JP2019176136A - Photoelectric conversion element and photoelectric conversion element module - Google Patents

Abstract

To provide a photoelectric conversion element with a good photoelectric conversion property and excellent temporal stability even in low-intensity light.SOLUTION: A photoelectric conversion element comprises a first electrode, an electron transport layer including a photosensitization compound, a hole transport layer, and a second electrode. The hole transport layer comprises a p-type semiconductor material and a basic compound. Ionization potential of the hole transport layer exceeds ionization potential of the p-type semiconductor material, and is less than 1.07 times of ionization potential of the p-type semiconductor material. Ionization potential of the photosensitization compound exceeds ionization potential of the hole transport layer, and an acid dissociation constant (pKa) of the basic compound is greater than or equal to 6 and less than or equal to 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photoelectric conversion element and a photoelectric conversion element module.

In recent years, the importance of solar cells has increased as an alternative energy to fossil fuels and as a countermeasure against global warming. Moreover, a solar cell and a photodiode apply a photoelectric conversion element that can convert light energy into electric energy.
Recently, light (illuminance: 20 lux or more and 1,000 lux) is not limited to sunlight (illuminance in direct light: about 100,000 lux) but also LEDs (light emitting diodes) and fluorescent lamps. However, indoor photoelectric conversion elements having high power generation performance are attracting attention.

Thus, a photoelectric conversion element having high photoelectric conversion properties has been proposed (for example, see Patent Document 1). However, in the case of the photoelectric conversion element of Patent Document 1, the temporal stability is insufficient, and there is a problem that it is difficult to achieve both good photoelectric conversion properties and temporal stability.
Therefore, a photoelectric conversion element that can achieve both high photoelectric conversion property and stability over time in low-illuminance light is desired.

  An object of this invention is to provide the photoelectric conversion element which has favorable photoelectric conversion property also in low illumination light, and is excellent in temporal stability.

  The photoelectric conversion element of the present invention as a means for solving the above problems is a photoelectric conversion element having a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode. a is, the hole transport layer has a p-type semiconductor material, and a basic compound, the ionization potential of the hole transport layer is greater than the ionization potential of the p-type semiconductor material and the p-type semiconductor material The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer, and the acid dissociation constant (pKa) of the basic compound is 6 or more and 10 or less. is there.

  According to the present invention, it is possible to provide a photoelectric conversion element that has good photoelectric conversion properties and excellent temporal stability even in low-illuminance light.

FIG. 1 is a schematic view showing an example of a cross section of the photoelectric conversion element of the present invention. FIG. 2 is a schematic view showing another example of the photoelectric conversion element of the present invention. FIG. 3 is a schematic view showing another example of the photoelectric conversion element of the present invention. FIG. 4 is a schematic view showing another example of the photoelectric conversion element of the present invention. FIG. 5 is a schematic view showing another example of the photoelectric conversion element of the present invention. FIG. 6 is a schematic view showing an example of the photoelectric conversion element module of the present invention. FIG. 7 is a schematic view of FIG. 6 observed from different angles. FIG. 8 is a schematic diagram illustrating an example in which a mouse is used as an electronic device. FIG. 9 is a schematic diagram illustrating an example in which a photoelectric conversion element is mounted on a mouse. FIG. 10 is a schematic diagram illustrating an example using a keyboard used in a personal computer as an electronic device. FIG. 11 is a schematic diagram illustrating an example in which a photoelectric conversion element is mounted on a keyboard. FIG. 12 is a schematic diagram illustrating an example in which a small photoelectric conversion element is mounted on a part of a key of a keyboard. FIG. 13 is a schematic diagram illustrating an example in which a sensor is used as an electronic device. FIG. 14 is a schematic diagram illustrating an example using a turntable as an electronic apparatus. Figure 15 is an example of an electronic device that combines the photoelectric conversion element and / or the photoelectric conversion element module, the photoelectric conversion element and / or the photoelectric conversion element module is a device that operates by electric power generated by photoelectric conversion of the present invention FIG. FIG. 16 is a schematic diagram illustrating an example in which a power supply IC for a photoelectric conversion element is incorporated between the photoelectric conversion element and the circuit of the device in FIG. FIG. 17 is a schematic diagram illustrating an example in which the power storage device is incorporated between the power supply IC and the circuit of the device in FIG. FIG. 18 is a schematic diagram illustrating an example of a power supply module including the photoelectric conversion element and / or photoelectric conversion element module of the present invention and a power supply IC. FIG. 19 is a schematic diagram illustrating an example of a power supply module in which a power storage device is added to the power supply IC in FIG.

As a result of intensive studies, the present inventors have found the following.
In order to generate electric power efficiently with low illuminance light for indoor use, it is necessary to suppress the loss current inside the photoelectric conversion element. For this purpose, it is necessary to control the internal resistance. However, if the internal resistance is increased, the short-circuit current density decreases, and if the internal resistance is decreased, the open-circuit voltage decreases. There is a problem that there is.

Here, the ionization potential will be described.
An organic semiconductor has a HOMO level and a LUMO level. The difference between the vacuum level and the LUMO level is called an electron affinity, and the difference between the vacuum level and the HOMO level is called an ionization potential.
The ionization potential can be measured in an air atmosphere. Specifically, the organic semiconductor is irradiated with ultraviolet rays to excite HOMO level electrons to the LUMO level. At this time, if the energy of the ultraviolet rays to be excited is changed by changing the wavelength of the ultraviolet rays to be irradiated, photoelectrons start to be emitted at a specific energy or higher. By obtaining the energy at which photoelectrons begin to be emitted, the ionization potential can be measured.

  The inventors of the present invention have the ionization potential of the hole transport layer exceeding the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material, and the ionization potential of the photosensitizing compound is When the ion dissociation constant (pKa) of the basic compound is 6 or more and 10 or less, exceeding the ionization potential of the hole transport layer, both high photoelectric conversion properties and stability over time can be achieved even in low illumination light. I found out that I can.

The ionization potential of the photosensitizing compound, the ionization potential of the hole transport material, and the ionization potential of the hole transport layer can be measured using, for example, an atmospheric photoelectron spectrometer.
Examples of the atmospheric photoelectron spectrometer include a device name: AC-2 (manufactured by Riken Keiki Co., Ltd.).
The ionization potential of the photosensitizing compound can be measured while adsorbed on the electron transport layer.

  The ionization potential of the hole transport layer may be measured by an atmospheric photoelectron spectrometer without peeling only the hole transport layer from the photoelectric conversion element, but it is preferable to measure only the hole transport layer alone.

(Photoelectric conversion element)
The photoelectric conversion element of the present invention is a photoelectric conversion element comprising a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode, wherein the hole transport layer is p An ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material. , The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer, and the acid dissociation constant (pKa) of the basic compound is 6 or more and 10 or less. Have. Each layer may have a single layer structure or a laminated structure.

<First electrode>
The photoelectric conversion element has a first electrode.
There is no restriction | limiting in particular about the shape and magnitude | size as a 1st electrode, According to the objective, it can select suitably.

  There is no restriction | limiting in particular as a structure of a 1st electrode, According to the objective, it can select suitably, A single layer structure may be sufficient, and the structure which laminates | stacks several materials may be sufficient.

  The material of the first electrode is not particularly limited as long as it has transparency and conductivity with respect to visible light, and can be appropriately selected according to the purpose. For example, transparent conductive metal oxide, carbon, A metal etc. are mentioned.

Examples of the transparent conductive metal oxide include indium tin oxide (hereinafter referred to as “ITO”), fluorine-doped tin oxide (hereinafter referred to as “FTO”), and antimony-doped tin oxide (hereinafter referred to as “ATO”). And niobium-doped tin oxide (hereinafter referred to as “NTO”), aluminum-doped zinc oxide, indium / zinc oxide, niobium / titanium oxide, and the like.
Examples of carbon include carbon black, carbon nanotube, graphene, fullerene and the like.
Examples of the metal include gold, silver, aluminum, nickel, indium, tantalum, and titanium.
These may be used individually by 1 type and may use 2 or more types together. Among these, a transparent conductive metal oxide having high transparency is preferable, and ITO, FTO, ATO, and NTO are more preferable.

  There is no restriction | limiting in particular as average thickness of a 1st electrode, Although it can select suitably according to the objective, 5 nm or more and 100 micrometers or less are preferable, and 50 nm or more and 10 micrometers or less are more preferable. In addition, when the material of the first electrode is carbon or metal, the average thickness of the first electrode is preferably an average thickness that can obtain translucency.

  The first electrode can be formed by a known method such as a sputtering method, a vapor deposition method, or a spray method.

The first electrode is preferably formed on the first substrate, and an integrated commercial product in which the first electrode is previously formed on the first substrate can be used.
Examples of integrated commercial products include FTO-coated glass, ITO-coated glass, zinc oxide: aluminum-coated glass, FTO-coated transparent plastic film, and ITO-coated transparent plastic film. Other integrated commercial products include, for example, tin oxide or indium oxide, transparent electrodes doped with cations or anions having different valences, or metal with a structure that can transmit light such as mesh or stripes Examples thereof include a glass substrate provided with an electrode.
These may be used individually by 1 type, and the thing mixed or laminated | stacked combining 2 or more types together. Moreover, a metal lead wire or the like may be used in combination for the purpose of lowering the electrical resistance value.

Examples of the material of the metal lead wire include aluminum, copper, silver, gold, platinum, nickel, and the like.
The metal lead wire can be used in combination by, for example, forming it on the substrate by vapor deposition, sputtering, pressure bonding or the like and providing an ITO or FTO layer thereon.

<Electron transport layer>
The photoelectric conversion element has an electron transport layer having a photosensitizing compound.
The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer. When the ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer, the hole conduction efficiency to the hole transport layer is excellent.
The electron transport layer is formed for the purpose of transporting electrons generated by the photosensitizing compound to the first electrode or the hole blocking layer. For this reason, the electron transport layer is preferably disposed adjacent to the first electrode or the hole blocking layer.

  The structure of the electron-transporting layer is not particularly limited and may be appropriately selected depending on the purpose, at least two photoelectric conversion elements adjacent to each other, the electron transport layer each other may be extended to each other It is preferable that it is not extended. Further, the structure of the electron transport layer may be a single layer or a multilayer in which a plurality of layers are stacked.

  The electron transport layer includes an electron transport material, and includes other materials as necessary.

There is no restriction | limiting in particular as an electron transport material, Although it can select suitably according to the objective, A semiconductor material is preferable.
The semiconductor material preferably has a fine particle shape and is formed into a porous film by bonding. The photosensitizing compound is chemically or physically adsorbed on the surface of the semiconductor fine particles constituting the porous electron transport layer.

There is no restriction | limiting in particular as a semiconductor material, A well-known thing can be used, For example, a single-piece | unit semiconductor, a compound semiconductor, the compound which has a perovskite structure, etc. are mentioned.
Examples of the single semiconductor include silicon and germanium.
Examples of compound semiconductors include metal chalcogenides, specifically oxides such as titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; Examples thereof include sulfides such as cadmium, zinc, lead, silver, antimony, and bismuth; selenides such as cadmium and lead; tellurides such as cadmium. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium, gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like.
Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
Among these, oxide semiconductors are preferable, and titanium oxide, zinc oxide, tin oxide, and niobium oxide are more preferable. When the electron transporting material of the electron transporting layer is titanium oxide, since the conduction band level is high, it is advantageous in that a high open-circuit voltage can be obtained and high photoelectric conversion characteristics can be obtained.
These may be used individually by 1 type and may use 2 or more types together. The crystal form of the semiconductor material is not particularly limited and may be appropriately selected depending on the purpose. The semiconductor material may be single crystal, polycrystal, or amorphous.

  There is no restriction | limiting in particular as an average particle diameter of the primary particle of a semiconductor material, Although it can select suitably according to the objective, 1 nm or more and 100 nm or less are preferable, and 5 nm or more and 50 nm or less are more preferable. Also, larger semiconductor materials may be mixed or stacked, and conversion efficiency may be improved by the effect of scattering incident light. In this case, the average particle size is preferably 50 nm or more and 500 nm or less.

  There is no restriction | limiting in particular as average thickness of an electron carrying layer, Although it can select suitably according to the objective, 50 nm or more and 100 micrometers or less are preferable, 100 nm or more and 50 micrometers or less are more preferable, 120 nm or more and 10 micrometers or less are still more preferable. If the average thickness of the electron transport layer is within a preferable range, a sufficient amount of photosensitizing compound per unit projected area can be secured, the light capture rate can be kept high, and the diffusion distance of injected electrons also increases. This is advantageous in that loss due to charge recombination can be reduced.

