JP6850435B2 - Tertiary amine compounds, photoelectric conversion elements, and solar cells - Google Patents

Description

The present invention relates to a tertiary amine compound, a photoelectric conversion element, and a solar cell including the same.

In recent years, the driving power in electronic circuits has become extremely small, and it has become possible to drive various electronic components such as sensors even with weak power. Furthermore, when using sensors, they are expected to be applied to self-sustaining power sources (environmental power generation elements) that can generate and consume electricity on the spot. Among them, solar cells are attracting attention as elements that can generate electricity anywhere with light.

Among the solar cells, the dye-sensitized solar cell announced by Graetzel et al. Of Swiss Federal Institute of Technology has been reported to have higher photoelectric conversion characteristics than the amorphous silicon solar cell in a weak indoor light environment (non-amorphous silicon solar cell). See Patent Document 1).
Dye-sensitized solar cells that use conventional electrolytes with high power generation performance have concerns about volatilization and leakage of the electrolytes. Therefore, when it is assumed that the electrolytic solution will be put into practical use, it is desired that the electrolytic solution be solidified. Many reports have been made on those using low-molecular-weight organic hole transport materials (see, for example, Patent Document 1, Non-Patent Documents 2 and 3). It has been reported that when converting weak light such as room light into electricity, the current loss due to the internal resistance of the photoelectric conversion element is remarkable (see Non-Patent Document 4).

As described above, all of the solid-state photoelectric conversion elements that have been studied so far have reported only the power generation performance in pseudo-sunlight, and not the power generation performance in indoor light. In addition, most of the reported anodes of solar cells are dry film forming using silver or gold, and wet film forming is desirable in order to obtain a lower cost solar cell. The organic solvent used during wet film formation has a problem of dissolving the hole transport layer, and it is desirable to use an aqueous paste of a polythiophene derivative (PEDOT / PSS, etc.). However, it is known that heating at 100 ° C. or higher is required to remove the water component after film formation, and the residual moisture causes deterioration of the performance of the solar cell. Therefore, heating at 120 ° C. or higher is preferable in order to obtain durability, but performance deterioration due to heating is remarkable, and a solid dye-sensitized solar cell that has obtained high output has not been reported.

Therefore, in view of the above problems, the present invention provides a tertiary amine compound capable of obtaining a photoelectric conversion element capable of obtaining excellent photoelectric conversion characteristics in weak irradiation light such as room light even through a high temperature process. With the goal.

（式中、Ａｒ₁、Ａｒ₂は、それぞれアルキル基もしくはアルコキシ基を有するベンゼン環、無置換のベンゼン環、アルキル基もしくはアルコキシ基を有するナフタレン環、及び無置換のナフタレン環のいずれかを表す。） The above problem is solved by the invention of the following (1).
(1) A tertiary amine compound represented by the following general formula (1).

(In the formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. )

By incorporating the tertiary amine compound of the present invention into the hole transport layer of the photoelectric conversion element, a photoelectric conversion element capable of obtaining excellent photoelectric conversion characteristics in weak irradiation light such as indoor light can be obtained even through a high temperature process. be able to.

It is the schematic of an example which shows the structure of the photoelectric conversion element which concerns on this invention. It is the schematic of another example which shows the structure of the photoelectric conversion element which concerns on this invention. The tertiary amine compound No. obtained in Example I-1. It is an IR spectrum of 1-1.

（式中、Ａｒ₁、Ａｒ₂は、それぞれアルキル基もしくはアルコキシ基を有するベンゼン環、無置換のベンゼン環、アルキル基もしくはアルコキシ基を有するナフタレン環、及び無置換のナフタレン環のいずれかを表す。）
前記アルキル基やアルコキシ基は、置換もしくは無置換のどちらでも構わない。Ａｒ₁、Ａｒ₂は同一でも異なってもよい。
前記アルキル基としては、炭素数が１〜４のアルキル基が好ましく、前記アルコキシ基としては、メトキシ基、エトキシ基が好ましい。 The tertiary amine compound of the present invention is represented by the following general formula (1).

(In the formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. )
The alkyl group or alkoxy group may be substituted or unsubstituted. Ar ₁ and Ar ₂ may be the same or different.
The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, and the alkoxy group is preferably a methoxy group or an ethoxy group.

When the tertiary amine compound of the present invention is contained in the hole transport layer of the photoelectric conversion element, a photoelectric conversion element having excellent photoelectric conversion characteristics can be obtained by undergoing a high temperature process. Furthermore, it was possible to verify that the superiority appears particularly remarkably when photoelectric conversion is performed in weak light such as indoor light.

Specific exemplary compounds in the general formula (1) are described below, but are not limited thereto.

Hereinafter, the photoelectric conversion element and the solar cell according to the present invention will be described with reference to the drawings.
The present invention is not limited to the embodiments shown below, and can be modified within the range conceivable by those skilled in the art, such as other embodiments, additions, modifications, and deletions. However, as long as the action and effect of the present invention are exhibited, it is included in the scope of the present invention.

The first aspect of the photoelectric conversion element of the present invention has a first electrode, a hole blocking layer, an electron transport layer, a hole transport layer, and a second electrode, and the hole transport layer is the present invention. Contains the tertiary amine compound of the invention.
The configuration of the photoelectric conversion element and the solar cell will be described with reference to FIG. Note that FIG. 1 is an example of a cross-sectional view of a photoelectric conversion element and a solar cell.
In the embodiment shown in FIG. 1, the first electrode 2 is formed on the substrate 1, the hole blocking layer 3 is formed on the first electrode 2, and the porous electron transport layer 4 is formed on the hole blocking layer 3. Is formed, the photosensitizer 5 is adsorbed on the electron transporting material in the porous electron transporting layer 4, and the hole transporting layer 6 is sandwiched between the first electrode 2 and the second electrode 7 facing the first electrode 2. It has an excellent structure. Further, FIG. 1 shows an example of a configuration in which lead lines 8 and 9 are provided so that the first electrode 2 and the second electrode 7 are conductive. The details will be described below.

<Board>
The substrate 1 used in the present invention is not particularly limited, and known substrates 1 can be used. The substrate 1 is preferably made of a transparent material, and examples thereof include glass, a transparent plastic plate, a transparent plastic film, and an inorganic transparent crystal.

<First electrode>
The first electrode 2 used in the present invention is not particularly limited as long as it is a conductive substance transparent to visible light, and is a known electrode used for a normal photoelectric conversion element, a liquid crystal panel, or the like. Can be used.
Examples of the material of the first electrode include 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), and indium. Examples thereof include zinc oxide, niobium titanium oxide, graphene and the like, and these may be used alone or in combination of two or more.
The thickness of the first electrode is preferably 5 nm to 10 μm, more preferably 50 nm to 1 μm.

Further, in order to maintain a certain degree of hardness, the first electrode 2 is preferably provided on a substrate 1 made of a material transparent to visible light, and the substrate includes, for example, glass, a transparent plastic plate, a transparent plastic film, or an inorganic substance. A transparent crystal or the like is used.
A known one in which the first electrode 2 and the substrate 1 are integrated can also be used. For example, FTO-coated glass, ITO-coated glass, zinc oxide: aluminum-coated glass, FTO-coated transparent plastic film, ITO-coated transparent. Examples include a plastic film.
Further, a transparent electrode in which tin oxide or indium oxide is doped with cations or anions having different valences, or a metal electrode having a structure capable of transmitting light such as a mesh or a stripe is provided on a substrate such as a glass substrate. But it may be.

