JP2023135855A - Compound, compound for photoelectric converter, photoelectric converter, electronic apparatus, and power supply module - Google Patents

Abstract

To provide a compound that has a high absorbance and a broad absorption wavelength and can serve solely as an absorption dye.SOLUTION: The present invention provides a compound represented by the following formula (where R1 and R2 each represent a C4-12 linear or branched alkyl group, and X represents the following structure or the like).SELECTED DRAWING: None

Description

The present invention relates to a compound, a compound for a photoelectric conversion element, a photoelectric conversion element, an electronic device, and a power supply module.

In recent years, solar cells, which can efficiently generate electricity even under low-intensity light, have attracted a lot of attention. Not only can it be installed anywhere, but it is also expected to have a wide range of applications as an independent power source that does not require battery replacement or power wiring.

Amorphous silicon and organic solar cells are known as photoelectric conversion elements for indoor use. Among organic solar cells, dye-sensitized solar cells are advantageous in that they can be easily produced because they are comprised of layers in which a charge generation function and a charge transport function are separated. Dye-sensitized solar cells generally have problems such as volatilization and leakage of the electrolyte because they contain an electrolyte, but in recent years, solid-state dye-sensitized solar cells using P-type semiconductor materials have also been developed. It is attracting attention.

More specifically, a photoelectric conversion element has been proposed that can suppress voltage drop and obtain high output even in a high temperature environment or a weak indoor light environment (for example, see Patent Document 1).

An object of the present invention is to provide a compound that has high absorbance and a wide absorption wavelength range, and can be used alone as an absorbing dye.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
The compound of the present invention as a means for solving the above problems is a compound represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

According to the present invention, it is possible to provide a compound that has high absorbance and a wide absorption wavelength range, and can be used alone as an absorbing dye.

FIG. 1 is a schematic diagram showing an example of the photoelectric conversion element of the first embodiment. FIG. 2 is a schematic diagram showing an example of a photoelectric conversion element according to the second embodiment. FIG. 3 is a schematic diagram showing an example of a photoelectric conversion element according to the third embodiment. FIG. 4 is a schematic diagram showing an example of a photoelectric conversion module according to the fourth embodiment. FIG. 5 is a schematic diagram showing an example of a photoelectric conversion module according to the fifth embodiment. FIG. 6 is a block diagram of a computer mouse as an example of the electronic device of the present invention. FIG. 7 is a schematic external view showing an example of the mouse shown in FIG. 6. FIG. 8 is a block diagram of a personal computer keyboard as an example of the electronic device of the present invention. FIG. 9 is a schematic external view showing an example of the keyboard shown in FIG. 8. FIG. 10 is a schematic external view showing another example of the keyboard shown in FIG. 8. FIG. 11 is a block diagram of a sensor as an example of the electronic device of the present invention. FIG. 12 is a block diagram of a turntable as an example of the electronic device of the present invention. FIG. 13 is a block diagram showing an example of the electronic device of the present invention. FIG. 14 is a block diagram showing an example in which a power supply IC is further incorporated into the electronic device shown in FIG. 13. FIG. 15 is a block diagram showing an example in which a power storage device is further incorporated into the electronic device shown in FIG. 14. FIG. 16 is a block diagram showing an example of the power supply module of the present invention. FIG. 17 is a block diagram showing an example in which a power storage device is further incorporated into the power supply module shown in FIG. 16. FIG. 18 is a diagram showing an example of an X-ray absorption fine structure (XAFS) spectrum measured using the photoelectric conversion element of Example 1. FIG. 19A is a diagram showing an FT-IR spectrum of the photosensitizing compound used in Example 1. FIG. 19B is a diagram showing the molar extinction coefficient of the photosensitizing compound used in Example 1.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
(Compound)
The compound of the present invention is represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

The present inventors conducted extensive studies and discovered a compound represented by the above general formula (1) that has high absorbance and a wide absorption wavelength range, and can be used alone as an absorbing dye. The technology of invention has been completed.
When the compound of the present invention is a compound represented by the above general formula (1), the absorbance is large and the absorption wavelength range is wide. Although it was necessary to mix two or more dye compounds having the above formula (1), it has been found that only one compound represented by the above general formula (1) can be used as an absorbing dye.

[Method for producing compound represented by general formula (1)]
For example, the compound represented by the general formula (1) may be prepared using the following raw materials 1 and 2, as described in J. Am. Chem. Soc. 2016, 138, 10742-10745.
In addition, the compound represented by the said raw material 1 is, for example, J. Mater. Chem. , 2009, 19, 4715-4724.
Further, the compound represented by the raw material 2 can be produced, for example, with reference to the method described in Polymers for Advanced Technologies (2018), 29(3), 1170-1181.

...Raw materials 1

...Raw materials 2

For example, the compound represented by the general formula (1) may be prepared using the following raw materials 1 and 2, as described in J. Am. Chem. Soc. It can be produced as follows with reference to the method described in 2016, 138, 10742-10745.

Furthermore, it is preferable that the general formula (1) is a compound represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

[Method for synthesizing the compound represented by general formula (2)]
As the compound represented by the general formula (2), for example, using the above raw material 2 and the following raw material 3, J. Am. Chem. Soc. 2016, 138, 10742-10745.
In addition, the compound represented by the said raw material 3 is, for example, J. Mater. Chem. , 2009, 19, 4715-4724.

...Raw materials 3
In addition, the compound represented by the said raw material 3 is, for example, J. Mater. Chem. , 2009, 19, 4715-4724.

As the compound represented by the general formula (2), for example, using the following raw materials 2 and 3, J. Am. Chem. Soc. It can be produced as follows with reference to the method described in 2016, 138, 10742-10745.

In addition, the compounds represented by general formulas (1) and (2) can be identified as follows.
[Method for identifying compounds represented by general formulas (1) and (2)]
Identification using a triple quadrupole mass spectrometer (MS/MS: TSQ Fortis) manufactured by Thermo Fisher Scientific Co., Ltd. or a Fourier transform infrared spectrophotometer (FT-IR: IRSpirit) manufactured by Shimadzu Corporation, etc. can do.

Specific example compounds of the compounds represented by general formulas (1) and (2) are shown below, but the present invention is not limited thereto.
(B1-1)
(B1-2)
(B1-3)
(B1-4)
(B1-5)
(B1-6)
(B1-7)
(B1-8)
(B1-9)

The compounds represented by (B1-1) to (B1-9) above can be synthesized, for example, as follows. An example of synthesizing compound (B1-6) is shown below.

[Method for synthesizing the compound represented by (B1-6)]
<Synthesis example 1a of raw material 1>
4-Iodoaniline, 1-Iodooctane, sodium carbonate, and dehydrated dimethylformamide are placed in a 500 ml four-necked flask, heated and stirred at 120° C. for 7 hours, and the organic phase is washed with water, extracted, and concentrated.
Column purification is then performed with dichloromethane.
The obtained compound was placed in a 200 m four-necked flask containing trimethylsilylacetylene, CuI, diisopropylamine, and palladium-tetrakis(triphenylphosphine) (Pd(PPh ₃ ) ₄ ) was added under an argon gas atmosphere, and the mixture was heated at 50°C. The mixture is heated and stirred for 3 hours, and the organic phase is washed with water, extracted and concentrated.
Thereafter, methanol, dichloromethane, and sodium hydroxide are added, stirred at room temperature for 2 hours, and the organic phase is washed with water, extracted, and concentrated.

<Synthesis example 1b of raw material 2>
4,4-bis(2-ethylhexyl)-4H-cyclopentadithiophene is dissolved in dehydrated tetrahydrofuran and stirred at -78°C under an argon gas atmosphere.
Next, 1.55M n-butyllithium hexane is added and stirred at -78°C for 3 hours.
Then, a solution prepared by diluting tributyltin chloride in dehydrated tetrahydrofuran is slowly added dropwise.
Stir at −78° C. for 1 hour, stir at room temperature for 1 hour, wash the organic phase with water, extract and concentrate.

<Synthesis example 1c>
4,7-dibromo-2,1,3-benzothiazole, 4-Formylphenylbenzoic acid, potassium carbonate, tetrahydrofuran, and water are placed in a 200 ml four-necked flask and stirred under an argon gas atmosphere.
Pd(PPh ₃ ) ₄ is added, heated and stirred at 50° C. for 10 hours, and the organic phase is washed with water, extracted, and concentrated.

<Synthesis example 1d>
The aldehyde obtained in Synthesis Example 1c, Pd(PPh ₃ ) ₂ Cl ₂ , and toluene are placed in a 200 ml four-necked flask, and heated and stirred at 40° C. under an argon gas atmosphere.
Next, a solution of the tin compound obtained in Synthesis Example 1b of Raw Material 2 and toluene is added dropwise, stirred under reflux for 2 hours, and the organic phase is washed with water, extracted, and concentrated.
Dissolve in dichloromethane, stir at 3°C, add NBS, and continue stirring for 4 hours. The organic phase is washed with water, extracted and concentrated.

<Synthesis example 1e>
The acetylene compound obtained in Synthesis Example 1a of Raw Material 1, the bromo compound obtained in Synthesis Example 1d, tetrahydrofuran, triethylamine, and CuI are placed in a 100 ml four-necked flask and stirred under an argon gas atmosphere.
Pd(PPh ₃ ) ₄ is added, reflux stirring is carried out for 1 hour, and the organic phase is washed with water, extracted and concentrated.
Column purification (dichloromethane/cyclohexane = 7 vol/3 vol) is performed, and further purification is performed by recycling GPC.
The entire amount of the purified product, cyanoacetic acid, ammonium acetate, and acetic acid are placed in a 100 ml four-necked flask, stirred under reflux for 2 hours, and the organic phase is washed with water, extracted, and concentrated.
Column purification (dichloromethane/methanol = 8 vol/2 vol) is performed, and the product is further dissolved in dichloromethane and reprecipitated with methanol.
The obtained purified product is dried to obtain a compound represented by (B1-6).

The absorbance of the compounds represented by (B1-1) to (B1-9) above can be measured by the method shown below.
For example, dilute acetonitrile/tertiary butanol (1/1 vol) 0.2 mM dye solution and measure the absorbance (abs) with an ultraviolet-visible spectrophotometer (equipment name: UV-3600, manufactured by Shimadzu Corporation). Then, the molar extinction coefficient can be calculated.
As an example, the molar extinction coefficient of the compound represented by (B1-6) is shown in FIG. 19B.

The compound of the present invention has high absorbance and a wide absorption wavelength range, and can be used alone as an absorption dye.
Furthermore, the compound of the present invention is a compound that is photoexcited by irradiated light and can obtain high output in solid-state dye-sensitized solar cells, so it can be suitably used exclusively for photoelectric conversion elements.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
(Compound for photoelectric conversion elements)
The compound for photoelectric conversion elements of the present invention is a compound represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

The compound for photoelectric conversion element of the present invention is the same as the compound of the present invention.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
(Photoelectric conversion element)
The photoelectric conversion element of the present invention is
a first electrode;
An electron transport layer containing a compound represented by the following general formula (1),
a hole transport layer;
and a second electrode, and further includes other layers as necessary.

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

The conventional technology has a problem in that the output decreases after being exposed to a high-intensity light environment.
In addition, in the conventional technology, the color of the dye compound used in the photoelectric conversion element was red, which caused the color of the photoelectric conversion element to stand out and its presence to be noticeable, making it difficult to use for indoor applications. .

The present inventors discovered that in the conventional technology, in order to widen the absorption wavelength range, it was necessary to mix two or more dye compounds (photosensitizing compounds) having different absorption wavelength ranges. It has been found that only one type of compound represented by the formula has a sufficient absorption wavelength range and can be used as an absorption dye.
In addition, the present inventors have found that a photoelectric conversion element having an electron transport layer containing the compound represented by the above general formula (1) exhibits a decrease in output under low-intensity light after being exposed to a high-intensity light environment. I found out that it can be suppressed.

In addition, in this specification, a "photoelectric conversion element" means an element that converts light energy into electrical energy, or an element that converts electrical energy into light energy, and specifically, a solar cell, a photodiode, etc. can be mentioned.
Note that, in the present invention, the layer includes not only a structure in which a plurality of films overlap, but also a single film (single layer).
Moreover, the lamination direction means a direction perpendicular to the plane direction of each layer in the photoelectric conversion element. Furthermore, connection means not only physical contact but also electrical connection to the extent that the effects of the present invention can be achieved.
The photoelectric conversion element of the present invention has a first electrode, a photoelectric conversion layer, and a second electrode, and the photoelectric conversion layer has at least a hole transport layer, and if necessary, a first electrode. It includes other members such as a substrate, a second substrate, a hole blocking layer, and a sealing member.

<First substrate>
The shape, structure, and size of the first substrate are not particularly limited and can be appropriately selected depending on the purpose.
The material of the first substrate is not particularly limited as long as it has translucency and insulating properties, and can be appropriately selected depending on the purpose. For example, substrates such as glass, plastic film, ceramic, etc. Can be mentioned. Among these, when forming the electron transport layer includes a step of firing as described later, a substrate having heat resistance to the firing temperature is preferable. Moreover, as the first substrate, one having flexibility is more preferable.

The substrate may be provided on one or both of the outermost part on the first electrode side and the outermost part on the second electrode side of the photoelectric conversion element.
Hereinafter, the substrate provided on the outermost side on the first electrode side will be referred to as a first substrate, and the substrate provided on the outermost side on the second electrode side will be referred to as a second substrate.

<First electrode>
The shape and size of the first electrode are not particularly limited and can be appropriately selected depending on the purpose.
The structure of the first electrode is not particularly limited and can be appropriately selected depending on the purpose, and may be a single layer structure or a structure in which a plurality of materials are laminated.
The material of the first electrode is not particularly limited as long as it has transparency to visible light and conductivity, and can be appropriately selected depending on the purpose. For example, transparent conductive metal oxide, carbon , metals, etc.

