JP7230524B2 - Photoelectric conversion element, photoelectric conversion element module, electronic device, and power supply module - Google Patents

Description

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

In recent years, the importance of solar cells has increased as an alternative energy to fossil fuels and as a countermeasure against global warming, and various solar cells (photoelectric conversion element modules) have been developed.

Among these, many reports have been made on solid state dye-sensitized solar cells using a solid hole transport layer. Materials for the solid hole transport layer can be broadly classified into, for example, 1) those using inorganic semiconductors, 2) those using low-molecular-weight organic hole transport materials, and 3) those using conductive polymers. can.

In such a solid-state dye-sensitized solar cell, since leakage current is generated when light is converted into electricity, various proposals have been made for countermeasures against it. For example, a transparent conductive film as a first electrode, a porous semiconductor layer as an electron transport layer disposed on the transparent conductive film and emitting electrons upon receiving light, and titanium oxide formed on the porous semiconductor layer a photoelectrode comprising a film and a dye layer formed on the titanium oxide film; a solid hole transport layer provided adjacent to the photoelectrode; and a counter electrode as a second electrode. is proposed, and by forming a titanium oxide film on the electron transport layer, it is possible to suppress the occurrence of leakage current that may occur between the electron transport layer and the hole transport layer, and prevent the output from decreasing. there is Furthermore, in order to further reduce leakage current, it has been proposed to provide a dense layer of titanium oxide between the transparent conductive film and the electron transport layer using a solution containing a titanium compound (see, for example, Patent Document 1). .

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoelectric conversion element capable of suppressing a decrease in output with low-illuminance light before and after being exposed to high-illuminance light.

A photoelectric conversion element of the present invention as a means for solving the problems has a first electrode, an electron transport layer, a hole transport layer, and a second electrode, wherein the hole transport layer and the second When the average thickness of the hole transport layer is X (nm), in the hole transport layer, from the surface opposite to the surface in contact with the second electrode, X + 50 (nm) When Rc(50) is the ratio of the area occupied by the projecting portion projecting toward the second electrode from the distant reference line, the following formula is 0%<Rc(50)≦0.75%. , satisfies.

ADVANTAGE OF THE INVENTION According to this invention, the photoelectric conversion element which can suppress the output fall by low illuminance light before and behind being exposed to high illuminance light can be provided.

FIG. 1 is a schematic diagram showing an example of the photoelectric conversion element of the present invention. FIG. 2 is an enlarged schematic diagram showing an example of the interface between the second electrode, the hole transport layer, and the electron transport layer in a conventional photoelectric conversion element. FIG. 3 is an enlarged schematic diagram showing an example of the interface between the second electrode, the hole transport layer and the electron transport layer in the photoelectric conversion device of the present invention. FIG. 4 is a schematic diagram showing another example of the photoelectric conversion element of the present invention. FIG. 5 is a schematic diagram showing another example of the photoelectric conversion element of the present invention. FIG. 6 is a schematic diagram showing another example of the photoelectric conversion element of the present invention. FIG. 7 is a schematic diagram showing an example of the photoelectric conversion element module of the present invention. FIG. 8 is a schematic diagram showing another example of the photoelectric conversion element module of the present invention. FIG. 9 is a schematic diagram showing another example of the photoelectric conversion element module of the present invention. FIG. 10 is a block diagram of a personal computer mouse as an example of the electronic device of the present invention. 11 is a schematic external view showing an example of the mouse shown in FIG. 10. FIG. FIG. 12 is a block diagram of a personal computer keyboard as an example of the electronic device of the present invention. 13 is a schematic external view showing an example of the keyboard shown in FIG. 12. FIG. 14 is a schematic external view showing another example of the keyboard shown in FIG. 12. FIG. FIG. 15 is a block diagram of a sensor as an example of the electronic device of the invention. FIG. 16 is a block diagram of a turntable as an example of the electronic device of the invention. FIG. 17 is a block diagram showing an example of the electronic device of the invention. 18 is a block diagram showing an example in which a power supply IC is further incorporated into the electronic equipment shown in FIG. 17. FIG. FIG. 19 is a block diagram showing an example in which the electronic device shown in FIG. 18 further incorporates a power storage device. FIG. 20 is a block diagram showing an example of the power supply module of the present invention. 21 is a block diagram showing an example in which a power storage device is further incorporated into the power supply module shown in FIG. 20. FIG.

(Photoelectric conversion element)
A photoelectric conversion device of the present invention has a first electrode, an electron transport layer, a hole transport layer, and a second electrode, and the hole transport layer and the second electrode are in contact with each other. Further, when the average thickness of the hole transport layer is X (nm), the surface of the hole transport layer opposite to the surface in contact with the second electrode is measured from the reference line located at a distance of X + 50 (nm). 0%<Rc(50)≦0.75%, where Rc(50) is the ratio of the area occupied by the projecting portion projecting toward the second electrode side. Fulfill.

In the photoelectric conversion element of the present invention, when a conventional photoelectric conversion element is exposed to light of high illuminance for a while and then to light of low illuminance, a large leakage current occurs between the electron transport layer and the hole transport layer. This is based on the knowledge that there is a problem that the photoelectric conversion efficiency deteriorates.
The present inventors paid attention to the structures of the hole transport layer and the counter electrode, and instead of reducing the roughness of the surface of the hole transport layer adjacent to the counter electrode, the surface roughness of the hole transport layer was increased to a predetermined height or more. It was found that the problem can be solved by reducing the area occupied by the protrusions. That is, in the photoelectric conversion device of the present invention, by reducing the area occupied by the protrusions having a predetermined height or more on the surface of the hole transport layer, the photoelectric conversion device can be exposed to a high-illuminance environment for a certain period of time and then irradiated with low-illuminance light. can maintain a high output with little leakage current. The reason why such an effect is obtained is presumed as follows.

FIG. 1 is a schematic diagram showing an example of the photoelectric conversion element of the present invention.
As shown in FIG. 1, a photoelectric conversion element 101 has a first electrode 2 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 forming the electron transport layer 4 . A hole transport layer 6 is formed on and inside the electron transport layer 4 , and a second electrode 7 is formed on the hole transport layer 6 . A second substrate 9 is arranged above the second electrode 7 , and the second substrate 9 is fixed between the first electrode 2 and the sealing member 8 .

FIG. 2 shows an enlarged schematic diagram of the electron transport layer 4, the hole transport layer 6, and the second electrode 7 in the conventional photoelectric conversion device.
As shown in FIG. 2, when the average thickness of the hole transport layer 6 is X (nm) (a dashed dotted line in FIG. 2), the surface of the hole transport layer 6 opposite to the surface in contact with the second electrode 7 , a reference line (broken line in FIG. 2) located at a distance of X+50 (nm) is drawn. In the hole transport layer 6, the ratio of the area occupied by the protruding portion protruding toward the second electrode 7 from the reference line (the area when the portion indicated by A in FIG. 2 is viewed in plan) was defined as Rc(50). When Rc(50) is high, leakage current is likely to occur. This is because when the height of the protrusions on the surface of the hole transport layer 6 is sufficiently high with respect to the average thickness of the second electrode 7 , the layer of the second electrode 7 directly above the protrusions of the hole transport layer 6 Since the thickness is reduced and the resistance is locally reduced, current is relatively concentrated at the interface between the hole transport layer 6 and the second electrode 7 during light irradiation, and it is considered to be a leak point.

FIG. 3 is an enlarged schematic diagram showing an example of the interface between the second electrode, the hole transport layer and the electron transport layer in the photoelectric conversion device of the present invention.
As shown in FIG. 3, when the area occupied by the protrusions on the surface of the hole transport layer 6 is small, there is relatively no place where current concentrates, so the occurrence of leak current can be suppressed.

The range of Rc(50) satisfies the following formula: 0.00%<Rc(50)≦0.75%, preferably 0.00%<Rc(50)≦0.50%. If Rc(50) is greater than 0.75%, current leakage becomes non-negligible and durability at high illuminance decreases. In addition, when Rc(50) is within the preferable range, it is possible to further suppress a decrease in output under low-illuminance light before and after exposure to high-illuminance light.
Leakage of current originating from such protrusions is inconspicuous in measurement under high illuminance, but becomes particularly noticeable when evaluated under low illuminance, resulting in a decrease in output.
One of the grounds for the above assumption is that the average thickness of the second electrode affects the leakage current amount.
Therefore, it is desirable that the number of protruding portions of the hole transport layer having a height of 1/2 or more with respect to the average thickness of the second electrode is small. However, in the solid dye-sensitized solar cell, since a solid hole transport layer is applied on the porous metal oxide semiconductor, the projecting portion does not become zero unlike the liquid type. The porous metal oxide semiconductor is made porous from the viewpoints of securing a surface area to which the dye adheres and securing the impregnation property of the hole transport layer to be coated, and the surface thereof is roughened to some extent. As the roughness increases, the height and area of the protruding portion of the adjacent hole transport layer also increase.

Leakage current is conspicuous when the average thickness of the second electrode is small with respect to the height of the protrusions on the surface of the hole transport layer. Therefore, the lower limit of the average thickness of the second electrode is preferably 25 nm or more, more preferably 50 nm or more. On the other hand, from the viewpoint of material cost, the second electrode is preferably thinner, so the upper limit of the average thickness of the second electrode is preferably 300 nm or less, more preferably 200 nm or less.