There is no restriction | limiting in particular as a preparation method of an electron carrying layer, According to the objective, it can select suitably, For example, the method of forming a thin film in vacuum, such as sputtering, the wet film forming method etc. are mentioned. Among these, from the viewpoint of production cost, a wet film-forming method is preferable, a paste in which a powder or sol of a semiconductor material is dispersed is prepared, and the first electrode as an electron collector electrode substrate or the hole blocking layer is prepared. The method of applying on top is more preferable.
The wet film forming method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, dipping method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method And die coating method.
As the wet printing method, for example, various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used.

Examples of a method for producing a semiconductor material dispersion include a method of mechanically pulverizing using a known milling device or the like. By this method, a dispersion liquid of a semiconductor material can be produced by dispersing a particulate semiconductor material alone or a mixture of a semiconductor material and a resin in water or a solvent.
Examples of the resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, Cellulose ester, cellulose ether, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin, polyamide resin, polyimide resin and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

Examples of the solvent include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, hydrocarbon solvents, and the like.
Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, α-terpineol, and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane and the like.
Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, 1-chloronaphthalene and the like. .
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, Examples include ethylbenzene and cumene.
These may be used individually by 1 type and may use 2 or more types together.

In order to prevent reaggregation of particles, an acid, a surfactant, a chelating agent, or the like may be added to a dispersion containing a semiconductor material or a paste containing a semiconductor material obtained by a sol-gel method or the like.
Examples of the acid include hydrochloric acid, nitric acid, acetic acid and the like.
Examples of the surfactant include polyoxyethylene octyl phenyl ether.
Examples of chelating agents include acetylacetone, 2-aminoethanol, ethylenediamine, and the like.
In addition, it is an effective means to add a thickener for the purpose of improving the film forming property.
Examples of the thickener include polyethylene glycol, polyvinyl alcohol, and ethyl cellulose.

  After applying the semiconductor material, between particles of the semiconductor material is electronically contacted, or fired in order to improve the adhesion between the film strength and the substrate, or microwave irradiation or an electron beam, or a laser beam Can be irradiated. These treatments may be performed singly or in combination of two or more.

When the electron transport layer formed from a semiconductor material is fired, the firing temperature is not particularly limited and can be appropriately selected according to the purpose. However, if the temperature is too high, the resistance of the substrate may increase. From the standpoint of melting, it is preferably 30 ° C. or higher and 700 ° C. or lower, and more preferably 100 ° C. or higher and 600 ° C. or lower. Moreover, there is no restriction | limiting in particular as baking time, Although it can select suitably according to the objective, 10 minutes or more and 10 hours or less are preferable.
When the electron transport layer formed of a semiconductor material is irradiated with microwaves, the irradiation time is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 hour or less. In this case, you may irradiate from the surface side in which the electron carrying layer is formed, and you may irradiate from the surface side in which the electron carrying layer is not formed.

After firing the electron transport layer made of a semiconductor material, for example, an aqueous solution of titanium tetrachloride or an organic solvent for the purpose of increasing the surface area of the electron transport layer and increasing the efficiency of electron injection from the photosensitizing compound described later to the semiconductor material. Chemical plating using a mixed solution and electrochemical plating using a titanium trichloride aqueous solution may be performed.
A film obtained by sintering a semiconductor material having a diameter of several tens of nanometers can form a porous shape. Such a nanoporous structure has a very high surface area, which can be expressed using a roughness factor. The roughness factor is a numerical value that represents the actual area inside the porous body relative to the area of the semiconductor particles applied to the first substrate. Accordingly, the roughness factor is preferably as large as possible, but is preferably 20 or more in relation to the average thickness of the electron transport layer.

<< photosensitized compound >>
The photosensitizing compound is adsorbed on the surface of the semiconductor material constituting the electron transport layer in order to further improve the output and photoelectric conversion efficiency.
The photosensitizing compound is not particularly limited as long as it is a compound that is photoexcited by light applied to the photoelectric conversion element, and can be appropriately selected according to the purpose. Examples thereof include the following known compounds. .
Specifically, a metal complex compound, J.M. Phys. Chem. C, 7224, Vol. 111 (2007) and the like, Chem. Commun. , 4887 (2007) and the like, J.M. 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) etc., thiophene compounds, cyanine dyes, merocyanine dyes, 9-arylxanthene compounds, triarylmethane compounds, Phys. Chem. , 2342, Vol. 91 (1987), J. MoI. Phys. Chem. B, 6272, Vol. 97 (1993), Electroanaly. Chem. , 31, Vol. 537 (2002) J. MoI. Porphyrins Phthalocyanines, 230, Vol. 3 (1999), Angew. Chem. Int. Ed. , 373, Vol. 46 (2007), Langmuir, 5436, Vol. 24 (2008) etc., and the phthalocyanine compound, porphyrin compound, etc. are mentioned.
Among these, a metal complex compound, a coumarin compound, a polyene compound, an indoline compound, and a thiophene compound are preferable, and are represented by the following structural formula (1), the following structural formula (2), and the following structural formula (3) manufactured by Mitsubishi Paper Industries Co., Ltd. More preferred is a compound comprising the following general formula (3): In addition, these photosensitizing compounds may be used independently and can also be used in mixture of 2 or more types.

In Formula _{(3), X 1, X} 2 represents an oxygen atom, a sulfur atom, a selenium atom. R ₁ represents a methine group which may have a substituent. Specific examples of the substituent include aryl groups such as phenyl group and naphthyl group, and heterocycles such as thienyl group and furyl group.
R ₂ represents an alkyl group, aryl group, or heterocyclic group which may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a 2-propyl group, and a 2-ethylhexyl group. Examples of the aryl group and the heterocyclic group include those described above.
R ₃ represents an acidic group such as carboxylic acid, sulfonic acid, phosphonic acid, boronic acid, and phenols. Z1 and Z2 represent substituents that form a cyclic structure.
Examples of Z1 include condensed hydrocarbon compounds such as a benzene ring and a naphthalene ring, and heterocycles such as a thiophene ring and a furan ring, each of which may have a substituent. Specific examples of the substituent include alkoxy groups such as the aforementioned alkyl group, methoxy group, ethoxy group, and 2-isopropoxy group.
Z2 includes (A-1) to (A-22) shown below.

  Specific examples of the photosensitizing compound containing the general formula (3) include (B-1) to (B-36) shown below. However, it is not limited to these.

  The surface of the semiconductor material of the electron transport layer, a method of adsorbing the photosensitizing compound, a solution of the photosensitizer compound, or a dispersion of the photosensitizer compound, immersing the electron transport layer including a semiconductor material A method, a method of applying a solution of a photosensitizing compound, or a dispersion of a photosensitizing compound to an electron transport layer and adsorbing it can be used. In the case of immersing the electron transport layer on which the semiconductor material is formed in the photosensitizing compound solution or in the photosensitizing compound dispersion, use the dipping method, dipping method, roller method, air knife method, etc. Can do. In the case of a method in which a photosensitizing compound solution or a photosensitizing compound dispersion is applied to the electron transport layer and adsorbed, the wire bar method, slide hopper method, extrusion method, curtain method, spin method, spray The method etc. can be used. Further, it can be adsorbed in a supercritical fluid using carbon dioxide or the like.

When adsorbing the photosensitizing compound to the semiconductor material, a condensing agent may be used in combination.
The condensing agent has a catalytic action that physically or chemically binds the photosensitizing compound to the surface of the semiconductor material, or a stoichiometric action that advantageously shifts the chemical equilibrium. Either may be sufficient. Furthermore, a thiol or a hydroxy compound may be added as a condensation aid.

Examples of the solvent for dissolving or dispersing the photosensitizing compound include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, hydrocarbon solvents and the like.
Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, and the like.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane and the like.
Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, 1-chloronaphthalene and the like. .
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, Examples include ethylbenzene and cumene.
These may be used individually by 1 type and may use 2 or more types together.

Depending on the type of photosensitizing compound, there are compounds that work more effectively when the aggregation between the compounds is suppressed. Therefore, an aggregation dissociator may be used in combination.
The aggregating / dissociating agent is not particularly limited and may be appropriately selected depending on the dye to be used, but steroid compounds such as cholic acid and chenodeoxycholic acid, long-chain alkyl carboxylic acids or long-chain alkyl phosphonic acids are preferred.
The content of the aggregating and dissociating agent is preferably 0.01 parts by mass or more and 500 parts by mass or less, and more preferably 0.1 parts by mass or more and 100 parts by mass or less with respect to 1 part by mass of the photosensitizing compound.

The temperature at which the photosensitizing compound, or the photosensitizing compound and the aggregation / dissociation agent are adsorbed on the surface of the semiconductor material constituting the electron transport layer is preferably −50 ° C. or higher and 200 ° C. or lower. The adsorption time is preferably from 5 seconds to 1,000 hours, more preferably from 10 seconds to 500 hours, still more preferably from 1 minute to 150 hours. The adsorbing step is preferably performed in a dark place. Moreover, the process of making it adsorb | suck may be left still and may be performed, stirring.
The stirring method is not particularly limited and can be appropriately selected depending on the purpose.For example, a method using a stirrer, ball mill, paint conditioner, sand mill, attritor, disperser, ultrasonic dispersion, etc. It is done.

<Hole transport layer>
The photoelectric conversion element has a hole transport layer.
The hole transport layer preferably has a p-type semiconductor material and a basic compound.

The hole transport layer has a p-type semiconductor material in order to obtain a function of transporting holes.
The ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and is less than 1.07 times the ionization potential of the p-type semiconductor material. When the ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and is less than 1.07 times the ionization potential of the p-type semiconductor material, high photoelectric conversion properties and high aging can be obtained even in low illumination light. It is possible to achieve both stability.

<< p-type semiconductor material >>
There is no restriction | limiting in particular as a p-type semiconductor material, According to the objective, it can select suitably, For example, an inorganic p-type semiconductor material, an organic p-type semiconductor material, etc. are mentioned.
The inorganic p-type semiconductor material is not particularly limited and may be appropriately selected depending on the purpose, for example, CuSCN, CuI, CuBr, NiO , V 2 O 5, etc. graphene oxide and the like.
Among these, organic p-type semiconductor materials are preferable.

There is no restriction | limiting in particular as an organic p-type semiconductor material, According to the objective, it can select suitably, For example, a well-known organic p-type semiconductor material can be used.
Examples of known organic p-type semiconductor materials include oxadiazole compounds, triphenylmethane compounds, pyrazoline compounds, hydrazone compounds, oxadiazole compounds, tetraarylbenzidine compounds, stilbene compounds, and spiro-type compounds. These may be used individually by 1 type and may use 2 or more types together. Among these, spiro type compounds are preferable.

Examples of the spiro compound include compounds containing the following general formula (4).
However, In the general formula (4), _{R 7} from _{R 4} is dimethylamino group, diphenylamino group, a substituted amino group, such as naphthyl-4-tolylamino group.

  There is no restriction | limiting in particular as a spiro-type compound, According to the objective, it can select suitably, For example, although illustrated compound D-1 to D-20 etc. which are shown below are mentioned, it is not limited to these. . These may be used individually by 1 type and may use 2 or more types together.

  Since the spiro-type compound has two benzidine skeleton molecules twisted and bonded, it forms a nearly spherical electron cloud and exhibits excellent photoelectric conversion characteristics due to good hopping conductivity between molecules. In addition, since it has high solubility, it dissolves in various organic solvents, is amorphous (amorphous substance having no crystal structure), and is easily packed in a porous electron transport layer. Furthermore, since it does not have a light absorption property of 450 nm or more, the photosensitizing compound can efficiently absorb light, which is particularly preferable for a solid-type dye-sensitized solar cell.

<< basic compound >>
The hole transport layer has a basic compound. The acid dissociation constant (pKa) of the basic compound is preferably 6 or more and 10 or less.
The basic compound is considered to exist at the interface in the vicinity of the electron transport layer, and is considered to suppress reverse electron transfer from the electron transport layer (that is, electron transfer from the electron transport layer to the hole transport layer). Moreover, when the hole transport layer has a basic compound having a pKa of 6 or more and 10 or less, the internal resistance of the photoelectric conversion element is increased. As a result, a loss current in light with low illuminance such as room light can be reduced, so that both high photoelectric conversion properties and stability over time can be achieved even in low illuminance light.
pKa can be calculated using software, for example, ACD / Labs Software V11.02.