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"). ), niobium-doped tin oxide (hereinafter referred to as "NTO"), aluminum-doped zinc oxide, indium/zinc oxide, niobium/titanium oxide, etc.
Examples of the carbon include carbon black, carbon nanotubes, graphene, and fullerene.
Examples of the metal include gold, silver, aluminum, nickel, indium, tantalum, and titanium.
These may be used alone or in combination of two or more. Among these, transparent conductive metal oxides with high transparency are preferred, and ITO, FTO, ATO, and NTO are more preferred.

The average thickness of the first electrode is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 nm or more and 100 μm or less, more preferably 50 nm or more and 10 μm or less. In addition, when the material of the first electrode is carbon or metal, it is preferable that the average thickness of the first electrode is set to an average thickness that allows light transmission.

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

Further, the first electrode is preferably formed on the first substrate, and an integrated commercial product in which the first electrode is formed on the first substrate in advance may be used. I can do it.
Examples of the 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 commercially available products include, for example, transparent electrodes made of tin oxide or indium oxide doped with cations or anions of different valences, or mesh-like or striped structures that allow light to pass through. Examples include a glass substrate provided with metal electrodes.
These may be used alone, or two or more may be used in combination, mixed or laminated. Furthermore, 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, and nickel.
The metal lead wire can be formed on the substrate by, for example, vapor deposition, sputtering, pressure bonding, etc., and can be used in combination by providing a layer of ITO or FTO thereon.

<Photoelectric conversion layer>
The photoelectric conversion layer includes a hole blocking layer, an electron transport layer, and a hole transport layer, and further includes other layers as necessary.
The photoelectric conversion layer may be a single layer or a multilayer in which a plurality of layers are laminated.

<<Hole blocking layer>>
Preferably, the hole blocking layer is formed between the first electrode and the electron transport layer. In other words, in the present invention, it is preferable to further include the hole blocking layer between the first electrode and the photoelectric conversion layer.
The hole blocking layer is very effective in improving the output and its sustainability.
The hole blocking layer is, for example, generated with the photosensitizing compound and can transport electrons transported to the electron transport layer to the first electrode and prevent contact with the hole transport layer. Thereby, 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. A solid-state photoelectric conversion element provided with the hole-transporting layer has a faster recombination speed between holes in the hole-transporting material and electrons on the electrode surface than a wet-type photoelectric conversion element using an electrolyte. The effect of the formation 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 electron transport properties, and can be appropriately selected depending on the purpose. For example, silicon, germanium, etc. These include elemental semiconductors, compound semiconductors typified by metal chalcogenides, and compounds having a perovskite structure.

Examples of the metal chalcogenide include oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; cadmium, zinc, lead, silver, Sulfides of antimony and bismuth; selenide of cadmium and lead; telluride of cadmium, etc. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium; gallium arsenide, copper-indium-selenide, and copper-indium-sulfide.
Examples of the compound having the perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, and the like.
Among these, oxide semiconductors are preferred, titanium oxide, niobium oxide, magnesium oxide, aluminum oxide, zinc oxide, tungsten oxide, tin oxide, etc. are more preferred, and titanium oxide is even more preferred.
These may be used alone or in combination of two or more. Moreover, it may be a single layer or a laminated layer. Further, the crystal type 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 producing the hole blocking layer is not particularly limited and can be appropriately selected depending on the purpose. Examples include a method of forming a thin film in vacuum (vacuum film forming method), a wet film forming method, etc. It will be done.
Examples of the vacuum film forming method include sputtering method, pulsed laser deposition method (PLD method), ion beam sputtering method, ion assist method, ion plating method, vacuum evaporation method, and atomic layer deposition method (ALD method). , chemical vapor deposition method (CVD method), and the like.
Examples of the wet film forming method include a sol-gel method. The sol-gel method is a method in which a gel is produced from a solution through chemical reactions such as hydrolysis, polymerization, and condensation, and then densification is promoted by heat treatment. When using the sol-gel method, there are no particular restrictions on the method for applying the sol solution, and it can be selected as appropriate depending on the purpose. For example, dip method, spray method, wire bar method, spin coat method, roller coat method, etc. In addition, examples of wet printing methods include letterpress, offset, gravure, intaglio, rubber plate, and screen printing. Furthermore, the temperature during the heat treatment after applying the sol solution is preferably 80°C or higher, more preferably 100°C or higher.

The average thickness of the hole blocking layer is not particularly limited and can be selected appropriately 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 in wet film formation, and 5 nm in dry film formation. The thickness is more preferably 30 nm or less.

<<Electron transport layer>>
The photoelectric conversion element has the electron transport layer containing a photosensitizing compound.
Preferably, the electron transport layer is disposed between the first electrode and the photosensitizing compound.
The electron transport layer is responsible for transporting electrons and also has a function of blocking holes (hole blocking function).
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 placed adjacent to the first electrode or the hole blocking layer.

The structure of the electron transport layer is not particularly limited and can be appropriately selected depending on the purpose, but the electron transport layers may extend from each other in at least two adjacent photoelectric conversion elements. However, it is preferable that it is not extended.
If the electron transport layers do not extend from each other, electron diffusion is suppressed and leakage current is reduced, which is advantageous in that light durability is improved.
Furthermore, the structure of the electron transport layer may be a single layer or a multilayer structure in which a plurality of layers are laminated.

The electron transport layer contains an electron transport material and, if necessary, other materials.

The electron-transporting material is not particularly limited and can be appropriately selected depending on the purpose, but semiconductor materials are preferred.
It is preferable that the semiconductor material has a shape of fine particles, and by bonding them together, a film having a porous structure is formed. A photosensitizing compound is chemically or physically adsorbed on the surface of semiconductor fine particles constituting the porous electron transport layer.

The semiconductor material is not particularly limited and any known material can be used, such as an elemental semiconductor, a compound semiconductor, a compound having a perovskite structure, and the like.
Examples of the single semiconductor include silicon and germanium.
Examples of the compound semiconductor include metal chalcogenides, specifically oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc. Semiconductors; sulfide semiconductors such as cadmium, zinc, lead, silver, antimony, and bismuth; selenide semiconductors such as cadmium and lead; and telluride semiconductors such as cadmium. Examples of other compound semiconductors include phosphide semiconductors such as zinc, gallium, indium, and cadmium, gallium arsenide, copper-indium-selenide semiconductors, and copper-indium-sulfide semiconductors.
Examples of the compound having the perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, and the like.
Among these, oxide semiconductors are preferred, and titanium oxide, zinc oxide, tin oxide, and niobium oxide are particularly preferred. When the electron transport material of the electron transport layer is titanium oxide, the conduction band level (conduction band) is high, so a high open circuit voltage can be obtained, and high photoelectric conversion characteristics can be obtained. It is advantageous. Furthermore, it has a high refractive index and a high short circuit current can be obtained due to the optical confinement effect. Furthermore, it is advantageous in that a high fill factor can be obtained due to the high dielectric constant and high mobility.
These may be used alone or in combination of two or more. Further, the crystal type of the semiconductor material is not particularly limited and can be appropriately selected depending on the purpose, and may be single crystal, polycrystal, or amorphous.

The average particle size of the primary particles of the semiconductor material is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.
Further, semiconductor materials larger than the number average particle size may be mixed or stacked, and the conversion efficiency may be improved due to the effect of scattering incident light. In this case, the number average particle diameter is preferably 50 nm or more and 500 nm or less.

The average thickness of the electron transport layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 50 nm or more and 100 μm or less, more preferably 100 nm or more and 50 μm or less, and even more preferably 120 nm or more and 10 μm or less. When 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, a high light capture rate can be maintained, and the diffusion distance of injected electrons can also be maintained. This is advantageous in that it is difficult to increase the amount of charge, and loss due to charge recombination can be reduced.

The method for producing the electron transport layer is not particularly limited and can be appropriately selected depending on the purpose, such as a method of forming a thin film in vacuum such as sputtering, a wet film forming method, a wet printing method, etc. can be mentioned. Among these, the wet film forming method is preferable from the viewpoint of manufacturing cost, in which a paste (semiconductor material dispersion liquid) in which the powder or sol of the semiconductor material is dispersed is prepared, and a first electrode as an electron collector electrode substrate is prepared. More preferred is a method in which it is coated on top of the hole-blocking layer or on the hole-blocking layer.
The wet film forming method is not particularly limited and can be appropriately selected depending on the purpose, such as a dip method, a spray method, a wire bar method, a spin coat method, a roller coat method, a blade coat method, and a gravure coat method. method, die coating method, etc.
As the wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber printing, and screen printing can be used.

Examples of methods for producing the dispersion of the semiconductor material include a method of mechanically pulverizing it using a known milling device or the like. According to this method, a dispersion of a semiconductor material can be prepared 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 esters, and methacrylic esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, and polyester resins. , cellulose ester resin, cellulose ether resin, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin, polyamide resin, polyimide resin and the like. These may be used alone or in combination of two or more.

Examples of the solvent include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.
Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, and α-terpineol.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
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, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
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. It will be done.
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. , ethylbenzene, cumene, etc.
These may be used alone or in combination of two or more.

An acid, a surfactant, a chelating agent, etc. may be added to the dispersion containing the semiconductor material or the paste containing the semiconductor material obtained by the sol-gel method etc. in order to prevent particle re-agglomeration. .
Examples of the acid include hydrochloric acid, nitric acid, and acetic acid.
Examples of the surfactant include polyoxyethylene octylphenyl ether.
Examples of the chelating agent include acetylacetone, 2-aminoethanol, and ethylenediamine.
Furthermore, for the purpose of improving film forming properties, it is also an effective means to add a thickener.
Examples of the thickener include polyethylene glycol, polyvinyl alcohol, and ethyl cellulose.

After applying the semiconductor material, in order to bring the particles of the semiconductor material into electronic contact and improve film strength and adhesion to the substrate, baking, irradiation with microwaves or electron beams, or laser irradiation is performed. Light can be irradiated. These treatments may be performed alone or in combination of two or more.

When firing the electron transport layer formed from the semiconductor material, the firing temperature is not particularly limited and can be selected as appropriate depending on the purpose; however, if the temperature is too high, the resistance of the substrate will increase. The temperature is preferably 30°C or more and 700°C or less, and more preferably 100°C or more and 600°C or less. Further, the firing time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 minutes or more and 10 hours or less.
When the electron transport layer formed from the semiconductor material is irradiated with microwaves, the irradiation time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 hour or less. In this case, irradiation may be performed from the side on which the electron transport layer is formed, or may be irradiated from the side on which the electron transport layer is not formed.

After firing the electron transport layer made of the semiconductor material, for example, an aqueous solution of titanium tetrachloride or Chemical plating using a mixed solution with an organic solvent or 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 be porous. Such nanoporous structures have a very high surface area, which can be expressed using a roughness factor. The roughness factor is a numerical value representing the actual area of the porous interior relative to the area of the semiconductor particles applied to the first substrate. Therefore, the roughness factor is preferably as large as possible, but from the viewpoint of the relationship with the average thickness of the electron transport layer, it is preferably 20 or more.
Further, the particles of the electron transporting material may be doped with a lithium compound. Specifically, a solution of a lithium bis(trifluoromethanesulfonimide) compound is deposited on particles of an electron-transporting material using spin coating or the like, and then fired.
The lithium compound is not particularly limited and can be appropriately selected depending on the purpose, such as lithium bis(trifluoromethanesulfonimide), lithium bis(fluoromethanesulfonimide), lithium bis(fluoromethanesulfonyl)( Examples include trifluoromethanesulfonyl)imide, lithium perchlorate, and lithium iodide.

A photosensitizing compound is provided between the electron transport layer and the hole transport layer.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
<<Photosensitizing compound>>
In the present invention, in order to further improve conversion efficiency, a photosensitizing compound is adsorbed on the surface of the electron transporting semiconductor of the electron transporting layer.
The photosensitizing compound is a compound represented by the following general formula (1).
By using a compound represented by the following general formula (1) as the photosensitizing compound, high output can be obtained in a photoelectric conversion element, particularly in a solid-state dye-sensitized solar cell.

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

Furthermore, it is preferable that the compound represented by the general formula (1) is a compound represented by the following general formula (2). When the compound represented by the general formula (1) is a compound represented by the following general formula (2), it is possible to improve the output in a low to high illuminance light environment.
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

Specific exemplary compounds of the compounds represented by the general formulas (1) and (2) are shown below, but the present invention is not limited thereto.
(B1-1)
(B1-2)
(B1-3)
(B1-4)
(B1-5)
(B1-6)
(B1-7)
(B1-8)
(B1-9)

The method for adsorbing the photosensitizing compound onto the surface of the semiconductor material of the electron transport layer includes adsorbing electrons containing the semiconductor material in a solution of the photosensitizing compound or in a dispersion of the photosensitizing compound. A method of immersing the transport layer, a method of applying a solution of the photosensitizing compound, or a dispersion of the photosensitizing compound to the electron transport layer and causing it to be adsorbed can be used. In the case of a method of immersing the electron transport layer formed of the semiconductor material in a solution of the photosensitizing compound or a dispersion of the photosensitizing compound, a dipping method, a dipping method, a roller method, an air knife method, etc. can be used.

In the case of a method of applying and adsorbing a solution of the photosensitizing compound or a dispersion of the photosensitizing compound to the electron transport layer, wire bar method, slide hopper method, extrusion method, curtain method, spin method, etc. method, spray method, etc. can be used. It is also possible to adsorb in a supercritical fluid using carbon dioxide or the like.

When adsorbing the photosensitizing compound onto the semiconductor material, a condensing agent may be used in combination.
The condensing agent may be one that acts as a catalyst to physically or chemically bind the photosensitizing compound to the surface of the semiconductor material, or one that acts stoichiometrically to favorably maintain chemical equilibrium. It can be anything that is moved. Furthermore, thiol, hydroxy compound, etc. 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, and hydrocarbon solvents.
Examples of the alcohol solvent include methanol, ethanol, and isopropyl alcohol.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
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, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
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. It will be done.
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. , ethylbenzene, cumene, etc.
These may be used alone or in combination of two or more.