<Method for measuring layer thickness (average thickness)>
A method for measuring the layer thickness of the hole transport layer and the second electrode is not particularly limited, and conventionally known methods can be used. be done. Specifically, when measuring the layer thickness of the hole transport layer 6 of the photoelectric conversion element shown in FIG. A portion of the electron transport layer 4 may be exposed to measure the difference in level. The layer thickness of layer 4 may be measured. In the former case, as a method of partially exposing the electron transport layer 4, for example, a method of dripping a solvent that dissolves the hole transport layer 6 such as tetrahydrofuran can be used. Furthermore, after adjusting the field of view so that the hole transport layer 6 and the lower electron transport layer 4 are included in the same photographed image, for example, photographing can be performed under the following measurement conditions. Then, the average thickness X in the hole transport layer 6 can be calculated by the average step analysis.

[Layer thickness measurement conditions]
Measurement mode: WAVE mode Objective lens magnification: 2.5 times Wavelength filter: 530 nm White
Observation area: 1,900 μm×1,400 μm
Number of pixels: 640 pix x 480 pix

<How to find Rc(50)>
Rc(50) can be obtained, for example, as follows.
The surface shape of the hole transport layer is observed in plan using a white interference microscope (VS1500, manufactured by Hitachi High-Tech Science Co., Ltd.) under the following measurement conditions. Next, by particle analysis, the total cross-sectional area of protrusions having a height of X+50 (nm) or more is calculated from the surface of the hole transport layer 6 opposite to the surface in contact with the second electrode 7 . Rc(50) can be obtained by dividing this by the area of the observation region and, for example, calculating the average value of the three fields of view.

[Measurement conditions for Rc (50)]
Measurement mode: WAVE mode Objective lens magnification: 10x Wavelength filter: 530nm White
Observation area: 470 nm x 350 nm
Number of pixels: 640 pix x 480 pix

<Photoelectric conversion element>
A photoelectric conversion element refers to an element that can convert light energy into electric energy, and is applied to solar cells, photodiodes, and the like. The photoelectric conversion element and photoelectric conversion element module of the present invention have high power generation performance not only with sunlight but also with light from indoor lighting fixtures such as LEDs and fluorescent lamps.
This photoelectric conversion device has a first electrode, an electron transport layer, a hole transport layer, a second electrode, and, if necessary, other members.

<<first electrode>>
The shape and size of the first electrode are not particularly limited, and can be appropriately selected according to the purpose.
The structure of the first electrode is not particularly limited and can be appropriately selected according to the purpose.

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 according to the purpose. Examples include transparent conductive metal oxides, carbon, A metal etc. are mentioned.

Examples of transparent conductive metal oxides 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, and the like.
Examples of carbon include carbon black, carbon nanotubes, graphene, and fullerene.
Examples of metals include gold, silver, aluminum, nickel, indium, tantalum, and titanium.
These may be used individually by 1 type, and may use 2 or more types together. Among these, 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 according to the purpose. Note that when the material of the first electrode is carbon or metal, the average thickness of the first electrode is preferably an average thickness that can provide translucency.

The first electrode can be formed by known methods such as sputtering, vapor deposition, and spraying.

Moreover, 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 can be used.
Commercially integrated products include, for example, FTO-coated glass, ITO-coated glass, zinc oxide:aluminum-coated glass, FTO-coated transparent plastic film, and ITO-coated transparent plastic film. Other integrated commercial products include, for example, transparent electrodes obtained by doping tin oxide or indium oxide with cations or anions having different valences, or metals with a structure that allows light to pass through, such as in a mesh or stripe shape. Examples include a glass substrate provided with electrodes.
These may be used singly, or two or more of them may be mixed or laminated together. Also, a metal lead wire or the like may be used together for the purpose of lowering the electrical resistance value.

Examples of materials for the metal lead wire include aluminum, copper, silver, gold, platinum, and nickel.
A metal lead wire can be used together by forming it on a substrate by, for example, vapor deposition, sputtering, pressure bonding, etc., and providing a layer of ITO or FTO thereon.

<<Electron transport layer>>
The electron transport layer is formed for the purpose of transporting electrons generated by the photosensitizing compound to the first electrode or hole blocking layer. For this reason, the electron transport layer is preferably positioned adjacent to the first electrode or hole blocking layer.
The structure of the electron transport layer may be a continuous monolayer or a multi-layer structure in which a plurality of layers are laminated.

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

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

The semiconductor material is not particularly limited, and known materials can be used. Examples thereof include single semiconductors, compound semiconductors, compounds having a perovskite structure, and the like.
Examples of single semiconductors include silicon and germanium.
Examples of compound semiconductors include metal chalcogenides, specifically oxides such as titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; sulfides such as cadmium, zinc, lead, silver, antimony and bismuth; selenides such as cadmium and lead; tellurides such as cadmium; Other compound semiconductors include phosphides such as zinc, gallium, indium and cadmium, gallium arsenide, copper-indium-selenide and copper-indium-sulfide.
Examples of compounds having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
Among these, oxide semiconductors are preferred, and titanium oxide, zinc oxide, tin oxide and niobium oxide are more preferred.
These may be used individually by 1 type, and may use 2 or more types together. 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 number average particle diameter of the primary particles of the semiconductor material is not particularly limited and can be appropriately selected according to the purpose. Also, a semiconductor material having a particle size larger than the number average particle size may be mixed or stacked, and the conversion efficiency may be improved by 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 intended purpose. When the average thickness of the electron transport layer is within the preferable range, the amount of the photosensitizing compound per unit projected area can be sufficiently secured, the light capture rate can be maintained high, and the diffusion distance of the injected electrons also increases. This is advantageous in that the loss due to recombination of electric charges can be reduced.

The method for producing the electron transport layer is not particularly limited and can be appropriately selected according to the intended purpose. Among these, a wet film-forming method is preferable from the viewpoint of manufacturing cost. A top coating method is more preferred.
The wet film-forming method is not particularly limited and can be appropriately selected depending on the intended purpose. etc.
As the wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used.

Examples of a method for producing a dispersion liquid of a semiconductor material include a method of mechanical pulverization using a known milling device or the like. According to this method, a semiconductor material dispersion 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 resins include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, Examples include cellulose ester resins, cellulose ether resins, urethane resins, phenol resins, epoxy resins, polycarbonate resins, polyarylate resins, polyamide resins, and polyimide resins. These may be used individually by 1 type, and may use 2 or more types together.

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

An acid, a surfactant, a chelating agent, or the like may be added to a dispersion containing a semiconductor material or a paste containing a semiconductor material obtained by a sol-gel method or the like in order to prevent reaggregation of particles.
Acids include, for example, hydrochloric acid, nitric acid, and acetic acid.
Examples of surfactants include polyoxyethylene octylphenyl ether.
Chelating agents include, for example, acetylacetone, 2-aminoethanol, ethylenediamine and the like.
Addition of a thickener is also an effective means for the purpose of improving the film formability.
Examples of thickeners include polyethylene glycol, polyvinyl alcohol and ethyl cellulose.

After the semiconductor material is applied, the particles of the semiconductor material are brought into electronic contact, and in order to improve the film strength and adhesion to the substrate, it is baked, irradiated with microwaves or electron beams, or irradiated with laser light. Can be irradiated. These treatments may be performed singly or in combination of two or more.

When firing an electron transport layer formed of a semiconductor material, the firing temperature is not particularly limited and can be appropriately selected according to the purpose. , and melting, the temperature is preferably 30° C. or higher and 700° C. or lower, more preferably 100° C. or higher and 600° C. or lower. 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 made of a 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 from the side on which the electron transport layer is not formed.

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

<<photosensitizing compound>>
The photosensitizing compound is adsorbed on the surface of the semiconductor material forming the electron transport layer in order to further improve the output and photoelectric conversion efficiency.
The photosensitizing compound is not particularly limited as long as it is a compound that is photoexcited by light irradiated to the photoelectric conversion element, and can be appropriately selected depending on the purpose. Examples include the following known compounds. . Specific examples include metal complex compounds, coumarin compounds, polyene compounds, indoline compounds, thiophene compounds, cyanine dyes, merocyanine dyes, 9-arylxanthene compounds, triarylmethane compounds, phthalocyanine compounds, porphyrin compounds, and the like.
Among these, metal complex compounds, coumarin compounds, polyene compounds, indoline compounds, and thiophene compounds are preferable, and are represented by the following structural formulas (1), (2), and (3) manufactured by Mitsubishi Paper Mills. and more preferably compounds containing the following general formula (3). These photosensitizing compounds may be used alone, or two or more of them may be used in combination.

（式中、Ｘ_１、Ｘ_２は酸素原子、硫黄原子、セレン原子を表す。Ｒ_１は置換基を有していてもよいメチン基を表す。その置換基の具体例としては、フェニル基、ナフチル基などのアリール基、チエニル基、フリル基などのヘテロ環が挙げられる。Ｒ_２は置換基を有していてもよいアルキル基、アリール基、ヘテロ環基を表す。アルキル基としては、メチル基、エチル基、２－プロピル基、２－エチルヘキシル基等、アリール基及びヘテロ環基としては前述のものが挙げられる。Ｒ_３はカルボン酸、スルホン酸、ホスホン酸、ボロン酸、フェノール類などの酸性基を表す。Ｚ１、Ｚ２は環状構造を形成する置換基を表し、Ｚ１は、ベンゼン環、ナフタレン環などの縮合炭化水素系化合物、チオフェン環、フラン環などのヘテロ環が挙げられ、それぞれ置換基を有していてもよい。その置換基の具体例としては前述のアルキル基、メトキシ基、エトキシ基、２－イソプロポキシ基等のアルコキシ基が挙げられる。Ｚ２はそれぞれ下記に示す（Ａ－１）～（Ａ－２２）が挙げられる。）

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

Specific examples of the photosensitizing compound containing general formula (3) include (B-1) to (B-28) shown below. However, it is not limited to these.