  As a basic compound, the basic compound which consists of the following general formula (A) or general formula (B) is preferable, and the tertiary amine compound shown by the following general formula (1) and general formula (2) is still more preferable. When the hole transport layer contains a basic compound of the following general formula (A) or general formula (B), it is advantageous in that a high open-circuit voltage is obtained and high photoelectric conversion characteristics are obtained. Furthermore, since the hole transport layer has at least one of the tertiary amine compounds represented by the general formula (1) and the general formula (2), high photoelectric conversion property and stability over time can be obtained even in low illumination light. Can be achieved.

However, in said general formula (A) formula, R < ₁ >, R < ₂ > represents an alkyl group or an aromatic hydrocarbon group each independently, represents the same or different group, or R < ₁ >, R < ₂ > is mutually And represents a heterocyclic group containing a nitrogen atom.
However, in said general formula (B), R < ₁ >, R < ₂ > represents an alkyl group or an aromatic hydrocarbon group each independently, represents the same or different group, or R < ₁ >, R < ₂ > is mutually And represents a heterocyclic group containing a nitrogen atom.

However, in said general formula (1) and said general formula (2), Ar < ₁ > and Ar < ₂ > represent the aryl group which may have a substituent, and said Ar < ₁ > and said Ar < ₂ > may be the same. They may be different and may be combined with each other.

  Specific examples of the basic compound of the general formula (A) and the general formula (B) are shown below, but the present invention is not limited thereto.

  Next, specific examples of the tertiary amine compound represented by the general formula (1) and the general formula (2) include, for example, exemplified compounds C-1 to C-20 shown below. It is not limited to. These may be used individually by 1 type and may use 2 or more types together.

  The content of the basic compound in the hole transport layer is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less with respect to the total amount of the hole transport material. When the content of the basic compound is in a preferable range, a high open-circuit voltage can be maintained, a high output can be obtained, and high stability and durability can be obtained even when used for a long time in various environments.

  The molecular weight of the basic compound is preferably 140 g / mol or more. When the molecular weight of the basic compound is 140 g / mol or more, the presence of the basic compound at the interface in the vicinity of the electron transport layer suppresses physical and electrical contact between the electron transport layer and the hole transport layer, and the reverse Since electron movement can be further reduced, high photoelectric conversion characteristics can be exhibited even in low illumination light.

  The form of the hole transport layer is not particularly limited as long as it has a function of transporting holes, and can be appropriately selected according to the purpose. For example, an electrolytic solution in which a redox pair is dissolved in an organic solvent, Examples include a gel electrolyte obtained by impregnating a polymer matrix with a liquid obtained by dissolving a redox couple in an organic solvent, a molten salt containing a redox couple, and a solid electrolyte. These may be used individually by 1 type and may use 2 or more types together.

<< Oxidant >>
The hole transport layer preferably has an oxidizing agent. When the hole transport layer has an oxidizing agent, a part of the organic hole transport material becomes a radical cation, so that conductivity is improved and durability and stability of output characteristics can be improved.
Oxidation of the organic hole transport material by the oxidizer shows good hole conductivity and suppresses the release (reduction) of the oxidized state due to the influence of the surrounding environment of the photoelectric conversion layer. Shows stability.

  The oxidizing agent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, tris (4-bromophenyl) aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluoroborate, silver nitrate, A metal complex etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, a metal complex is preferable.

As a metal complex, the structure comprised from a metal cation, a ligand, and an anion etc. are mentioned, for example.
There is no restriction | limiting in particular as a metal cation, According to the objective, it can select suitably, For example, chromium, manganese, zinc, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium And cations such as osmium, iridium, vanadium, gold, and platinum. Among these, the cation of manganese, zinc, iron, cobalt, nickel, copper, ruthenium, silver, and vanadium is preferable, and a cobalt complex is more preferable.

  The ligand preferably contains a 5- and / or 6-membered heterocycle containing at least one nitrogen, and may have a substituent. Specific examples include, but are not limited to, the following.

Examples of the anion include hydride ion (H ⁻ ), fluoride ion (F ⁻ ), chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), iodide ion (I ⁻ ), hydroxide ion ( OH ⁻ ), cyanide ion (CN ⁻ ), nitrate ion (NO ₃ ⁻ ), nitrite ion (NO ₂ ⁻ ), hypochlorite ion (ClO ⁻ ), chlorite ion (ClO ₂ ⁻ ), chlorine Acid ion (ClO ₃ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), permanganate ion (MnO ₄ ⁻ ), acetate ion (CH ₃ COO ⁻ ), hydrogen carbonate ion (HCO ₃ ⁻ ), dihydrogen phosphate ion _(H 2 PO ₄ ^-), hydrogen sulfate ion (HSO ₄ ^-), hydrogen sulphide ions (HS ^-), thiocyanate ion (SCN ^-), tetra fluoroalkyl boronic acid ion _(BF ⁴ -), Kisa fluorophosphate ion (PF ₆ ^-), tetracyanoquinodimethane boronic acid ions ^{_{(B (CN) 4 -)}} , dicyano amine ion ^{_{(N (CN) 2 -)}} , p- toluenesulfonate ion (TsO ^-), trifluoro Methyl sulfonate ion (CF ₃ SO ₂ ⁻ ), bis (trifluoromethylsulfonyl) amine ion (N (SO ₂ CF ₃ ) ²⁻ ) tetrahydroxoaluminate ion ([Al (OH) ₄ ] ⁻ , or [Al (OH) ₄ (H ₂ O) ₂ ] ⁻ ), dicyano silver (I) acid ion ([Ag (CN) ₂ ] ⁻ ), tetrahydroxochromium (III) acid ion ([Cr (OH) ₄ ] ⁻ ) , Tetrachloroauric (III) ion ([AuCl ₄ ] ⁻ ), oxide ion (O ²⁻ ), sulfide ion (S ²⁻ ), peroxide ion (O ₂₎ ^2- ), sulfate ion (SO ₄ ²⁻ ), sulfite ion (SO ₃ ²⁻ ), thiosulfate ion (S ₂ O ₃ ²⁻ ), carbonate ion (CO ₃ ²⁻ ), chromate ion (CrO ₄ ^{2) −} ), Dichromate ion (Cr ₂ O ₇ ²⁻ ), monohydrogen phosphate ion (HPO ₄ ²⁻ ), tetrahydroxozinc (II) ion ([Zn (OH) ₄ ] ²⁻ ), tetracyanozinc (II) acid ion ([Zn (CN) ₄ ] ²⁻ ), tetrachlorocopper (II) acid ion ([CuCl ₄ ] ²⁻ ), phosphate ion (PO ₄ ³⁻ ), hexacyanoiron (III) acid Ions ([Fe (CN) ₆ ] ³⁻ ), bis (thiosulfato) silver (I) acid ions ([Ag (S ₂ O ₃ ) ₂ ] ³⁻ ), hexacyanoiron (II) acid ions ([Fe (CN ) ₆ ] ^4- ) It is. Among these, tetrafluoroboronate ion, hexafluorophosphate ion, tetracyanoboronate ion, bis (trifluoromethylsulfonyl) amine ion, and perchlorate ion are preferable.

  As the metal complex, a trivalent cobalt complex represented by the following general formula (5) is particularly preferable. When the metal complex is a trivalent cobalt complex, it is advantageous in that the function as an oxidizing agent is excellent.

However, the general formula _{(5), R} 8 ~R ₁₀ is a hydrogen atom, a methyl group, an ethyl group, tert-butyl group, or a trifluoromethyl group. X represents any one selected from the above anions.

  Below, the specific example of the cobalt complex represented by the said General formula (5) is described. However, it is not limited to these. These may be used individually by 1 type and may use 2 or more types together.

  Further, as the metal complex, a trivalent cobalt complex represented by the following general formula (6) is also effectively used.

However, in the general formula _{(6), R} 11 ~R ₁₂ is a hydrogen atom, a methyl group, an ethyl group, tert-butyl group, or a trifluoromethyl group. X represents any one selected from the above anions.

  Specific examples of the cobalt complex represented by the general formula (6) are described below. However, it is not limited to these. These may be used individually by 1 type and may use 2 or more types together.

  As content of an oxidizing agent, it is preferable that it is 0.5 mass part or more and 50 mass parts or less with respect to 100 mass parts of hole transport materials, and it is more preferable that it is 5 mass parts or more and 30 mass parts or less. It is not necessary for all hole transport materials to be oxidized by the addition of the oxidizing agent, and it is effective if only a part is oxidized.

<< Alkali metal salt >>
The hole transport layer preferably has an alkali metal salt as an additive. This is advantageous in that the movement of charges becomes smooth and good photoelectric conversion characteristics can be obtained.

  The cation of the alkali metal salt is considered to exist at the interface in the vicinity of the electron transport layer, and the anion of the alkali metal salt is considered to be doped in the hole transport layer.

  Examples of the alkali metal salt include lithium chloride, lithium bromide, lithium iodide, lithium perchlorate, lithium bis (trifluoromethanesulfonyl) diimide, lithium diisopropylimide, lithium acetate, lithium tetrafluoroborate, and pentafluorophosphoric acid. Lithium salts such as lithium and lithium tetracyanoborate, sodium chloride, sodium bromide, sodium iodide, sodium perchlorate, sodium bis (trifluoromethanesulfonyl) diimide, sodium acetate, sodium tetrafluoroborate, pentafluorophosphoric acid Examples thereof include sodium salts such as sodium and sodium tetracyanoborate, and potassium salts such as potassium chloride, potassium bromide, potassium iodide and potassium perchlorate. Among these, lithium bis (trifluoromethanesulfonyl) diimide and lithium diisopropylimide are preferable.

  The content of the alkali metal salt is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the hole transport material.

  The hole transport layer may have a single layer structure made of a single material, or may have a laminated structure including a plurality of compounds. When the hole transport layer has a laminated structure, it is preferable to use a polymer material for the hole transport layer close to the second electrode. The use of a polymer material having excellent film forming properties is advantageous in that the surface of the porous electron transport layer can be smoothed and the photoelectric conversion characteristics can be improved. In addition, since the polymer material does not easily penetrate into the porous electron transport layer, it has excellent coverage on the surface of the porous electron transport layer, and is effective in preventing short circuit when an electrode is provided. There is.

Examples of the polymer material used for the hole transport layer include known hole transport polymer materials.
Examples of the hole transporting polymer material include polythiophene compounds, polyphenylene vinylene compounds, polyfluorene compounds, polyphenylene compounds, polyarylamine compounds, and polythiadiazole compounds.
Examples of the polythiophene compound include poly (3-n-hexylthiophene), poly (3-n-octyloxythiophene), poly (9,9′-dioctyl-fluorene-co-bithiophene), poly (3,3 ′ '' -Didodecyl-quarterthiophene), poly (3,6-dioctylthieno [3,2-b] thiophene), poly (2,5-bis (3-decylthiophen-2-yl) thieno [3,2- b] thiophene), poly (3,4-didecylthiophene-co-thieno [3,2-b] thiophene), poly (3,6-dioctylthieno [3,2-b] thiophene-co-thieno [3] , 2-b] thiophene), poly (3,6-dioctylthieno [3,2-b] thiophene-co-thiophene), poly (3,6-dioctylthieno [3,2-b] thiophene- Co-bithiophene) and the like.
Examples of the polyphenylene vinylene compound include 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-ethylphenyloxy) -1,4-phenylene vinylene) -co- (4,4′-biphenylene-vinylene)] and the like. .
Examples of the polyfluorene compound include poly (9,9′-didodecylfluorenyl-2,7-diyl) and 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.
Examples of the polyphenylene compound include poly [2,5-dioctyloxy-1,4-phenylene], poly [2,5-di (2-ethylhexyloxy-1,4-phenylene], and the like.
Examples of the polyarylamine compound include poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (N, N′-diphenyl) -N, N′-di (p- Hexylphenyl) -1,4-diaminobenzene], poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (N, N′-bis (4-octyloxyphenyl) benzidine -N, N '-(1,4-diphenylene)], poly [(N, N'-bis (4-octyloxyphenyl) benzidine-N, N'-(1,4-diphenylene)], poly [( N, N′-bis (4- (2-ethylhexyloxy) phenyl) benzidine-N, N ′-(1,4-diphenylene)], poly [phenylimino-1,4-phenylenevinylene-2,5-dioctyl Oxy-1,4-fe Lembinylene-1,4-phenylene], poly [p-tolylimino-1,4-phenylenevinylene-2,5-di (2-ethylhexyloxy) -1,4-phenylenevinylene-1,4-phenylene], poly [ 4- (2-ethylhexyloxy) phenylimino-1,4-biphenylene] and the like.
Examples of the polythiadiazole compound include poly [(9,9-dioctylfluorenyl-2,7-diyl) -alt-co- (1,4-benzo (2,1 ′, 3) thiadiazole], poly ( 3,4-didecylthiophene-co- (1,4-benzo (2,1 ′, 3) thiadiazole) and the like.
Among these, a polythiophene compound and a polyarylamine compound are preferable from the viewpoint of carrier mobility and ionization potential.