Depending on the type of the photosensitizing compound, there are some that work more effectively when the aggregation between the compounds is suppressed, and therefore an aggregation dissociating agent may be used in combination.
Examples of the aggregation-dissociating agent include steroid compounds such as cholic acid and chenodeoxycholic acid, long-chain alkylcarboxylic acids, and long-chain alkylphosphonic acids, and compounds represented by the following general formula (3) are particularly preferred, and 4- Benzyloxybenzoic acid (compound B2-1 below) is more preferred.
...General formula (3)
(In general formula (3), n represents a natural number from 1 to 3, and Ar ₃ represents a phenyl group or a naphthyl group that may have a substituent.)
Specific exemplary compounds of the aggregation dissociating agent represented by the general formula (3) are shown below, but the present invention is not limited thereto.

(B2-1)
(B2-2)
(B2-3)
(B2-4)
(B2-5)
(B2-6)
(B2-7)
(B2-8)
(B2-9)
(B2-10)
(B2-11)
(B2-13)
(B2-14)

The content of the aggregation-dissociating agent is preferably 0.5 to 100 mole parts, more preferably 10 to 50 mole parts, per 1 mole part of the photosensitizing compound.

The temperature at which the photosensitizing compound, or the photosensitizing compound and the aggregation dissociating agent are adsorbed onto 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 5 seconds or more and 1,000 hours or less, more preferably 10 seconds or more and 500 hours or less, and even more preferably 1 minute or more and 150 hours or less.
The adsorption step is preferably performed in a dark place. Further, the adsorption step may be performed while standing still or may be performed while stirring.
The method of stirring is not particularly limited and can be selected as appropriate depending on the purpose. Examples include methods using a stirrer, ball mill, paint conditioner, sand mill, attritor, disperser, ultrasonic dispersion, etc. It will be done.

<<Hole transport layer>>
The hole transport layer is a layer that functions to transport holes.
The hole transport layer can be made of a known material as long as it has the function of transporting holes, such as an electrolytic solution in which a redox couple is dissolved in an organic solvent, or an electrolytic solution in which a redox couple is dissolved in an organic solvent. Examples include gel electrolytes in which a polymer matrix is impregnated with a liquid, molten salts containing redox couples, solid electrolytes, inorganic hole transport materials, organic hole transport materials, and the like. Among these, solid electrolytes are preferred, and organic hole transport materials are more preferred, although electrolytes and gel electrolytes can also be used.

The hole transport layer preferably contains a p-type semiconductor material, an alkali metal salt, and a basic compound.

-p-type semiconductor material-
The hole transport layer contains a p-type semiconductor material in order to obtain the 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 aging properties can be achieved even in low-intensity light. It is possible to achieve both stability and stability.
The p-type semiconductor material is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic p-type semiconductor materials, organic p-type semiconductor materials, and the like.
The inorganic p-type semiconductor material is not particularly limited and can be appropriately selected depending on _the purpose, and examples thereof include CuSCN, CuI, CuBr, NiO, _V2O5 , graphene oxide, and the like. Among these, organic p-type semiconductor materials are preferred.

The organic p-type semiconductor material is not particularly limited and can be appropriately selected depending on the purpose. For example, known organic p-type semiconductor materials can be used.
Examples of the 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 alone or in combination of two or more. Among these, spiro-type compounds are preferred.

As the spiro-type compound, a compound containing the following general formula (20) is preferable.

However, in the general formula (20), R ₃₁ to R ₃₄ each independently represent a substituted amino group such as a dimethylamino group, a diphenylamino group, or a naphthyl-4-tolylamino group.
Specific examples of spiro-type compounds include (D-1) to (D-22) shown below. However, it is not limited to these.

Further, as the spiro-type compound as the hole transport material, a compound represented by the following general formula (4) can be particularly suitably used.
However, in the general formula (4), R ₃ represents a hydrogen atom or an alkyl group.

For example, among the above (D-1) to (D-20), those represented by the above general formula (4) are (D-7) and (D-10).

In addition to having high hole mobility, these spiro-type compounds have two benzidine skeleton molecules that are twisted and bonded to each other, forming a nearly spherical electron cloud, and exhibiting intermolecular hopping conductivity. It shows excellent photoelectric conversion characteristics due to good . It also has high solubility, so it dissolves in various organic solvents, and since it is amorphous (an amorphous substance with no crystal structure), it tends to be densely packed into the porous electron transport layer. Furthermore, since it does not have light absorption characteristics of 450 nm or more, it is possible to make the photosensitizing compound absorb light efficiently, and it is particularly preferable for solid-state dye-sensitized solar cells.

-Alkali metal salt-
When the hole transport layer contains an alkali metal salt, the output can be improved, and furthermore, the light irradiation resistance and high temperature storage resistance can be improved.
Specific examples of alkali metal salts include, but are not limited to, those shown in (C-1) to (C-86) below and those represented by general formula (5) below. It's not a thing.

However, in the general formula (5), A and B represent any substituent of F, CF ₃ , C ₂ F ₅ , C ₃ F ₇ , and C ₄ F ₉ , and the substituent of A and B The substituents may be the same or different.

Examples of the lithium salt represented by the general formula (5) include lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide (Li-FTFSI), lithium ( fluorosulfonyl) (pentafluoroethanesulfonyl) imide (Li-FPFSI), lithium (fluorosulfonyl) (nonafluorobutanesulfonyl) imide (Li-FNFSI), lithium (nonafluorobutanesulfonyl) (trifluoromethanesulfonyl) imide (Li- NFTFSI), lithium (pentafluoroethanesulfonyl)(trifluoromethanesulfonyl)imide (Li-PFTFSI), etc. Among these, lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium (fluorosulfonyl)( Particularly preferred is trifluoromethylsulfonyl)imide (Li-FTFSI).

The structural formula of a specific example of the lithium salt represented by the general formula (5) is as follows.

The lithium salt represented by the general formula (5) is involved in charge transfer, and by containing this lithium salt, good photoelectric conversion characteristics can be obtained.

Here, for example, when coating is performed using a coating solution for forming a hole transport layer containing a lithium salt represented by the general formula (5), in the formed film, the lithium salt has an anion and a cation. It does not need to be contained in the form of a combined salt, but may be in a separated state into a lithium cation and an anion.
Specifically, when the lithium salt represented by the general formula (5) is contained in a coating solution for forming a hole transport layer to form a hole transport layer, lithium cations migrate to the electron transport layer. The inventors of the present invention found that the electron transport layer contains more of , than the hole transport layer. On the other hand, the present inventors have found that, for example, although some anions are migrated to the electron transport layer, they are contained in a larger amount in the hole transport layer than in the electron transport layer.
In the present invention, it is preferable that the cation and anion of the lithium salt represented by the general formula (5) are separated and form different distribution states. Even in a low-temperature environment, high output can be obtained for low-intensity light, and the effects of excellent output sustainability can be further improved.

The form of the hole transport layer is not particularly limited as long as it has the function of transporting holes, and can be appropriately selected depending on the purpose. For example, an electrolytic solution in which a redox couple is dissolved in an organic solvent. , a gel electrolyte in which a polymer matrix is impregnated with a liquid obtained by dissolving a redox couple in an organic solvent, a molten salt containing a redox couple, a solid electrolyte, an inorganic hole transport material, an organic hole transport material, and the like. Among these, solid electrolytes are preferred, and organic hole transport materials are more preferred. These may be used alone or in combination of two or more.

In addition to the above-mentioned lithium salt, the hole transport layer in the photoelectric conversion layer can also contain other lithium salts. These lithium salts may have symmetric anion species, such as lithium bis(fluorosulfonyl)imide (Li-FSI), lithium bis(pentafluoroethanesulfonyl)imide (Li-BETI), lithium bis(fluorosulfonyl)imide (Li-FSI), lithium bis(pentafluoroethanesulfonyl)imide (Li-BETI) (nonafluorobutanesulfonyl)imide and the like. Also included are cyclic imides such as lithium (cyclohexafluoropropane) (disulfone) imide.
However, since these lithium salts have symmetrical anions, they have low compatibility and it is difficult to increase the amount added, so it is preferable to add a small amount.

The content of the lithium salt represented by the above general formula (5) is preferably 5 mol% or more and 50 mol% or less, and 20 mol% or more and 35 mol% or less, based on the hole transport material. More preferred. When the content is within the above range, the output with respect to low-intensity light is high, the output maintenance rate is improved, and high durability can be achieved at the same time.

The cation of the lithium salt represented by the general formula (5) is thought to exist at the interface near the electron transport layer, and the anion of the lithium salt represented by the general formula (5) is doped in the hole transport layer. It is thought that it will be done.

The content of the alkali metal salt is preferably 30 mol% or more and 80 mol% or less, more preferably 50 mol% or more and 70 mol% or less, based on the total amount of the hole transport material.

Furthermore, the lithium cations in the lithium salt represented by the above general formula (5) may be in a state where they have migrated to the electron transport layer, for example, in a state in which more than half of the lithium cations are included in the electron transport layer described below. There may be.
In addition, the hole transport layer in the present invention is more preferable because the output can be further improved by being filled inside the electron transport layer to be described later. In this case, the hole transport layer filled in the electron transport layer is also treated as a hole transport layer.

-Basic compounds-
The basic compound is considered to exist at the interface near the electron transport layer, and is thought to suppress reverse electron transfer from the electron transport layer (that is, electron transfer from the electron transport layer to the hole transport layer).

The basic compound is preferably a basic compound (pyridine compound) represented by the following general formula (A) or general formula (B), and a tertiary amine compound represented by the following general formula (A1) or general formula (B1). is even more preferable. Containing a basic compound represented by the following general formula (A) or general formula (B) in the hole transport layer is advantageous in that a high open circuit voltage can be obtained and high photoelectric conversion characteristics can be obtained. Furthermore, since the hole transport layer contains at least one of the tertiary amine compounds represented by the general formula (A1) and the general formula (B1), it has high photoelectric conversion properties and stability over time even in low-intensity light. Can be compatible.

(In the formula, R ₁ and R ₂ each independently represent an alkyl group or an aromatic hydrocarbon group, and represent the same or different groups, or R ₁ and R ₂ are bonded to each other and contain a nitrogen atom. (Represents a heterocyclic group.)

(In the formula, R ₁ and R ₂ each independently represent an alkyl group or an aromatic hydrocarbon group, and represent the same or different groups, or R ₁ and R ₂ are bonded to each other and contain a nitrogen atom. (Represents a heterocyclic group.)

However, in the general formula (A1) and the general formula (B1), Ar ₁ and Ar ₂ represent an aryl group that may have a substituent, and Ar ₁ and Ar ₂ may be the same or They may be different or may be combined with each other.

Specific example compounds of the basic compounds 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 compounds represented by the above general formula (A1) and general formula (B1) include the following exemplary compounds C-1 to C-20. It is not limited to. These may be used alone or in combination of two or more.

Examples of the aryl group for Ar ₁ and Ar ₂ include a phenyl group, a naphthyl group, and a biphenyl group. Examples of the substituent include an alkyl group and an alkoxy group.

The hole transport layer preferably contains a basic compound represented by the above general formula (A1). Containing a basic compound represented by the above general formula (A1) in the hole transport layer is advantageous in improving the output stability of the photoelectric conversion element. In particular, it is advantageous in that it is possible to reduce variations in output characteristics with respect to low-intensity light and to stably generate power.

Specific exemplary compounds of the basic compound represented by the above general formula (A1) are shown below, but the present invention is not limited thereto.

In addition to the above basic compounds, basic compounds such as 4-dimethylaminopyridine (DMAP), 4-pyrrolidinopyridine (PYP), 4-piperidinopyridine (PPP), and tertiary butylpyridine (TBP) are also preferred.

The content of the basic compound in the hole transport layer is preferably 20 mol% or more and 65 mol% or less, more preferably 35 mol% or more and 50 mol% or less, based on the hole transport material. . By having the content of the basic compound within a preferable range, a high open circuit voltage can be maintained, high output can be obtained, and high stability and durability can be obtained even after long-term use in various environments.

-Oxidant-
Preferably, the hole transport layer contains an oxidizing agent.
When the hole transport layer contains the oxidizing agent, a part of the organic hole transport material becomes a radical cation, thereby improving conductivity and increasing the durability and stability of output characteristics.
By oxidizing the organic hole transport material with the oxidizing agent, it exhibits good hole conductivity, and it also suppresses release (reduction) of the oxidized state due to the influence of the surrounding environment of the photoelectric conversion layer, resulting in good aging performance. Indicates stability.

The oxidizing agent is not particularly limited and can be appropriately selected depending on the purpose, for example, tris(4-bromophenyl)aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluoroborate, silver nitrate. , metal complexes, hypervalent iodine compounds, etc. These may be used alone or in combination of two or more. Among these, metal complexes and hypervalent iodine compounds are preferred. When the oxidizing agent is a metal complex or a hypervalent iodine compound, it is advantageous in that it has high solubility in organic solvents and can be added in large quantities.

--Metal complex--
The metal complex is composed of, for example, a metal cation, a ligand, and an anion.

The metal cation is not particularly limited and can be selected as appropriate depending on the purpose, for example, chromium, manganese, zinc, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, Examples include cations such as rhenium, osmium, iridium, vanadium, gold, and platinum. Among these, cations of manganese, zinc, iron, cobalt, nickel, copper, ruthenium, silver, and vanadium are preferred, and cobalt complexes are more preferred.