These may be used alone, or a mixture of two or more kinds, or a laminated one. Further, for the purpose of lowering the resistance, a metal lead wire or the like may be used together.
Examples of the material of the metal lead wire include metals such as aluminum, copper, silver, gold, platinum, and nickel. The metal lead wire can be formed by installing it on a substrate by thin film deposition, sputtering, crimping or the like, and then providing ITO or FTO on the metal lead wire.

<Hole blocking layer>
The material constituting the hole blocking layer 3 used in the present invention is not particularly limited as long as it is transparent to visible light and is an electron transporting material, but titanium oxide is particularly preferable. The hole blocking layer is provided in order to suppress a decrease in power due to the electrolyte coming into contact with the electrode and the electrons in the electrolyte recombining (so-called reverse electron transfer) with the holes in the electrolyte. The effect of the whole blocking layer 3 is particularly remarkable in the solid dye-sensitized solar cell. Compared with the wet dye-sensitized solar cell using the electrolytic solution, the solid dye-sensitized solar cell using the organic hole transport material etc. recombines the electrons in the hole in the hole transport material and the electrode surface ( (Reverse electron transfer) This is due to the high speed.

The film forming method of the hole blocking layer is not limited, but a high internal resistance is required to suppress the loss current in the room light, and the film forming method is also important. Generally, a sol-gel method, which is a wet film forming method, can be mentioned, but the film density is low and the loss current cannot be sufficiently suppressed. Therefore, a dry film forming method such as a sputtering method is more preferable, and the film density is sufficiently high and the loss current can be suppressed.
The hole blocking layer is also formed for the purpose of preventing electronic contact between the first electrode 2 and the hole transport layer 6. The film thickness of this hole blocking layer is not particularly limited, but is preferably 5 nm to 1 μm, more preferably 500 to 700 nm for wet film formation, and more preferably 10 nm to 30 nm for dry film formation.

<Electron transport layer>
The photoelectric conversion element and the solar cell of the present invention form a porous electron transport layer 4 on the hole blocking layer 3, and the electron transport layer may be a single layer or a multi-layer. Good.
The electron transport layer is composed of an electron transport material, and semiconductor fine particles are preferably used as the electron transport material.
In the case of multiple layers, dispersions of semiconductor fine particles having different particle sizes can be applied in multiple layers, or different types of semiconductors, resins, and coating layers having different composition of additives can be applied in multiple layers.
Multilayer coating is an effective means when the film thickness is insufficient after one coating.
In general, as the film thickness of the electron transport layer increases, the amount of supported photosensitizer material per unit projected area also increases, so the light capture rate increases, but the diffusion distance of the injected electrons also increases, so the charge is regenerated. The loss due to bonding 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 known semiconductors can be used.
Specific examples thereof include elemental semiconductors such as silicon and germanium, compound semiconductors typified by metallic chalcogenides, and compounds having a perovskite structure.
Metallic chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, ittrium, lantern, vanadium, niobium, or tantalum oxides, cadmium, zinc, lead, silver, antimony, bismuth. Examples include sulfide, cadmium, lead selenium, and cadmium telluride.
As other compound semiconductors, phosphides such as zinc, gallium, indium and cadmium, gallium arsenic, copper-indium-selenium, copper-indium-sulfide and the like are preferable.
Further, as the compound having a perovskite structure, strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate and the like are preferable.

Among these, oxide semiconductors are preferable, titanium oxide, zinc oxide, tin oxide, and niobium oxide are particularly preferable, and they may be used alone or in a mixture of two or more kinds. The crystal type of these semiconductors is not particularly limited, and may be single crystal, polycrystalline, or amorphous.
The size of the semiconductor fine particles is not particularly limited, but the average particle size of the primary particles is preferably 1 to 100 nm, more preferably 5 to 50 nm.
It is also possible to improve efficiency by the effect of mixing or laminating semiconductor fine particles having a larger average particle size to scatter incident light. In this case, the average particle size of the semiconductor is preferably 50 to 500 nm.

The method for producing the electron transport layer is not particularly limited, and examples thereof include a method of forming a thin film in a vacuum such as sputtering and a wet film forming method.
In consideration of manufacturing cost and the like, a wet film forming method is particularly preferable, and a method of preparing a paste in which a powder of semiconductor fine particles or a sol is dispersed and applying it on 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 carried out 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 various wet printing methods such as letterpress, offset, gravure, concave plate, rubber plate, screen printing, etc. Method can be used.
When the dispersion liquid of the semiconductor fine particles is mechanically pulverized or produced by using a mill, it is formed by at least the semiconductor fine particles alone or a mixture of the semiconductor fine particles and the resin dispersed in water or an organic solvent.

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

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

The dispersion of semiconductor fine particles or the paste of semiconductor fine particles obtained by the sol-gel method or the like contains acids such as hydrochloric acid, nitric acid and acetic acid, polyoxyethylene (10) octylphenyl ether and the like in order to prevent reaggregation of the particles. Surfactants, chelating agents such as acetylacetone, 2-aminoethanol, ethylenediamine and the like 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 to be added at this time include polymers such as polyethylene glycol and polyvinyl alcohol, and thickeners such as ethyl cellulose.

After coating the semiconductor fine particles, the particles are preferably electronically contacted with each other, and firing, microwave irradiation, electron beam irradiation, or laser light irradiation is preferably performed in order to improve the film strength and the adhesion to the substrate. .. These processes may be performed individually or in combination of two or more types.
In the case of 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 increase or the substrate may melt. Therefore, 30 to 700 ° C. is preferable, and 100 to 600 ° C. is more preferable. preferable. The firing time is also not particularly limited, but is preferably 10 minutes to 10 hours.
The microwave irradiation may be performed from the electron transport layer forming side or from the back side.
The irradiation time is not particularly limited, but it is preferably performed within 1 hour.

After firing, for the purpose of increasing the surface area of the semiconductor fine particles and increasing the electron injection efficiency from the photosensitizing material into the semiconductor fine particles, for example, chemical plating using an aqueous solution of titanium tetrachloride or a mixed solution with an organic solvent or titanium trichloride An electrochemical plating treatment using an aqueous solution may be performed.
A film obtained by laminating semiconductor fine particles having a diameter of several tens of nm by sintering or the like forms a porous state. This nanoporous structure has a very high surface area, which can be expressed using the roughness factor.
This roughness factor is a numerical value representing the actual area inside the porous medium with respect to the area of the semiconductor fine particles coated on the substrate. Therefore, the larger the roughness factor is, the more preferable it is, but in the present invention, it is preferably 20 or more because of the relationship with the film thickness of the electron transport layer.

<Photosensitizer material>
In the present invention, in order to further improve the conversion efficiency, it is preferable to adsorb the photosensitizer material on the surface of the electron transporting material which is the porous electron transporting layer 4.
The photosensitizing material 5 is not limited to the above as long as it is a compound that is photoexcited by the excitation light used, and specific examples thereof include the following compounds.