As a method for adsorbing the photosensitizing compound on the surface of the semiconductor material of the electron transporting layer, the electron transporting layer containing the semiconductor material is immersed in a photosensitizing compound solution or a photosensitizing compound dispersion. method, a solution of a photosensitizing compound, or a method of applying a dispersion of a photosensitizing compound to the electron-transporting layer for adsorption. In the case of the method of immersing the electron transport layer formed with the semiconductor material in the solution of the photosensitizing compound or the dispersion of the photosensitizing compound, an immersion method, a dipping method, a roller method, an air knife method, or the like can be used. can be done. In the case of the method of applying a solution of a photosensitizing compound or a dispersion of a photosensitizing compound to the electron transport layer and adsorbing it, the wire bar method, the slide hopper method, the extrusion method, the curtain method, the spin method, and the spray method. method, etc. can be used. Adsorption in a supercritical fluid using carbon dioxide or the like is also possible.

A condensing agent may be used in combination when the photosensitizing compound is adsorbed on the semiconductor material.
The condensing agent may be one that has a catalytic action such as physically or chemically binding the photosensitizing compound to the surface of the semiconductor material, or one that has a stoichiometric action and favorably shifts the chemical equilibrium. Either can be used. Furthermore, a thiol, a hydroxy compound, or the like may be added as a condensation aid.

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

Since some photosensitizing compounds work more effectively by suppressing aggregation between compounds depending on the type thereof, an aggregation-dissociating agent may be used in combination.
The disaggregating agent is not particularly limited and can be appropriately selected depending on the dye used, but steroid compounds such as cholic acid and chenodeoxycholic acid, long-chain alkylcarboxylic acids, and long-chain alkylphosphonic acids are preferred.
The content of the aggregation dissociation agent is preferably 0.01 parts by mass or more and 500 parts by mass or less, more preferably 0.1 parts by mass or more and 100 parts by mass or less with respect to 1 part by mass of the photosensitizing compound.

The temperature for adsorbing the photosensitizing compound or the photosensitizing compound and the aggregation dissociation agent on the surface of the semiconductor material constituting the electron transport layer is preferably -50°C or higher and 200°C or lower. The adsorption time is preferably from 5 seconds to 1,000 hours, more preferably from 10 seconds to 500 hours, and even more preferably from 1 minute to 150 hours. The adsorption step is preferably performed in a dark place. Moreover, the step of adsorbing may be carried out while standing still, or may be carried out while stirring.
The stirring method is not particularly limited and can be appropriately selected depending on the intended purpose. be done.

<<Hole transport layer>>
For the hole transport layer, known materials can be used as long as they have a function of transporting holes. are impregnated in a polymer matrix, molten salts containing redox couples, solid electrolytes, inorganic hole transport materials, organic hole transport materials, and the like. Among these, electrolytic solutions and gel electrolytes can be used, but solid electrolytes are preferred, and organic hole transport materials are more preferred.

The hole transport layer contains a basic compound represented by the following general formula (1) or general formula (2).

（式中、Ｒ_１、Ｒ_２は、それぞれ独立に、アルキル基または芳香族炭化水素基を表し、同一または異なる基を表すか、若しくは、Ｒ_１、Ｒ_２は互いに結合し、窒素原子を含む複素環基を表す。）

(wherein 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.)

（式中、Ｒ_１、Ｒ_２は、それぞれ独立に、アルキル基または芳香族炭化水素基を表し、同一または異なる基を表すか、若しくは、Ｒ_１、Ｒ_２は互いに結合し、窒素原子を含む複素環基を表す。）

(wherein 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.)

The hole transport layer preferably contains a basic compound represented by general formula (1) or general formula (2). When the hole transport layer contains the basic compound represented by the general formula (1) or (2), it is advantageous in enhancing the output stability of the photoelectric conversion device. In particular, it is advantageous in that it is possible to reduce variations in output characteristics for low-illuminance light and stably generate power.
Specific exemplary compounds of the basic compound represented by general formula (1) or general formula (2) are shown below, but the present invention is not limited thereto.

The content of the basic compound represented by general formula (1) or general formula (2) in the hole transport layer is preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the hole transport material. , more preferably 10 parts by mass or more and 30 parts by mass or less. When the content of the basic compound is within the preferred range, a high open-circuit voltage can be maintained, a high output can be obtained, and high stability and durability can be obtained even after long-term use in various environments.

The hole transport layer contains a hole transport material or a p-type semiconductor material in order to obtain the function of transporting holes. A known organic hole-transporting compound is used as the hole-transporting material or the p-type semiconductor material. Specific examples thereof include oxadiazole compounds, triphenylmethane compounds, pyrazoline compounds, hydrazone compounds, oxadiazole compounds, tetraarylbenzidine compounds, stilbene compounds, and spiro-type compounds. Among these, spiro-type compounds are more preferable.
As the spiro-type compound, a compound containing the following general formula (4) is preferable.

（式中、Ｒ_９～Ｒ_１２は、ジメチルアミノ基、ジフェニルアミノ基、ナフチル－４－トリルアミノ基等の置換アミノ基を表す。）

(In the formula, R ₉ to R ₁₂ represent substituted amino groups such as dimethylamino group, diphenylamino group and naphthyl-4-tolylamino group.)

Specific examples of spiro-type compounds include (D-1) to (D-20) shown below. However, it is not limited to these.

In addition to having high hole mobility, these spiro-type compounds form a nearly spherical electron cloud due to the twisted bonding of two benzidine skeleton molecules, and intermolecular hopping conductivity. A good photoelectric conversion characteristic is exhibited. In addition, since it is highly soluble, it dissolves in various organic solvents, and since it is an amorphous substance (amorphous substance having no crystal structure), it tends to be densely packed in the porous electron transport layer. Furthermore, since it does not have a light absorption property at a wavelength of 450 nm or longer, the photosensitizing compound can efficiently absorb light, which is particularly preferable for solid dye-sensitized solar cells.

It is preferable to add an oxidizing agent to the hole transport layer in addition to the hole transport material and the basic compound. By containing an oxidizing agent, the electrical conductivity is improved, and the durability and stability of the output characteristics can be enhanced.

Examples of the oxidizing agent include tris(4-bromophenyl)aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluoroborate, silver nitrate, and metal complexes. Among these, metal complexes are more preferable. . When the oxidizing agent is a metal complex, it is advantageous in that it can be added in large amounts due to its high solubility in organic solvents.

Metal complexes consist of metal cations, ligands and anions.
Examples of metal cations include cations such as chromium, manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium, osmium, iridium, gold, and platinum. Among them, cations of cobalt, iron, nickel, and copper are preferred, and cobalt complexes are more preferred. The ligand is preferably one containing at least one nitrogen-containing 5- and/or 6-membered heterocyclic ring, and may have a substituent. Specific examples include, but are not limited to, the following.

Examples of anions include hydride ion (H ⁻ ), fluoride ion (F ⁻ ), chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), iodide ion (I ⁻ ), hydroxide ion ( OH ⁻ ), cyanide ion (CN ⁻ ), nitrate ion (NO ₃ ⁻ ), nitrite ion (NO ₂ ⁻ ), hypochlorite ion (ClO ⁻ ), chlorite ion (ClO ₂ ⁻ ), chlorine acid ion (ClO ₃ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), permanganate ion (MnO ₄ ⁻ ), acetate ion (CH ₃ COO ⁻ ), hydrogen carbonate ion (HCO ₃ ⁻ ), dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ), hydrogen sulfate ion (HSO ₄ ⁻ ), hydrogen sulfide ion (HS ⁻ ), thiocyanate ion (SCN ⁻ ), tetrafluoroborate ion (BF ₄ ⁻ ), hexafluorophosphate ion (PF ₆ ⁻ ), tetracyanoborate ion (B(CN) ₄ ⁻ ), dicyanoamine ion (N(CN) ₂ ⁻ ), p-toluenesulfonate ion (TsO ⁻ ), trifluoromethylsulfonate ion (CF ₃ SO ₂ ⁻ ), bis(trifluoromethylsulfonyl)amine ion (N(SO ₂ CF ₃ ) ²⁻ ) tetrahydroxoaluminate ion ([Al(OH) ₄ ] ⁻ , or [Al(OH) ₄ (H ₂ O) ₂ ] ⁻ ), dicyanoargentate ion ([Ag(CN) ₂ ] ⁻ ), tetrahydroxochromate (III) ion ([Cr(OH) ₄ ] ⁻ ), tetrachlorogold (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) ion ([Zn(OH) ₄ ] ^2- ), tetracyanozinc(II) ion ([Zn(CN) ₄ ] ^2- ), tetrachlorocuprate ion ([CuCl ₄ ] ^2- ), phosphate ion (PO ₄ ^3- ), hexacyana ferrate (III) ([Fe(CN) ₆ ] ^3- ), bis(thiosulfato)argentate (I) ([Ag(S ₂ O ₃ ) ₂ ] ^3- ), hexacyanoferrate (II) acid ions ([Fe(CN) ₆ ] ^4- ) and the like. Among these, tetrafluoroboronate ion, hexafluorophosphate ion, tetracyanoborate ion, bis(trifluoromethylsulfonyl)amine ion, and perchlorate ion are preferred.
Among these metal complexes, cobalt complexes represented by the following structural formulas (4) and (5) are particularly preferred. When the metal complex is a cobalt complex, it is advantageous in that it is possible to further suppress the decrease in output with low-illuminance light before and after exposure to high-illuminance light.

