g, white amorphous). The infrared absorption 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 is applied on the above-mentioned 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 granular electron transport layer. Got.

(Preparation of dye-sensitized solar cell)
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 is left to stand in a dark place for 1 hour for photosensitization. The compound was adsorbed.
A solution obtained by adding 1-n-hexyl-3-methylimidazolinium trifluorosulfonyldiimide (27 mM) to a chlorobenzene (20% solids) solution in which the exemplified compound (No. 1) is dissolved is photosensitized. A film was formed on the titanium oxide semiconductor electrode carrying the agent by spin coating, heated at 150 ° C. for 20 minutes, and then dried by heating to form a hole transport layer. On this, gold was vacuum-deposited to a thickness of 100 nm to prepare a dye-sensitized solar cell. On this, gold was vacuum-deposited to a thickness of 100 nm to prepare a dye-sensitized solar cell.
In addition, when the hole transport layer was immersed in chlorobenzene separately from the produced dye-sensitized solar cell, it was confirmed that the exemplified compound (No. 1) was not eluted and a polymer was formed.

(Evaluation of dye-sensitized solar cell)
The photoelectric conversion efficiency of the obtained dye-sensitized solar cell under pseudo-sunlight irradiation (AM1.5, 100 mW / cm ² ) was measured.
The simulated sunlight was measured by a solar simulator SS-80XIL manufactured by Eiko Seiki, and the evaluation equipment was measured by 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 = 0.94 V, a short circuit current density of 4.75 mA / cm ² , a form factor = 0.64, and a conversion efficiency = 2.86% were exhibited.

[Example 2]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound of Example 1 was changed to the hole transporting compound of Compound No. 2 shown in Table 1. The results are shown in Table 2.

[Example 3]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound of Example 1 was changed to the hole transporting compound of Compound No. 3 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 transporting compound of Example 1 was changed to the hole transporting compound of Compound No. 4 shown in Table 1. The results are shown in Table 2.

[Example 5]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound of Example 1 was changed to the hole transporting compound of Compound No. 5 shown in Table 1. The results are shown in Table 2.

[Example 6]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound of Example 1 was changed to the hole transporting compound of Compound No. 6 shown in Table 1. The results are shown in Table 2.

[Example 7]
A first hole transport layer was formed in the same manner as in Example 1 except that the chlorobenzene solution in which the exemplified compound (No. 1) was dissolved was replaced with 10% solid content.
Furthermore, 1-n-hexyl-3-methylimidazolinium trifluorosulfonyldiimide (27 mM) was added to chlorobenzene (solid content 2%) in which poly (3-n-hexylthiophene) manufactured by Aldrich was dissolved. The solution was spray-coated on the hole transport layer to form a film having a thickness of about 100 nm to form a second hole transport layer. On this, gold was vacuum-deposited to a thickness of 100 nm to prepare a dye-sensitized solar cell.

[Comparative Example 1]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound in Example 1 was changed to the hole transporting compound of Compound No07 shown below. The results are shown in Table 3.

[Comparative Example 2]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound in Example 1 was changed to the hole transporting compound of Compound No. 08 shown below. The results are shown in Table 3.

[Comparative Example 3]
A photoelectric conversion device was prepared and evaluated in the same manner as in Example 1 except that the hole transporting compound in Example 1 was changed to the hole transporting compound of Compound No09 shown below. The results are shown in Table 3.

As is clear from Tables 2 and 3, it can be seen that the hole transporting compounds of the present invention all exhibit good characteristics. Among these, the exemplified compound No. 1, no. 3, no. No. 5 showed good characteristics.
Further, it is apparent that the hole transporting compound of the comparative example has lower characteristics than the hole transporting compound of the present invention. In addition, it is clear that Comparative Examples 1 and 3 in which a polymer in which a vinyl compound is formed by a thermal reaction cannot be obtained have remarkably low characteristics.

[Example 8]
Dye-sensitized type in the same manner as in Example 1 except that 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide in Example 1 was changed to lithium bis (trifluoromethanesulfonyl) imide. Solar cells were fabricated and evaluated.
As a result, excellent characteristics of an open circuit voltage = 0.92 V, a short circuit current density = 4.71 mA / cm ² , a form factor = 0.62, and a conversion efficiency = 2.69% were exhibited.