Metal complex compounds described in JP-A-7-500630, JP-A-10-233238, JP-A-2000-26487, JP-A-2000-323191, JP-A-2001-59062, etc. 10-93118, JP-A-2002-164809, JP-A-2004-95450, J. Mol. Phys. Chem. C, 7224, Vol. 111 (2007) and the like, coumarin compounds, JP-A-2004-954450, Chem. Commun. , 4887 (2007) and the like, JP-A-2003-264010, JP-A-2004-63274, JP-A-2004-115636, JP-A-2004-200068, JP-A-2004-235502. , J.M. Am. Chem. Soc. , 12218, Vol. 126 (2004), Chem. Commun. , 3036 (2003), Angew. Chem. Int. Ed. , 1923, Vol. 47 (2008) and the like. Am. Chem. Soc. , 16701, Vol. 128 (2006), J. Mol. Am. Chem. Soc. , 14256, Vol. The thiophene compound described in 128 (2006) and the like, JP-A-11-86916, JP-A-11-214730, JP-A-2000-106224, JP-A-2001-76773, JP-A-2003-7359. Cyanine dyes described in JP-A-11-214731, JP-A-11-238905, JP-A-2001-52766, JP-A-2001-76775, JP-A-2003-7360 and the like. Dyes, 9-arylxanthene compounds described in JP-A-10-92477, JP-A-11-273754, JP-A-11-273755, JP-A-2003-31273, etc., JP-A-10-93118, Triarylmethane compounds described in JP-A-2003-31273, JP-A-9-199744, JP-A-10-233238, JP-A-11-204821, JP-A-11-265738, J. Mol. Phys. Chem. , 2342, Vol. 91 (1987), J. Mol. Phys. Chem. B, 6272, Vol. 97 (1993), Electrical. Chem. , 31, Vol. 537 (2002), JP-A-2006-032260, J. Mol. Porphyrins Phthalocyanines, 230, Vol. 3 (1999), Angew. Chem. Int. Ed. , 373, Vol. 46 (2007), Langmuir, 5436, Vol. 24 (2008) and the like, the phthalocyanine compound, the porphyrin compound and the like can be mentioned. In particular, among these, it is preferable to use a metal complex compound, a coumarin compound, a polyene compound, an indoline compound, and a thiophene compound.
More preferably, D131 represented by the following structural formula (3), D102 represented by the following structural formula (4), and D358 represented by the following structural formula (5) manufactured by Mitsubishi Paper Mills Limited can be mentioned.

As a method of adsorbing the photosensitizing material 5 on the porous electron transport layer 4, a method of immersing an electron collecting electrode containing semiconductor fine particles in a photosensitizing material solution or a dispersion liquid, a solution or a dispersion liquid. Can be applied to a porous electron transport layer and adsorbed.
In the former case, a dipping method, a dip method, a roller method, an air knife method, or the like can be used.
In the latter case, the wire bar method, the slide hopper method, the extrusion method, the curtain method, the spin method, the spray method and the like can be used.
Further, it may be adsorbed in a supercritical fluid using carbon dioxide or the like.

When adsorbing the photosensitizer, a condensing agent may be used in combination.
The condensing agent has a catalytic action that seems to physically or chemically bind the photosensitizer and the electron transport compound to the surface of the inorganic substance, or acts stoichiometrically to favorably shift the chemical equilibrium. Any of them may be used.
Further, a thiol or a hydroxy compound may be added as a condensation aid.

Examples of the solvent for dissolving or dispersing the photosensitizer include water, methanol, ethanol, alcohol-based solvents such as isopropyl alcohol, and the like.
Ketone solvents such as acetone, methyl ethyl ketone, or methyl isobutyl ketone,
Ester solvents such as ethyl formate, ethyl acetate, or n-butyl acetate,
Ether-based 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,
Halogenated hydrocarbon solvents such as dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichlorethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, or 1-chloronaphthalene.
Hydrocarbons such as n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, or cumene. System solvents can be mentioned, and these can be used alone or as a mixture of two or more kinds.

Further, depending on the type of photosensitizer, there is a material that works more effectively if the aggregation between compounds is suppressed. Therefore, a coagulation dissociator may be used in combination.
As the coagulation dissociator, a steroid compound such as cholic acid or chenodeoxycholic acid, a long-chain alkylcarboxylic acid or a long-chain alkylphosphonic acid is preferable, and the photosensitizer to be used is appropriately selected.
The amount of these coagulation dissociators added 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 photosensitizer.

Using these, the temperature at which the photosensitizer or the photosensitizer and the coagulation / dissociator are adsorbed is preferably −50 ° C. or higher and 200 ° C. or lower.
Further, this adsorption may be carried out while standing or stirring.
Examples of the method for stirring 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 even more preferably 1 minute or more and 150 hours.
Further, the adsorption is preferably performed in a dark place.

（式中、Ｒ₁は、水素原子もしくはメチル基を表す。） <Hall transport layer>
Generally, the hole transport layer includes an electrolytic solution in which a redox pair is dissolved in an organic solvent, a gel electrolyte in which a liquid in which a redox pair is dissolved in an organic solvent is impregnated in a polymer matrix, a molten salt containing a redox pair, and a solid. An electrolyte, an inorganic hole transport material, an organic hole transport material, and the like are used, and the hole transport layer 6 of the present invention preferably contains an organic hole transport material represented by the following general formula (2).

(In the formula, R ₁ represents a hydrogen atom or a methyl group.)

The hole transport layer in the present invention may have a single-layer structure or a laminated structure composed of different compounds. In the case of a laminated structure, it is preferable to use a polymer material for the organic hole transport material layer near the second electrode 7.
This is because the surface of the porous electron transport layer can be further smoothed and the photoelectric conversion characteristics can be improved by using a polymer material having excellent film forming properties.
In addition, since it is difficult for the polymer material to penetrate into the porous electron transport layer, it is also excellent in covering the surface of the porous electron transport layer, and is also effective in preventing short circuits when providing electrodes. Therefore, it is possible to obtain higher performance.

Known organic hole transporting compounds are used as the organic hole transporting material used in the single layer structure and the organic hole transporting material used in the hole transporting layer far from the second electrode 7 in the laminated structure.
Specific examples thereof include the oxadiazole compound shown in Japanese Patent Publication No. 34-5466, the triphenylmethane compound shown in Japanese Patent Publication No. 45-555, and Japanese Patent Publication No. 52-4188. Pyrazoline compounds shown, hydrazone compounds shown in JP-A-55-42380, etc., oxadiazole compounds shown in JP-A-56-123544, etc., JP-A-54-58445. Examples thereof include the tetraarylbenzidine compound shown in Japanese Patent Application Laid-Open No. 58-65440 or the stillben compound shown in Japanese Patent Application Laid-Open No. 60-98437.

Among them, the organic hole transporting material represented by the general formula (2), the organic hole transporting material represented by the following structural formula (6) described in Non-Patent Document 2, and the following structure described in Non-Patent Document 3. The organic hole transport material represented by the formula (7) exhibits particularly excellent photoelectric conversion characteristics.

The hole transport layer having a single-layer structure and the hole transport layer far from the second electrode 7 in the laminated structure preferably contain 50 to 95% by mass of the organic hole transport material represented by the general formula (2). , 70 to 85% by mass is more preferable.