These may be used individually by 1 type, and may use 2 or more types together.

The content of the oxidizing agent is preferably 0.5 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the hole transport material. The addition of the oxidizing agent does not necessarily oxidize all of the hole-transporting material, and it is effective if only a portion of the material is oxidized.

Moreover, the hole transport layer preferably further contains an alkali metal salt. When the hole transport layer contains an alkali metal salt, the output can be improved, and the light irradiation resistance and high-temperature storage resistance can be improved.
Alkali metal salts include, for example, lithium chloride, lithium bromide, lithium iodide, lithium perchlorate, lithium bis(trifluoromethanesulfonyl)diimide, lithium diisopropylimide, lithium acetate, lithium tetrafluoroborate, pentafluorophosphate Lithium, lithium salts such as lithium tetracyanoborate, sodium chloride, sodium bromide, sodium iodide, sodium perchlorate, sodium bis(trifluoromethanesulfonyl)diimide, sodium acetate, sodium tetrafluoroborate, pentafluorophosphate Examples include sodium salts such as sodium and sodium tetracyanoboronate, and potassium salts such as potassium chloride, potassium bromide, potassium iodide and potassium perchlorate. Among these, lithium bis(trifluoromethanesulfonyl)diimide and lithium diisopropylimide are preferred.

The content of the alkali metal salt is preferably 1 part 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, relative to 100 parts by mass of the hole transport material.

The hole transport layer may have a single layer structure made of a single material, or may have a laminated structure 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. The use of a polymeric material having 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 hardly permeates into the porous electron transport layer, the coverage of the surface of the porous electron transport layer is excellent, and it is effective in preventing short circuits when electrodes are provided. There is

Polymer materials used for the hole transport layer include known hole transport polymer materials.
Examples of hole-transporting polymer materials include polythiophene compounds, polyphenylene vinylene compounds, polyfluorene compounds, polyphenylene compounds, polyarylamine compounds, polythiadiazole compounds, and the like.
Examples of polythiophene compounds include poly(3-n-hexylthiophene), poly(3-n-octyloxythiophene), poly(9,9'-dioctyl-fluorene-co-bithiophene), poly(3,3'''-didodecyl-quaterthiophene), poly(3,6-dioctylthieno[3,2-b]thiophene), poly(2,5-bis(3-decylthiophen-2-yl)thieno[3,2- b]thiophene), poly(3,4-didecylthiophene-co-thieno[3,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thieno[3 ,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-bithiophene) ) and the like.
Examples of polyphenylene vinylene compounds 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)], and the like. .
Examples of polyfluorene compounds 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 polyphenylene compounds include poly[2,5-dioctyloxy-1,4-phenylene] and poly[2,5-di(2-ethylhexyloxy-1,4-phenylene].
Examples of polyarylamine compounds include poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N'-diphenyl)-N,N'-di(p- hexylphenyl)-1,4-diaminobenzene], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N'-bis(4-octyloxyphenyl)benzidine -N,N'-(1,4-diphenylene)], poly[(N,N'-bis(4-octyloxyphenyl)benzidine-N,N'-(1,4-diphenylene)], poly[( N,N'-bis(4-(2-ethylhexyloxy)phenyl)benzidine-N,N'-(1,4-diphenylene)], poly[phenylimino-1,4-phenylenevinylene-2,5-dioctyl oxy-1,4-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 polythiadiazole compounds include poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo(2,1′,3)thiadiazole], poly( 3,4-didecylthiophene-co-(1,4-benzo(2,1′,3)thiadiazole) and the like.
Among these, polythiophene compounds and polyarylamine compounds are preferred from the viewpoint of carrier mobility and ionization potential.

The average thickness of the hole-transporting layer is not particularly limited and can be appropriately selected according to the purpose. 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 still more preferably 0.2 μm or more and 2 μm or less.

The hole-transporting layer can be formed directly on the electron-transporting layer with the photosensitizing compound adsorbed thereon. The method for producing the hole transport layer is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include a method of forming a thin film in a vacuum such as vacuum deposition, a wet film forming method, and the like. Among these, the wet film-forming method is particularly preferable from the viewpoint of manufacturing cost, and the method of coating on the electron-transporting layer is preferable.
When a wet film-forming method is used, the coating method is not particularly limited and can be performed according to a known method. In order to reduce the size, a conventionally known blade coating method, die coating method, gravure coating method, or the like, which enables smooth coating regardless of the unevenness of the substrate, is preferable.

Alternatively, the film may be formed in a supercritical fluid or a subcritical fluid at a temperature and pressure lower than the critical point. A supercritical fluid exists as a non-aggregating high-density fluid in a temperature and pressure range that exceeds the limit (critical point) at which gas and liquid can coexist. There is no particular limitation as long as the fluid is in the state of, and it can be appropriately selected according to the purpose, but a fluid with a low critical temperature is preferable.

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

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

Furthermore, in addition to supercritical fluids and subcritical fluids, organic solvents and entrainers can also be used in combination. Addition of an organic solvent and an entrainer makes it easier to adjust the solubility in the supercritical fluid.
The organic solvent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.
Ketone solvents include, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
Ester solvents include, for example, ethyl formate, ethyl acetate, n-butyl acetate and the like.
Ether solvents include, for example, diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane and the like.
Amide solvents include, for example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and the like.
Halogenated hydrocarbon solvents include, for example, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, 1-chloronaphthalene and the like. .
Examples of hydrocarbon solvents include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, Examples include ethylbenzene and cumene.
These may be used individually by 1 type, and may use 2 or more types together.

Moreover, after laminating a hole-transporting material on the electron-transporting layer on which the photosensitizing compound is adsorbed, a pressing process may be performed. By applying the press treatment, the hole-transporting material is brought into close contact with the electron-transporting layer, which is a porous electrode, so that the efficiency can be improved in some cases.
The method of press treatment is not particularly limited, and can be appropriately selected according to the purpose. Examples include a press molding method using a flat plate as typified by an IR tablet molding machine, a roll press method using rollers, and the like. can be mentioned.
The pressure is preferably 10 kgf/cm ² or higher, more preferably 30 kgf/cm ² or higher.
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. Also, heat may be applied during the press treatment. During the press treatment, a release agent may be interposed between the press and the electrode.

Release agents include, for example, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer, perfluoroalkoxy fluororesin, polyvinylidene fluoride, and ethylene tetrafluoroethylene copolymer. , ethylene chlorotrifluoride ethylene copolymer, and fluororesin such as polyvinyl fluoride. These may be used individually by 1 type, and may use 2 or more types together.

After performing the pressing step and before providing the second electrode, a metal oxide may be provided between the hole transport material and the second electrode.
Examples of metal oxides include molybdenum oxide, tungsten oxide, vanadium oxide, and nickel oxide. These may be used individually by 1 type, and may use 2 or more types together. 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 appropriately selected according to the purpose. Examples include a method of forming a thin film in vacuum such as sputtering and vacuum deposition, a wet film forming method, and the like. is mentioned.

As a wet film-forming method, a method of preparing a paste in which metal oxide powder or sol is dispersed and applying the paste onto the hole transport layer is preferable. The coating method in the case of using a wet film-forming method is not particularly limited, and can be carried out according to known methods such as dipping, spraying, wire bar method, spin coating, roller coating, blade coating, etc. Various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used as coating methods, gravure coating methods, and wet printing methods.
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>>
A second electrode can be formed on the hole transport layer or on the metal oxide in the hole transport layer. Also, the second electrode can be the same as the first electrode, and the support is not necessarily required if the strength is sufficiently maintained.
Examples of materials for the second electrode include metals, carbon compounds, conductive metal oxides, and conductive polymers.
Examples of metals include platinum, gold, silver, copper, and aluminum.
Carbon compounds include, for example, graphite, fullerene, carbon nanotubes, and graphene.
Examples of conductive metal oxides include ITO, FTO, and ATO.
Examples of conductive polymers include polythiophene and polyaniline.
These may be used individually by 1 type, and may use 2 or more types together.

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

<Other parts>
Other members are not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include a hole blocking layer, first substrate, second substrate and sealing member.

<<Hole blocking layer>>
A hole blocking layer may be formed between the first electrode and the electron transport layer. The hole-blocking layer is formed with a photosensitizing compound and transports electrons transported to the electron-transporting layer to the first electrode and prevents contact with the hole-transporting layer. As a result, the hole blocking layer makes it difficult for holes to flow into the first electrode, and can suppress a decrease in output due to recombination of electrons and holes. Solid-type photoelectric conversion elements with a hole-transporting layer have a faster recombination rate of holes in the hole-transporting material and electrons on the electrode surface than wet-type photoelectric conversion elements that use an electrolytic solution. effect 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 according to the purpose. Examples include silicon, germanium, and the like. Single semiconductors, compound semiconductors represented by metal chalcogenides, and compounds having a perovskite structure can be used.
Metal chalcogenides include, for example, oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; cadmium, zinc, lead, silver, and antimony. , sulfide of bismuth; selenide of cadmium and lead; telluride of cadmium. Other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium; gallium arsenide, copper-indium-selenide, and copper-indium-sulfide.
Examples of compounds having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
Among these, oxide semiconductors are preferred, titanium oxide, niobium oxide, magnesium oxide, aluminum oxide, zinc oxide, tungsten oxide, tin oxide, and the like are more preferred, and titanium oxide is even more preferred.
These may be used individually by 1 type, and may use 2 or more types together. Moreover, it may be a single layer or a laminate. The crystal type of these semiconductors is not particularly limited and can be appropriately selected according to the purpose, and may be single crystal, polycrystal, or amorphous.