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

Examples of the anions include hydride ions (H ⁻ ), fluoride ions (F ⁻ ), chloride ions (Cl ⁻ ), bromide ions (Br ⁻ ), iodide ions (I ⁻ ), and hydroxide ions. (OH ⁻ ), cyanide ion (CN ⁻ ), nitrate ion (NO ₃ ⁻ ), nitrite ion (NO ₂ ⁻ ), hypochlorite ion (ClO ⁻ ), chlorite ion (ClO ₂ ⁻ ), Chlorate ion (ClO ₃ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), permanganate ion (MnO ₄ ⁻ ), acetate ion (CH ₃ COO ⁻ ), hydrogen carbonate ion (HCO ₃ ⁻ ), diphosphate ion Hydrogen ion (H ₂ PO ₄ ⁻ ), hydrogen sulfate ion (HSO ₄ ⁻ ), hydrogen sulfide ion (HS ⁻ ), thiocyanate ion (SCN ⁻ ), tetrafluoroborate ion (BF ₄ ⁻ ), hexafluoroline Acid ion (PF ₆ ⁻ ), tetracyanoborate ion (B(CN) ₄ ⁻ ), dicyanoamine ion (N(CN) ₂ ⁻ ), p-toluenesulfonic acid ion (TsO ⁻ ), trifluoromethylsulfonic acid ion (CF ₃ SO2-), bis(trifluoromethylsulfonyl)amine ion (N(SO ₂ CF ₃ ) ₂ ^- ), tetrahydroxoaluminate ion ([Al(OH) ₄ ] ^- , or [Al(OH) ₄ (H ₂ O) ₂ ] ^- ), dicyanosilver(I) ion ([Ag(CN) ₂ ] ^- ), tetrahydroxochrom(III) ion ([Cr(OH) ₄ ] ^- ), tetrachloro Au(III) acid 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) acid ion ([Z _n (OH) ₄ ] ^2- ), tetracyanozinc(II) acid ion ([Zn(CN ) ₄ ] ^2- ), tetrachlorocuprate ion ([CuCl ₄ ] ^2- ), phosphate ion (PO ₄ ^3- ), hexacyanoferrate (III) ion ([Fe(CN) ₆ ] ^{3 )} , bis(thiosulfato)argent(I) ion ([Ag(S ₂ O ₃ ) ₂ ] ^3- ), hexacyanoferrate(II) ion ([Fe(CN) ₆ ] ^4- ), etc. . Among these, preferred are tetrafluoroborate ion, hexafluorophosphate ion, tetracyanoborate ion, bis(trifluoromethylsulfonyl)amine ion, and perchlorate ion.

As the metal complex, it is particularly preferable to add a trivalent cobalt complex. When a trivalent cobalt complex is added as an oxidizing agent, the hole transport material can be oxidized and stabilized, and the hole transport properties can be improved.
In the present invention, for example, it is preferable to use a trivalent cobalt complex to be added to the coating liquid for forming a hole transport layer, but the hole transport of a photoelectric conversion element obtained using the coating liquid for forming a hole transport layer is preferable. Preferably, the layer contains a divalent cobalt complex. This is because when the trivalent cobalt complex is mixed with the hole transport material, the hole transport material is oxidized and the cobalt complex becomes divalent. In other words, in the present invention, it is preferable that the photoelectric conversion layer further contains a divalent cobalt complex.
In particular, it is particularly preferable that almost no trivalent cobalt complex remains in the hole transport layer of the photoelectric conversion element, and that almost all the cobalt complexes are divalent. This not only improves and stabilizes the hole transportability, improves high output and its sustainability, but also makes it possible to exhibit its effects even in a low-temperature environment.

The valence of the cobalt complex contained in the hole transport layer can be clarified by, for example, performing XAFS analysis. XAFS analysis is an abbreviation for X-ray Absorption Fine Structure and is called X-ray absorption fine structure analysis. For example, an XAFS spectrum can be obtained by irradiating a sample with X-rays and measuring the amount of absorption thereof.
In the XAFS spectrum, the structure near the absorption edge is called XANES (X-ray Absorption Near Edge Structure), and the wide-range X-ray absorption fine structure that appears on the high energy side of about 100 eV or more from the absorption edge is called EXAFS (Extended X-ray Absorption Fine Structure). ture) However, information regarding the valence and structure of the atom of interest can mainly be obtained from the former XANES. In this case, for example, the value of the cobalt complex contained in the hole transport layer can be determined by separately measuring the XAFS spectra of divalent and trivalent cobalt complex powders and comparing them with the XAFS spectrum of the cobalt complex contained in the hole transport layer. The number can be revealed.
FIG. 18 shows the results of acquiring the XAFS spectrum as described above for the photoelectric conversion element of the present invention (Example 1). As shown in FIG. 18, the cobalt complex contained in the hole transport layer of an example of the photoelectric conversion element of the present invention matches well with the divalent cobalt complex powder, and the part that matches the trivalent cobalt complex powder. Since there is no cobalt complex, it can be determined that almost all of the cobalt complexes contained are divalent.

As the trivalent cobalt complex added to the hole transport layer forming coating solution, cobalt complexes represented by the following structural formulas (4) and (5) can be preferably used.

However, in the structural formulas (4) and (5), R ₈ to R ₁₀ represent a hydrogen atom, a methyl group, an ethyl group, a tertiary butyl group, or a trifluoromethyl group. X represents any one of the following structural formulas (6) to (9).

Regarding X, among the structural formulas (6) to (9), structural formula (8) is more preferable. The use of structural formula (8) is effective in that the hole transport material can be stably maintained in an oxidized state.

Specific examples of these cobalt complexes include (F-1) to (F-24) shown below. However, it is not limited to these.

Among these, (F-18) and (F-23) are preferred.

--Hypervalent iodine compounds--
The hypervalent iodine compound refers to a compound containing iodine having nine or more formal valence electrons exceeding eight octets. In other words, a hypervalent iodine compound means a compound containing an iodine atom that has more electrons than the eight required by the octet rule and is in a hypervalent state. Here, the valence electron is also referred to as a valence electron, and means an electron that occupies an outer electron shell excluding inner shell electrons in the electron configuration of an atom.
The photoelectric conversion element can improve the durability and stability of output by including the hypervalent iodine compound in the hole transport layer.

The hypervalent iodine compound that can be used in the present invention is not particularly limited and can be appropriately selected depending on the purpose, but preferably contains at least one of a periodinane compound and a diaryliodonium salt.
Periodinane compounds and diaryliodonium salts have high solubility in halogenated solvents such as chlorobenzene, and low crystallinity and acidity. Therefore, by including at least one of a periodinane compound and a diaryliodonium salt in the hole transport layer, the output of the photoelectric conversion element can be improved.
Here, in the photoelectric conversion element, by lowering the acidity of the hole transport layer, the open circuit voltage can be improved, so a material with low acidity is preferable as the material used for the hole transport layer. As a method for lowering the acidity of the hole transport layer, for example, by increasing the proportion (content) of basic material in the hole transport layer, the acidity of the hole transport layer can be lowered. In this case, the proportion of the hole-transporting compound in the hole-transporting layer decreases. Therefore, if the open-circuit voltage is improved by increasing the proportion of basic material in the hole transport layer, the series resistance increases and the output in high-intensity light decreases.
For the above reasons, when reducing the acidity of the hole transport layer, it is necessary to use materials such as periodinane compounds and diaryliodonium salts that have high solubility in halogenated solvents such as chlorobenzene, and have low crystallinity and acidity. is preferred.

As the hypervalent iodine compound, in particular, a periodinane compound represented by the following general formula (8) and a diaryliodonium salt represented by the following general formula (9) have high solubility, low crystallinity, and low acidity. It has been found that high output can be obtained when used as an oxidizing agent in a hole transport layer. If the acidity of the hole transport layer is high, the open circuit voltage will be low. Although it is possible to increase the open circuit voltage by increasing the amount of basic material added, the decrease in the concentration of the hole transporting material increases the series resistance and reduces the output in high-intensity light.
...General formula (8)
(In the formula, R ₁ to R ₅ represent a hydrogen atom or a methyl group. _{R 6} and R ₇ represent a methyl group or a trifluoromethyl group.)
...General formula (9)
(In the formula, X represents any of the following structural formulas.)
BF ₄ ...Structural formula (1)
PF ₆ ... Structural formula (2)
...Structural formula (3)
...Structural formula (4)

Specific examples of the periodinane compound represented by the general formula (8) and the diaryliodonium salt represented by the general formula (9) include (G-1) to (G-10) shown below. Can be mentioned. However, it is not limited to these.

Other hypervalent iodine compounds having the following structural formula may also be used.

Further, a compound represented by the following general formula (10) may be contained as an oxidizing agent.

・・・一般式（１０）
（一般式（１０）において、Ｒ１～Ｒ５は水素原子、ハロゲン原子、アルキル基、アルコキシ基、アリール基を表し、同一であっても異なっていても良い。Ｘはカチオンを表す。

...General formula (10)
(In general formula (10), R1 to R5 represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or an aryl group, and may be the same or different. X represents a cation.

Specific examples of the compound represented by general formula (10) include, but are not limited to, the following (I-1) to (I-28).

The content of the oxidizing agent is preferably 0.5 parts by mass or more and 50 parts by mass or less, more preferably 5 parts by mass or more and 30 parts by mass or less, based on 100 parts by mass of the hole transport material. It is not necessary that all of the hole transport material be oxidized by the addition of an oxidizing agent; it is effective if only a portion of the hole transport material is oxidized.

The hole transport layer may have a single layer structure made of a single material, or may have a laminated structure containing 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 near the second electrode, which will be described later. Use of a polymeric material with excellent film-forming properties is advantageous in that the surface of the porous electron transport layer can be made smoother and the photoelectric conversion characteristics can be improved. In addition, since the polymer material is difficult to penetrate into the porous structure of the electron transport layer, it has excellent covering properties on the surface of the porous structure of the electron transport layer, and is effective in preventing short circuits when providing electrodes. You may be able to get it.

The polymer material used for the hole transport layer is not particularly limited, and may 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 compounds include poly(3-n-hexylthiophene), poly(3-n-octyloxythiophene), poly(9,9'-dioctyl-fluorene-co-bithiophene), and poly(3,3-hexylthiophene). '''-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), etc.
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-phenylenevinylene], poly[(2-methoxy-5-(2-ethylphexyloxy)-1,4-phenylenevinylene)-co-(4,4'-biphenylene-vinylene)], etc. It will be done.
Examples of the polyfluorene compound include poly(9,9'-didodecylfluorenyl-2,7-diyl), poly[(9,9-dioctyl-2,7-divinylenefluorene)-alt-co -(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorene)-alt-co-(4,4'-biphenylene)], poly[(9,9-dioctyl) -2,7-divinylenefluorene)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)], poly[(9,9-dioctyl-2,7-diyl) )-co-(1,4-(2,5-dihexyloxy)benzene)] and the like.
Examples of the polyphenylene compound include poly[2,5-dioctyloxy-1,4-phenylene] and poly[2,5-di(2-ethylhexyloxy-1,4-phenylene)].
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- Dioctyloxy-1,4-phenylenevinylene-1,4-phenylene], poly[p-tolylimino-1,4-phenylenevinylene-2,5-di(2-ethylhexyloxy)-1,4-phenylenevinylene-1 , 4-phenylene], poly[4-(2-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]), polythiadiazole (3,4-didecylthiophene-co-(1,4-benzo(2,1′,3)thiadiazole)) and the like.
Among these, polythiophene compounds and polyarylamine compounds are preferred from the viewpoint of carrier mobility and ionization potential.

Various additives may be added to the hole transport material.
Examples of additives include metal iodides such as iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, and silver iodide, and tetraalkyl iodide. Quaternary ammonium salts such as ammonium and pyridinium iodide, metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, and calcium bromide, and quaternary ammonium such as tetraalkylammonium bromide and pyridinium bromide. Bromine salts of compounds, metal chlorides such as copper chloride and silver chloride, metal acetates such as copper acetate, silver acetate and palladium acetate, metal sulfates such as copper sulfate and zinc sulfate, ferrocyanates - ferricyanates , metal complexes such as ferrocene-ferricinium ions, sulfur compounds such as sodium polysulfide, alkylthiol-alkyl disulfides, viologen dyes, hydroquinone, etc., 1,2-dimethyl-3-n-propylimidazoinium iodide salts, iodine 1-Methyl-3-n-hexylimidazolinium salt, 1,2-dimethyl-3-ethylimidazolium trifluoromethanesulfonate, 1-methyl-3-butylimidazolium nonafluorobutyl sulfonate, 1 -Methyl-3-ethylimidazolium bis(trifluoromethyl)sulfonylimide and the like. Chem. 35 (1996) 1168, basic compounds such as pyridine, 4-t-butylpyridine, benzimidazole, or derivatives thereof, and alkali metal salts.

The average thickness of the hole transport layer is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that the hole transport layer has a structure that penetrates into the pores of the electron transport layer with a porous structure. The thickness on the layer is preferably 0.01 μm or more and 20 μm or less, more preferably 0.1 μm or more and 10 μm or less, and even more preferably 0.2 μm or more and 2 μm or less.

The hole transport layer may be formed directly on the electron transport layer to which a photosensitizing compound is adsorbed.
The method for producing the hole transport layer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method of forming a thin film in a vacuum such as a vacuum evaporation method, a wet film forming method, and the like. Among these, the wet film forming method is particularly preferred from the viewpoint of manufacturing cost, and the method of coating on the electron transport layer is preferred.
When the wet film forming method is used, there are no particular limitations on the coating method, and any known method can be used, such as a dip method, a spray method, a wire bar method, a spin coat method, a roller coat method, Various methods such as a blade coating method, a gravure coating method, a die coating method, and a wet printing method such as letterpress, offset, gravure, intaglio, rubber printing, and screen printing can be used.

Alternatively, the film may be formed in a supercritical fluid or a subcritical fluid at a temperature and pressure lower than the critical point. The supercritical fluid exists as a non-cohesive high-density fluid in a temperature and pressure region exceeding the limit (critical point) where gas and liquid can coexist, does not cohere even when compressed, and has a temperature above the critical temperature and a critical pressure. There is no particular restriction as long as the fluid is in the above state, and it can be selected as appropriate depending on the purpose, but one with a low critical temperature is preferred.