As the polymer material used for the hole transport layer close to the second electrode 7 used in the laminated structure, a known hole transport polymer material is used.
Specific examples thereof include poly (3-n-hexylthiophene), poly (3-n-octyloxythiophene), poly (9,9'-dioctyl-fluorene-co-bithiophene), and poly (3,3''. '-Gidodecyl-quarterthiophene), poly (3,6-dioctylthiophene [3,2-b] thiophene), poly (2,5-bis (3-decylthiophen-2-yl) thieno [3,2-b] ] Thiophene), poly (3,4-didecylthiophene-cothieno [3,2-b] thiophene), poly (3,6-dioctylthiophene [3,2-b] thiophene-cothieno [3, 2-b] thiophene), poly (3,6-dioctylthiophene [3,2-b] thiophene-co-thiophene), poly (3.6-dioctylthiophene [3,2-b] thiophene-co-bithiophene) Polythiophene compounds, etc.
Poly [2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene vinylene], poly [2-methoxy-5- (3,7-dimethyloctyloxy) -1,4-phenylene vinylene], poly Polyphenylene vinylene compounds such as [(2-methoxy-5- (2-ethylphenyloxy) -1,4-phenylene vinylene) -co- (4,4'-biphenylene vinylene)],
Poly (9,9'-zidodecylfluorenyl-2,7-diyl), poly [(9,9-dioctyl-2,7-divinylenefluorene) -alt-co- (9,10-anthracene)] , Poly [(9,9-dioctyl-2,7-divinylene fluorene) -alt-co- (4,4'-biphenylene)], poly [(9,9-dioctyl-2,7-divinylene fluorene) -Alt-co- (2-methoxy-5- (2-ethylhexyloxy) -1,4-phenylene)], poly [(9,9-dioctyl-2,7-diyl) -co- (1,4-diyl) (2,5-dihexyloxy) benzene)] and other polyfluorene compounds,
Polyphenylene compounds such as poly [2,5-dioctyloxy-1,4-phenylene] and poly [2,5-di (2-ethylhexyloxy-1,4-phenylene]],
Poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (N, N'-diphenyl) -N, N'-di (p-hexylphenyl) -1,4-diamino Benzene], 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-diphenylene)] (2-Ethylhexyloxy) phenyl) benzidine-N, N'-(1,4-diphenylene)], poly [phenylimino-1,4-phenylene vinylene-2,5-dioctyloxy-1,4-phenylene vinylene- 1,4-Phenylene], poly [p-triluimino-1,4-phenylene vinylene-2,5-di (2-ethylhexyloxy) -1,4-phenylene vinylene-1,4-phenylene], poly [4- (2-Ethylhexyloxy) 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- Polythiadiazole compounds such as co- (1,4-benzo (2,1', 3) thiadiazole) can be mentioned.
Among these, polythiophene compounds and polyarylamine compounds are particularly preferable in consideration of carrier mobility and ionization potential.

Further, various additives may be added to the organic hole transport material shown above.
Examples of the additive include metal iodides such as iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, and silver iodide.
Quaternary ammonium salts such as tetraalkylammonium iodide and pyridinium iodide, metallic bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, calcium bromide, etc.
Bromates 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 sulphate and zinc sulphate, metal complexes such as ferrocyanate-ferricanate and ferrocene-ferricinium ion,
Sulfur compounds such as polysodium sulfide, alkylthiols-alkyldisulfides,
Viologen dye, hydroquinone, etc., 1,2-dimethyl-3-n-propyl imidazolinium iodide, 1-methyl-3-n-hexylmidazolinium iodide, 1,2-dimethyl-3-ethylimidazo Rium trifluoromethanesulfonate, 1-methyl-3-butylimidazolium nonafluorobutyl sulfonate, 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide, 1-methyl-3 -Inorg. Such as ethylimidazolium bis (trifluoromethylsulfonyl) imide. Chem. 35 (1996) 1168. Ionic liquid imidazolium compounds, basic compounds such as pyridine, 4-t-butylpyridine, benzimidazole, etc.
Examples thereof include lithium compounds such as lithium trifluoromethanesulfonylimide, lithium diisopropylimide, and lithium bis (trifluoromethanesulfonyl) imide.
An ionic liquid imidazolium compound may be used, and specifically, 1-n-hexyl-3-methylimidazolinium bis (trifluoromethylsulfonyl) imide is preferable.

（式中、Ａｒ₁、Ａｒ₂は、それぞれアルキル基もしくはアルコキシ基を有するベンゼン環、無置換のベンゼン環、アルキル基もしくはアルコキシ基を有するナフタレン環、及び無置換のナフタレン環のいずれかを表す。アルキル基やアルコキシ基は、置換もしくは無置換のどちらでも構わない。Ａｒ₁、Ａｒ₂は同一でも異なってもよい。） In the present invention, by adding the tertiary amine compound represented by the following general formula (1) to the hole transport layer, excellent photoelectric conversion characteristics can be obtained even through a high temperature process.

(In the formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. The alkyl group and the alkoxy group may be substituted or unsubstituted. Ar _{1 and Ar 2} may be the same or different.)

Tarsal butyl pyridine, which is a conventionally reported basic compound, is a liquid material having a relatively small molecular weight. A 60 ° C heat resistance test using tarsal butyl pyridine has been reported (ACS Appl. Mater. Interfaces, 2015, 7 (21), pp 11107-11116). It is considered that the output of conventional materials is reduced due to changes in the morphology of organic P-type semiconductors in the hole transport layer and constituent materials such as basic compounds and lithium salts during the high temperature process.
In order to suppress morphological changes, it is considered that one solution is to use an organic P-type semiconductor as a highly crystalline material, but the organic P-type semiconductor in a solid dye-sensitized solar cell must be in an amorphous state. High output cannot be obtained. Therefore, as a result of diligent studies, it was discovered that increasing the molecular weight of the basic material can suppress the change in morphology. Specifically, even if it is heated to a high temperature such as 120 ° C., the output does not deteriorate, and on the contrary, both the open circuit voltage and the short-circuit current density increase, and as a result, a solid dye-sensitized solar cell with higher output can be obtained. I was able to do it.

The amount of the tertiary amine compound represented by the general formula (1) added to the hole transport layer is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the organic hole transport material. More preferably, it is 10 parts by mass or more and 30 parts by mass or less.

Further, by containing the tertiary amine compound represented by the general formula (1), the internal resistance of the photoelectric conversion element is further increased, and the current loss in ultra-weak light such as indoor light can be reduced. Further, the tertiary amine compound represented by the general formula (1) is an amine derivative having a tribenzyl skeleton, and has a higher oxidation potential than the hole transport material represented by the general formula (2), thereby inhibiting hole transport. Never. Amine derivatives with an alkyl skeleton have a low oxidation potential and inhibit hole transport. There are also compounds with two benzyl groups, but their basicity is weak and the output of the solar cell is inferior. Therefore, it was found that the amine derivative having a tribenzyl skeleton has a high basicity and an oxidation potential that does not inhibit hole transport, and an appropriate internal resistance can be obtained by adding it to the hole transport layer.

Further, for the purpose of improving the conductivity, an oxidizing agent for converting a part of the organic hole transport material into a radical cation may be added.
Examples of the oxidizing agent include tris (4-bromophenyl) aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluovorate, silver nitrate, and cobalt complex compounds.
It is not necessary that all the organic hole transport materials are oxidized by the addition of this oxidizing agent, and only a part of the organic hole transport material needs to be oxidized. Further, the added oxidizing agent may or may not be taken out of the system after being added.

The hole transport layer directly forms the hole transport layer on the porous electron transport layer 4 carrying the photosensitizer material. The method for producing the hole transport layer is not particularly limited, and examples thereof include a method of forming a thin film in vacuum such as vacuum deposition and a wet film forming method. In consideration of manufacturing cost and the like, a wet film forming method is particularly preferable, and a method of coating on a porous electron transport layer is preferable.