The method for forming the hole blocking layer is not particularly limited and can be appropriately selected depending on the intended purpose. Among them, the sputtering method is preferable. When the method of forming the hole blocking layer is the sputtering method, the film density can be sufficiently increased, and the loss current can be suppressed.

The film thickness of the hole blocking layer is not particularly limited and can be appropriately selected depending on the purpose. 30 nm or less is more preferable.

<<First Substrate>>
The shape, structure, and size of the first substrate are not particularly limited, and can be appropriately selected according to 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. Examples thereof include glass, plastic film, and ceramics. Among these, a substrate having heat resistance to the firing temperature is preferable when the step of firing is included when forming the electron transport layer as described later. Moreover, as the first substrate, one having flexibility is preferable.

<<Second substrate>>
The second substrate is not particularly limited, and known substrates can be used. Examples thereof include substrates such as glass, plastic film, and ceramics. An uneven portion may be formed in the joint portion between the second substrate and the sealing member in order to improve adhesion.
The method for forming the uneven portion is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include sandblasting, waterblasting, abrasive paper, chemical etching, and laser processing.
As means for increasing the adhesion between the second substrate and the sealing member, for example, organic matter on the surface may be removed, or hydrophilicity may be improved. The means for removing the organic substances on the surface of the second substrate is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include UV ozone cleaning and oxygen plasma treatment.

<<sealing member>>
Examples of sealing resins include acrylic resins and epoxy resins.
As the cured acrylic resin, any known material can be used as long as it is a cured monomer or oligomer having an acrylic group in the molecule.
As the cured epoxy resin, any known material can be used as long as it is a cured monomer or oligomer having an epoxy group in the molecule.
Epoxy resins include, for example, water dispersion type, solventless type, solid type, heat curing type, curing agent mixed type, ultraviolet curing type, and the like. Among these, the thermosetting type and the ultraviolet curable type are preferred, and the ultraviolet curable type is more preferred. It should be noted that even if it is an ultraviolet curing type, it is possible to heat, and it is preferable to heat even after ultraviolet curing.

Examples of epoxy resins include bisphenol A type, bisphenol F type, novolac type, cyclic aliphatic type, long chain aliphatic type, glycidylamine type, glycidyl ether type, glycidyl ester type, and the like. These may be used individually by 1 type, and may use 2 or more types together.

The epoxy resin is preferably mixed with a curing agent and various additives as necessary.

Curing agents are classified into amine-based, acid anhydride-based, polyamide-based and other curing agents, and are appropriately selected according to the purpose.
Examples of amine curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone.
Acid anhydride-based curing agents include, for example, phthalic anhydride, tetra- and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, hetic anhydride, and dodecenylsuccinic anhydride. .
Other curing agents include, for example, imidazoles and polymercaptans. These may be used individually by 1 type, and may use 2 or more types together.

Additives include, for example, fillers, gap agents, polymerization initiators, desiccants (hygroscopic agents), curing accelerators, coupling agents, flexible agents, coloring agents, flame retardant aids, and antioxidants. agents, organic solvents, and the like. Among these, fillers, gap agents, curing accelerators, polymerization initiators, and desiccants (hygroscopic agents) are preferred, and fillers and polymerization initiators are more preferred.

In addition to being effective in suppressing the infiltration of moisture and oxygen, fillers reduce volume shrinkage during curing, reduce outgassing during curing or heating, improve mechanical strength, 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 cannot be ignored not only due to the effects of intruding moisture and oxygen, but also due to the effects of outgassing generated during curing or heating of the sealing member. In particular, the influence of outgassing generated during heating has a great influence on the output characteristics in high-temperature environment storage.
In this case, by including a filler, a gap agent, and a desiccant in the sealing member, these themselves can suppress the infiltration of moisture and oxygen. 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 known fillers can be used. For example, inorganic fillers such as crystalline or amorphous silica, talc, alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate System fillers are preferably used. These may be used individually by 1 type, and may use 2 or more types together. The average primary particle size of the filler is preferably 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 preferable range, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, the adhesion to the substrate and the defoaming property are improved, or the width of the sealing portion is improved. It is also effective for the control and workability of
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 with respect to 100 parts by mass of the entire sealing member. When the content of the filler is within the above range, the effect of suppressing penetration of moisture and oxygen is sufficiently obtained, the viscosity becomes appropriate, and the adhesion and workability become good.

A gap agent is also called a gap control agent or a spacer agent, and makes it possible to control the gap of the sealing portion. For example, when a sealing member is provided on the first substrate or the first electrode, and the second substrate is placed thereon for sealing, the gap agent is mixed with the epoxy resin. Since the gap of the sealing portion is uniform in size of the gap agent, the gap of the sealing portion can be easily controlled.
As the gap agent, known materials can be used as long as they are granular, have a uniform particle size, and have high solvent resistance and heat resistance. Those having a high affinity with the epoxy resin and having a spherical particle shape are preferred. Specific examples include glass beads, silica fine particles, organic resin fine particles, and the like. These may be used individually by 1 type, and may use 2 or more types together.
The particle diameter of the gap agent can be selected according to the gap of the sealing portion to be set, but is preferably 1 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less.

A polymerization initiator is a material added for the purpose of initiating polymerization using heat or light.

Thermal polymerization initiators are compounds that generate active species such as radicals and cations by heating. Specifically, azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and benzoyl peroxide (BPO ) and other peroxides are used. A benzenesulfonic acid ester, an alkylsulfonium salt, or the like is used as the thermal cationic polymerization initiator. On the other hand, as the photopolymerization initiator, a photocationic polymerization initiator is preferably used in the case of an epoxy resin. When a cationic photopolymerization initiator is mixed with an epoxy resin and irradiated with light, the cationic photopolymerization initiator decomposes to generate a strong acid, which causes polymerization of the epoxy resin and progresses the curing reaction. A photocationic polymerization initiator has effects such as little volume shrinkage during curing, no oxygen inhibition, and high storage stability.

Examples of photocationic polymerization initiators include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metacelone compounds, and silanol/aluminum complexes.
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, ionic sulfonium salt-based and iodonium salt-based onium salts composed of a cation portion and an anion portion. These may be used individually by 1 type, and may use 2 or more types together.

The amount of the polymerization initiator added may vary depending on the material used, but 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 with respect to 100 parts by mass of the entire sealing member. The following are more preferred. When the addition amount is within the above range, curing proceeds appropriately, the residual uncured material can be reduced, and excessive outgassing can be prevented, which is effective.

A desiccant, also called a hygroscopic agent, is a material that has the function of physically or chemically absorbing and absorbing moisture. It is effective because there are cases where it can be done.
The desiccant is preferably particulate, and examples thereof include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, and zeolite. Among these, zeolites with high moisture absorption are preferred. These may be used individually by 1 type, and may use 2 or more types together.

Curing accelerators, also called curing catalysts, are used for the purpose of increasing the curing speed, and are mainly used for thermosetting epoxy resins.
Examples of curing accelerators include DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5). Primary amines or tertiary amine salts, imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, phosphines and phosphoniums such as triphenylphosphine and tetraphenylphosphonium/tetraphenylborate Examples include salt. These may be used individually by 1 type, and may use 2 or more types together.

The coupling agent has the effect of increasing the molecular bonding force, and includes silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxy Propylmethyldimethoxysilane, 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 individually by 1 type, and may use 2 or more types together.

Furthermore, as the sealing member, an epoxy resin composition commercially available as a sealing material, sealing material, or adhesive is known, and can be effectively used in the present invention as well. Among others, there are epoxy resin compositions developed and marketed for use in solar cells and organic EL devices, which can be used particularly effectively in the present invention. Examples include TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyoritsu Chemical Co., Ltd.), WB90US(P) (manufactured by Moresco), and the like.

A sheet-like sealing material can be used in the present invention.
The sheet sealing material is a sheet on which an epoxy resin layer is formed in advance, and the sheet is made of glass, a film having a high gas barrier property, or the like, and corresponds to the second substrate in the present invention. The sealing member and the second substrate can be formed at once by attaching the sheet-like sealing material to the second substrate and then curing the same. It is also effective to provide a structure having a hollow portion depending on the formation pattern of the epoxy resin layer formed on the sheet.

The method for forming the sealing member is not particularly limited, and can be carried out according to known methods such as dispensing, wire bar, spin coating, roller coating, blade coating, gravure coating, letterpress. , offset, intaglio, rubber plate, screen printing, etc. can be used.
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 is not in contact with the second electrode, and can be appropriately selected depending on the purpose. It is preferably used.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and redundant description may be omitted.