Examples of the supercritical fluid include carbon monoxide, carbon dioxide, ammonia, nitrogen, water, alcohol solvents, hydrocarbon solvents, halogen solvents, and ether solvents.
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, and toluene.
Examples of the halogen solvent include methylene chloride and chlorotrifluoromethane.
Examples of the ether solvent include dimethyl ether.
These may be used alone or in combination of two or more.
Among these, carbon dioxide is preferred because it has a critical pressure of 7.3 MPa and a critical temperature of 31° C., so it can easily create a supercritical state, is nonflammable, and is 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 region near the critical point, and can be appropriately selected depending on the purpose. Compounds listed as supercritical fluids can also be suitably used as subcritical fluids.

The critical temperature and critical pressure of the supercritical fluid are not particularly limited and can be appropriately selected depending on the purpose, but the critical temperature is preferably -273°C or more and 300°C or less, and 0°C or more and 200°C or less. is more preferable.

Furthermore, in addition to the supercritical fluid and the subcritical fluid, an organic solvent or an entrainer can also be used in combination. By adding an organic solvent and an entrainer, the solubility in a supercritical fluid can be more easily adjusted.
The organic solvent is not particularly limited as long as it contains chlorobenzene, and can be appropriately selected depending on the purpose. For example, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, carbonized Examples include hydrogen solvents.
Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
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, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
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. It will be done.
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. , ethylbenzene, cumene, etc.
These may be used alone or in combination of two or more.

Further, the method for producing the hole transport layer includes applying a hole transport layer forming material containing the material for forming the hole transport layer onto the electron transport layer to which the photosensitizing compound has been adsorbed, and then It is preferable to perform drying and control, and preferably heat drying, before forming.
There is no particular restriction on the pressure under the heating drying conditions, but it is preferable to carry out under normal pressure.
The temperature under the heating drying conditions is preferably 30°C or more and 130°C or less, more preferably 50°C or more and 100°C or less.
The treatment time under the heat drying conditions is preferably 10 minutes or more and 24 hours or less, more preferably 30 minutes or more and 2 hours or less.
The method for performing the heat drying is not particularly limited as long as the above heat drying conditions can be achieved, and can be appropriately selected depending on the purpose. Examples include the following methods. Any conventionally known method can be used as long as it can be heated, such as an oven, dryer, thermostat, hot plate, etc.

Moreover, after laminating the hole transport material on the electron transport layer on which the photosensitizing compound is adsorbed, a press treatment step may be performed. By applying the press treatment, the hole transport material comes into close contact with the electron transport layer, which is a more porous electrode, so efficiency may be improved in some cases.
The method of the press treatment is not particularly limited and can be selected as appropriate depending on the purpose, such as a press molding method using a flat plate as typified by an IR tablet press, a roll press method using a roller, etc. etc. can be mentioned.
The pressure is preferably 10 kgf/cm ² or more, more preferably 30 kgf/cm ² or more.
The time for the press treatment is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 hour or less. Furthermore, heat may be applied during the press treatment. During the pressing process, a mold release agent may be interposed between the press and the electrode.

Examples of the mold release agent include polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkoxy fluoride resin, polyvinylidene fluoride, and ethylene tetrafluoroethylene copolymer. Examples include fluororesins such as polymers, ethylene chlorotrifluoroethylene copolymers, and polyvinyl fluoride. These may be used alone or in combination of two or more.

After performing the press treatment step and before providing the second electrode, a metal oxide may be provided between the hole transport material and the second electrode.
Examples of the metal oxide include molybdenum oxide, tungsten oxide, vanadium oxide, and nickel oxide. These may be used alone or in combination of two or more. Among these, molybdenum oxide is preferred.
The method for providing the metal oxide on the hole transport layer is not particularly limited and can be selected as appropriate depending on the purpose. Examples include the membrane method.

The wet film forming method is preferably a method in which a paste in which metal oxide powder or sol is dispersed is prepared and applied onto the hole transport layer. The coating method when using the wet film forming method is not particularly limited and can be carried out according to known methods, such as dipping method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, etc. As the coating method, gravure coating method, die coating method, and wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber printing, and screen printing can be used.
The average thickness of the applied metal oxide is preferably 0.1 nm or more and 50 nm or less, more preferably 1 nm or more and 10 nm or less.

<Second electrode>
The second electrode can be formed on the hole transport layer or on a metal oxide in the hole transport layer. Furthermore, the second electrode can be the same as the first electrode, and the second substrate is not necessarily required if sufficient strength is maintained.

Examples of the material for 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 nanotubes, and graphene.
Examples of the conductive metal oxide include ITO, FTO, and ATO.
Examples of the conductive polymer include polythiophene and polyaniline.
Examples of the structure having translucency include silver nanowires alone or a mixture with carbon nanotubes.
These may be used alone or in combination of two or more.

Regarding the formation of the second electrode, depending on the type of material used and the type of hole transport layer, it can be formed on the hole transport layer by a coating method, a lamination method, a vapor deposition method, a CVD method, a bonding method, etc. as appropriate. It is.
In the photoelectric conversion element of the present invention, it is preferable that at least one of the first electrode and the second electrode is substantially transparent. Preferably, the first electrode side is transparent and the incident light is made to enter from the first electrode side. In this case, it is preferable to use a material that reflects light on the second electrode side, and metal, glass deposited with a conductive oxide, plastic, or a metal thin film is preferably used. It is also an effective means to provide an antireflection layer on the incident light side.

<Second board>
The second substrate is not particularly limited, and any known substrate can be used, such as glass, plastic film, ceramic substrates, and the like. In order to improve adhesion, an uneven portion may be formed at the joint between the second substrate and the sealing member.
The method for forming the uneven portions is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include sandblasting, waterblasting, abrasive paper, chemical etching, laser processing, and the like.

As 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 organic substances from the surface of the second substrate is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include UV ozone cleaning, oxygen plasma treatment, and the like.

<Sealing member>
The photoelectric conversion element of the present invention can effectively use a sealing member that can shield at least the electron transport layer and the hole transport layer from the external environment of the photoelectric conversion element. In other words, in the present invention, it is preferable to further include a sealing member that shields the photoelectric conversion layer from the external environment of the photoelectric conversion element.
As the sealing member, any conventionally known member can be used as long as it can reduce the intrusion of excessive moisture, oxygen, etc. from the external environment into the interior of the seal. The sealing member also has the effect of preventing mechanical destruction due to external pressure, and any conventionally known member can be used as long as it can achieve this.

There are two types of sealing methods: "frame sealing" in which a sealing member is provided at the periphery of the power generation region made up of the photoelectric conversion layer of the photoelectric conversion element and adhered to the second substrate, and "frame sealing" in which the entire surface of the power generation region is sealed. It can be roughly divided into "surface sealing" in which a member is provided and bonded to the second substrate. The former type of "frame sealing" can form a hollow part inside the seal, so it is possible to appropriately adjust the amount of moisture and oxygen inside the seal, and the second electrode can be placed inside the seal. Since it is not in contact with the stopper member, it has the effect of reducing the effects of electrode peeling. On the other hand, the latter type of "surface sealing" has an excellent effect of preventing excessive water and oxygen from entering from the outside, and has a large adhesive area with the sealing member, so the sealing strength is high, especially for the first part. This is suitable when a flexible substrate is used as the first substrate.

The type of the sealing member is not particularly limited and can be appropriately selected depending on the purpose, and examples include hardened resin and low-melting glass resin.
The cured resin is not particularly limited as long as it is a resin that is cured by light or heat, and can be appropriately selected depending on the purpose, and among them, acrylic resins and epoxy resins are preferably used.

The cured product of the acrylic resin can be any known material as long as it is a cured monomer or oligomer having an acrylic group in its molecule.

As the cured product of the epoxy resin, any known material can be used as long as it is a cured monomer or oligomer having an epoxy group in its molecule.
Examples of the epoxy resin include water dispersion type, solventless type, solid type, heat curing type, curing agent mixed type, and ultraviolet curing type. Among these, the thermosetting type and the ultraviolet curing type are preferable, and the ultraviolet curing type is more preferable. Note that even if the material is of the ultraviolet curing type, it is possible to heat it, and it is preferable to heat it even after it has been cured with ultraviolet light.
Examples of the epoxy resin include bisphenol A type, bisphenol F type, novolak type, cycloaliphatic type, long chain aliphatic type, glycidylamine type, glycidyl ether type, and glycidyl ester type. These may be used alone or in combination of two or more.

It is preferable that the epoxy resin is mixed with a curing agent and various additives, if necessary.
The curing agent is classified into amine-based, acid anhydride-based, polyamide-based, and other curing agents, and is appropriately selected depending on the purpose.
Examples of the amine curing agent include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.
Examples of the acid anhydride curing agent include phthalic anhydride, tetra- and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, hetacetic anhydride, dodecenylsuccinic anhydride, and the like. It will be done.
Examples of the other curing agents include imidazoles and polymercaptans. These may be used alone or in combination of two or more.

Examples of the additives include fillers, gap agents, polymerization initiators, desiccants (hygroscopic agents), curing accelerators, coupling agents, softening agents, coloring agents, flame retardant aids, and oxidizing agents. Examples include inhibitors and organic solvents. Among these, fillers, gap agents, curing accelerators, polymerization initiators, and drying agents (hygroscopic agents) are preferred, and fillers and polymerization initiators are more preferred.

The filler is effective in suppressing the infiltration of moisture and oxygen, as well as reducing volumetric shrinkage during curing, reducing the amount of outgassing during curing or heating, improving mechanical strength, and improving thermal conductivity and fluidity. It is very effective in maintaining stable output even in various environments. In particular, the output characteristics and durability of a photoelectric conversion element are affected not only by moisture and oxygen that enter, but also by outgas generated during curing or heating of the sealing member, which cannot be ignored. In particular, the influence of outgas generated during heating has a large effect on output characteristics when stored in a high-temperature environment.
In this case, by including a filler, gap agent, or desiccant in the sealing material, these substances themselves can suppress the infiltration of moisture and oxygen, and the amount of sealing material used can be reduced, which has the effect of reducing outgassing. can be obtained. This is effective not only during curing but also when the photoelectric conversion element is stored in a high temperature environment.

The filler is not particularly limited and can be selected as appropriate depending on the purpose; for example, inorganic materials such as crystalline or amorphous silica, talc, alumina, aluminum nitride, silicon nitride, calcium silicate, calcium carbonate, fillers are preferably used. These may be used alone or in combination of two or more.
The average primary particle size of the filler is preferably 0.1 μm or more and 10 μm, more preferably 1 μm or more and 5 μm or less. When the amount added is within the preferred range, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained, the viscosity is appropriate, the adhesion with the substrate, the defoaming property is improved, and the width of the sealing part is improved. It is also effective for control and workability.

The content of the filler is preferably 10 parts by mass or more and 90 parts by mass or less, more preferably 20 parts by mass or more and 70 parts by mass or less, based on 100 parts by mass of the entire sealing member. When the content of the filler is within the above range, a sufficient effect of inhibiting moisture and oxygen penetration can be obtained, the viscosity is also appropriate, and the adhesion and workability are also good.

The gap agent is also called a gap control agent or a spacer agent, and it becomes possible to control the gap of the sealing part. For example, when sealing is performed by applying a sealing member on the first substrate or the first electrode and placing the second substrate on top of the sealing member, the gap agent is mixed with the epoxy resin. 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, any known material can be used as long as it is granular, has a uniform particle size, and has high solvent resistance and heat resistance. It is preferable that the particles have a high affinity with the epoxy resin and have a spherical particle shape. Specific examples include glass beads, silica particles, organic resin particles, and the like. These may be used alone or in combination of two or more.
The average particle size of the gap agent can be selected depending on the gap of the sealing part to be set, but is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less.

Examples of the polymerization initiator include a thermal polymerization initiator that initiates polymerization using heat, a photopolymerization initiator that initiates polymerization using light, and the like.
The thermal polymerization initiator is a compound that generates active species such as radicals and cations when heated, and specifically includes an azo compound such as 2,2'-azobisbutyronitrile (AIBN), and benzoyl peroxide ( Peroxides such as BPO) are used. As the thermal cationic polymerization initiator, benzenesulfonic acid ester, alkylsulfonium salt, etc. are used. On the other hand, in the case of an epoxy resin, a cationic photopolymerization initiator is preferably used as the photopolymerization initiator. When a cationic photopolymerization initiator is mixed with an epoxy resin and irradiated with light, the cationic photopolymerization initiator decomposes and generates a strong acid.The acid causes polymerization of the epoxy resin, and the curing reaction progresses. The cationic photopolymerization initiator has the following effects: less volumetric shrinkage during curing, no inhibition by oxygen, and high storage stability.
Examples of the photocationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metatheron compounds, and silanol/aluminum complexes.

Furthermore, a photoacid generator having a function of generating an acid upon irradiation with light can also be used. The photoacid generator acts as an acid that initiates cationic polymerization, and includes, for example, onium salts such as ionic sulfonium salts and iodonium salts consisting of a cationic part and an anionic part. These may be used alone or in combination of two or more.

The amount of the polymerization initiator added may vary depending on the material used, but it is preferably 0.5 parts by mass or more and 10 parts by mass or less, and 1 part by mass or more and 5 parts by mass, based on 100 parts by mass of the entire sealing member. Part or less is more preferable. When the amount added is within the above range, curing proceeds appropriately, the amount of uncured material remaining can be reduced, and excessive outgassing can be prevented, which is effective.

The desiccant is also called a moisture absorbent, and is a material that has the function of adsorbing and absorbing moisture physically or chemically. By including it in the sealing member, it can further increase moisture resistance and reduce the effects of outgassing. It is effective because it can sometimes reduce the amount of water used.
The desiccant is preferably in the form of particles, and includes, for example, inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieve, and zeolite. Among these, zeolite, which absorbs a large amount of moisture, is preferred. These may be used alone or in combination of two or more.

The curing accelerator is also called a curing catalyst and is used for the purpose of increasing the curing speed, and is mainly used for thermosetting epoxy resins.
Examples of the curing accelerator include DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5). Tertiary amines or tertiary amine salts, imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, phosphines such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, or Examples include phosphonium salts. These may be used alone or in combination of two or more.