When this wet film forming method is used, the coating method is not particularly limited and can be carried out 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 various wet printing methods such as letterpress, offset, gravure, concave plate, rubber plate, screen printing, etc. Method can be used. Further, the film may be formed in a supercritical fluid or a subcritical fluid having a temperature and pressure lower than the critical point.

The supercritical fluid exists as a non-aggregating high-density fluid in a temperature / pressure region exceeding the limit (critical point) at which a gas and a liquid can coexist, does not aggregate even when compressed, and has a critical temperature or higher and a critical pressure. As long as the fluid is in the above state, there is no particular limitation and it can be appropriately selected depending on the intended purpose, but a fluid having a low critical temperature is preferable.

Examples of supercritical fluids include 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 suitable. 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, is nonflammable, and is easy to handle.
Further, these fluids may be used alone or in a mixture of two or more kinds.

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 depending on the intended purpose.
The compounds listed as the above-mentioned supercritical fluids can also be suitably used as subcritical fluids.

The critical temperature and critical pressure of the supercritical fluid are not particularly limited and can be appropriately selected depending on the intended purpose. However, the critical temperature is preferably -273 ° C or higher and 300 ° C or lower, and 0 ° C or higher and 200 ° C or lower in particular. preferable.

Further, in addition to the above-mentioned 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 a 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.
For example, a ketone solvent such as acetone, methyl ethyl ketone, or methyl isobutyl ketone,
Ester solvents such as ethyl formate, ethyl acetate, or n-butyl acetate,
Ether-based solvents such as diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane,
Amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone,
Halogenated hydrocarbon solvents such as dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichlorethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, or 1-chloronaphthalene.
Hydrocarbons such as n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, or cumene. Examples include system solvents.

In the present invention, the hole transport layer may be provided on the first electrode provided with the electron transport layer coated with the photosensitizer, and then the press treatment step may be performed.
It is believed that the press treatment will improve the efficiency because the organic hole transport material will be in close contact with the porous electrode.
The press processing method is not particularly limited, and examples thereof include a press molding method using a flat plate as represented by an IR tablet shaper, and a roll press method using a roller or the like.
The pressure is preferably 10 kgf / cm ² or more, and more preferably 30 kgf / cm ² or more. The press processing time is not particularly limited, but it is preferably performed within 1 hour. Further, heat may be applied during the pressing process.
Further, during the above-mentioned pressing process, a mold release material may be sandwiched between the press machine and the electrodes.

Examples of the release material include polytetrafluoride ethylene, polychlorotrifluoroethylene, tetrafluoride ethylene hexafluoride propylene copolymer, perfluoroalkoxyfluororesin, polyvinylidene fluoride, ethylene tetrafluoride ethylene copolymer, and ethylene. Fluororesin such as chlorotrifluoroethylene copolymer and polyvinylidene fluoride can be mentioned.

After performing the above press processing step and before providing the counter electrode, a metal oxide may be provided between the hole transport layer and the second 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.

The method of providing these metal oxides on the hole transport layer is not particularly limited, and examples thereof include a method of forming a thin film in vacuum such as sputtering and vacuum deposition, and a wet film forming method.
In the wet film forming method, a method in which a metal oxide powder or a sol-dispersed paste is prepared and applied onto the hole transport layer is preferable.
When this wet film forming method is used, the coating method is not particularly limited and can be carried out 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 various wet printing methods such as letterpress, offset, gravure, concave plate, rubber plate, screen printing, etc. Method can be used. The film thickness is preferably 0.1 to 50 nm, more preferably 1 to 10 nm.

<Second electrode>
The second electrode is newly applied after the hole transport layer is formed or on the above-mentioned metal oxide.
Further, as the second electrode, the same one as that of the first electrode described above can be usually used, and a support is not always necessary in a configuration in which sufficient strength and sealing property are maintained.
Specific examples of the second electrode material include metals such as platinum, gold, silver, copper and aluminum, carbon-based compounds such as graphite, fullerenes, carbon nanotubes and graphene, and conductive metal oxides such as ITO, FTO and ATO. , Polythiophene, polyaniline and other conductive polymers.

The film thickness of the second electrode layer is not particularly limited, and may be used alone or in a mixture of two or more kinds.
The coating of the second electrode can be appropriately formed on the hole transport layer by a method such as coating, laminating, vapor deposition, CVD, or bonding, depending on the type of material used and the type of hole transport layer.
When the second electrode is wet-formed, if an organic solvent is used during the wet film formation, there is a problem of dissolving the hole transport layer, and an aqueous paste such as a polythiophene derivative (PEDOT / PSS, etc.) or a metal nanowire is used. Is desirable. Since the residual moisture causes deterioration of the performance of the photoelectric conversion element, heating at 100 ° C. or higher, preferably about 120 ° C. is required in order to remove the water component after film formation.
Although the performance of the conventional photoelectric conversion element deteriorates when the high temperature process as described above is performed, the photoelectric conversion element of the present invention is excellent in photoelectric conversion in weak irradiation light such as room light even after the high temperature process. The characteristics are obtained.

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

A second aspect of the photoelectric conversion element of the present invention is provided on a transparent conductive film substrate, a first electrode, a hole blocking layer provided on the first electrode, and a hole blocking layer. An electron transport layer, an organic-inorganic perovskite compound layer provided on the electron transport layer, a hole transport layer provided on the organic-inorganic perobskite compound layer, and a second electrode provided on the hole transport layer. The hole transport layer is a photoelectric conversion element containing the tertiary amine compound of the present invention.
The configuration of the photoelectric conversion element and the solar cell will be described with reference to FIG. Note that FIG. 2 is an example of a cross-sectional view of the photoelectric conversion element and the solar cell.
In the embodiment shown in FIG. 2, the transparent conductive film substrate 1, the first electrode 2 provided on the transparent conductive film substrate 1, the hole blocking layer 3 provided on the first electrode 2, and the hole blocking layer Hole transport provided on the porous electron transport layer 4 provided on the 3, the organic-inorganic perovskite compound layer 10 provided on the porous electron transport layer 4, and the organic-inorganic perovskite compound layer 10. The layer 6 has a second electrode 7 provided on the hole transport layer 6.
The first electrode, the hole blocking layer, the electron transport layer, the hole transport layer, and the second electrode in the second aspect are the first electrode, the hole blocking layer, the electron transport layer, and the holes in the first aspect. Since it is the same as the transport layer and the second electrode, only different components will be described.

<Organic-inorganic perovskite compound layer>
The organic-inorganic perovskite compound layer 10 in the present invention contains the organic-inorganic perovskite compound and is provided on the electron transport layer.
The organic-inorganic perovskite compound in the present invention is a composite substance of an organic compound and an inorganic compound, and preferably exhibits a layered perovskite-type structure in which layers made of metal halide and layers in which organic cation molecules are arranged are alternately laminated. It is preferably a compound represented by the general formula (a).
X _α Y _β M _γ・ ・ ・ General formula (a)

In the above general formula (a), X is a halogen atom, Y is at least one selected from alkylammonium, formamidinium, and cesium (except when only cesium is used), M is lead and / or tin, α: The ratio of β: γ is 3: 1: 1.
Specifically, X can include halogen atoms such as chlorine, bromine and iodine, which can be used alone or as a mixture. Y can be at least one selected from alkylammoniums such as methylammonium, ethylammonium, n-butylammonium, formamidinium, and cesium. However, the case of only cesium is excluded. M represents lead and / or tin.
As the alkylammonium, methylammonium is preferable.
When two or more types of X, Y, and M are used, α, β, and γ are the sum of the two or more types of ions used.