Various additives may be added to the hole transport material.
Additives include iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, silver iodide and other metal iodides, tetraalkylammonium iodide, Quaternary ammonium salts such as pyridinium iodide, metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide and calcium bromide, quaternary ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide Metal chlorides such as bromine salts, copper chloride and silver chloride, metal acetates such as copper acetate, silver acetate and palladium acetate, metal sulfates such as copper sulfate and zinc sulfate, ferrocyanate-ferricyanate, ferrocene -Sulfur compounds such as metal complexes such as ferricinium ion, sodium polysulfide, alkylthiol-alkyl disulfides Viologen dye, hydroquinone, 1,2-dimethyl-3-n-propylimidazolinium iodide, 1-methyl-3-n-hexylimidazolinium iodide, 1,2-dimethyl-3-ethylimidazo Inorg. Such as lithium trifluoromethanesulfonate, 1-methyl-3-butylimidazolium nonafluorobutylsulfonate, 1-methyl-3-ethylimidazolium bis (trifluoromethyl) sulfonylimide. Chem. 35 (1996) 1168, basic compounds such as pyridine, 4-t-butylpyridine, benzimidazole, and derivatives thereof, and alkali metal salts.

  The average thickness of the hole transport layer is not particularly limited and may be appropriately selected depending on the intended purpose, but preferably has a structure that enters the pores of the porous electron transport layer. Is preferably from 0.01 μm to 20 μm, more preferably from 0.1 μm to 10 μm, and still more preferably from 0.2 μm to 2 μm.

The hole transport layer can be directly formed on the electron transport layer on which the photosensitizing compound is adsorbed. There is no restriction | limiting in particular as a preparation method of a hole transport layer, Although it can select suitably according to the objective, The method of forming a thin film in vacuum, such as vacuum evaporation, the wet film forming method, etc. are mentioned. Among these, the wet film-forming method is particularly preferable in terms of production cost, and the method of coating on the electron transport layer is preferable.
When the wet film forming method is used, the coating method is not particularly limited and can be performed according to a known method, for example, a dip method, a spray method, a wire bar method, a spin coating method, a roller coating method, a blade. As a coating method, a gravure coating method, a die coating method, and a wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used.

  Alternatively, the film may be formed in a supercritical fluid or a subcritical fluid having a temperature and pressure lower than the critical point. A supercritical fluid exists as a non-aggregating high-density fluid in a temperature and pressure range that exceeds the limit (critical point) at which gas and liquid can coexist, and does not aggregate even when compressed, above the critical temperature and above the critical pressure 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.

Examples of the supercritical fluid include carbon monoxide, carbon dioxide, ammonia, nitrogen, water, alcohol solvent, hydrocarbon solvent, halogen solvent, ether solvent, and the like.
Examples of the alcohol solvent include methanol, ethanol, n-butanol and the like.
Examples of the hydrocarbon solvent include ethane, propane, 2,3-dimethylbutane, benzene, toluene, and the like. Examples of the halogen solvent include methylene chloride and chlorotrifluoromethane.
Examples of the ether solvent include dimethyl ether.
These may be used individually by 1 type and may use 2 or more types together.
Among these, carbon dioxide is preferable in that it has a critical pressure of 7.3 MPa and a critical temperature of 31 ° C., so that it can easily create a supercritical state and is nonflammable and easy to handle.

  The subcritical fluid is not particularly limited as long as it exists as a high-pressure liquid in the temperature and pressure regions near the critical point, and can be appropriately selected according to the purpose. The compound mentioned as a supercritical fluid can be used suitably also as a subcritical fluid.

  The critical temperature and critical pressure of the supercritical fluid is not particularly limited and may be appropriately selected depending on the purpose, as the critical temperature, is preferably -273 ° C. or higher 300 ° C. or less, 0 ° C. or higher 200 ° C. or less More preferred.

Furthermore, in addition to a supercritical fluid and a subcritical fluid, an organic solvent or an entrainer can be used in combination. By adding an organic solvent and an entrainer, the solubility in the supercritical fluid can be adjusted more easily.
There is no restriction | limiting in particular as an organic solvent, According to the objective, it can select suitably, For example, a ketone solvent, an ester solvent, an ether solvent, an amide solvent, a halogenated hydrocarbon solvent, a hydrocarbon solvent etc. are mentioned.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane and the like.
Examples of the amide solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone and the like.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, 1-chloronaphthalene and the like. .
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, Examples include ethylbenzene and cumene.
These may be used individually by 1 type and may use 2 or more types together.

Further, after the hole transport material is laminated on the electron transport layer on which the photosensitizing compound is adsorbed, a press treatment step may be performed. By performing the press treatment, the hole transport material is more closely attached to the electron transport layer which is a porous electrode, and thus the efficiency may be improved.
There is no restriction | limiting in particular as a method of press processing, According to the objective, it can select suitably, The press molding method using the flat plate represented by IR tablet molding machine, the roll press method using a roller etc. Can be mentioned.
The pressure is preferably 10 kgf / cm ² or more, more preferably 30 kgf / cm ² or more.
There is no restriction | limiting in particular in the time to press-process, Although it can select suitably according to the objective, 1 hour or less is preferable. Further, heat may be applied during the pressing process. During the press treatment, a release agent may be sandwiched between the press and the electrode.

  Examples of the release agent include polytetrafluoroethylene, polychlorotrifluoride ethylene, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkoxy fluoride resin, polyvinylidene fluoride, and ethylene tetrafluoride ethylene copolymer. And fluororesins such as ethylene chlorotrifluoride ethylene copolymer and polyvinyl fluoride. These may be used individually by 1 type and may use 2 or more types together.

After performing the press treatment step, a metal oxide may be provided between the hole transport material and the second electrode before providing the second electrode.
Examples of the metal oxide include molybdenum oxide, tungsten oxide, vanadium oxide, nickel oxide, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, molybdenum oxide is preferable.
The method for providing the metal oxide on the hole transport layer is not particularly limited and may be appropriately selected according to the purpose. Examples include a method for forming a thin film in a vacuum such as sputtering and vacuum deposition, a wet film forming method, and the like. Is mentioned.

As the wet film forming method, a method of preparing a paste in which a metal oxide powder or sol is dispersed and applying the paste on the hole transport layer is preferable. There is no restriction | limiting in particular as an application | coating method at the time of using a wet film forming method, It can carry out according to a well-known method, for example, a dip method, a spray method, a wire bar method, a spin coat method, a roller coat method, a blade As a coating method, a gravure coating method, a die coating method, and a wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used.
The average thickness of the applied metal oxide is preferably 0.1 nm to 50 nm, and more preferably 1 nm to 10 nm.

<Second electrode>
The photoelectric conversion element has a second electrode.
The second electrode can be formed on the hole transport layer or on the metal oxide in the hole transport layer. The second electrode can be the same as the first electrode, and the support is not necessarily required when the strength is sufficiently maintained.
Examples of the material of the second electrode include metals, carbon compounds, conductive metal oxides, and conductive polymers.
Examples of the metal include platinum, gold, silver, copper, and aluminum.
Examples of the carbon compound include graphite, fullerene, carbon nanotube, and graphene.
Examples of the conductive metal oxide include ITO, FTO, and ATO.
Examples of the conductive polymer include polythiophene and polyaniline.
These may be used individually by 1 type and may use 2 or more types together.

The method for providing these metal oxides on the hole transport material is not particularly limited, and examples thereof include a method for forming a thin film in a vacuum such as sputtering and vacuum deposition, and a wet film formation method. In the wet film forming method, it is preferable to prepare a paste in which a metal oxide powder or sol is dispersed and apply the paste on the hole transport layer.
When this wet film-forming method is used, the coating method is not particularly limited, and can be performed according to a known method.
For example, dip method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, die coating method, and wet printing methods such as letterpress, offset, gravure, intaglio, rubber plate, screen Various methods such as printing can be used. The film thickness is preferably from 0.1 nm to 50 nm, more preferably from 1 nm to 10 nm.
The second electrode is newly applied after the hole transport layer is formed or on the metal oxide.
The second electrode can be usually the same as the first electrode described above, and the support is not necessarily required in a configuration in which the strength and sealability are sufficiently maintained.

Regarding the formation of the second electrode, depending on the type of material used and the type of hole transport layer, it can be appropriately formed on the hole transport layer by techniques such as coating, laminating, vapor deposition, CVD, and bonding. is there.
In the photoelectric conversion element, it is preferable that at least one of the first electrode and the second electrode is substantially transparent. A method in which the first electrode side is transparent and incident light is incident from the first electrode side is preferable. In this case, a material that reflects light is preferably used on the second electrode side, and glass, plastic, or metal thin film on which metal, conductive oxide is deposited is preferably used. It is also effective to provide an antireflection layer on the incident light side.

<Sealing member>
It is preferable to have a sealing member that shields the electron transport layer and the hole transport layer from the external environment of the photoelectric conversion element.
It is preferable that the sealing member is sandwiched between a pair of substrates, and at least the electron transporting layer and the hole transporting layer have a void inside the sealed photoelectric conversion element shielded from the external environment.

It is preferable to have a sealing member that shields the electron transport layer, the hole transport layer, and the second electrode from the external environment of the photoelectric conversion element.
The sealing member is sandwiched between a pair of substrates, and at least the electron transport layer, the hole transport layer, and the second electrode are sealed in the sealed portion of the photoelectric conversion element shielded from the external environment. It is preferable to have.

  An epoxy resin is used as the sealing member, and the hole transport layer has at least one of the tertiary amine compounds represented by the general formula (1) and the general formula (2), whereby the photoelectric conversion element can be used in a high-temperature and high-humidity environment. Even when stored below, high output before storage can be maintained. Further, even when light with low illuminance is continuously irradiated, high output can be maintained.

The epoxy resin is not particularly limited as long as it is a resin in which a monomer or oligomer having an epoxy group in the molecule is cured, and can be appropriately selected according to the purpose. For example, a water dispersion type, a solventless type , Solid type, thermosetting type, curing agent mixed type, ultraviolet curable type and the like. Among these, a thermosetting type and an ultraviolet curable type are preferable, and an ultraviolet curable type is more preferable. In addition, even if it is an ultraviolet curable type, you may heat.
Examples of the epoxy resin include bisphenol A type, bisphenol F type, novolac type, cyclic aliphatic type, long chain aliphatic type, glycidylamine type, glycidyl ether type, and glycidyl ester type. These may be used individually by 1 type and may use 2 or more types together.

The epoxy resin may contain a curing agent and various additives as necessary.
Examples of the curing agent include amine-based, acid anhydride-based, polyamide-based, and other curing agents.
Examples of the amine curing agent include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.
Examples of the acid anhydride curing agent include phthalic anhydride, tetra- and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, pyromellitic anhydride, het acid anhydride, dodecenyl succinic anhydride, and the like. .
Examples of other curing agents include imidazoles and polymercaptan. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the additives include fillers (filler), a gap material, a polymerization initiator, drying agents (hygroscopic agent), curing accelerator, coupling agent, flexibilizer agents, coloring agents, flame retardant agents, antioxidants Agents, organic solvents, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, a filler, a gap agent, a curing accelerator, a polymerization initiator, and a drying agent (hygroscopic agent) are preferable, and a filler and a polymerization initiator are particularly preferable.

As a filler, it is effective in suppressing the ingress of moisture and oxygen in the external environment, reducing volume shrinkage during curing, reducing gas generation during curing or heating, and improving mechanical strength Thus, effects such as control of thermal conductivity and fluidity can be obtained, and the present invention is very effective in maintaining a stable output in various environments.
The output characteristics and durability of the photoelectric conversion element may ignore not only the influence of moisture and oxygen entering the photoelectric conversion element from the external environment, but also the influence of the gas generated when the sealing member is cured and heated. Can not. In particular, the effect of gas generated during heating has a great effect on output characteristics when stored in a high temperature environment.
In this case, by containing a filler, a gap agent, and a desiccant in the sealing member, they themselves can suppress the intrusion of moisture and oxygen, and the amount of sealing member used can be reduced, thereby reducing gas generation. Effect can be obtained. This is effective not only at the time of curing but also when the photoelectric conversion element is stored in a high temperature environment.