The coupling agent has the effect of increasing molecular bonding strength, and includes silane coupling agents, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. Xypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N -(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3 Examples include silane coupling agents such as -aminopropyltrimethoxysilane hydrochloride and 3-methacryloxypropyltrimethoxysilane. These may be used alone or in combination of two or more.

Furthermore, as the sealing member, epoxy resin compositions that are commercially available as sealants, sealants, or adhesives are known, and can be effectively used in the present invention. Among these, there are epoxy resin compositions that have been developed and commercially available for use in solar cells and organic EL devices, and can be used particularly effectively in the present invention. Examples include TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyoritsu Kagaku Co., Ltd.), and WB90US (P) (manufactured by Moresco).

On the other hand, in the case of a low-melting glass resin, the resin component is decomposed by a baking process at about 550° C. after the resin is applied, and then it is brought into close contact with the glass substrate while being melted by an infrared laser or the like. At this time, the low melting point glass component diffuses into the metal oxide layer and is physically bonded, thereby achieving high sealing performance. In addition, since the resin component has disappeared, no outgas is generated like in acrylic resins or epoxy resins, and the photoelectric conversion element is not deteriorated, which is effective.

In the present invention, a sheet-like sealing material can also be used as the sealing member.
The sheet-shaped sealing material is, for example, a sheet on which an epoxy resin layer is formed in advance, and the sheet is made of glass, a film with high gas barrier properties, or the like, and corresponds to the second substrate in the present invention.
By pasting the sheet-like sealing material onto the second electrode and then curing it, the sealing member and the second substrate can be formed at the same time.
Depending on the formation pattern of the epoxy resin layer formed on the sheet, it is also possible to form a structure with a hollow portion, which is effective. If the resin layer formed on the sheet is formed on the entire surface, it will be "surface sealing", but depending on the formation pattern of the resin layer, it is necessary to pattern the resin layer so that a hollow part is provided inside the photoelectric conversion element. This will result in "frame sealing".

There are no particular restrictions on the method for forming the sealing member, and any known method may be used, such as a dispense method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, a gravure coating method, and a letterpress method. Various methods can be used, such as , offset, intaglio, rubber printing, and screen printing.

Furthermore, a passivation layer may be provided between the sealing member and the second electrode.
The passivation layer is not particularly limited as long as it is arranged so that the sealing member does not touch the second electrode, and can be appropriately selected depending on the purpose, but aluminum oxide, silicon nitride, silicon oxide, etc. is preferably used.
By containing oxygen in the hollow space inside the seal, the hole transport function of the hole transport layer can be stably maintained over a long period of time, which may be effective in improving the durability of photoelectric conversion elements. . In the present invention, the hollow portion inside the seal provided by sealing preferably contains oxygen, and the oxygen concentration is more preferably 10.0 volume % or more and 21.0 volume % or less.

The oxygen concentration in the hollow portion can be controlled by sealing the inside of the glove box in which the oxygen concentration is adjusted. The oxygen concentration can be adjusted by using a gas cylinder having a specific oxygen concentration or by using a nitrogen gas generator. The oxygen concentration in the glove box can be measured using a commercially available oxygen concentration meter or oxygen monitor.
The oxygen concentration within the hollow portion formed by sealing can be measured by, for example, IVA (Internal Vapor Analysis). Specifically, this is a method in which a photoelectric conversion element is loaded in a high vacuum, a hole is drilled, and the gas and moisture generated are subjected to mass spectrometry. With this method, the oxygen concentration contained within the sealed interior of the photoelectric conversion element can be determined. There are two types of mass spectrometers: quadrupole and time-of-flight, and the latter allows for more sensitive measurements.

As the gas other than oxygen contained inside the seal, an inert gas is preferable, and nitrogen, argon, etc. are preferable.
When sealing is performed, it is preferable to control the oxygen concentration and dew point inside the glove box, which is effective in improving output and durability. Dew point is defined as the temperature at which condensation begins when a gas containing water vapor is cooled.
The dew point is not particularly limited, but is preferably 0°C or lower, more preferably -20°C or lower. The lower limit is preferably -50°C or higher.

Hereinafter, an example of the photoelectric conversion element of the present invention will be described with reference to the drawings. However, the present invention is not limited to these, and for example, the number, position, shape, etc. of the following constituent members that are not described in this embodiment are also included in the scope of the present invention.

<First embodiment>
FIG. 1 is a schematic diagram showing an example of a photoelectric conversion element according to the first embodiment. In the photoelectric conversion element 101 of the first embodiment shown in FIG. 1, a first electrode 2 is formed on a first substrate 1. An electron transport layer 4 is formed on the first electrode 2, and a 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 above 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 arranged above the second electrode 7 , and the second substrate 9 is fixed to the first electrode 2 by a sealing member 8 . At this time, the sealing member 8 may be bonded to the first substrate 1 instead of the first electrode 2, which may be effective in improving the sealing performance.
The photoelectric conversion element 101 of the first embodiment shown in FIG. 1 has a hollow portion 10 between the second electrode 7 and the second substrate 9. By having the hollow part 10, it becomes possible to control the moisture content and oxygen concentration in the hollow part, thereby improving power generation performance and durability. Furthermore, since the second electrode 7 and the second substrate 9 are not in contact with each other, peeling and destruction of the second electrode 7 can be prevented. The oxygen concentration within the hollow space is not particularly limited and can be freely controlled, but is preferably 10% or more and 21% or less.
Although not shown, the first electrode 2 and the second electrode 7 each have a conductive path to the electrode extraction terminal.

<Second embodiment>
FIG. 2 is a schematic diagram showing an example of a photoelectric conversion element according to the second embodiment. In the photoelectric conversion element 101 of the second embodiment shown in FIG. 2, a hole blocking layer 3 is formed between the first substrate 1 and the electron transport layer 4. By forming the hole blocking layer 3, recombination of electrons and holes can be prevented, which is effective in improving power generation performance. The photoelectric conversion element shown in FIG. 2 has a hollow portion 10 between the second electrode 7 and the second substrate 9, as in FIG.

<Third embodiment>
FIG. 3 is a schematic diagram showing an example of a photoelectric conversion element according to the third embodiment. In the photoelectric conversion element 101 of the third embodiment shown in FIG. 3, the hollow portion 10 shown in FIG. 2 is covered with a sealing member 8 to seal the entire surface. For example, the sealing member 8 can be formed by applying the sealing member 8 over the entire surface of the second electrode 7 and providing the second substrate 9 thereon, or by using the sheet-shaped sealing material described above. In this case, it is possible to provide a passivation layer 11 between the second electrode 7 and the sealing member 8, which may be effective in preventing peeling of the second electrode. By covering almost the entire surface with the sealing member in this way, it is possible to increase the mechanical strength of the photoelectric conversion element.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
(Method for manufacturing photoelectric conversion element)
The method for manufacturing a photoelectric conversion element according to the present invention includes:
The method includes an electron transport layer forming step of forming an electron transport layer containing a compound represented by the following general formula (1) on the first electrode, and further includes other steps as necessary.

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

The method for manufacturing a photoelectric conversion element of the present invention includes forming a first electrode on a first substrate, forming a photoelectric conversion layer on the first electrode, and forming a second electrode on the photoelectric conversion layer. , further including the step of disposing other members such as a hole blocking layer and a sealing member as necessary.

In the method for manufacturing a photoelectric conversion element of the present invention, the first electrode, photoelectric conversion layer, second electrode, and other members and layers are the same as those described in the photoelectric conversion element of the present invention.

<Electron transport layer formation process>
The electron transport layer forming step is a step of forming an electron transport layer containing a compound represented by the following general formula (1) on the first electrode.
The electron transport layer forming step is a step of forming an electron transport layer by a method similar to the method for forming the electron transport layer described in the photoelectric conversion element of the present invention.

<Other processes>
Other steps include forming each layer by the same method as the method for forming each layer described in the photoelectric conversion element of the present invention.

(Photoelectric conversion module)
The photoelectric conversion module has a plurality of photoelectric conversion elements of the present invention, and the photoelectric conversion elements adjacent to each other are electrically connected in series or in parallel.
The photoelectric conversion module has, for example, a photoelectric conversion element arrangement area in which a plurality of photoelectric conversion elements are arranged adjacent to each other and connected in series or in parallel, and the plurality of photoelectric conversion elements are connected to a first electrode. A photoelectric conversion layer including an electron transport layer and a hole transport layer is formed between the second electrode and the second electrode.

The photoelectric conversion module may have a plurality of photoelectric conversion elements. Further, the plurality of photoelectric conversion elements may be connected in series and/or in parallel, or may include independent photoelectric conversion elements that are not connected.
The structure of each layer of the photoelectric conversion module may be the same as that of the photoelectric conversion element.

The structure of the photoelectric conversion module is not particularly limited and can be appropriately selected depending on the purpose. It is preferable that the circuit is divided, thereby reducing the risk of short circuit. On the other hand, the hole transport layer may be divided into at least two photoelectric conversion elements adjacent to each other, or may be in the form of a continuous layer in which the hole transport layers are mutually extended.

Further, in the photoelectric conversion module having at least two photoelectric conversion elements adjacent to each other, the first electrode in one of the photoelectric conversion elements and the second electrode in the other photoelectric conversion element It is preferable that the electrode is electrically connected to the photoelectric conversion layer by a conductive portion passing through the photoelectric conversion layer.

Further, the photoelectric conversion module has a pair of substrates, and has a photoelectric conversion element arrangement area connected in series or parallel between the pair of substrates, and the sealing member is sandwiched between the pair of substrates. It can be configured as follows. In particular, the photoelectric conversion module preferably includes a sealing member that shields the photoelectric conversion layers of the plurality of photoelectric conversion elements in the photoelectric conversion module from an external environment of the photoelectric conversion module.

An example of the photoelectric conversion element module of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these, and for example, the number, position, shape, etc. of the following constituent members that are not described in this embodiment are also included in the scope of the present invention.

<Fourth embodiment>
FIG. 4 is a schematic diagram showing an example of the photoelectric conversion element module 102 of the present invention, and is an example showing a cross section of a part of the photoelectric conversion element module including a plurality of photoelectric conversion elements connected in series. be.
FIG. 4 shows that after forming the hole transport layer 6, the penetration part 12 is formed, and then the second electrodes 7a and 7b are formed, so that the material of the second electrode is introduced into the penetration part 12. , can be electrically connected to the first electrode 2b of an adjacent cell. Although not shown in FIG. 4, the first electrode 2a and the second electrode 7b further have a conductive path to an electrode of an adjacent photoelectric conversion element or an output extraction terminal.

The penetrating portion 12 may penetrate the first electrode 2 and reach the first substrate 1, or the penetrating portion 12 may stop processing inside the first electrode 2 and may not reach the first substrate 1. Good too.
When the shape of the penetration part 12 is a microhole that penetrates the first electrode 2 and reaches the first substrate 1, if the total opening area of the microholes becomes too large relative to the area of the penetration part 12, the As the film cross-sectional area of 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 penetrating portion 12 is preferably 5/100 or more and 60/100 or less.

The method for forming the penetration portion 12 is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include sandblasting, waterblasting, abrasive paper, chemical etching, laser processing, and the like. Among these, laser processing is preferred. As a result, fine holes can be formed without using sand, etching, resist, etc., and processing can be performed cleanly and with good reproducibility. Furthermore, when forming the penetration part 12, it is possible to remove at least one of the hole blocking layer 3, the electron transport layer 4, the hole transport layer 6, and the second electrode 7 by impact peeling using a laser processing method. Become. Thereby, there is no need to provide a mask during lamination, and removal and formation of the minute penetration portions 12 can be easily performed at the same time.

<Fifth embodiment>
FIG. 5 is a schematic diagram showing an example of the photoelectric conversion element module 102 of the present invention, and unlike FIG. 4, the hole transport layer 6 is separated from the adjacent photoelectric conversion element, and each has an independent layer structure. ing. This is effective in suppressing electron diffusion, reducing leakage current, and further improving durability.

(Electronics)
An electronic device of the present invention includes either the photoelectric conversion element of the present invention or the photoelectric conversion module, and a device that operates using electric power generated by photoelectric conversion by the photoelectric conversion element or the photoelectric conversion module. , and further includes other devices as necessary.
Further, the electronic device of the present invention includes either the photoelectric conversion element of the present invention or the photoelectric conversion module, and a storage battery capable of storing electric power generated by photoelectric conversion by the photoelectric conversion element or the photoelectric conversion module. , a device operated by the electric power stored in the storage battery, and further includes other devices as necessary.

(power module)
The power supply module of the present invention includes the photoelectric conversion module and a power supply circuit (IC; Integrated Circuit), and further includes other devices as necessary.

Next, a specific embodiment of an electronic device including the photoelectric conversion module and a device that operates using the power generated by the photoelectric conversion module will be described.

FIG. 6 is a block diagram of a computer mouse as an example of the electronic device of the present invention.
As shown in FIG. 6, a photoelectric conversion module, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the control circuit of the mouse. As a result, the power storage device can be charged when the mouse is not in use, and the mouse can be operated using that power, making it possible to obtain a mouse that does not require wiring or battery replacement. Furthermore, since no batteries are required, weight reduction becomes possible, which is effective.

FIG. 7 is a schematic external view showing an example of the mouse shown in FIG. 6.
As shown in Figure 7, the photoelectric conversion module, power supply IC, and power storage device are mounted inside the mouse, but the top of the photoelectric conversion element is covered with a transparent casing so that light hits the photoelectric conversion element of the photoelectric conversion module. It is being said. It is also possible to mold the entire mouse casing from transparent resin. The arrangement of the photoelectric conversion element is not limited to this. For example, it is possible and preferable to arrange the photoelectric conversion element at a position where light is irradiated even when the mouse is covered with the hand.

Next, another embodiment of an electronic device including the photoelectric conversion module and a device operated by the power generated by the photoelectric conversion module will be described.