The organic-inorganic perovskite compound in the present invention is, for example, a solution prepared by dissolving or dispersing a metal halide (a mixture of lead halide and tin halide) and an alkylamine halide or formamidine halide in a solvent on an electron transport layer. A one-step precipitation method formed by coating and drying the mixture, or a solvent in which a metal halide is dissolved or dispersed is applied onto the electron transport layer and dried, and then alkylamine halide or formamidine halide is dissolved in the solvent. Any of the two-step precipitation methods for forming an organic-inorganic perovskite compound by immersing in a solution may be used, but the two-step precipitation method is particularly preferable. As the halogenated alkylamine, methylamine halide is preferable, and it is preferable to contain either methylamine halide or formamidine halogenated.
As a method of applying on the electron transport layer, a dipping method, a spin coating method, a spray method, a dip method, a roller method, an air knife method and the like can be used. Further, it may be deposited on the electron transport layer in a supercritical fluid using carbon dioxide or the like.

In the case of the two-step precipitation method, the method of contacting the metal halide formed on the electron transport layer with a solution such as an alkylamine halide is a dipping method, a spin coating method, a spray method, a dip method, or a roller method. , Air knife method and the like can be used. Further, it may be precipitated by contacting with an alkylamine halide in a supercritical fluid using carbon dioxide or the like.
The film thickness of the organic-inorganic perovskite compound layer is preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm.

Further, the photosensitizer may be adsorbed after the perovskite compound layer is formed on the electron transport layer. The photosensitizer 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 compound used as the photosensitizer in the first aspect. Further, it can be adsorbed in the same manner as the photosensitizer material in the first aspect. The organic-inorganic perovskite compound layer also has an empty wall between the crystal structures, and the photosensitizer in a solution state permeates and can be adsorbed on the surface of the porous electron transport layer.

In the organic photoelectric conversion element of the present invention, in order to prevent deterioration of the element due to oxygen, moisture, etc., a sealing material can be used for sealing.
The sealing material and the sealing method are not particularly limited and may be appropriately selected depending on the intended purpose.

<Use>
The photoelectric conversion element of the present invention can be applied to a solar cell and a power supply device including the solar cell.
As an application example, any device that has conventionally used a solar cell or a power supply device using the solar cell can be used.
For example, it may be used for a solar cell for an electronic desk calculator or a wristwatch, and an example of utilizing the features of the photoelectric conversion element of the present invention is a power supply device such as a mobile phone, an electronic organizer, or an electronic paper. It can also be used as an auxiliary power source to prolong the continuous use time of rechargeable or dry battery type electric appliances. Furthermore, it can be used as a self-supporting power source for a sensor and as a substitute for a primary battery in combination with a secondary battery.

（上記式中、Ａｒ₁、Ａｒ₂は、それぞれアルキル基もしくはアルコキシ基を有するベンゼン環、無置換のベンゼン環、アルキル基もしくはアルコキシ基を有するナフタレン環、及び無置換のナフタレン環のいずれかを表す。アルキル基やアルコキシ基は、置換もしくは無置換のどちらでも構わない。Ａｒ₁、Ａｒ₂は同一でも異なってもよい。Ｘは、ハロゲン元素を表す。） <Method for synthesizing the tertiary amine compound of the present invention>
Similar to the reported example (J. Org .Chem., 67 (2002) 3029), it can be easily synthesized from the following route.

(In the above formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. The alkyl group and the alkoxy group may be substituted or unsubstituted. Ar _{1 and Ar 2} may be the same or different. X represents a halogen element.)

Hereinafter, the present invention will be specifically described with reference to Examples, but the embodiments of the present invention are not limited to these Examples.

４−ブロモベンジルブロミド（東京化成社製）：４．９９ｇとジベンジルアミン（東京化成社製）：３．９５ｇと炭酸カリウム（関東化学社製）：４．１４ｇとオルトジクロロベンゼン（関東化学社製）：５０ｍｌを３つ口フラスコに秤量し、９０℃で３時間加熱攪拌を行った。反応物を、抽出し、硫酸マグネシウムを加えた後、濾過し、濃縮した。粗収物をカラムクロマトグラフィー（トルエン／シクロヘキサン＝１／１）で精製し、無色オイル状のブロモ中間体（７．０８ｇ）を得た。 [Example I-1]
(Synthesis of tertiary amine compound (Compound No. 1-1))

4-Bromobenzyl bromide (manufactured by Tokyo Kasei Co., Ltd.): 4.99 g and dibenzylamine (manufactured by Tokyo Kasei Co., Ltd.): 3.95 g and potassium carbonate (manufactured by Kanto Chemical Co., Inc.): 4.14 g and ortodichlorobenzene (manufactured by Kanto Chemical Co., Inc.) (Manufactured): 50 ml was weighed in a three-necked flask, and heated and stirred at 90 ° C. for 3 hours. The reaction was extracted, magnesium sulfate was added, filtered and concentrated. The crude product was purified by column chromatography (toluene / cyclohexane = 1/1) to obtain a colorless oily bromo intermediate (7.08 g).

Synthesized bromo intermediate: 5.9 g and 4-pyridylboronic acid (manufactured by Tokyo Kasei Co., Ltd.): 1.18 g and tetrakis (triphenylphosphine) palladium (manufactured by Tokyo Kasei Co., Ltd.): 0.93 g, potassium carbonate (Kanto Chemical Co., Inc.) ): 8.9 g, ethanol: 100 ml, and water: 100 ml were weighed and stirred under reflux in an argon gas atmosphere. The reaction was extracted, magnesium sulfate was added, and the mixture was filtered and concentrated. The crude product was purified by column chromatography (toluene / ethyl acetate = 1/1) to obtain a colorless powdery tertiary amine compound (Compound No. 1-1) (1.3 g). The IR spectrum of the obtained tertiary amine compound is shown in FIG.

[Example II-1]
(Manufacturing of titanium oxide semiconductor electrode)
A dense hole blocking layer of titanium oxide was formed on the ITO-based glass substrate by reactive sputtering with oxygen gas using a target made of metallic titanium.
Next, bead mill with 3 g of titanium oxide (P90 manufactured by Nippon Aerosil), 0.2 g of acetylacetone, 0.3 g of surfactant (polyoxyethylene octylphenyl ether manufactured by Wako Pure Chemical Industries, Ltd.) with 5.5 g of water and 1.0 g of ethanol. The treatment was carried out 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 hole blocking layer so as to have a film thickness of 1.5 μm, dried at room temperature, and then calcined in air at 500 ° C. for 30 minutes to form a porous electron transport layer.

(Manufacturing of photoelectric conversion element)
The titanium oxide semiconductor electrode is immersed as a sensitizing dye in D102 (0.5 mM, acetonitrile / t-butanol (volume ratio 1: 1) solution) manufactured by Mitsubishi Paper Mills Limited represented by the structural formula (4). It was allowed to stand in a dark place for a while to adsorb the photosensitizer.
On a semiconductor electrode carrying a photosensitizer, an organic hole transport material (H101, Dyesol) represented by the following structural formula (8): 183.3 mg of a chlorobenzene solution: 1 ml, and a lithium bis (trifluo) manufactured by Kanto Chemical Co., Inc. A photosensitizer was carried on the solution obtained by adding 12.83 mg of lomethanesulfonyl) imide and 36.66 mg of a tertiary amine compound (Compound No. 1-1) represented by the general formula (1). A hole transport layer was formed on the semiconductor electrode by spin coating. A PEDOT / PSS (Aldrich: Orgacon ^TM EL-P-5015) paste was formed on this by screen printing and dried by heating at 120 ° C. for 30 minutes to prepare a second electrode to prepare a photoelectric conversion element.