  The filler is not particularly limited, and a known material can be used. For example, crystalline or amorphous silica, talc, alumina, aluminum nitride, silicon nitride, calcium silicate, calcium carbonate and the like are inorganic. A filler is preferably used. These may be used individually by 1 type and may use 2 or more types together.

  The average primary particle size of the filler is preferably from 0.1 μm to 10 μm, and more preferably from 1 μm to 5 μm. The average primary particle size of the filler is 0.1μm or more 10μm or less, it is possible to obtain a sufficient effect of suppressing the entry of moisture or oxygen, the viscosity becomes appropriate, adhesion and degassing of the substrate This is also effective for improving the width, controlling the width of the sealing portion, and workability.

  As content of a filler, 10 mass parts or more and 90 mass parts or less are preferable with respect to sealing member whole quantity, and 20 mass parts or more and 70 mass parts or less are more preferable. When the content of the filler is 10 parts by mass or more and 90 parts by mass or less, the effect of suppressing the intrusion of moisture and oxygen is sufficiently obtained, the viscosity is appropriate, and the adhesion and workability are also improved.

  The gap agent is also called a gap control agent or a spacer agent, and can control the gap of the sealing portion. For example, when a sealing member is provided on the first substrate or the first electrode and sealing is performed by placing the second substrate thereon, a gap agent is mixed with the epoxy resin. Thus, since the gap of the sealing part is equal to the size of the gap agent, the gap of the sealing part can be easily controlled.

  As the gap agent, a known material can be used as long as it is granular and has a uniform particle diameter and high solvent resistance and heat resistance. Those having high affinity with the epoxy resin and having a spherical particle shape are preferred. Specific examples include glass beads, silica fine particles, and organic resin fine particles. These may be used individually by 1 type and may use 2 or more types together.

  The particle size of the gap agent can be selected according to the gap of the sealing portion to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

A polymerization initiator is a material added for the purpose of initiating polymerization using heat or light.
Thermal polymerization initiators are compounds that generate active species such as radicals and cations by heating. Specifically, azo compounds such as 2,2′-azobisbutyronitrile (AIBN), benzoyl peroxide (BPO), and the like. ) And the like.
As the thermal cationic polymerization initiator, benzenesulfonic acid ester, alkylsulfonium salt or the like is used.

  On the other hand, the photopolymerization initiator is preferably a photocationic polymerization initiator in the case of an epoxy resin. When a cationic photopolymerization initiator is mixed with an epoxy resin and light irradiation is performed, the cationic photopolymerization initiator is decomposed to generate a strong acid, and the acid causes polymerization of the epoxy resin, and the curing reaction proceeds. The cationic photopolymerization initiator has effects such as little volume shrinkage during curing, no oxygen inhibition, and high storage stability.

Examples of the photocationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metatheron compounds, silanol / aluminum complexes, and the like. Moreover, the photo-acid generator which has a function which generate | occur | produces an acid by irradiating light can also be used.
The photoacid generator acts as an acid that initiates cationic polymerization, and examples thereof include ionic salts of an ionic sulfonium salt and an iodonium salt composed of a cation portion and an anion portion. These may be used individually by 1 type and may use 2 or more types together.

  As content of a polymerization initiator, 0.5 mass part or more and 10 mass parts or less are preferable with respect to the whole quantity of a sealing member, and 1 mass part or more and 5 mass parts or less are more preferable. When the content of the polymerization initiator is 0.5 parts by mass or more and 10 parts by mass or less, the curing proceeds appropriately, the remaining of the uncured product can be reduced, and the generation amount of gas is prevented from being excessive. It is possible and effective.

The desiccant is also referred to as a hygroscopic agent, and is a material having a function of physically or chemically adsorbing and absorbing moisture. By including the desiccant in the sealing member, the desiccant can be further enhanced, or the influence of the outgas This is effective because it can be reduced.
The desiccant is preferably in the form of particles, and examples thereof include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieve, and zeolite. These may be used individually by 1 type and may use 2 or more types together. Among these, zeolite with a large amount of moisture absorption is preferable.

The curing accelerator is also referred to as a curing catalyst, and is used for the purpose of increasing the curing speed, and is mainly used for a thermosetting epoxy resin.
Examples of the curing accelerator include three compounds such as DBU (1,8-diazabicyclo (5,4,0) -undecene-7) and DBN (1,5-diazabicyclo (4,3,0) -nonene-5). Primary amines or tertiary amine salts, imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, phosphines such as triphenylphosphine, tetraphenylphosphonium and tetraphenylborate Or a phosphonium salt etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

  Coupling agents has the effect of increasing the molecular bonding force, a silane coupling agent can be mentioned, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl methyl dimethoxysilane, 3-glycidoxy propyl methyl dimethoxy silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- phenyl--γ- aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyl methyl dimethoxysilane, N- (2-aminoethyl) 3-aminopropyl methyl trimethoxy silane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2- (vinyl benzylamino) ethyl) 3- Aminopropyltrimethoxysilane hydrochloride , 3-methacryloxypropyl trimethoxy silane Silane coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.

As the sealing member, an epoxy resin composition marketed as a sealing material, a sealing material or an adhesive is known, and can be used effectively in the present invention. Among them, there are epoxy resin compositions developed and marketed for solar cells and organic EL device applications, and can be used particularly effectively in the present invention.
Examples of the commercial products include trade names: TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond Co., Ltd.), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyoritsu Chemical Industry Co., Ltd.), WB90US (P) (and above) Moresco).
In addition, the epoxy resin composition is disclosed in, for example, Japanese Patent No. 4918975, Japanese Patent No. 5812275, Japanese Patent No. 5835664, Japanese Patent No. 5930248, Japanese Patent Application Laid-Open No. 2012-136614, and these are also used. can do.
Moreover, in this invention, a sheet-like sealing material can also be used effectively.
The sheet-like sealing material is a sheet in which an epoxy resin layer is formed in advance, and the sheet is made of glass or a film having a high gas barrier property, and corresponds to the substrate in the present invention. A sealing member and a board | substrate can be formed at once by sticking a sheet-like sealing material on the 2nd electrode of a photoelectric conversion element or a photoelectric conversion element module, and making it harden | cure after that. A structure in which a void portion is provided inside the photoelectric conversion element is effective because of the formation pattern of the epoxy resin layer formed on the sheet.

The position of the sealing member is not particularly limited as long as it is arranged at a position that shields at least the electron transport layer, the hole transport layer, and the second electrode from the external environment of the photoelectric conversion element. For example, it may be provided on the entire surface so as to cover the electron transport layer, the hole transport layer, and the second electrode, or a substrate is disposed above the second electrode, and a sealing member is provided. May be provided on the outer edge of the substrate and adhered to at least one of the first substrate, the first electrode, and the hole blocking layer.
A configuration in which a substrate is provided and a sealing member is provided on the outer edge thereof as in the latter can provide a gap in the photoelectric conversion element or the photoelectric conversion element module. The air gap can control oxygen and humidity, and is effective in improving output and durability.

  In the present invention, it is particularly preferable that oxygen be contained in the gap. By containing oxygen, the hole transport function of the hole transport layer can be stably maintained over a long period of time, and the durability of the photoelectric conversion element or the photoelectric conversion element module can be improved. In the present invention, the oxygen concentration in the gap inside the photoelectric conversion element provided by sealing is effective as long as it contains oxygen, but it is 1.0 vol% or more and 21.0 vol% or less. Preferably, 3.0 volume% or more and 15.0 volume% or less are more preferable.

  The oxygen concentration in the void can be controlled by sealing in a glove box in which the oxygen concentration is set. The oxygen concentration can be set by a method using a gas cylinder having a specific oxygen concentration or a method using a nitrogen gas generator. The oxygen concentration in the glove box is measured using a commercially available oxygen concentration meter or oxygen monitor.

The measurement of the oxygen concentration in the void formed by sealing can be performed by, for example, an atmospheric pressure ionization mass spectrometer (API-MS). Specifically, by installing a photoelectric conversion element or photoelectric conversion element module in a chamber filled with an inert gas, opening the seal in the chamber, and quantitatively analyzing the gas in the chamber with API-MS The oxygen concentration can be obtained by quantifying all the components in the gas contained in the void and calculating the ratio of oxygen to the sum.
As the gas other than oxygen, an inert gas is preferable, and nitrogen, argon, and the like can be given.

When sealing, it is preferable to control the dew point as well as the oxygen concentration in the glove box, which is effective for improving the output and its durability.
The dew point is defined as the temperature at which condensation starts when a gas containing water vapor is cooled. As a dew point, 0 degrees C or less is preferable and -20 degrees C or less is more preferable. As a minimum, -50 ° C or more is preferred.

  Further, a passivation layer may be provided between the second electrode and the sealing member. There is no restriction | limiting in particular as a passivation layer, According to the objective, it can select suitably, For example, aluminum oxide, silicon nitride, silicon oxide etc. are preferable.

  As a method for forming the sealing member is not particularly limited and may be appropriately selected depending on the purpose, for example, a dispensing method, a wire bar method, spin coating, roller coating, blade coating, gravure coating, Letterpress, offset, intaglio, rubber plate, screen printing and the like can be mentioned.

<First substrate>
The photoelectric conversion element may have a first substrate.
There is no restriction | limiting in particular about the shape, structure, and magnitude | size as a 1st board | substrate, According to the objective, it can select suitably.
The material of the first substrate is not particularly limited as long as it has translucency and insulation, and can be appropriately selected according to the purpose. For example, glass, plastic plate, plastic film, plastic film, Examples of the substrate include ceramics and inorganic transparent crystals. Among these, a substrate having heat resistance with respect to the firing temperature is preferable when a step of firing when forming the electron transport layer as described later is included. In addition, the first substrate is preferably a flexible substrate.

<Second substrate>
The photoelectric conversion element may have a second substrate.
The second substrate is not particularly limited, and a known substrate can be used. Examples thereof include substrates such as glass, a transparent plastic plate, a transparent plastic film, an inorganic transparent crystal, a plastic film, and a ceramic. It is done. An uneven portion may be formed in the joint portion between the second substrate and the sealing member in order to improve adhesion.
There is no restriction | limiting in particular as a formation method of an uneven | corrugated | grooved part, According to the objective, it can select suitably, For example, a sand blast method, a water blast method, abrasive paper, a chemical etching method, a laser processing method etc. are mentioned.
As a means for increasing the adhesion between the second substrate and the sealing member, for example, organic substances on the surface may be removed or hydrophilicity may be improved. The means for removing the organic substance on the surface of the second substrate is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include UV ozone cleaning and oxygen plasma treatment.

<Hole blocking layer>
The photoelectric conversion element may have a hole blocking layer.
The hole blocking layer is preferably formed between the first electrode and the electron transport layer.
The hole blocking layer transports electrons generated by the photosensitizing compound and transported to the electron transport layer to the first electrode and prevents contact with the hole transport layer. As a result, the hole blocking layer makes it difficult for holes to flow into the first electrode, and can suppress a decrease in output due to recombination of electrons and holes. The solid-type photoelectric conversion element provided with a hole transport layer has a faster hole recombination rate between the holes in the hole transport material and the electrons on the electrode surface than the wet type using an electrolyte solution. The effect of is very large.

The material of the hole blocking layer is not particularly limited as long as it is transparent to visible light and has an electron transporting property, and can be appropriately selected according to the purpose. For example, silicon, germanium, etc. Examples thereof include a single semiconductor, a compound semiconductor typified by a metal chalcogenide, and a compound having a perovskite structure.
Examples of metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum oxides; cadmium, zinc, lead, silver, antimony Bismuth sulfide; cadmium, lead selenide; cadmium telluride. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium; gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like.
Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
Among these, an oxide semiconductor is preferable, titanium oxide, niobium oxide, magnesium oxide, aluminum oxide, zinc oxide, tungsten oxide, and tin oxide are more preferable, and titanium oxide is still more preferable.
These may be used individually by 1 type and may use 2 or more types together. Moreover, you may laminate | stack as a single layer. Further, the crystal form of these semiconductors is not particularly limited and can be appropriately selected depending on the purpose, and may be single crystal, polycrystal, or amorphous.

  The method for forming the hole blocking layer is not particularly limited and may be appropriately selected depending on the purpose. For example, the sol-gel method for wet film formation, the hydrolysis method from titanium tetrachloride, the sputtering method for dry film formation Among them, the sputtering method is preferable among these. When the film forming method of the hole blocking layer is the sputtering method, the film density can be sufficiently increased, and the loss current can be suppressed.