FIG. 8 is a block diagram of a personal computer keyboard as an example of the electronic device of the present invention.
As shown in FIG. 8, the photoelectric conversion element of the photoelectric conversion module, the power supply IC, and the power storage device are combined, and the supplied power is connected to the power supply of the control circuit of the keyboard. As a result, the power storage device can be charged when the keyboard is not in use, and the keyboard can be operated using that power, making it possible to obtain a keyboard that does not require wiring or battery replacement. Furthermore, since no batteries are required, weight reduction becomes possible, which is effective.

FIG. 9 is a schematic external view showing an example of the keyboard shown in FIG. 8.
As shown in Figure 9, the photoelectric conversion element, power supply IC, and power storage device of the photoelectric conversion module are mounted inside the keyboard, but the top of the photoelectric conversion element is covered with a transparent casing so that the photoelectric conversion element is exposed to light. It is being said. It is also possible to mold the entire keyboard casing from transparent resin. The arrangement of the photoelectric conversion elements is not limited to this. In the case of a small keyboard in which the space for incorporating the photoelectric conversion element is small, it is possible and effective to embed the small photoelectric conversion element in a part of the key, as shown in FIG.

Next, another embodiment of an electronic device including the photoelectric conversion module and a device operated by the power generated by the photoelectric conversion module will be described.

FIG. 11 is a block diagram of a sensor as an example of the electronic device of the present invention.
As shown in FIG. 11, the photoelectric conversion element of the photoelectric conversion module, the power supply IC, and the power storage device are combined, and the supplied power is connected to the power source of the sensor circuit. This makes it possible to configure a sensor module without the need to connect to an external power source or replace the battery. The present invention can be effectively applied to various sensors such as temperature/humidity, illuminance, human sensation, CO ₂ , acceleration, UV, noise, geomagnetism, and atmospheric pressure. As shown in FIG. 12, the sensor module is configured to periodically sense the measurement target and transmit the read data to a PC, smartphone, etc. via wireless communication.

With the advent of the Internet of Things (IoT) society, the number of sensors is expected to increase rapidly. Replacing the batteries of these countless sensors one by one takes a lot of effort and is not practical. Additionally, sensors are located in places where it is difficult to replace batteries, such as on ceilings or walls, which also makes work easier. The fact that power can be supplied by the photoelectric conversion element is also a great advantage. Further, the photoelectric conversion module can obtain a high output even at low illuminance, and the dependence of the output on the light incident angle is small, so that it also has the advantage of having a high degree of installation freedom.

Next, another embodiment of an electronic device including the photoelectric conversion module and a device operated by the power generated by the photoelectric conversion module will be described.

FIG. 12 is a block diagram of a turntable as an example of the electronic device of the present invention.
As shown in FIG. 12, 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. This makes it possible to construct a turntable without having to connect it to an external power source or replacing batteries.
Turntables are used, for example, in showcases to display products, but the power supply wiring is unsightly and the display items must be removed when replacing batteries, which requires a lot of effort. By using the photoelectric conversion module, such problems can be solved and it is effective.

Above, the photoelectric conversion module, an electronic device having a device that operates using the electric power generated by these modules, and a power supply module have been described, but these are just a few, and the photoelectric conversion module It is not limited to the use of

<Application>
The photoelectric conversion element and photoelectric conversion module of the present invention can function as a self-contained power source, and the device can be operated using the electric power generated by photoelectric conversion. Since the photoelectric conversion module of the present invention can generate power by being irradiated with light, there is no need to connect the electronic device to a power source or replace the battery. Therefore, it is possible to operate electronic devices even in places without power supply facilities, carry them around on your person, and operate electronic devices without changing batteries even in places where battery replacement is difficult. In addition, when using dry batteries, the electronic device becomes heavier and larger, which may make it difficult to install it on a wall or ceiling or carry it around. However, the photoelectric conversion of the present invention Because the module is lightweight and thin, it has a high degree of freedom in installation and has great advantages when worn or carried around.

In this way, the photoelectric conversion module of the present invention can be used as a stand-alone power source and can be combined with various electronic devices. For example, display devices such as electronic desktop calculators, wristwatches, mobile phones, electronic notebooks, and electronic paper, computer accessories such as mice and keyboards, various sensor devices such as temperature/humidity sensors and human sensors, and transmitters such as beacons and GPS. It can be used in combination with a number of electronic devices such as flashlights, auxiliary lights, and remote controls.
The photoelectric conversion module of the present invention can generate electricity even with particularly low-intensity light, so it can generate electricity indoors or even in dim shadows, so it has a wide range of applications. Additionally, unlike dry batteries, they do not leak, and unlike button batteries, they cannot be accidentally swallowed, making them highly safe. Furthermore, it can be used as an auxiliary power source to extend the continuous use time of rechargeable or battery-powered electrical appliances. In this way, by combining the photoelectric conversion module of the present invention with a device that operates using the electric power generated by the photoelectric conversion, it is lightweight and easy to use, has a high degree of installation flexibility, does not require replacement, and is safe. It can be reborn as an electronic device that has excellent performance and is effective in reducing environmental impact.

FIG. 13 shows a basic configuration diagram of an electronic device that combines the photoelectric conversion module of the present invention and a device that operates using the power generated by the photoelectric conversion module. When the photoelectric conversion element is irradiated with light, it generates electricity and can extract electric power. The circuitry of the device is enabled to operate using the electrical power.
However, since the output of the photoelectric conversion element of the photoelectric conversion module changes depending on the ambient illuminance, the electronic device shown in FIG. 13 may not be able to operate stably. In this case, as shown in FIG. 14, it is possible and effective to incorporate a power supply IC for the photoelectric conversion element between the photoelectric conversion element and the device circuit in order to supply a stable voltage to the circuit side. .

However, the photoelectric conversion element of a photoelectric conversion module can generate electricity if it is illuminated with light of sufficient illuminance, but if the illuminance is insufficient to generate electricity, the desired power cannot be obtained, and this is also a drawback of the photoelectric conversion element. be. In this case, as shown in Figure 15, by installing a power storage device such as a capacitor between the power supply IC and the device circuit, it becomes possible to charge the power storage device with surplus power from the photoelectric conversion element, and the illumination level Even if the current is too low or the photoelectric conversion element is not exposed to light, the power stored in the power storage device can be supplied to the device circuit, allowing stable operation.
In this way, in an electronic device that combines the photoelectric conversion module of the present invention and a device circuit, by combining a power IC and a power storage device, it can operate even in an environment without a power source, does not require battery replacement, and is stable. This makes it possible to drive the photoelectric conversion element to the fullest, thereby maximizing the benefits of the photoelectric conversion element.

On the other hand, the photoelectric conversion module of the present invention can also be used as a power supply module and is useful. For example, as shown in FIG. 16, when the photoelectric conversion module of the present invention and a power supply IC for a photoelectric conversion element are connected, the power generated by photoelectric conversion by the photoelectric conversion element of the photoelectric conversion module is fixed at the power supply IC. It is possible to construct a DC power supply module that can supply voltage at a voltage level of

Furthermore, as shown in Figure 17, by adding a power storage device to the power supply IC, it becomes possible to charge the power generated by the photoelectric conversion element of the photoelectric conversion module into the power storage device, so that the power storage device can be charged when the illuminance is too low or when the illuminance is too low. , it is possible to configure a power supply module that can supply power even when the photoelectric conversion element is not exposed to light.
The power supply module of the present invention shown in FIGS. 16 and 17 can be used as a power supply module without replacing the battery unlike conventional primary batteries.

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

[Method for synthesizing the compound represented by (B1-6)]
<Synthesis example 1a of raw material 1>
4-Iodoaniline (manufactured by Tokyo Chemical Industry Co., Ltd.: 10.95 g), 1-Iodooctane (manufactured by Tokyo Chemical Industry Co., Ltd.: 39.6 g), sodium carbonate (manufactured by Kanto Kagaku Co., Ltd.: 10.6 g), dehydrated dimethylformamide ( (manufactured by Kanto Kagaku Co., Ltd.: 150 ml) was placed in a 500 ml four-necked flask, heated and stirred at 120° C. for 7 hours, and the organic phase was washed with water, extracted, and concentrated.
Thereafter, column purification was performed using dichloromethane. The yield was 24.87g.
The obtained compound (13.3 g) was mixed with trimethylsilylacetylene (manufactured by Tokyo Chemical Industry Co., Ltd.: 3.83 g), CuI (manufactured by Kanto Kagaku Co., Ltd.: 114 mg), diisopropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.: 50 ml), Place in a 200 m four-necked flask, add palladium-tetrakis(triphenylphosphine) (Pd(PPh ₃ ) ₄ , Tokyo Chemical Industry Co., Ltd.: 347 mg) under an argon gas atmosphere, and heat at 50°C for 3 hours. Stirring was carried out and the organic phase was washed with water, extracted and concentrated.
Then, methanol (Kanto Kagaku Co., Ltd.: 65 ml), dichloromethane (Kanto Kagaku Co., Ltd.: 65 ml), and sodium hydroxide (Kanto Kagaku Co., Ltd.: 15 g) were added to the obtained concentrate, and the mixture was stirred at room temperature for 2 hours. The organic phase was washed with water, extracted and concentrated. The yield was 5.12g.

<Synthesis example 1b of raw material 2>
4,4-bis(2-ethylhexyl)-4H-cyclopentadithiophene (manufactured by Tokyo Kasei Kogyo Co., Ltd.: 5 g) was dissolved in dehydrated tetrahydrofuran (manufactured by Kanto Kagaku Co., Ltd.: 50 ml), and under an argon gas atmosphere, - The mixture was stirred at 78°C.
Next, 1.55M n-butyllithium hexane (manufactured by Kanto Chemical Co., Ltd.: 9 ml) was added, and the mixture was stirred at -78°C for 3 hours.
Thereafter, a solution prepared by diluting tributyltin chloride (manufactured by Kanto Kagaku Co., Ltd.: 5.25 g) in dehydrated tetrahydrofuran (manufactured by Kanto Kagaku Co., Ltd.: 30 ml) was slowly added dropwise.
The mixture was stirred at −78° C. for 1 hour, stirred at room temperature for 1 hour, and the organic phase was washed with water, extracted, and concentrated. The yield of purple oil was 9.6 g.

<Synthesis example 1c>
4,7-dibromo-2,1,3-benzothiazole (manufactured by Kanto Kagaku Co., Ltd.: 4.7 g), 4-Formylphenylbenzoic acid (manufactured by Kanto Kagaku Co., Ltd.: 2.5 g), potassium carbonate (manufactured by Kanto Kagaku Co., Ltd.) : 6.64 g), tetrahydrofuran (manufactured by Kanto Kagaku Co., Ltd.: 100 ml), and water (10 ml) were placed in a 200 ml four-necked flask and stirred under an argon gas atmosphere.
Pd(PPh ₃ ) ₄ (manufactured by Kanto Kagaku Co., Ltd.: 1.85 g) was added, heated and stirred at 50° C. for 10 hours, and the organic phase was washed with water, extracted, and concentrated. The yield was 8.6g.

<Synthesis example 1d>
200 ml of the aldehyde obtained in Synthesis Example 1c (synthesis 3: 0.87 g), Pd(PPh ₃ ) ₂ Cl ₂ (manufactured by Kanto Kagaku Co., Ltd.: 47.7 mg), and toluene (manufactured by Kanto Kagaku Co., Ltd.: 100 ml). The mixture was placed in a four-necked flask and heated and stirred at 40°C under an argon gas atmosphere.
Next, a solution of the tin body obtained in Synthesis Example 1b of Raw Material 2 (Synthesis 2: 2.65 g) and toluene (manufactured by Kanto Kagaku Co., Ltd.: 10 ml) was added dropwise, and reflux stirring was performed for 2 hours. The organic phase was washed with water, extracted and concentrated. The yield was 4.8g.
The obtained concentrate is dissolved in dichloromethane (manufactured by Kanto Kagaku Co., Ltd.: 100 ml), stirred at 3° C., NBS (manufactured by Kanto Kagaku Co., Ltd.: 1 g) is added, and the mixture is stirred for 4 hours. The organic phase is washed with water, extracted and concentrated. Column purification (cyclohexane) yielded 1.4 g of red oil.

<Synthesis example 1e>
Acetylene form obtained in Synthesis Example 1a of Raw Material 1 (Synthesis 1: 0.73 g), Bromo form obtained in Synthesis Example 1d (Synthesis 4: 1.4 g), Tetrahydrofuran (manufactured by Kanto Kagaku Co., Ltd.: 30 ml), Triethylamine (manufactured by Kanto Kagaku Co., Ltd.: 5 ml) and CuI (manufactured by Kanto Kagaku Co., Ltd.: 37 mg) were placed in a 100 ml four-necked flask and stirred under an argon gas atmosphere.
Pd(PPh ₃ ) ₄ (manufactured by Kanto Kagaku Co., Ltd.: 216 mg) was added, stirred under reflux for 1 hour, and the organic phase was washed with water, extracted, and concentrated.
Column purification (dichloromethane/cyclohexane = 7/3 vol) was performed, and further purification was performed by recycling GPC. The yield was 0.84g.
The total amount of the purified product, cyanoacetic acid (manufactured by Kanto Kagaku Co., Ltd.: 227 mg), ammonium acetate (manufactured by Kanto Kagaku Co., Ltd.: 207 mg), and acetic acid (manufactured by Kanto Kagaku Co., Ltd.: 50 ml) were placed in a 100 ml four-necked flask, and the mixture was stirred under reflux. was carried out for 2 hours, and the organic phase was washed with water, extracted and concentrated.
Column purification (dichloromethane/methanol = 8/2 vol) was performed, and the residue was further dissolved in dichloromethane and reprecipitated with methanol.
The obtained purified product was dried to obtain a compound represented by (B1-6). Product yield was 0.62g.
The identification data of the compound represented by (B1-6) above by FT-IR is shown in FIG. 19A.

Next, examples will be shown regarding the photoelectric conversion element of the present invention.

(Example 1)
<Production of photoelectric conversion element 1>
On a glass substrate as a first substrate, indium-doped tin oxide (ITO) and niobium-doped tin oxide (NTO) as a first electrode were sequentially formed by sputtering. Next, a dense layer (average thickness 20 nm) made of titanium oxide was formed as a hole blocking layer by reactive sputtering using oxygen gas.

Next, titanium oxide (18NR-T, manufactured by Greatcell Solar Materials) paste was applied onto the hole blocking layer by screen printing to an average thickness of about 1.2 μm. After drying at 120°C, it was fired in air at 500°C for 30 minutes to form an electron transport layer with a porous structure.
The glass substrate on which the electron transport layer was formed was immersed in a stirred solution of a photosensitizing compound (0.2 mM) represented by B1-1 below and a mixed solution of acetonitrile/t-butanol (volume ratio 1:1). Then, it was left standing in a dark place for 1 hour to allow the photosensitizing compound to be adsorbed onto the surface of the electron transport layer.
In addition, in "Synthesis Example 1a of Raw Material 1", "Synthesis Example 1b of Raw Material 2", and <Synthesis Example 1c>, the photosensitizing compound B1-1 has a corresponding alkyl group of the photosensitizing compound B1-1. Photosensitizing compound B1-1 was synthesized in the same manner as in "Method for synthesizing compound represented by (B1-6)" except for the modified synthesis.
(B1-1)

Next, 1 mL of chlorobenzene solution was added with 150 mM of the organic hole transport material represented by D-7 (SHT-263, manufactured by Merck & Co., Ltd.) and lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI, Kishida Chemical Co., Ltd.) as a lithium salt. Co., Ltd.), 135 mM of a basic compound of 4-pyrrolidinopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.), and 15 mM of an oxidizing agent of FK209 (manufactured by Aldrich Co., Ltd.) represented by F-11 above were added and dissolved. Transport layer coating liquid 1 was prepared.

Next, on the electron transport layer on which the photosensitizing compound was adsorbed, a hole transport layer having an average thickness of about 500 nm was applied by die coating using hole transport layer coating liquid 1.
The hole transport layer coating solution was applied onto the electron transport layer to which the photosensitizing compound had been adsorbed, and then heated and dried in an oven at 60° C. for 60 minutes under normal pressure.
Thereafter, the end portion of the glass substrate on which the sealing member was to be provided was etched by laser processing, and a through hole for connection to the ITO layer, which would become a terminal extraction portion, was further formed by laser processing.

After installing a mask between the end of the glass substrate and the cells, silver was vacuum deposited to form a second electrode with a thickness of about 70 nm.

An ultraviolet curable resin (TB3118, manufactured by Three Bond Holdings Co., Ltd.) was applied to the edge of the glass substrate using a dispenser (2300N, manufactured by Sanei Tech Co., Ltd.) so that the power generation area was surrounded. Thereafter, it was transferred to a glove box whose dew point was adjusted to minus 40°C and oxygen concentration was adjusted to 10% by volume, and a cover glass as a second substrate was placed on top of the ultraviolet curing resin and cured by ultraviolet irradiation. After that, it was heated at 80°C for 60 minutes. As described above, the power generation region was sealed, and the photoelectric conversion element 1 as shown in FIG. 1 was manufactured.

Next, the performance of the produced photoelectric conversion element was evaluated as follows. The results are shown in Table 1.

<Evaluation of photoelectric conversion element>
For the obtained photoelectric conversion element, the IV characteristics were evaluated using a solar cell evaluation system (As-510-PV03, manufactured by NF Circuit Design Block Co., Ltd.) under 2700K warm LED irradiation adjusted to 500lux, and the initial The open circuit voltage Voc1 (V) and the maximum output power Pmax1 (μW/cm ² ) were determined.
Next, it was irradiated under sunlight (AM1.5G) at 25°C for 150 hours, and the IV characteristics of the light source under the same conditions were evaluated again, and the open circuit voltage Voc2 and maximum output power Pmax2 (μW/ cm ² ) was measured, and the respective retention rates Voc2/Voc1 (%) and Pmax2/Pmax1 (%) were determined.

(Examples 2 to 7)
Photoelectric conversion elements 2 to 7 were produced in the same manner as in Example 1, except that the photosensitizing compound in Example 1 was changed to the photosensitizing compound shown in Table 1. Furthermore, the performance of photoelectric conversion elements 2 to 7 was also evaluated in the same manner as photoelectric conversion element 1. The results are shown in Table 1.
The photosensitizing compounds B1-2 and B1-5 to B1-9 shown in Table 1 are as follows. In addition, photosensitizing compounds B1-2 and B1-5 to B1-9 are different from photosensitizing compound B1 in "Synthesis example 1a of raw material 1", "Synthesis example 1b of raw material 2", and Photosensitizing compound B1- 2 and B1-5 to B1-9 were synthesized.
(B1-2)
(B1-5)
(B1-7)
(B1-8)
(B1-9)

(Example 8)
In Example 4, a photoelectric conversion element 8 was produced in the same manner as in Example 4, except that an aggregation-dissociating agent (5 mM) represented by B2-1 was further added to the solution of the photosensitizing compound. Furthermore, the performance of the photoelectric conversion element 8 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.

(Example 9)
In Example 8, except that lithium bis(trifluoromethanesulfonylimide) (Li-TFSI) was changed to lithium (fluoromethanesulfonyl)(trifluoromethanesulfonyl)imide (Li-FTFSI, manufactured by Tokyo Kasei Kogyo Co., Ltd.), A photoelectric conversion element 9 was produced in the same manner as in Example 8. Furthermore, the performance of the photoelectric conversion element 9 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.

(Example 10)
A photoelectric conversion element 10 was produced in the same manner as in Example 9, except that 4-pyrrolidinopyridine was changed to a basic compound represented by H-1. Furthermore, the performance of the photoelectric conversion element 10 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.

(Example 11)
Photoelectric conversion element 11 was produced in the same manner as in Example 9, except that 4-pyrrolidinopyridine was changed to a basic compound represented by H-3. Furthermore, the performance of the photoelectric conversion element 11 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.

・・・化合物Ａ (Comparative example 1)
A photoelectric conversion element 12 was produced in the same manner as in Example 1, except that the photosensitizing compound was changed to a compound represented by Compound A below (XY3b (manufactured by Dyenamo)). Furthermore, the performance of the photoelectric conversion element 12 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.

...Compound A

(Comparative example 2)
A photoelectric conversion element 13 was produced in the same manner as in Example 1, except that the photosensitizing compound in Example 1 was changed to a compound represented by Compound B below. Furthermore, the performance of the photoelectric conversion element 13 was also evaluated in the same manner as the photoelectric conversion element 1. The results are shown in Table 1.
...Compound B
Compound B was synthesized based on the method described in the following paper (J. Phys. Chem. C 2015, 119, 24282-24289).

From the results in Table 1, it was found that Examples 1 to 11 were able to suppress characteristic deterioration in low-intensity light even after being exposed to sunlight, compared to Comparative Examples 1 to 2.
It has been found that in solid-state dye-sensitized solar cells, the association state and interaction between dyes are extremely important for efficient photoelectric conversion under sunlight irradiation environments.

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜２＞ 前記一般式（１）が下記一般式（２）で表される、前記＜１＞に記載の化合物である。
・・・一般式（２）
（一般式（２）中、Ｒ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜３＞ 下記一般式（１）で表されることを特徴とする光電変換素子用化合物である。

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜４＞ 前記一般式（１）が下記一般式（２）で表される、前記＜３＞に記載の光電変換素子用化合物である。
・・・一般式（２）
（一般式（２）中、Ｒ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜５＞ 第１電極と、
下記一般式（１）で表される化合物を含有する電子輸送層と、
ホール輸送層と、
第２電極と、を有することを特徴とする光電変換素子である。

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜６＞ 前記電子輸送層が、前記一般式（１）で表される化合物を有する酸化チタン粒子を含み、多孔質状構造である、前記＜５＞に記載の光電変換素子である。
＜７＞ 前記一般式（１）が下記一般式（２）で表される化合物である、前記＜５＞から＜６＞のいずれかに記載の光電変換素子である。
・・・一般式（２）
（一般式（２）中、Ｒ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
＜８＞前記電子輸送層が下記一般式（３）で表される化合物をさらに含有する、前記＜５＞から＜７＞のいずれかに記載の光電変換素子である。
・・・一般式（３）
（一般式（３）中、ｎは、１から３の自然数を表し、Ａｒ_３は、置換基を有してもよいフェニル基又はナフチル基を表す。）
＜９＞前記ホール輸送層がリチウム（フルオロスルホニル）（トリフルオロメタンスルホニル）イミドを含有する、前記＜５＞から＜８＞のいずれかに記載の光電変換素子である。
＜１０＞前記ホール輸送層が下記一般式（Ａ１）で表されるピリジン化合物を含有する、前記＜５＞から＜９＞のいずれかに記載の光電変換素子である。
・・・一般式（Ａ１）
（一般式（Ａ１）中、Ａｒ_１及びＡｒ_２は、置換基を有していてもよいアリール基を表す。）
＜１１＞ 前記＜５＞から＜１０＞のいずれかに記載の光電変換素子を有することを特徴とする電子機器である。
＜１２＞ 前記＜５＞から＜１０＞のいずれかに記載の光電変換素子と、電源ＩＣとを有することを特徴とする電源モジュールである。
＜１３＞ 第一の電極上に下記一般式（１）で表される化合物を含有する電子輸送層を形成する電子輸送層形成工程を含む、ことを特徴とする光電変換素子の製造方法である。

・・・一般式（１）
（一般式（１）中、Ｒ_１及びＲ_２は、炭素数４から１２の直鎖状又は分岐鎖状のアルキル基を表し、Ｘは、下記構造のいずれかを表す。）
Examples of aspects of the present invention are as follows.
<1> A compound characterized by being represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<2> The compound according to <1> above, wherein the general formula (1) is represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<3> A compound for photoelectric conversion elements characterized by being represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<4> The compound for a photoelectric conversion element according to <3> above, wherein the general formula (1) is represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<5> A first electrode,
an electron transport layer containing a compound represented by the following general formula (1);
a hole transport layer;
A photoelectric conversion element characterized by having a second electrode.

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<6> The photoelectric conversion element according to <5>, wherein the electron transport layer includes titanium oxide particles having a compound represented by the general formula (1) and has a porous structure.
<7> The photoelectric conversion element according to any one of <5> to <6>, wherein the general formula (1) is a compound represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
<8> The photoelectric conversion element according to any one of <5> to <7>, wherein the electron transport layer further contains a compound represented by the following general formula (3).
...General formula (3)
(In general formula (3), n represents a natural number from 1 to 3, and Ar ₃ represents a phenyl group or a naphthyl group that may have a substituent.)
<9> The photoelectric conversion element according to any one of <5> to <8>, wherein the hole transport layer contains lithium (fluorosulfonyl) (trifluoromethanesulfonyl)imide.
<10> The photoelectric conversion element according to any one of <5> to <9>, wherein the hole transport layer contains a pyridine compound represented by the following general formula (A1).
...General formula (A1)
(In general formula (A1), Ar ₁ and Ar ₂ represent an aryl group that may have a substituent.)
<11> An electronic device comprising the photoelectric conversion element according to any one of <5> to <10>.
<12> A power supply module comprising the photoelectric conversion element according to any one of <5> to <10> and a power supply IC.
<13> A method for manufacturing a photoelectric conversion element, comprising an electron transport layer forming step of forming an electron transport layer containing a compound represented by the following general formula (1) on a first electrode. .

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)

The compound according to any one of <1> to <2> above, the compound for photoelectric conversion element according to any one of <3> to <4> above, the compound according to any one of <5> to <10> above. The photoelectric conversion element, the electronic device described in <11> above, the power supply module described in <12> above, and the method for manufacturing a photoelectric conversion element described in <13> above solve the conventional problems, and the present invention can achieve the objectives of

Japanese Patent Application Publication No. 2018-113305

1 First substrate 2, 2a, 2b First electrode 3 Hole blocking layer 4 Electron transport layer 5 Photosensitizing compound 6 Hole transport layer 7, 7a, 7b Second electrode 8 Sealing member 9 Second substrate 10 Hollow part 11 Passivation layer 12 Penetration part (conducting part)
101 Photoelectric conversion element 102 Photoelectric conversion module

Claims (12)

A compound characterized by being represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
The compound according to claim 1, wherein the general formula (1) is represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
A compound for photoelectric conversion elements, characterized by being represented by the following general formula (1).

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
The compound for a photoelectric conversion element according to claim 3, wherein the general formula (1) is represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
a first electrode;
An electron transport layer containing a compound represented by the following general formula (1),
a hole transport layer;
A photoelectric conversion element characterized by having a second electrode.

...General formula (1)
(In general formula (1), R ₁ and R ₂ represent a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
The photoelectric conversion element according to claim 5, wherein the electron transport layer includes titanium oxide particles having a compound represented by the general formula (1) and has a porous structure. The photoelectric conversion element according to claim 5, wherein the general formula (1) is a compound represented by the following general formula (2).
...General formula (2)
(In general formula (2), R ₂ represents a linear or branched alkyl group having 4 to 12 carbon atoms, and X represents any of the following structures.)
The photoelectric conversion element according to any one of claims 5 to 7, wherein the electron transport layer further contains a compound represented by the following general formula (3).
...General formula (3)
(In general formula (3), n represents a natural number from 1 to 3, and Ar ₃ represents a phenyl group or a naphthyl group that may have a substituent.) The photoelectric conversion element according to any one of claims 5 to 8, wherein the hole transport layer contains lithium (fluorosulfonyl) (trifluoromethanesulfonyl)imide. The photoelectric conversion element according to any one of claims 5 to 9, wherein the hole transport layer contains a pyridine compound represented by the following general formula (A1).
... General formula (A1)
(In general formula (A1), Ar ₁ and Ar ₂ represent an aryl group that may have a substituent.) An electronic device comprising the photoelectric conversion element according to claim 5. A power supply module comprising the photoelectric conversion element according to claim 5 and a power supply IC.

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