(Evaluation of photoelectric conversion element)
The photoelectric conversion efficiency of the obtained photoelectric conversion element under white LED irradiation (100 lux: 25 μW / cm ^{2) was measured.} The white LED was measured by a desk lamp CDS-90α (study mode) manufactured by Cosmo Techno Co., Ltd., and the evaluation device was measured by a solar cell evaluation system As-510-PV03 manufactured by NF Circuit Design Block Co., Ltd. The results are shown in Table 1.

[Example II-2]
Implementation except that the organic hole transport material in Example II-1 was changed to the organic hole transport material (SHT-263, Merck Co., Ltd.) represented by the structural formula (6) represented by the general formula (2). A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-1. The results are shown in Table 1.

[Example II-3]
Except that the organic hole transport material in Example II-1 was changed to the organic hole transport material (LT-S9170, Luminescence Technology Co., Ltd.) represented by the structural formula (7) represented by the general formula (2). A photoelectric conversion element was produced and evaluated in the same manner as in Example II-1. The results are shown in Table 1.

[Examples II-4 to 7]
Compound No. in Example II-3. A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-3 except that the tertiary amine compound 1-1 was changed to the tertiary amine compound shown in Table 1. The results are shown in Table 1.

[Example II-8]
A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-2, except that silver was formed into a 100 nm film by vacuum vapor deposition for the second electrode in Example II-2. The results are shown in Table 1.

[Example III-1]
(Manufacturing of titanium oxide semiconductor electrode)
Titanium tetra-n-propoxide (2 ml), acetic acid (4 ml), ion-exchanged water (1 ml), and 2-propanol (40 ml) were mixed, spin-coated on an FTO glass substrate, dried at room temperature, and then fired in air at 450 ° C. for 30 minutes. Using the same solution again, it was applied on the obtained electrode by spin coating so as to have a film thickness of 50 nm, and calcined in air at 450 ° C. for 30 minutes to form a dense hole blocking layer.
18NR-T (titanium oxide paste) manufactured by Diesol is applied on the hole blocking layer by spin coating so as to have a film thickness of 300 nm, dried with warm air at 120 ° C. for 3 minutes, and then fired in air at 500 ° C. for 30 minutes. Then, a porous electron transport layer was formed.

(Preparation of organic-inorganic perovskite compound layer)
A solution of lead (II) iodide (0.461 g, manufactured by Tokyo Kasei Co., Ltd.) and methylamine iodide (0.159 g, manufactured by Tokyo Kasei Co., Ltd.) dissolved in N, N-dimethylformamide (1 ml, manufactured by Kanto Chemical Co., Inc.). , The porous titanium oxide electrode was coated with a spin coat and dried at 120 ° C. for 10 minutes to form an organic-inorganic perovskite compound layer of _{CH 3} NH ₃ PbI _3.

(Preparation of hole transport layer)
Organic hole transport material represented by the structural formula (6) SHT-263 (60 mM, Merck Co., Ltd.), lithium bis (trifluoromethanesulfonyl) imide (14 mM, manufactured by Kanto Chemical Co., Inc.), represented by the general formula (1). A chlorobenzene solution in which the tertiary amine compound (Compound No. 1-1) (53 mM) was dissolved was formed by spin coating and air-dried. Gold was formed on this by vacuum deposition at about 100 nm to produce a solar cell element.

(Evaluation of photoelectric conversion element)
The photoelectric conversion efficiency of the obtained photoelectric conversion element under white LED irradiation (1000 lux: 250 μW / cm ^{2) was measured.} The white LED was measured by a desk lamp CDS-90α (study mode) manufactured by Cosmo Techno Co., Ltd., and the evaluation device was measured by a solar cell evaluation system As-510-PV03 manufactured by NF Circuit Design Block Co., Ltd.
As a result, the open circuit voltage was 0.68 V, the short circuit current density was 140.2 μA / cm ² , the curve factor was 0.69, and the maximum output was 65.78 μW / cm ² .

[Example III-2]
Compound No. in Example III-1. No. 1-1 tertiary amine compound was designated as No. A photoelectric conversion element was produced and evaluated in the same manner as in Example III-1 except that it was changed to 1-5.
As a result, the open circuit voltage was 0.67 V, the short circuit current density was 145.2 μA / cm ² , the curve factor was 0.67, and the maximum output was 65.18 μW / cm ² .

[Example III-3]
The outer circumference of the photoelectric conversion element produced in Example III-1 was sealed with an epoxy resin and glass, and placed in an oven heated to 60 ° C. for 100 hours.
The photoelectric conversion element after the durability test at 60 ° C. for 100 hours was evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.62 V, the short circuit current density was 146.6 μA / cm ² , the curve factor was 0.68, and the maximum output was 61.80 μW / cm ² .
The maximum output retention rate after the durability test is 93.9% of the initial value (maximum output of the photoelectric conversion element of Example III-1), and it can be seen that the product has good durability.

[Example III-4]
The outer circumference of the photoelectric conversion element produced in Example III-2 was sealed with an epoxy resin and glass, and placed in an oven heated to 60 ° C. for 100 hours.
The photoelectric conversion element after the durability test at 60 ° C. for 100 hours was evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.63 V, the short circuit current density was 148.2 μA / cm ² , the curve factor was 0.66, and the maximum output was 61.62 μW / cm ² .
The maximum output retention rate after the durability test is 94.5% of the initial value (maximum output of the photoelectric conversion element of Example III-2), and it can be seen that the product has good durability.

[Example III-5]
Lead (II) iodide (0.461 g, manufactured by Tokyo Kasei Co., Ltd.) in Example III-1 was replaced with lead (II) iodide (0.415 g, manufactured by Tokyo Kasei Co., Ltd.) and tin iodide (II) (0. A photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1 except that it was changed to 037 g (manufactured by Alfa Aesar).
As a result, the open circuit voltage is 0.57 V, the short-circuit current density is 155.2 μA / cm ² , the curve factor is 0.65, and the maximum output is 57.50 μW / cm ² , which are slightly lower characteristics than lead iodide alone. It showed a good value.

[Example III-6]
Lead iodide (II) (0.461 g, manufactured by Tokyo Kasei Co., Ltd.) in Example III-1 was replaced with lead iodide (II) (0.369 g, manufactured by Tokyo Kasei Co., Ltd.) and tin iodide (II) (0. A photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1 except that it was changed to 075 g (manufactured by Alfa Aesar).
As a result, the open circuit voltage was 0.54 V, the short-circuit current density was 157.7 μA / cm ² , the curve factor was 0.64, and the maximum output was 54.50 μW / cm ² . It showed a good value.

[Example III-7]
Methylamine iodide (0.159 g, manufactured by Tokyo Kasei Co., Ltd.) in Example III-1 was mixed with methylamine iodide (0.135 g, manufactured by Tokyo Kasei Co., Ltd.) and formamidine iodide (0.024 g, manufactured by Tokyo Kasei Co., Ltd.). ) Was changed, and a photoelectric conversion element was produced and evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.65 V, the short circuit current density was 140.4 μA / cm ² , the curve factor was 0.70, and the maximum output was 63.88 μW / cm ² .