  The thickness of the hole blocking layer is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 5 nm or more and 1 μm or less, more preferably 500 nm or more and 700 nm or less for wet film formation, and 5 nm or more for dry film formation. 30 nm or less is more preferable.

[Embodiment]
Below, an example of the photoelectric conversion element of this invention is demonstrated using drawing. However, the present invention is not limited to these, and for example, the number, position, shape, and the like of the following constituent members that are not described in the present embodiment are also included in the category of the present invention.

FIG. 1 is a schematic view showing an example of the photoelectric conversion element of the present invention.
As shown in FIG. 1, in the photoelectric conversion element 101, the first electrode 2 is formed on the first substrate 1, and the hole blocking layer 3 is formed on the first electrode 2. An electron transport layer 4 is formed on the hole blocking layer 3, and the photosensitizing compound 5 is adsorbed on the surface of the electron transport material constituting the electron transport layer 4. A hole transport layer 6 is formed on and inside the electron transport layer 4, and a second electrode 7 is formed on the hole transport layer 6. A second substrate 9 is disposed above the second electrode 7, and the second substrate 9 is fixed between the hole blocking layer 3 and the sealing member 8. By forming the hole blocking layer 3, recombination of electrons and holes can be prevented, so that power generation performance can be improved.
The photoelectric conversion element shown in FIG. 1 can have a gap 10 between the second electrode 7 and the second substrate 9. By having the void portion, the oxygen concentration in the void portion can be controlled, so that power generation performance and durability can be improved. Further, since the second electrode 7 and the second substrate 9 are not in direct contact, it is possible to prevent the second electrode 7 from being peeled off or broken.
There is no restriction | limiting in particular as oxygen concentration in a space | gap part, Although it can select suitably according to the objective, 1.0 volume% or more and 21.0 volume% or less are preferable, 3.0 volume% or more and 15.0 volume% % Or less is more preferable.
Although not shown, each of the first electrode 2 and the second electrode 7 can have a path that conducts to the electrode extraction terminal.

FIG. 2 is a schematic view showing another example of the photoelectric conversion element of the present invention, and shows a case where a gap portion is not provided and the gap portion of FIG.
There is no restriction | limiting in particular as a preparation method of the photoelectric conversion element which does not provide a space | gap part, According to the objective, it can select suitably, For example, the sealing member 8 is apply | coated to the whole surface on the 2nd electrode 7, Examples thereof include a method of providing the second substrate 9 thereon, a method of using the above-described sheet-shaped sealing material, and the like.
The gap inside the seal may be completely eliminated, or a part of the gap may be left as shown in FIG. By covering almost the entire surface with a sealing member, when stress is applied to the photoelectric conversion element by twisting or dropping, the second substrate 9 can be reduced from being peeled off or destroyed, and the photoelectric conversion element machine Strength can be increased. Further, as a modification of FIG. 2, a configuration in which the second substrate is not provided as shown in FIG.

  FIG. 5 is a schematic view showing another example of the photoelectric conversion element of the present invention, and shows a case where the sealing member 8 is bonded to the first substrate 1 and the second substrate 9. By adopting such a configuration, the adhesiveness between the sealing member 8 and the substrate is increased, and the effect of increasing the mechanical strength of the photoelectric conversion element is obtained. Moreover, the effect which raises the sealing effect which prevents the excessive penetration | invasion of a water | moisture content or oxygen can be acquired by improving adhesiveness.

(Photoelectric conversion element module)
The photoelectric conversion element module of the present invention has a photoelectric conversion element arrangement region in which a plurality of photoelectric conversion elements are arranged adjacent to each other, and the plurality of photoelectric conversion elements have a first electrode and a photosensitizing compound. An epoxy resin having an electron transport layer, a hole transport layer, and a second electrode, disposed at an outer edge of the photoelectric conversion element placement region, and shielding the electron transport layer from an external environment of the photoelectric conversion element The hole transport layer has a p-type semiconductor material and a basic compound, and the ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material, and The ionization potential of the p-type semiconductor material is less than 1.07 times, the ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer, and the basification Acid dissociation constant of the object (pKa) is, and at 6 to 10, if necessary, includes other layers. Each layer may have a single layer structure or a laminated structure.

Moreover, the photoelectric conversion element module of this invention can be set as the structure which has multiple said photoelectric conversion elements.
As a structure of each layer of a photoelectric conversion element module, it can be set as the structure similar to the said photoelectric conversion element.

  Examples of the photoelectric conversion element module include a configuration in which a plurality of photoelectric conversion elements are connected in series or in parallel.

  The photoelectric conversion element module may be in the form of a continuous layer in which at least the hole transport layers extend from each other in at least two of the photoelectric conversion elements adjacent to each other.

  The photoelectric conversion element module may include a pair of substrates, the photoelectric conversion element arrangement region between the pair of substrates, and the sealing member sandwiched between the pair of substrates.

[Embodiment]
Below, an example of the photoelectric conversion element module of this invention is demonstrated using drawing. However, the present invention is not limited to these, and for example, the number, position, shape, and the like of the following constituent members that are not described in the present embodiment are also included in the category of the present invention.

FIG. 6 is a schematic diagram illustrating an example of a photoelectric conversion element module according to the present invention, which is an example illustrating a cross section of a part of a photoelectric conversion element module including a plurality of photoelectric conversion elements and connected in series. .
In FIG. 6, after the hole transport layer 6 is formed, the penetrating part 11 is formed, and then the second electrode 7 is formed, whereby the second electrode material is introduced into the penetrating part 11 and adjacent to each other. It is possible to conduct with the first electrode 2b of the cell. Although not shown in FIG. 6, the first electrode 2a and the second electrode 7b further have a path that conducts to the electrode of the adjacent cell or the output extraction terminal.
The penetrating part 11 may penetrate the first electrode 2 and reach the first substrate 1, or may stop processing inside the first electrode 2 and not reach the first substrate 1. Also good.
When the shape of the penetrating part 11 is a fine hole penetrating the first electrode 2 and reaching the first substrate 1, if the total opening area of the fine holes is too large with respect to the area of the penetrating part 11, When the film cross-sectional area of one electrode 2 decreases, the resistance value increases, which may cause a decrease in photoelectric conversion efficiency. Therefore, the ratio of the total opening area of the micropores to the area of the through-hole 11 is preferably 5/100 or more and 60/100 or less.
There is no restriction | limiting in particular as a formation method of the penetration part 11, According to the objective, it can select suitably, For example, a sand blast method, a water blast method, polishing paper, a chemical etching method, a laser processing method etc. are mentioned. Among these, the laser processing method is preferable. As a result, fine holes can be formed without using sand, etching, resist, or the like, and can be processed cleanly with high reproducibility. Further, when forming the penetrating portion 11, at least one of the hole blocking layer 3, the electron transport layer 4, the hole transport layer 6, and the second electrode 7 can be removed by impact peeling by a laser processing method. Become. Thereby, it is not necessary to provide a mask at the time of lamination, and removal and formation of the fine through portion 11 can be easily performed at a time.

FIG. 7 is a schematic view showing an example of the photoelectric conversion element module of the present invention, which includes a plurality of photoelectric conversion elements, which are connected in series, and the sealing member 12 is formed like a beam in a gap between cells. It is an example which shows a partial cross section with a provided photoelectric conversion element module.
As shown in FIG. 2, when a gap is provided between the second electrode 7 and the second substrate 9, the second electrode 7 can be prevented from peeling and breaking, but the mechanical strength of sealing is reduced. There is a case. On the other hand, as shown in FIG. 3, when the space between the second electrode 7 and the second substrate 9 is filled with a sealing member, the mechanical strength of the sealing is increased, but the second electrode 7 is peeled off. There are concerns. Here, in order to increase the generated power, it is effective to increase the area of the photoelectric conversion element module. However, in the case where the gap portion is included, a decrease in mechanical strength is inevitable.
Therefore, by providing the sealing member 12 like a beam as shown in FIG. 7, it is possible to prevent the second electrode 7 from being peeled or broken, and to increase the mechanical strength of the sealing. is there.

(Electronics)
The electronic device of the present invention includes the photoelectric conversion element and / or the photoelectric conversion element module of the present invention, and a device that operates with electric power generated by the photoelectric conversion of the photoelectric conversion element and / or the photoelectric conversion element module. In addition, other devices are provided as necessary.

(Power module)
The power supply module of the present invention includes the photoelectric conversion element and / or photoelectric conversion element module of the present invention and a power supply IC, and further includes other devices as necessary.

A specific embodiment of an electronic apparatus having the photoelectric conversion element and the photoelectric conversion element module of the present invention and a device that operates with electric power obtained by generating electricity will be described.
FIG. 8 shows an example in which a mouse is used as the electronic device.
As shown in FIG. 8, a photoelectric conversion element, a photoelectric conversion element module, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of a mouse control circuit. Thereby, when the mouse is not used, the power storage device can be charged and the mouse can be operated with the electric power, and a mouse that does not require wiring or battery replacement can be obtained. Further, since the battery is not necessary, the weight can be reduced, which is effective.
FIG. 9 shows a schematic diagram in which a photoelectric conversion element is mounted on a mouse. The photoelectric conversion element, the power supply IC, and the power storage device are mounted inside the mouse, but the upper portion of the photoelectric conversion element is covered with a transparent casing so that light strikes the photoelectric conversion element. It is also possible to mold the entire case of the mouse with a transparent resin. The arrangement of the photoelectric conversion element is not limited to this. For example, even if the mouse is covered with a hand, it can be arranged at a position where light is irradiated, which may be preferable.

Another embodiment of the electronic device having the photoelectric conversion element and the photoelectric conversion element module of the present invention and a device that operates with the electric power obtained by generating power will be described.
FIG. 10 shows an example in which a keyboard used in a personal computer is used as the electronic device.
As shown in FIG. 10, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the keyboard control circuit. Thereby, when the keyboard is not used, the power storage device can be charged, and the keyboard can be operated with the power, and a keyboard that does not require wiring or battery replacement can be obtained. Further, since the battery is not necessary, the weight can be reduced, which is effective.
FIG. 11 shows a schematic diagram in which a photoelectric conversion element is mounted on a keyboard. The photoelectric conversion element, the power supply IC, and the power storage device are mounted inside the keyboard, but the upper portion of the photoelectric conversion element is covered with a transparent casing so that light strikes the photoelectric conversion element. It is also possible to mold the entire keyboard casing with a transparent resin. The arrangement of the photoelectric conversion elements is not limited to this.
In the case of a small keyboard with a small space for incorporating a photoelectric conversion element, as shown in FIG. 12, it is possible to embed a small photoelectric conversion element in a part of the key, which is effective.

Another embodiment of the electronic device having the photoelectric conversion element and the photoelectric conversion element module of the present invention and a device that operates with the electric power obtained by generating power will be described.
FIG. 13 shows an example in which a sensor is used as the electronic device.
As shown in FIG. 13, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the sensor circuit. Thereby, it is not necessary to connect to an external power source, and it is not necessary to replace the battery, so that the sensor module can be configured. The sensing object is effective because it can be applied to various sensors such as temperature and humidity, illuminance, human feeling, CO ₂ , acceleration, UV, noise, geomagnetism, and atmospheric pressure. The sensor module is configured to periodically sense a measurement target and transmit the read data to a PC, a smartphone, or the like by wireless communication, as indicated by A in FIG.
With the arrival of the IoT society, the number of sensors is expected to increase rapidly. Replacing the countless sensor batteries one by one takes a lot of time and is not practical. In addition, the sensor is in a place where it is difficult to replace the battery, such as a ceiling or a wall, which makes workability worse. The merit of being able to supply power by the photoelectric conversion element is also very large. In addition, the photoelectric conversion element of the present invention can obtain a high output even at low illuminance, and has a merit that the degree of freedom in installation is high because the output has a small dependence on the light incident angle.

Another embodiment of the electronic device having the photoelectric conversion element and the photoelectric conversion element module of the present invention and a device that operates with the electric power obtained by generating power will be described.
FIG. 14 shows an example in which a turntable is used as the electronic device.
As shown in FIG. 14, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the turntable circuit. Thereby, it is not necessary to connect to an external power source, and it is not necessary to replace the battery, so that a turntable can be configured.
The turntable is used for, for example, a showcase for displaying products, but the power supply wiring is not good-looking, and the battery must be removed when replacing the battery. By using the photoelectric conversion element of the present invention, such a problem can be solved and it is effective.