<Structure of element>
Description of FIGS. 1, 2, and 3 is omitted because they are as described above.
Note that the photoelectric conversion element shown in FIG. 1 has a hollow portion between the second electrode 7 and the second substrate 9 . By having the hollow portion, it is possible to control the moisture content and oxygen concentration in the hollow portion, and there is an advantage that the power generation performance and durability thereof can be improved. Moreover, since the second electrode 7 and the second substrate 9 are not in contact with each other, it is possible to prevent peeling and breakage of the second electrode 7 . The oxygen concentration in the hollow portion is not particularly limited and can be freely selected, but is preferably 0% or more and 21% or less, more preferably 0.05% or more and 10% or less, and even more preferably 0.1% or more and 5% or less. . Further, each of the first electrode 2 and the second electrode 7 has a conductive path to an electrode extraction terminal.

FIG. 4 is a schematic diagram showing another example of the photoelectric conversion device of the present invention, in which a hole blocking layer 3 is formed between a first substrate 1 and an electron transport layer 4. As shown in FIG. 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. 4 has a hollow portion between the second electrode 7 and the second substrate 9 as in FIG.

FIG. 5 is a schematic diagram showing another example of the photoelectric conversion element of the present invention, which is an example in which the hollow portion of FIG. 4 is covered with the sealing member 8 without providing the hollow portion of the sealing portion. . For example, it can be formed by applying the sealing member 8 to the entire surface of the second electrode 7 and providing the second substrate 9 thereon, or by using the aforementioned sheet-like sealing material. In this case, the hollow part inside the sealing may be completely eliminated, or a part of the hollow part may be left. By covering almost the entire surface with the sealing member in this way, the second substrate 9 can be prevented from being peeled off or destroyed, and the mechanical strength of the photoelectric conversion element can be increased.

FIG. 6 is a schematic diagram showing another example of the photoelectric conversion element of the present invention, in which a sealing member 8 is adhered to the first substrate 1 and the second substrate 9. As shown in FIG. By adopting such a structure, the adhesiveness of the sealing member 8 to the substrate is increased, and the effect of increasing the mechanical strength of the photoelectric conversion element is obtained. In addition, by increasing the adhesion, it is possible to obtain the effect of further enhancing the sealing effect to prevent the infiltration of moisture and oxygen.

FIG. 7 is a schematic diagram showing an example of a photoelectric conversion element module of the present invention, which is an example of a photoelectric conversion element module including a plurality of photoelectric conversion elements connected in series. In the example of FIG. 7, after forming the hole transport layer 6, the penetrating portion 10 is formed, and then the second electrode 7 is formed. can be electrically connected to the first electrode 2b of the cell. Although not shown in FIG. 7, the first electrode 2a and the second electrode 7b have paths that lead to electrodes of adjacent cells or output terminals.
In the photoelectric conversion element module 102 of FIG. 7, as shown in FIG. 3, the area occupied by the protrusions on the surface of the hole transport layer 6 is small, and relatively there are no places where the current concentrates. can be suppressed. Moreover, the photoelectric conversion element module 102 connects the hole transport layers 6 without connecting the hole blocking layers 3 in at least two adjacent photoelectric conversion elements. As a result, the photoelectric conversion element module 102 is less likely to generate leakage current under high-intensity light, and the photosensitizing compound is less likely to be damaged. can be suppressed. Therefore, the photoelectric conversion element module 102 can have a high power generation output even after being exposed to sunlight, even with the light of indoor lighting fixtures such as LEDs and fluorescent lamps.

The penetrating portion 10 may pass through the first electrode 2 and reach the first substrate 1 , or may stop processing inside the first electrode 2 and reach the first substrate 1 . It doesn't have to be. When the shape of the penetrating portion 10 is a fine hole that penetrates the first electrode 2 and reaches the first substrate 1, if the total opening area of the fine holes becomes too large with respect to the area of the penetrating portion 10, the A decrease in the film cross-sectional area of the electrode 2 of 1 increases the resistance value, which may cause a decrease in the photoelectric conversion efficiency. Therefore, the ratio of the total opening area of the fine holes to the area of the penetrating portion 10 is preferably 5/100 to 60/100.

Examples of the method for forming the penetrating portion 10 include sandblasting, waterblasting, abrasive paper, chemical etching, laser processing, etc. In the present invention, laser processing is preferred. The reason for this is that fine holes can be formed without using sand, etching, resist, or the like, and this enables clean processing with good reproducibility. Another reason why the laser processing method is preferable is that at least one of the hole blocking layer 3, the electron transport layer 4, the hole transport layer 6, and the second electrode 7, and possibly all of them, are used when forming the through portion 10. It is possible to remove by impact peeling by a laser processing method. As a result, there is no need to provide a mask during lamination, and removal and formation of fine through portions 10 can be easily performed at the same time.

FIG. 8 is a schematic diagram showing an example of the photoelectric conversion element module of the present invention. Unlike FIG. 7, the electron-transporting layer 4 is cut from the adjacent photoelectric conversion elements, and each has an independent layer structure. there is As a result, in the photoelectric conversion element module 102 shown in FIG. 8, since the electron transport layers 4 are not extended from each other, electron diffusion is suppressed and leakage current is reduced, so that the light durability is improved. Advantageous.

FIG. 9 is a schematic diagram showing an example of a photoelectric conversion element module of the present invention, which includes a plurality of photoelectric conversion elements connected in series, and a beam-like sealing member provided in the hollow space between the cells. This is an example of a photoelectric conversion element module. As shown in FIG. 4, when a hollow portion is provided between the second electrode 7 and the second substrate 9, peeling and breakage of the second electrode 7 can be prevented, but the mechanical strength of the sealing is lowered. Sometimes. On the other hand, when the space between the second electrode 7 and the second substrate 9 is filled with the sealing member as shown in FIG. I have concerns. Although it is effective to increase the area of the photoelectric conversion element module in order to increase the generated power, the decrease in mechanical strength is inevitable when the module has a hollow portion. In this case, by providing a beam-shaped sealing member as shown in FIG. 9, the second substrate 9 can be prevented from being peeled off or broken, and the mechanical strength of the sealing can be increased.

The photoelectric conversion element and photoelectric conversion element module of the present invention can be applied to a power supply device by combining with a circuit board or the like for controlling the generated current. Devices that use power supply devices include, for example, electronic desk calculators and wristwatches. In addition, the power supply device having the photoelectric conversion element of the present invention can be applied to mobile phones, electronic notebooks, electronic paper, and the like. A power supply device having the photoelectric conversion element of the present invention can also be used as an auxiliary power source for extending the continuous use time of a rechargeable or dry battery type electric appliance.

(Electronics)
An electronic device of the present invention includes the photoelectric conversion element and/or photoelectric conversion element module of the present invention, and a device that operates on electric power generated by photoelectric conversion of the photoelectric conversion element and/or photoelectric conversion element module. and other equipment as required.

(power supply module)
A power supply module of the present invention includes the photoelectric conversion element and/or photoelectric conversion element module of the present invention, a power supply IC (Integrated Circuit), and, if necessary, other devices.

Next, a specific embodiment of an electronic device having a photoelectric conversion element and a photoelectric conversion element module of the present invention, and a device that operates on the electric power obtained by the generation thereof will be described.

FIG. 10 is a block diagram of a personal computer mouse as an example of the electronic device of the present invention.
As shown in FIG. 10, a photoelectric conversion element, a photoelectric conversion element module, a power supply IC, and an electric 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 electric storage device can be charged when the mouse is not in use, and the electric power can be used to operate the mouse, and a mouse that does not require wiring or battery replacement can be obtained. In addition, it is possible to reduce the weight by eliminating the need for a battery, which is effective.

11 is a schematic external view showing an example of the mouse shown in FIG. 10. FIG.
As shown in FIG. 11, the photoelectric conversion element, the power supply IC, and the electric storage device are mounted inside the mouse, and the upper part of the photoelectric conversion element is covered with a transparent housing so that the photoelectric conversion element is exposed to light. It is also possible to mold the entire housing of the mouse with 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 in a position where it is irradiated with light even when the mouse is covered with a hand.

Next, another embodiment of an electronic device having a photoelectric conversion element and a photoelectric conversion element module of the present invention, and a device that operates on the electric power obtained by the generation thereof will be described.

FIG. 12 is a block diagram of a personal computer keyboard 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 an electric storage device are combined, and the supplied electric 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 with the electric power, and a keyboard that does not require wiring or battery replacement can be obtained. In addition, it is possible to reduce the weight by eliminating the need for a battery, which is effective.

13 is a schematic external view showing an example of the keyboard shown in FIG. 12. FIG.
As shown in FIG. 13, the photoelectric conversion element, the power supply IC, and the electric storage device are mounted inside the keyboard, and the upper part of the photoelectric conversion element is covered with a transparent housing so that the photoelectric conversion element is exposed to light. It is also possible to mold the entire keyboard housing with transparent resin. The arrangement of the photoelectric conversion elements is not limited to this.
In the case of a small keyboard having a small space for incorporating a photoelectric conversion element, it is possible and effective to embed a small photoelectric conversion element in a part of the key as shown in FIG.

Next, another embodiment of an electronic device having a photoelectric conversion element and a photoelectric conversion element module of the present invention, and a device that operates on the electric power obtained by the generation thereof will be described.

FIG. 15 is a block diagram of a sensor as an example of the electronic device of the invention.
As shown in FIG. 15, a photoelectric conversion element, a power supply IC, and an electric storage device are combined, and the supplied electric power is connected to the power supply of the sensor circuit. This makes it possible to configure the sensor module without connecting to an external power source and without the need to replace the battery. As a sensing object, it can be applied to various sensors such as temperature and humidity, illuminance, human sensation, _CO2 , acceleration, UV, noise, geomagnetism, atmospheric pressure, etc., and is effective. As shown in A in FIG. 15, the sensor module is configured to periodically sense the object to be measured and transmit the read data to a PC (Personal Computer), a smart phone, or the like by wireless communication.
With the advent of the IoT (Internet of Things) society, the number of sensors is expected to increase rapidly. Replacing the batteries of these countless sensors one by one takes a lot of time and effort, and is not practical. In addition, the sensor is located in a location where it is difficult to replace the battery, such as the ceiling or wall, which also reduces workability. The fact that electric power can be supplied by a photoelectric conversion element is also a great advantage. Further, the photoelectric conversion element of the present invention can obtain a high output even at low illuminance, and has a small dependence of the output on the incident angle of light, so that it has the advantage of a high degree of freedom in installation.

Next, another embodiment of an electronic device having a photoelectric conversion element and a photoelectric conversion element module of the present invention, and a device that operates on the electric power obtained by the generation thereof will be described.

FIG. 16 is a block diagram of a turntable as an example of the electronic device of the invention.
As shown in FIG. 16, a photoelectric conversion element, a power supply IC, and an electric storage device are combined, and the supplied electric power is connected to the power supply of the turntable control circuit. As a result, the turntable can be configured without connecting to an external power source and without the need to replace the battery.
Turntables are used, for example, as showcases for displaying merchandise, but the wiring for the power supply is unattractive, and the displayed items must be removed when replacing the batteries, which is a great deal of time and effort. By using the photoelectric conversion element of the present invention, such problems can be effectively eliminated.

<Application>
The photoelectric conversion element and the photoelectric conversion element module of the present invention, and the electronic device and the power supply module having a device that operates on the electric power obtained by the electric power generated by the photoelectric conversion element and the photoelectric conversion element module of the present invention have been described above, but these are just a few examples. , the photoelectric conversion element or the photoelectric conversion element module of the present invention is not limited to these applications.

A photoelectric conversion element and a photoelectric conversion element module can be applied to, for example, a power supply device by combining with a circuit board or the like that controls the generated current.
Devices that use power supply devices include, for example, electronic desk calculators, wristwatches, mobile phones, electronic notebooks, and electronic paper.
Moreover, a power supply device having a photoelectric conversion element can be used as an auxiliary power supply for extending the continuous use time of a rechargeable or dry battery electric appliance.

The photoelectric conversion element and the photoelectric conversion element module of the present invention can function as an independent power supply, and the power generated by photoelectric conversion can be used to operate the device. Since the photoelectric conversion element and the photoelectric conversion element 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 the electronic device even in a place where there is no power supply facility, carry it around by wearing it, or operate the electronic device without replacing the battery even in a place where it is difficult to replace the battery. Moreover, when a dry cell is used, the electronic device becomes heavier and larger in size, which may hinder the installation on the wall or ceiling or the carrying of the device. , and the photoelectric conversion element module are lightweight and thin, and therefore have a high degree of freedom in installation, and are highly advantageous in wearing and carrying.
Thus, the photoelectric conversion element and the photoelectric conversion element module of the present invention can be used as an independent power source and can be combined with various electronic devices. For example, electronic desktop calculators, wristwatches, mobile phones, electronic notebooks, display devices such as electronic paper, personal computer accessories such as mice and keyboards, various sensor devices such as temperature and humidity sensors and human sensors, beacons and GPS (Global Positioning System) System), auxiliary lights, remote controllers, and many other electronic devices.

INDUSTRIAL APPLICABILITY The photoelectric conversion element and the photoelectric conversion element module of the present invention can generate electricity even with light of low illuminance, so that they can generate electricity indoors or even in a dark place, and thus have a wide range of applications. In addition, unlike dry batteries, there is no liquid leakage, and unlike button batteries, there is no accidental ingestion, so safety is high. Furthermore, it can be used as an auxiliary power source for extending the continuous use time of rechargeable or dry battery electric appliances. Thus, by combining the photoelectric conversion element and the photoelectric conversion element module of the present invention with a device that operates on the power generated by the photoelectric conversion, the device is lightweight, easy to use, and has a high degree of installation freedom. It can be reborn as an electronic device that does not need to be replaced, is excellent in safety, and is effective in reducing environmental impact.

FIG. 17 is a block diagram showing an example of an electronic device of the present invention in which the photoelectric conversion element and/or photoelectric conversion element module of the present invention and a device that operates on the electric power generated by the photoelectric conversion thereof are combined. This can generate power when the photoelectric conversion element is irradiated with light, and power can be taken out. The circuitry of the device is allowed to operate from that power.

However, since the output of the photoelectric conversion element changes depending on the ambient illuminance, the electronic device shown in FIG. 17 may not operate stably. In this case, as shown in FIG. 18, in order to supply a stable voltage to the circuit side, it is possible and effective to incorporate a power source IC for the photoelectric conversion element between the photoelectric conversion element and the circuit of the device. .
However, a photoelectric conversion element can generate electricity if it is irradiated with light of sufficient illuminance, but if the illuminance for generating electricity is insufficient, the desired electric power cannot be obtained, and this is also a drawback of the photoelectric conversion element. In this case, as shown in FIG. 19, by mounting an electricity storage device such as a capacitor between the power supply IC and the equipment circuit, it becomes possible to charge the electricity storage device with the surplus power from the photoelectric conversion element. is too low or the photoelectric conversion element is not exposed to light, the electric power stored in the electricity storage device can be supplied to the equipment circuit, and stable operation is possible.
As described above, in an electronic device in which the photoelectric conversion element and/or photoelectric conversion element module of the present invention is combined with a device circuit, by combining a power supply IC and an electric storage device, it is possible to operate even in an environment without a power supply, and This eliminates the need for battery replacement, enables stable operation, and maximizes the merits of photoelectric conversion elements.

On the other hand, the photoelectric conversion element and/or photoelectric conversion element module of the present invention can also be used as a power source module and is useful. For example, as shown in FIG. 20, when the photoelectric conversion element and/or photoelectric conversion element module of the present invention is connected to a power supply IC for the photoelectric conversion element, the power generated by the photoelectric conversion of the photoelectric conversion element is transferred to the power supply IC. It is possible to configure a DC power supply module capable of supplying a constant voltage level at .
Furthermore, as shown in FIG. 21, by adding an electricity storage device to the power supply IC, it becomes possible to charge the electricity storage device with the power generated by the photoelectric conversion element. It is possible to configure a power supply module capable of supplying power even when the light is not applied to the device.
The power supply module of the present invention shown in FIGS. 20 and 21 can be used as a power supply module without replacing batteries unlike conventional primary batteries.

EXAMPLES The present invention will now be described with reference to examples and comparative examples. It should be noted that the present invention is not limited to the examples illustrated herein.

(Example 1)
<Fabrication of photoelectric conversion element module>
Indium-doped tin oxide (ITO) as a first electrode and niobium-doped tin oxide (NTO) are sequentially formed by sputtering on a glass substrate as a first substrate, and then a dense layer made of titanium oxide as a hole blocking layer. was formed by reactive sputtering with oxygen gas. Then, the ITO/NTO and part of the hole blocking layer formed on the substrate were etched by laser processing to form a distance of 10 μm from adjacent photoelectric conversion elements.

Next, 3 g of titanium oxide (ST-21 manufactured by Ishihara Sangyo Co., Ltd.), 0.2 g of acetylacetone, 0.3 g of surfactant (polyoxyethylene octylphenyl ether, manufactured by Wako Pure Chemical Industries, Ltd.), 5.5 g of water, ethanol A paste was prepared by adding 1.2 g of polyethylene glycol (#20,000, manufactured by Wako Pure Chemical Industries, Ltd.) to the obtained titanium oxide dispersion liquid after bead milling for 12 hours. The obtained paste was coated on the hole blocking layer so as to have an average thickness of about 1.5 μm, dried at 60° C., and then fired in the air at 550° C. for 30 minutes to form a porous electron transport layer. formed.

A glass substrate having an electron transport layer formed thereon was coated with 120 mg of the photosensitizing compound represented by B-5, 150 mg of chenodeoxycholic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and a mixture of acetonitrile/t-butanol (volume ratio 1:1). was immersed in the stirred solution and allowed to stand in a dark place for 1 hour to allow the photosensitizing compound to be adsorbed on the surface of the electron transport layer.

Next, 1 mL of a chlorobenzene solution of 183 mg of the hole transport material (manufactured by Merck Co., Ltd.) represented by D-7 was added with 15.0 mg of lithium bis(trifluoromethanesulfonyl)imide (manufactured by Kanto Chemical Co., Ltd.) and C-12. 40 mg of a basic compound represented by was added and dissolved to prepare a hole transport layer coating solution.

Next, a hole transporting layer coating liquid was used to form a hole transporting layer having an average thickness of about 400 nm on the electron transporting layer on which the photosensitizing compound was adsorbed by blade coating. After that, the end portion of the glass substrate on which the sealing member was to be provided was etched by laser processing, and through-holes for connecting the elements in series were formed by laser processing. Furthermore, silver was vacuum-deposited thereon to form a second electrode with an average thickness of about 60 nm. At this time, it was confirmed that silver was vapor-deposited also on the inner wall of the through-hole and adjacent elements were connected in series. Six serial numbers were formed.