[Example 9]
Implemented except that 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide in Example 1 was changed to 1-ethyl-3-methylimidazolinium bis (pentafluoroethylsulfonyl) imide. A dye-sensitized solar cell was prepared and evaluated in the same manner as in Example 1.
As a result, excellent characteristics of an open circuit voltage of 0.93 V, a short circuit current density of 4.68 mA / cm ² , a form factor of 0.61, and a conversion efficiency of 2.65% were exhibited.

[Example 10]
1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide in Example 1 was converted to 1-ethyl-3-methylimidazolinium bis (pentafluoroethylsulfonyl) imide / lithium bis (trifluoromethane). A dye-sensitized solar cell was prepared and evaluated in the same manner as in Example 1 except that the sulfonyl) imide (weight ratio = 1/1) was changed.
As a result, excellent characteristics of an open circuit voltage = 0.92 V, a short circuit current density = 4.62 mA / cm ² , a form factor = 0.59, and a conversion efficiency = 2.51% were exhibited.

[Example 11]
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide in Example 1 was changed to lithium perchlorate. And evaluated.
As a result, excellent characteristics of an open circuit voltage = 0.93 V, a short circuit current density = 4.61 mA / cm ² , a form factor = 0.61, and a conversion efficiency = 2.62% were exhibited.

[Example 12]
On the hole transporting layer in Example 1, molybdenum oxide was vacuum-deposited by 5 nm, and gold was further vacuum-deposited by 100 nm to produce a dye-sensitized solar cell. On this, gold was vacuum-deposited to a thickness of 100 nm to prepare a dye-sensitized solar cell.
As a result, excellent characteristics of an open circuit voltage = 0.96 V, a short circuit current density = 4.71 mA / cm ² , a form factor = 0.65, and a conversion efficiency = 2.93% were exhibited.

[Example 13]
On the second hole transport layer in Example 7, molybdenum oxide was vacuum-deposited by 5 nm, and gold was further vacuum-deposited by 100 nm to produce a dye-sensitized solar cell. On this, gold was vacuum-deposited to a thickness of 100 nm to prepare a dye-sensitized solar cell.
As a result, excellent characteristics of an open circuit voltage = 0.95 V, a short circuit current density = 5.12 mA / cm 2, a form factor = 0.61, and a conversion efficiency = 2.96% were exhibited.

From the comparison of the evaluation results of the respective examples and comparative examples, when a material that does not exhibit polymerization reactivity is used, the photoelectric conversion characteristics deteriorate. That is, in the present embodiment, since the vinyl compound represented by the general formula (1) includes a polymer formed by a thermal reaction, the resistance is specifically lowered and the hole transport property is improved. Short-circuit current density and form factor can be obtained, and photoelectric conversion characteristics are improved.
As is apparent from the above, it can be seen that the dye-sensitized solar cell of the present invention exhibits excellent photoelectric conversion characteristics.

Japanese Patent No. 2664194 Japanese Patent Laid-Open No. 11-144773 JP 2000-106223 A

Nature, 353 (1991) 737 J. et al. 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

Claims (7)

A first electrode; an electron transport layer; a hole transport layer; and a second electrode. The hole transport layer includes a polymer derived from a vinyl compound represented by the following general formula (1): Photoelectric conversion element.

(In the formula, Ar represents an aryl group which may have a substituent.) The photoelectric conversion element according to claim 1, wherein the compound represented by the general formula (1) includes a compound represented by the following structural formula A.

The photoelectric conversion element according to claim 1 or 2, wherein the compound represented by the general formula (1) includes a compound represented by the following structural formula B.

  4. The photoelectric conversion element according to claim 1, wherein the electron transport layer includes at least one material selected from the group consisting of titanium oxide, zinc oxide, tin oxide, and niobium oxide.   The photoelectric conversion element according to claim 1, wherein the hole transport layer includes an ionic liquid.   The photoelectric conversion element according to claim 5, wherein the ionic liquid contains an imidazolium compound.   The second hole transport layer is provided between the hole transport layer and the second electrode, and the second hole transport layer includes a hole transporting polymer material. The photoelectric conversion element as described in any one of thru | or 6.

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