<Application>
As described above, the photoelectric conversion element and the photoelectric conversion element module according to the present invention, the electronic device including the device that operates with the electric power obtained by generating the power, and the power supply module have been described, but these are only a part. The photoelectric conversion element or the photoelectric conversion element module of the present invention is not limited to these applications.

The photoelectric conversion element and the photoelectric conversion element module can be applied to, for example, a power supply device by combining with a circuit board that controls the generated current.
Examples of the devices using the power supply device include an electronic desk calculator, a wristwatch, a mobile phone, an electronic notebook, and electronic paper.
In addition, a power supply device having a photoelectric conversion element can be used as an auxiliary power source for extending the continuous use time of a rechargeable or dry battery type electric appliance.

The photoelectric conversion element and the photoelectric conversion element module of the present invention can function as a self-supporting power source, and can operate the apparatus using power generated by photoelectric conversion. Since the photoelectric conversion element and the photoelectric conversion element module of the present invention can generate electric power when irradiated with light, it is not necessary to connect an electronic device to a power source or replace a battery. Therefore, it is possible to operate the electronic device even in a place where there is no power supply facility, to carry it around, or to operate the electronic device in a place where it is difficult to replace the battery without replacing the battery. In addition, when using a dry cell, the electronic equipment becomes heavier or larger in size, which may hinder installation on the wall or ceiling or carrying, but the photoelectric conversion of the present invention. Since the element and the photoelectric conversion element module are lightweight and thin, the degree of freedom of installation is high, and there are great merits in wearing and carrying.
As described above, the photoelectric conversion element and the photoelectric conversion element module of the present invention can be used as a self-supporting power source and can be combined with various electronic devices. For example, display devices such as electronic desk calculators, watches, mobile phones, electronic notebooks, electronic papers, personal computer accessories such as mice and keyboards, various sensor devices such as temperature and humidity sensors and human sensors, beacon and GPS transmissions It can be used in combination with many electronic devices such as a machine, auxiliary light, and remote control.

  Photoelectric conversion elements, and photoelectric conversion element module of the present invention is capable of power generation at particularly low illuminance of the light, for indoors, it is possible to generate power even at the further dim shadow, Flexible. Moreover, there is no liquid leakage like a dry battery, and it is safe without accidental ingestion like a button battery. Furthermore, it can be used as an auxiliary power source for extending the continuous use time of rechargeable or dry battery type electric appliances. Thus, the photoelectric conversion element of the present invention, and a photoelectric conversion element module, it is possible to combine a device that operates by electric power generated by photoelectric conversion, lightweight good usability, high degree of freedom of installation, It can be reborn as an electronic device that does not require replacement, has excellent safety, and is effective in reducing environmental impact.

  FIG. 15 shows a basic configuration diagram of an electronic apparatus in which the photoelectric conversion element and / or the photoelectric conversion element module of the present invention is combined with a device that operates with electric power generated by photoelectric conversion. This generates electricity when the photoelectric conversion element is irradiated with light, and can extract electric power. The circuit of the device can be operated by its power.

However, since the output of the photoelectric conversion element varies depending on ambient illuminance, the electronic device illustrated in FIG. 15 may not be able to operate stably. In this case, as shown in FIG. 16, in order to supply a stable voltage to the circuit side, it is possible to incorporate a power supply IC for the photoelectric conversion element between the photoelectric conversion element and the circuit of the device, which is effective. .
However, the photoelectric conversion element can generate power if it is irradiated with light with sufficient illuminance, but if the illuminance sufficient to generate power is insufficient, desired power cannot be obtained, which is also a drawback of the photoelectric conversion element. In this case, as shown in FIG. 17, by mounting a power storage device such as a capacitor between the power supply IC and the equipment circuit, surplus power from the photoelectric conversion element can be charged to the power storage device. Even when the power is too low or the photoelectric conversion element is not exposed to light, the electric power stored in the power storage device can be supplied to the device circuit and can be operated stably.
As described above, in an electronic device in which the photoelectric conversion element and / or photoelectric conversion element module of the present invention is combined with a device circuit, it can be operated in an environment without a power source by combining a power supply IC and a power storage device. It is not necessary to replace the battery and can be driven stably, so that the merit of the photoelectric conversion element can be fully utilized.

On the other hand, the photoelectric conversion element and / or photoelectric conversion element module of the present invention can be used as a power supply module and is useful. For example, as shown in FIG. 18, when the photoelectric conversion element and / or photoelectric conversion element module of the present invention is connected to a power supply IC for the photoelectric conversion element, the power generated by the photoelectric conversion of the photoelectric conversion element is converted into the power supply IC. A DC power supply module that can be supplied at a constant voltage level can be configured.
Furthermore, as shown in FIG. 19, by adding an electricity storage device to the power supply IC, it becomes possible to charge the electricity generated by the photoelectric conversion element to the electricity storage device, and when the illuminance is too low, A power supply module capable of supplying electric power even when light is not exposed to can be configured.
The power supply module of the present invention shown in FIGS. 18 and 19 can be used as a power supply module without replacing the battery as in a conventional primary battery.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
<Production of photoelectric conversion element>
First, a reaction by oxygen gas is performed on an ITO coat glass in which indium doped tin oxide (ITO) and niobium doped tin oxide (NTO) as a first electrode are sequentially sputtered on a glass substrate as a first substrate. A dense layer made of titanium oxide was formed as a hole blocking layer by reactive sputtering.
Next, 3 g of titanium oxide (trade name: P90, manufactured by Nippon Aerosil Co., Ltd.), 0.2 g of acetylacetone, and 0.3 g of polyoxyethylene octylphenyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) as a surfactant, A bead mill treatment was performed for 12 hours with 5.5 g of water and 1.0 g of ethanol to prepare a titanium oxide dispersion. 1.2 g of polyethylene glycol (trade name: polyethylene glycol 20,000, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the produced titanium oxide dispersion to prepare a paste. The prepared paste was applied on the hole blocking layer (average thickness: 1.5 μm), dried at 50 ° C., and then baked in air at 500 ° C. for 30 minutes to form a porous electron transport layer. .
The glass substrate on which the electron transport layer was formed was subjected to photosensitizing compound (trade name: DN455, manufactured by Chemicrea Co., Ltd.) 0.2 mM represented by the following structural formula (A) and chenodeoxycholic acid (CDCA, Tokyo Chemical Industry Co., Ltd.). (Manufactured) It was immersed in a 0.4 mM acetonitrile / t-butanol (volume ratio 1: 1) solution and allowed to stand in the dark for 1 hour to adsorb the photosensitizing compound on the surface of the electron transport layer. Next, to 1 mL of a chlorobenzene solution of 186.5 mg of the hole transport material (Merck Co., Ltd.) represented by D-7, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide as an additive ( Product name: EMIMIm, Tokyo Chemical Industry Co., Ltd. 25.5 mg, N, N-dimethyl-4-aminopyridine (trade name: DMAP, Tokyo Chemical Industry Co., Ltd.) 14.8 mg which is a basic compound It melt | dissolved and the hole transport layer coating liquid was prepared.

However, Ph represents a phenyl group.

  Next, a hole transport layer was formed on the electron transport layer on which the photosensitizing compound was adsorbed by spin coating using the hole transport layer coating solution (average thickness: 600 nm). Silver was vacuum-deposited thereon to form a second electrode (average thickness: 100 nm), and the photoelectric conversion element of Example 1 was produced.

(Example 2)
A photoelectric conversion element of Example 2 was produced in the same manner as in Example 1 except that the hole transport material was changed to the hole transport material represented by the following structural formula (FDT) in Example 1.

However, Me represents a methyl group.

(Example 3)
In Example 1, the photoelectric conversion element of Example 3 was produced like Example 1 except having changed the hole transport material into the hole transport material represented by said D-10.

(Examples 4 to 6)
In Example 3, except that the content of N, N-dimethyl-4-aminopyridine, which is a basic compound, was changed to 16.3 mg, 11.8 mg, and 8.9 mg, respectively, in the same manner as in Example 3. The photoelectric conversion elements of Examples 4 to 6 were produced.

(Example 7)
In Example 6, the photoelectric conversion element of Example 7 was produced in the same manner as in Example 6 except that the photosensitizing compound was changed to trade name: D358 (manufactured by Mitsubishi Paper Industries Co., Ltd.).

(Examples 8 to 14)
In Example 1, the basic compound was changed to a basic compound represented by each of the following P-1 to P-7, and the contents were 41.1 mg, 37.1 mg, 24.7 mg, 24.5 mg, 27, respectively. Photoelectric conversion elements of Examples 8 to 14 were produced in the same manner as in Example 1 except that the amount was 0.8 mg, 16.6 mg, and 19.5 mg.

(Example 15)
Example 1 Example 1 except that 12.5 mg of an oxidizing agent (trade name: FK269, manufactured by Sigma-Aldrich Japan Co., Ltd.) represented by the following structural formula A was added as an oxidizing agent to the hole transport layer coating solution. in the same manner as to prepare a photoelectric conversion element of example 15.

[Structural Formula A]

(Example 16)
Example 15 was carried out in the same manner as in Example 15 except that the oxidizing agent was changed to the oxidizing agent (DN-Cu08) represented by the following structural formula B and the content of the oxidizing agent was 9.8 mg. The photoelectric conversion element of Example 16 was produced.

[Structural formula B]

(Example 17)
In Example 15, the example was changed to Example 15 except that the oxidizing agent was changed to tris (4-bromophenyl) aminium hexachlorochloromonate (T4AH) and the content of the oxidizing agent was 7.7 mg. Seventeen photoelectric conversion elements were produced.

(Example 18)
In Example 15, except that 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide as an additive was changed to lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) as an alkali metal salt. A photoelectric conversion element of Example 18 was produced in the same manner as Example 15.

(Example 19)
In Example 18, Example 19 was carried out in the same manner as Example 18 except that the alkali metal salt was changed to sodium bis (trifluoromethanesulfonyl) imide (NaTFSI) and the content of the alkali metal salt was 19.7 mg. A photoelectric conversion element was prepared.

(Example 20)
In Example 18, the alkali metal salt was changed to lithium bis (fluorosulfonyl) imide (LiFSI), and the content of the alkali metal salt was changed to 12.9 mg. A photoelectric conversion element was produced.

(Examples 21 to 25)
In Example 18, each basic compound was referred to as Compound No. 13, a basic compound represented by the following P-8, a basic compound represented by the following P-9, and the compound No. 12, Example 18 except that the basic compound represented by P-10 below was changed and the contents were changed to 18.0 mg, 33.2 mg, 52.7 mg, and 37.0 mg, 55.3 mg, respectively. Similarly, the photoelectric conversion elements of Examples 21 to 24 were produced.

(Example 26)
In Example 24, except that the oxidizing agent was changed to a cobalt complex compound of the following structural formula C (FK209, manufactured by Sigma-Aldrich Japan Co., Ltd.) and the content of the oxidizing agent was changed to 17.8 mg, the same as in Example 24. Thus, a photoelectric conversion element of Example 25 was produced.

[Structural formula C]

(Examples 27 to 29)
In Example 26, after forming the second electrode, the hole transport layer on the outer periphery of the glass substrate where the electron transport layer is not formed is removed, and acrylic resin A (ultraviolet curable type) as a sealing member is removed. , Trade name: TB3035B, manufactured by Three Bond Holdings Co., Ltd., epoxy resin A (ultraviolet curable, product name: TB3118, manufactured by Three Bond Holdings Co., Ltd.), epoxy resin B (ultraviolet curable, product name: WorldRock No. 5910, Kyoritsu) Chemical Industrial Co., Ltd.) was applied using a dispenser (trade name: 2300N, manufactured by Sunei Tech Co., Ltd.). Next, nitrogen gas is introduced into the glove box, transferred into the glove box, a cover glass as a second substrate is placed on the sealing member, and then the sealing member is cured by ultraviolet irradiation. Then, the power generation region was sealed, and photoelectric conversion elements of Examples 27 to 29 were produced in the same manner as in Example 26 (FIG. 2).

(Examples 30 to 35)
In Example 29, an epoxy resin B (ultraviolet curable type, trade name: WorldRock No. 5910, manufactured by Kyoritsu Chemical Industry Co., Ltd.) was dispensed (trade name: 2300N, manufactured by Sanei Tech Co., Ltd.) so that the power generation region was surrounded. It applied using. Thereafter, a mixed gas of nitrogen and oxygen (oxygen concentration: 0.6 vol%, 3.0 vol%, 5.0 vol%, 10.0 vol%, 15.0 vol%, 20.0 vol) in the glove box %) Is introduced, and the cover glass as the second substrate is placed on the epoxy resin B, and then the epoxy resin B is cured by ultraviolet irradiation to seal the power generation region. Then, a photoelectric conversion element of Example 30 was produced (FIG. 1).