An ultraviolet curable resin (TB3118, manufactured by ThreeBond Holdings Co., Ltd.) was applied to the edge of the glass substrate using a dispenser (2300N, manufactured by Sanei Tech Co., Ltd.) so as to surround the power generation area. After that, it is transferred to a glove box controlled to a low humidity and an oxygen concentration of 0.5%, a cover glass as a second substrate is placed on the ultraviolet curable resin, and cured by ultraviolet irradiation to seal the power generation area. were carried out to produce the photoelectric conversion element module 1 of the present invention shown in FIG.
The layer thicknesses of the second electrode and the hole transport layer were measured using a white light interference microscope (VS1500, manufactured by Hitachi High-Tech Science). When measuring the layer thickness of the second electrode, after forming the second electrode, part of the second electrode was peeled off with a tape, and the field of view was adjusted so that the lower hole transport layer could be included in the same photographed image. After adjustment, the second electrode was photographed under the following measurement conditions. In addition, when measuring the layer thickness of the hole transport layer, tetrahydrofuran is dropped after forming the hole transport layer to remove a part of the hole transport layer, and the electron transport layer further below is included in the same photographed image. After adjusting the field of view, the hole transport layer was photographed under the following measurement conditions. The average thickness of the lower layer and the layer to be measured was calculated by average step analysis.

[Layer thickness measurement conditions]
Measurement mode: WAVE mode Objective lens magnification: 2.5 times Wavelength filter: 530 nm White
Observation area: 1,900 μm×1,400 μm
Number of pixels: 640 pix x 480 pix

Also, Rc(50) was determined as follows.
The surface shape of the hole transport layer was observed in plan using a white interference microscope (VS1500, manufactured by Hitachi High-Tech Science Co., Ltd.) under the following measurement conditions. Next, by particle analysis, the total cross-sectional area of protrusions having a height of X+50 (nm) or more was calculated from the surface of the hole transport layer 6 opposite to the surface in contact with the second electrode 7 . Rc(50) was obtained by dividing this by the area of the observation region and calculating the average value of the three fields of view.

[Measurement conditions for Rc (50)]
Measurement mode: WAVE mode Objective lens magnification: 10x Wavelength filter: 530nm White
Observation area: 470 nm x 350 nm
Number of pixels: 640 pix x 480 pix

<Evaluation of photoelectric conversion element module>
For the obtained photoelectric conversion element module 1, IV characteristics were evaluated using a DC voltage current source/monitor (ADCMT, 6241A) under illumination of a white LED adjusted to a low illuminance of 200 lux, and the initial maximum output power was obtained. Pmax (μW/cm ² ) was determined. Then, the photoelectric conversion element module 1 was continuously irradiated with a white LED adjusted to a high illuminance of 10,000 lux for 200 hours, then the IV characteristics at 200 lux were evaluated again, and the maximum output power after high illuminance light irradiation was measured. to obtain the retention rate. Table 1 shows the results.

(Example 2)
Pmax and retention rate were determined in the same manner as in Example 1, except that the average thickness of the hole transport layer was changed to about 500 nm. Table 1 shows the results.

(Example 3)
Pmax and retention rate were determined in the same manner as in Example 1, except that the average thickness of the hole transport layer was changed to about 600 nm. Table 1 shows the results.

(Example 4)
Pmax and retention rate were determined in the same manner as in Example 1, except that the average thickness of the hole transport layer was changed to about 800 nm. Table 1 shows the results.

(Example 5)
Pmax and retention rate were obtained in the same manner as in Example 2, except that the second electrode was formed with an average thickness of about 20 nm. Table 1 shows the results.

(Example 6)
Pmax and retention rate were obtained in the same manner as in Example 5, except that the average thickness of the second electrode was changed to about 45 nm. Table 1 shows the results.

(Example 7)
Pmax and retention rate were obtained in the same manner as in Example 5, except that the average thickness of the second electrode was changed to about 30 nm. Table 1 shows the results.

(Comparative example 1)
In Example 1, a hole transport layer having a thickness of about 300 nm was formed by spin coating the hole transport layer coating solution, and silver was vacuum-deposited on the hole transport layer to form a second electrode having an average thickness of about 100 nm. Pmax and retention rate were determined in the same manner as in Example 1 except for the above. Table 1 shows the results.

(Comparative example 2)
Pmax and retention rate were obtained in the same manner as in Comparative Example 1, except that the average thickness of the hole transport layer was changed to about 500 nm and the average thickness of the second electrode was changed to about 60 nm. . Table 1 shows the results.

(Comparative Example 3)
In Comparative Example 2, Pmax and retention rate were obtained in the same manner as in Comparative Example 2, except that the average thickness of the second electrode was changed to about 20 nm. Table 1 shows the results.

From the results in Table 1, Examples 1 to 7 have a maintenance rate of 80% or more, and compared to Comparative Examples 1 to 3, it can be seen that the decrease in output with low illuminance light can be suppressed before and after exposure to high illuminance light. rice field. Further, when comparing Example 5 and Example 7, even if Rc(50) is 0.75% or less, when the layer thickness of the second electrode is 25 nm or less, Pmax and after continuous irradiation It was found that the Pmax retention rate was low, and not only Rc(50) but also the layer thickness of the second electrode was important. Further, a comparison of Examples 1 to 4 revealed that a higher Pmax and Pmax retention rate after continuous irradiation can be obtained by setting the layer thickness of the second electrode to 50 nm or more.

As described above, in the photoelectric conversion element of the present invention, if Rc(50) is the ratio of the area of the protrusion having a height of 50 nm or more to the unit area of the surface of the hole transport layer on the second electrode side, The following formula is satisfied: 0%<Rc(50)≦0.75%. As a result, since the photoelectric conversion element of the present invention has fewer portions where the second electrode is thin, leakage current is less likely to occur and the photosensitizing compound is less likely to be damaged, so that it is exposed to high-intensity light. It is possible to suppress a decrease in output with low illuminance light before and after the light is turned on. For this reason, the photoelectric conversion device of the present invention can have a high power generation output even after being exposed to sunlight, even with the light of lighting fixtures used indoors, such as LEDs and fluorescent lamps.

Embodiments of the present invention are, for example, as follows.
<1> having a first electrode, an electron transport layer, a hole transport layer, and a second electrode,
the hole transport layer and the second electrode are in contact;
When the average thickness of the hole transport layer is X (nm),
In the hole transport layer,
From the surface opposite to the surface in contact with the second electrode, Rc( 50), the photoelectric conversion element satisfies the following formula: 0%<Rc(50)≦0.75%.
<2> The photoelectric conversion element according to <1>, which satisfies the following formula: 0%<Rc(50)≦0.50%.
<3> The photoelectric conversion element according to any one of <1> to <2>, wherein the second electrode has an average thickness of 25 nm or more.
<4> The photoelectric conversion element according to any one of <1> to <3>, wherein the second electrode has an average thickness of 50 nm or more.
<5> A photoelectric conversion element module including a plurality of the photoelectric conversion elements according to any one of <1> to <4>.
<6> the photoelectric conversion element and/or photoelectric conversion element module according to any one of <1> to <5>;
a device operated by electric power generated by photoelectric conversion of the photoelectric conversion element and/or the photoelectric conversion element module;
An electronic device comprising:
<7> the photoelectric conversion element and/or photoelectric conversion element module according to any one of <1> to <5>;
a power supply IC;
A power supply module characterized by comprising:

The photoelectric conversion element according to any one of <1> to <4>, the photoelectric conversion element module according to <5>, the electronic device according to <6>, and the power supply module according to <7>. According to the invention, various problems in the conventional art can be solved and the object of the present invention can be achieved.

JP 2014-241243 A

REFERENCE SIGNS LIST 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 Penetrating portion 11 Sealing member 101 Photoelectric conversion element 102 Photoelectric conversion element module

Claims (7)

having a first electrode, an electron transport layer, a hole transport layer, and a second electrode;
the hole transport layer and the second electrode are in contact;
When the average thickness of the hole transport layer is X (nm),
In the observation area where the surface shape of the hole transport layer is planarly viewed using a white light interference microscope (VS1500, manufactured by Hitachi High-Tech Science Co., Ltd.) ,
By particle analysis, the total cross-sectional area of protrusions with a height of X+50 (nm) or more is calculated from the surface of the hole transport layer opposite to the surface in contact with the second electrode, and this is the observation area. A photoelectric conversion device , wherein an average value Rc(50) of the ratio divided by the area for three fields of view satisfies the following formula: 0%<Rc(50)≦0.75%. 2. The photoelectric conversion device according to claim 1, which satisfies the following formula: 0%<Rc(50)≤0.50%. 3. The photoelectric conversion element according to claim 1, wherein the second electrode has an average thickness of 25 nm or more. 4. The photoelectric conversion element according to claim 1, wherein the second electrode has an average thickness of 50 nm or more. A photoelectric conversion element module comprising a plurality of the photoelectric conversion elements according to any one of claims 1 to 4. a photoelectric conversion element and/or photoelectric conversion element module according to any one of claims 1 to 5;
a device operated by electric power generated by photoelectric conversion of the photoelectric conversion element and/or the photoelectric conversion element module;
An electronic device comprising: a photoelectric conversion element and/or photoelectric conversion element module according to any one of claims 1 to 5;
a power supply IC;
A power supply module comprising:

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