[Example III-8]
Methylamine iodide (0.159 g, manufactured by Tokyo Kasei Co., Ltd.) in Example III-1 was mixed with methylamine iodide (0.135 g, manufactured by Tokyo Kasei Co., Ltd.) and formamidine iodide (0.017 g, manufactured by Tokyo Kasei Co., Ltd.). ) And cesium iodide (0.013 g, manufactured by Aldrich), a photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.64 V, the short circuit current density was 142.1 μA / cm ² , the curve factor was 0.69, and the maximum output was 62.75 μW / cm ² .

[Example III-9]
Methylamine iodide (0.159 g, manufactured by Tokyo Kasei Co., Ltd.) in Example III-1 was converted to methylamine iodide (0.143 g, manufactured by Tokyo Kasei Co., Ltd.) and cesium iodide (0.026 g, manufactured by Aldrich Co., Ltd.). A photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1 except that it was changed.
As a result, the open circuit voltage was 0.62 V, the short circuit current density was 139.1 μA / cm ² , the curve factor was 0.69, and the maximum output was 59.51 μW / cm ² .

[Comparative Example 1]
Compound No. in Example II-2. A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-2 except that the tertiary amine compound 1-1 was changed to tarsal butylpyridine (tBP: manufactured by Aldrich). The results are shown in Table 1.

[Comparative Example 2]
Compound No. in Example II-2. A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-2 except that the tertiary amine compound 1-1 was changed to the following compound (DBAP). The results are shown in Table 1.

[Comparative Example 3]
Compound No. in Example II-8. A photoelectric conversion element was prepared and evaluated in the same manner as in Example II-8 except that the tertiary amine compound 1-1 was changed to tarsal butylpyridine (tBP: manufactured by Aldrich). The results are shown in Table 1.

[Comparative Example 4]
Compound No. in Example III-1. A photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1 except that the tertiary amine compound 1-1 was changed to tarsal butylpyridine (tBP: manufactured by Aldrich).
As a result, the open circuit voltage was 0.52 V, the short circuit current density was 102.2 μA / cm ² , the curve factor was 0.66, and the maximum output was 35.07 μW / cm ² .

[Comparative Example 5]
Compound No. in Example III-1. A photoelectric conversion element was prepared and evaluated in the same manner as in Example III-1 except that the tertiary amine compound 1-1 was changed to the above compound (DBAP).
As a result, the open circuit voltage was 0.58 V, the short circuit current density was 115.4 μA / cm ² , the curve factor was 0.67, and the maximum output was 44.84 μW / cm ² .

[Comparative Example 6]
The outer circumference of the photoelectric conversion element produced in Comparative Example 4 was sealed with an epoxy resin and glass, and placed in an oven heated to 60 ° C. for 100 hours.
The photoelectric conversion element after the durability test at 60 ° C. for 100 hours was evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.43 V, the short circuit current density was 95.5 μA / cm ² , the curve factor was 0.57, and the maximum output was 23.04 μW / cm ² .
The maximum output retention rate after the durability test was 65.7% of the initial value (maximum output of the photoelectric conversion element of Comparative Example 4).

[Comparative Example 7]
The outer circumference of the photoelectric conversion element produced in Comparative Example 5 was sealed with an epoxy resin and glass, and placed in an oven heated to 60 ° C. for 100 hours.
The photoelectric conversion element after the durability test at 60 ° C. for 100 hours was evaluated in the same manner as in Example III-1.
As a result, the open circuit voltage was 0.49 V, the short circuit current density was 103.3 μA / cm ² , the curve factor was 0.61, and the maximum output was 30.87 μW / cm ² .
The maximum output retention rate after the durability test was 68.8% of the initial value (maximum output of the photoelectric conversion element of Comparative Example 5).

The photoelectric conversion elements of Examples II-1 to 7 are heat-dried at the time of producing the second electrode, and have higher short-circuit current density and open circuit voltage than those of Example II-8 which are not heat-dried. Therefore, the output is specifically improved. Comparing Comparative Example 1 and Comparative Example 3 using general tarsal butyl pyridine (tBP), output deterioration as in the conventional results is observed due to heating. Further, in the photoelectric conversion element of Comparative Example 2, DBAP is a tertiary amine compound, but the benzyl group is two compounds, and the basicity is slightly weak, so that the internal resistance is lowered and the output is lowered.
The photoelectric conversion elements of Examples III-1 to 10 to 10 have better initial characteristics shown in the open circuit voltage, short-circuit current density, curve factor, and maximum output as compared with Comparative Examples 4 to 7, and after the durability test. It was also excellent in the maximum output maintenance rate of, and showed excellent durability even when stored at high temperature after production.
As is clear above, the photoelectric conversion element of the present invention is more excellent in photoelectric conversion characteristics in a weak light environment. Furthermore, it can be seen that the output becomes higher by going through the high temperature process, which is a problem in the low cost manufacturing process.

Japanese Unexamined Patent Publication No. 11-144773

Panasonic Electric Works, 56 (2008) 87 J. Am. Chem. Soc., 133 (2011) 18042 J. Am. Chem. Soc., 135 (2013) 7378 Fujikura Technical Report, 121 (2011) 42

Claims (9)

A tertiary amine compound represented by the following general formula (1).

(In the formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. ) It has a first electrode, a hole blocking layer, an electron transport layer, a hole transport layer, and a second electrode, and the hole transport layer is a photoelectric conversion containing the tertiary amine compound according to claim 1. element. The photoelectric conversion element according to claim 2, wherein the hole transport layer includes a hole transport material represented by the following general formula (2).

(In the formula, R ₁ represents a hydrogen atom or a methyl group.) The photoelectric conversion element according to claim 2 or 3, wherein the electron transport layer contains titanium oxide. The photoelectric conversion element according to any one of claims 2 to 4, wherein the hole blocking layer contains titanium oxide. The first electrode, the hole blocking layer provided on the first electrode, the electron transport layer provided on the hole blocking layer, and the electron transport layer provided on the transparent conductive film substrate are provided on the electron transport layer. The organic-inorganic perovskite compound layer, the hole transport layer provided on the organic-inorganic perobskite compound layer, and the second electrode provided on the hole transport layer are provided, and the hole transport layer is generally described below. A photoelectric conversion element containing a tertiary amine compound represented by the formula (1).

(In the formula, Ar ₁ and Ar ₂ represent any of a benzene ring having an alkyl group or an alkoxy group, an unsubstituted benzene ring, a naphthalene ring having an alkyl group or an alkoxy group, and an unsubstituted naphthalene ring, respectively. ) The photoelectric conversion element according to claim 6, wherein the organic-inorganic perovskite compound in the organic-inorganic perovskite compound layer is represented by the following general formula (a).
X _α Y _β M _γ・ ・ ・ General formula (a)
(In the formula, X is a halogen atom, Y is at least one selected from alkylammonium, formamidinium, and cesium (except when only cesium is used), M is lead and / or tin, and α: β: γ. The ratio is 3: 1: 1.) The photoelectric conversion element according to claim 7, wherein the alkylammonium is methylammonium. A solar cell comprising the photoelectric conversion element according to any one of claims 2 to 8.

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