(Example 36)
In Example 32, the ITO conductive film, which is the first electrode, was laser-etched by a laser device and processed into a 6-cell series substrate. After the hole transport layer was formed, through holes for connecting the photoelectric conversion elements in series were formed by laser processing. Thereafter, the same procedure as in Example 32 was performed, except that a second electrode (average thickness: 100 nm) was formed by vacuum deposition of silver using a mask patterned so as to be in series with 6 cells on the hole transport layer. A photoelectric conversion element module of Example 36 was produced (FIGS. 6 and 7). 6 and 7 are schematic views in which the directions to be observed are different from each other.

(Comparative Example 1)
In Example 6, the photosensitizing compound was changed to the photosensitizing compound represented by the structural formula (2) (trade name: D102, manufactured by Mitsubishi Paper Industries Co., Ltd.), and chenodeoxycholic acid (CDCA) was not added. The photoelectric conversion element of the comparative example 1 was produced like Example 6 except having changed the property compound into 4-tert- butylpyridine (tBP).

(Comparative Example 2)
A photoelectric conversion device of Comparative Example 2 was produced in the same manner as in Example 6 except that the basic compound was changed to 4-tert-butylpyridine (tBP) in Example 6.

(Comparative Examples 3-4)
In Example 6, the basic compound was changed to a basic compound represented by the following P-11 and a basic compound represented by the following P-12, respectively. Three to four photoelectric conversion elements were produced.

(Comparative Example 5)
In Example 7, the basic compound was changed to 4-tert-butylpyridine (tBP), the basic compound content was 7.4 mg, and the ionization potential of the hole transport layer was adjusted to the values shown in Table 1. Produced a photoelectric conversion element of Comparative Example 5 in the same manner as in Example 7.

(Comparative Example 6)
In Comparative Example 5, except that the photosensitizing compound was changed to the photosensitizing compound represented by the structural formula (2) (trade name: D102, manufactured by Mitsubishi Paper Industries Co., Ltd.), in the same manner as in Comparative Example 5, A photoelectric conversion element of Comparative Example 6 was produced.

[Ionization potential]
The ionization potential of the photosensitizing compound, the ionization potential of the hole transport material, and the ionization potential of the hole transport layer were measured using an atmospheric photoelectron spectrometer (device name: AC-2, manufactured by Riken Keiki Co., Ltd.). In addition, the ionization potential of the photosensitizing compound was measured in a state of being adsorbed on the electron transport layer.
The ratio of the ionization potential of the hole transport material to the ionization potential of the hole transport layer (the ionization potential of the hole transport layer / the ionization potential of the hole transport material) was obtained.

[PKa and molecular weight]
The pKa and molecular weight of the basic compound were calculated using software (ACD / Labs Software V11.02).

  Next, for each of the produced photoelectric conversion elements, “initial value maintenance rate after continuous irradiation” was evaluated as follows. The results are shown in Table 1.

[Initial value maintenance rate after continuous irradiation]
About each produced photoelectric conversion element, IV characteristics were evaluated using the solar cell evaluation system (DC voltage / current source / monitor, 6241A, manufactured by ADC Co., Ltd.) under irradiation of white LED adjusted to 200 lux. The initial maximum output power P _max1 (μW / cm ² ) was determined.
Next, the photoelectric conversion element is stored for 500 hours under irradiation of a white LED adjusted to 1,000 lux in a nitrogen gas atmosphere, and then the IV characteristics are evaluated again, and the maximum output power after 1,000 lux continuous irradiation is obtained. P _max2 (μW / cm ² ) was determined. By dividing the obtained P _max2 by the initial value P _max1 , an “initial value maintenance ratio after continuous irradiation” (P _max2 / P _max1 ) was obtained.

From the results of Table 1, it can be seen that the photoelectric conversion elements of Examples 1 to 36 exhibit high photoelectric conversion characteristics even at low illuminance, and exhibit good stability over time. This allows high internal resistance to be obtained while maintaining good hole conduction from the photosensitizing compound at low illuminance, and can suppress minute crystallinity changes over time of the hole transport layer, and interface contact This is considered to be because of maintaining good.
On the other hand, in the photoelectric conversion elements of Comparative Examples 1 to 6 that deviate from the range defined by the present invention, desired characteristics were not obtained.
As can be seen from the above results, the photoelectric conversion element of the present invention has a good photoelectric conversion property even in low illuminance light and is excellent in stability over time.

As an aspect of this invention, it is as follows, for example.
<1> A photoelectric conversion element having a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode,
The hole transport layer has a p-type semiconductor material and a basic compound;
The ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material;
The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer;
The photoelectric conversion element, wherein the basic compound has an acid dissociation constant (pKa) of 6 or more and 10 or less.
<2> The photoelectric conversion element according to <1>, wherein the hole transport layer includes an oxidizing agent.
<3> The photoelectric conversion element according to <2>, wherein the oxidizing agent is a complex of at least one metal selected from Fe, Cu, Co, V, Zn, Ag, Mn, and Ru.
<4> The photoelectric conversion element according to any one of <1> to <3>, wherein the hole transport layer includes an alkali metal salt.
<5> The photoelectric conversion device according to any one of <1> to <4>, wherein the basic compound has a molecular weight of 140 g / mol or more.
<6> The photoelectric conversion according to any one of <1> to <5>, wherein the basic compound is at least one of tertiary amine compounds represented by the following general formula (1) and general formula (2): It is an element.
However, in said general formula (1) and said general formula (2), Ar < ₁ > and Ar < ₂ > represent the aryl group which may have a substituent, and said Ar < ₁ > and said Ar < ₂ > may be the same. They may be different and may be combined with each other.
<7> The photoelectric conversion element according to any one of <1> to <6>, further including a sealing member that shields the electron transport layer and the hole transport layer from an external environment of the photoelectric conversion element.
<8> The sealing member is sandwiched between a pair of substrates, and at least the electron transport layer and the hole transport layer have a void inside the sealed seal of the photoelectric conversion element shielded from an external environment. 7>.
<9> The device according to any one of <1> to <6>, further including a sealing member that shields the electron transport layer, the hole transport layer, and the second electrode from an external environment of the photoelectric conversion element. It is a photoelectric conversion element.
<10> The sealing member is sandwiched between a pair of substrates, and at least the electron transport layer, the hole transport layer, and the second electrode are sealed inside the photoelectric conversion element shielded from an external environment. And it is a photoelectric conversion element as described in said <9> which has a space | gap part.
<11> The photoelectric conversion element according to any one of <7> to <10>, wherein the sealing member includes an epoxy resin.
<12> The photoelectric conversion element according to any one of <8> and <10>, wherein the void portion contains at least oxygen.
<13> A photoelectric conversion element module comprising a plurality of the photoelectric conversion elements according to any one of <1> to <12>.
<14> The photoelectric conversion element module according to <13>, wherein the plurality of photoelectric conversion elements are connected in series or in parallel.
<15> In at least two photoelectric conversion element modules adjacent to each other,
A first electrode of the one photoelectric conversion element;
The second electrode in the other photoelectric conversion element,
The photoelectric conversion element module according to any one of <13> to <14>, wherein the photoelectric conversion element module is electrically connected by a conductive portion penetrating at least from the hole transport layer to the hole blocking layer in the form of a continuous layer.
<16> A photoelectric conversion element arrangement region in which a plurality of photoelectric conversion elements are arranged adjacent to each other,
The plurality of photoelectric conversion elements have a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode,
An epoxy resin sealing member is disposed at the outer edge of the photoelectric conversion element arrangement region and shields the electron transport layer from the external environment of the photoelectric conversion element,
The hole transport layer has a p-type semiconductor material and a basic compound;
The ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material;
The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer;
The photoelectric conversion element module is characterized in that an acid dissociation constant (pKa) of the basic compound is 6 or more and 10 or less.
<17> The photoelectric conversion element and / or photoelectric conversion element module according to any one of <1> to <16>,
A device that operates with electric power generated by photoelectric conversion of the photoelectric conversion element and / or photoelectric conversion element module;
It is an electronic device characterized by having.
<18> The photoelectric conversion element and / or photoelectric conversion element module according to any one of <1> to <16>,
A power supply IC;
It is a power supply module characterized by having.

  The photoelectric conversion element according to any one of <1> to <12>, the photoelectric conversion element module according to any one of <13> to <16>, the electronic device according to <17>, and the < 18> can solve the conventional problems and achieve the object of the present invention.

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2, 2a, 2b 1st electrode 3 Hole blocking layer 4 Electron transport layer 5 Photosensitizing compound 6 Hole transport layer 7, 7a, 7b 2nd electrode 8 Sealing member 9 2nd board | substrate 10 Cavity 11 Penetration 12 Sealing member 101 Photoelectric conversion element 102 Photoelectric conversion element module

JP 2016-178102 A

Claims (18)

A photoelectric conversion element having a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode,
The hole transport layer has a p-type semiconductor material and a basic compound;
The ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material;
The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer;
The photoelectric conversion element, wherein the basic compound has an acid dissociation constant (pKa) of 6 or more and 10 or less.   The photoelectric conversion element according to claim 1, wherein the hole transport layer has an oxidizing agent.   3. The photoelectric conversion element according to claim 2, wherein the oxidizing agent is a complex of at least one metal selected from Fe, Cu, Co, V, Zn, Ag, Mn, and Ru.   The photoelectric conversion element according to claim 1, wherein the hole transport layer has an alkali metal salt.   The photoelectric conversion element according to any one of claims 1 to 4, wherein the basic compound has a molecular weight of 140 g / mol or more. The photoelectric conversion element according to claim 1, wherein the basic compound is at least one of tertiary amine compounds represented by the following general formula (1) and general formula (2).
However, in said general formula (1) and said general formula (2), Ar < ₁ > and Ar < ₂ > represent the aryl group which may have a substituent, and said Ar < ₁ > and said Ar < ₂ > may be the same. They may be different and may be combined with each other.   The photoelectric conversion element according to claim 1, further comprising a sealing member that shields the electron transport layer and the hole transport layer from an external environment of the photoelectric conversion element.   8. The sealing member according to claim 7, wherein the sealing member is sandwiched between a pair of substrates, and at least the electron transport layer and the hole transport layer have a gap inside the sealed photoelectric conversion element shielded from an external environment. Photoelectric conversion element.   The photoelectric conversion element according to claim 1, further comprising a sealing member that shields the electron transport layer, the hole transport layer, and the second electrode from an external environment of the photoelectric conversion element.   The sealing member is held between a pair of substrates, at least the electron-transporting layer, the hole transport layer and the second electrode, the sealing inside the photoelectric conversion element is shielded from the external environment, the gap portion The photoelectric conversion element of Claim 9 which has these.   The photoelectric conversion element according to claim 7, wherein the sealing member contains an epoxy resin.   The photoelectric conversion element according to claim 8, wherein the gap contains at least oxygen.   A photoelectric conversion element module comprising a plurality of the photoelectric conversion elements according to claim 1.   The photoelectric conversion element module according to claim 13, wherein the plurality of photoelectric conversion elements are connected in series or in parallel. In at least two photoelectric conversion element modules adjacent to each other,
A first electrode of the one photoelectric conversion element;
The second electrode in the other photoelectric conversion element,
The photoelectric conversion element module according to any one of claims 13 to 14, wherein the photoelectric conversion element module is electrically connected by a conductive portion penetrating at least from the hole transport layer to the hole blocking layer in the form of a continuous layer. Having a photoelectric conversion element arrangement region in which a plurality of photoelectric conversion elements are arranged adjacent to each other;
The plurality of photoelectric conversion elements have a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode,
An epoxy resin sealing member is disposed at the outer edge of the photoelectric conversion element arrangement region and shields the electron transport layer from the external environment of the photoelectric conversion element,
The hole transport layer has a p-type semiconductor material and a basic compound;
The ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and less than 1.07 times the ionization potential of the p-type semiconductor material;
The ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer;
The photoelectric conversion element module, wherein the basic compound has an acid dissociation constant (pKa) of 6 or more and 10 or less. The photoelectric conversion element and / or photoelectric conversion element module according to any one of claims 1 to 16,
A device that operates with electric power generated by photoelectric conversion of the photoelectric conversion element and / or photoelectric conversion element module;
An electronic device comprising: The photoelectric conversion element and / or photoelectric conversion element module according to any one of claims 1 to 16,
A power supply IC;
A power supply module comprising: