Photoelectric conversion element, method for producing photoelectric conversion element, photoelectric conversion module and electronic device

Abstract

The present invention provides a photoelectric conversion element and a method for producing the photoelectric conversion element, a photoelectric conversion module and an electronic device. The photoelectric conversion element includes a first electrode, a photoelectric conversion layer and a second electrode. The photoelectric conversion layer includes a hole transport layer, the hole transport layer includes a lithium salt having an asymmetric structure, and the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less.

Description

Technical Field

[0001] The invention relates to a photoelectric conversion element and a method for producing the photoelectric conversion element, a photoelectric conversion module and an electronic device. Background Art

[0002] In recent years, solar cells that can generate electricity efficiently under low illumination have attracted attention. Solar cells are expected to be widely used as self-collecting power sources that do not require replacement of batteries or installation of power lines, and can be applied regardless of the installation location.

[0003] For example, as photoelectric conversion elements for indoor use, amorphous silicon-based solar cells and organic solar cells are already known. Among organic solar cells, dye-sensitized solar cells are advantageous because dye-sensitized solar cells are composed of separate layers each having charge generation capability and charge transport capability, can achieve high output, and such dye-sensitized solar cells can be easily produced.

[0004] Traditionally, dye-sensitized solar cells encapsulate electrolyte solutions, so there are problems with solution evaporation or leakage. However, in recent years, solid dye-sensitized solar cells using p-type semiconductor materials have been recently developed, and their production processes have been further simplified. In addition, perovskite solar cells are a mixture of organic and inorganic materials, have high conversion efficiency similar to silicon-based solar cells in the art, and are easy to produce. Therefore, perovskite solar cells have aroused great interest.

[0005] A photoelectric conversion element that can be used for a solar cell unit is intended to achieve high output in a high temperature environment or an indoor environment with weak light. For example, a photoelectric conversion element is proposed, which includes a first electrode, an electron transport layer including a photosensitive compound, a hole transport layer, and a second electrode, wherein the hole transport layer includes a pyridine compound A and an ionic compound B (for example, see Japanese Unexamined Patent Application Publication No. 2018-113305). Summary of the invention

[0006] According to one aspect of the present invention, a photoelectric conversion element includes a first electrode, a photoelectric conversion layer, and a second electrode. The photoelectric conversion layer includes a hole transport layer. The hole transport layer includes a lithium salt having an asymmetric structure, and the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram showing an example of a photoelectric conversion element according to the first embodiment;

[0008] Figure 2is a schematic diagram showing an example of a photoelectric conversion element according to the second embodiment;

[0009] Figure 3 is a schematic diagram showing an example of a photoelectric conversion element according to the third embodiment;

[0010] Figure 4 is a schematic diagram showing an example of a photoelectric conversion module according to a fourth embodiment;

[0011] Figure 5 is a schematic diagram showing an example of a photoelectric conversion module according to a fifth embodiment;

[0012] Figure 6 is a block diagram of a mouse for a personal computer as an embodiment of the electronic device of the present invention;

[0013] Figure 7 It shows Figure 6 A schematic external view of an embodiment of a mouse;

[0014] Figure 8 is a block diagram of a keyboard for a personal computer as an embodiment of the electronic device of the present invention;

[0015] Fig. 9 It shows Figure 8 A schematic external view of an embodiment of a keyboard of;

[0016] Fig.10 It shows Figure 8 A schematic external view of another embodiment of a keyboard of;

[0017] Fig.11 is a block diagram of a sensor as an embodiment of an electronic device of the present invention;

[0018] Fig.12 is a block diagram of a turntable as an embodiment of the electronic device of the present invention;

[0019] Fig.13 is a block diagram showing an embodiment of an electronic device of the present invention;

[0020] Fig.14 It shows Fig.13 A block diagram of an embodiment of an electronic device including a power supply IC;

[0021] Fig.15 It shows Fig.14 A block diagram of an embodiment of an electronic device, further comprising an electrical storage device;

[0022] Fig.16 is a block diagram showing an embodiment of a power module of the present invention;

[0023] Fig.17 It shows Fig.16 A block diagram of an embodiment of a power module, further comprising an electrical storage device;

[0024] Fig.18 is a diagram depicting an example of an X-ray absorption fine structure (XAFS) spectrum measured by using the photoelectric conversion module of Example 1. DETAILED DESCRIPTION

[0025] An object of the present invention is to provide a photoelectric conversion element that can achieve high output with light of low illumination and has excellent output retention and durability against light in any temperature environment.

[0026] The present invention can provide a photoelectric conversion element that can achieve high output with light of low illuminance and has excellent output retention and durability against light in any temperature environment.

[0027] (Photoelectric conversion element)

[0028] The photoelectric conversion element of the present invention includes a first electrode, a photoelectric conversion layer including a hole transport layer, and a second electrode. The photoelectric conversion element may further include other layers as required.

[0029] In the photoelectric conversion element of the present invention, the hole transport layer contains a lithium salt having an asymmetric structure, and the amount of the solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less.

[0030] The present inventors have found that when a certain amount or more of a solvent used to form a hole transport layer of a photoelectric conversion element remains after the production of the photoelectric conversion element, the light durability of the photoelectric conversion element may be deteriorated.

[0031] In this specification, the term "photoelectric conversion element" refers to an element configured to convert light energy into electric energy or an element configured to convert electric energy into light energy. Specific examples thereof include solar cells and photodiodes.

[0032] In the present invention, the term "layer" means a single-layer film (single layer) as well as a structure in which a plurality of films are stacked.

[0033] Furthermore, the term "stacking direction" refers to a direction perpendicular to the plane direction of each layer of the photoelectric conversion element. The term "connection" refers not only to physical connection but also to electrical connection that can exert the effect of the present invention.

[0034] The photoelectric conversion element of the present invention comprises a first electrode, a photoelectric conversion layer and a second electrode, wherein the photoelectric conversion layer comprises at least a hole transport layer. The photoelectric conversion element may further comprise other components, such as a first substrate, a second substrate, a hole blocking layer and a sealing component, as required.

[0035] <First Substrate>

[0036] The shape, structure, and size of the first substrate are not particularly limited and can be appropriately selected depending on the intended purpose.

[0037] The material of the first substrate is not particularly limited as long as the material has transparency and insulation, and can be appropriately selected according to the intended purpose. Examples include glass, plastic film or ceramic substrates. In the above examples, when the firing process is included in the process of forming the electron transport layer described later, a substrate with heat resistance to the firing temperature is preferred. In addition, the first substrate is more preferably a flexible substrate.

[0038] The substrate may be provided on either or both sides of the outer side of the photoelectric conversion element, the photoelectric conversion element including the outer first electrode side and the outer second electrode side.

[0039] The substrate provided outside the photoelectric conversion element on the side where the first electrode is provided is referred to as a first substrate, and the substrate provided outside the photoelectric conversion element on the side where the second electrode is provided is referred to as a second substrate.

[0040] <First Electrode>

[0041] The shape and size of the first electrode are not particularly limited and can be appropriately selected depending on the intended purpose.

[0042] The structure of the first electrode is not particularly limited and can be appropriately selected depending on the intended purpose. The first electrode may have a single layer structure or a structure in which a plurality of materials are stacked.

[0043] The material of the first electrode is not particularly limited as long as the material is transparent to visible light and is conductive, and can be appropriately selected depending on the intended purpose. Examples thereof include transparent conductive metal oxides, carbon, and metals.

[0044] Examples of transparent conductive metal oxides include tin-doped indium oxide (hereinafter referred to as "ITO"), fluorine-doped tin oxide (hereinafter referred to as "FTO"), 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 and niobium titanium oxide.

[0045] Examples of carbon include carbon black, carbon nanotubes, graphene, and fullerene.

[0046] Examples of metals include gold, silver, aluminum, nickel, indium, tantalum, and titanium.

[0047] The above examples may be used alone or in combination. Among the above materials, transparent conductive metal oxides with high transparency are preferred, and ITO, FTO, ATO and NTO are more preferred.

[0048] The average thickness of the first electrode is not particularly limited and can be appropriately selected according to the intended purpose. The average thickness of the first electrode is preferably 5 nm or more but 100 μm or less, more preferably 50 nm or more but 10 μm or less. When the material of the first electrode is carbon or metal, the average thickness of the first electrode is preferably an average thickness that allows the first electrode to obtain light transmittance or transparency.

[0049] The first electrode may be formed by any method known in the art, such as sputtering, vapor deposition, and spraying.

[0050] In addition, preferably, the first electrode is formed on the first substrate. As the first electrode, a commercially available integrated product in which the first electrode is formed on the first substrate in advance can be used.

[0051] Examples of commercially available integrated products include FTO coated glass, ITO coated glass, zinc oxide-aluminum coated glass, FTO coated transparent plastic film, and ITO coated transparent plastic film. Examples of other commercially available integrated products include (a glass substrate with a transparent electrode (wherein tin oxide or indium oxide is doped with cations or anions having different atomic values) and a glass substrate (which is provided with a metal electrode having a structure that allows light to pass through in a mesh or stripe shape).

[0052] The above examples may be used alone, or two or more of the above examples may be used together or in a stacked form. In addition, in order to reduce the resistance value of the first electrode, a metal lead may also be used in combination.

[0053] Examples of the material of the metal lead include aluminum, copper, silver, gold, platinum, and nickel.

[0054] For example, the metal leads may be used in combination by disposing the metal leads on the substrate by vapor deposition, sputtering, or pressure welding, and depositing an ITO or FTO layer thereon.

[0055] <Photoelectric Conversion Layer>

[0056] The photoelectric conversion layer includes a hole transport layer, and may further include an electron transport layer as necessary.

[0057] The photoelectric conversion layer is composed of a single layer or a plurality of layers stacked together.

[0058] <<Hole Transport Layer>>

[0059] The hole transport layer is a layer capable of transporting holes (positive holes).

[0060] The embodiment of the hole transport layer is not particularly limited, as long as the hole transport layer can transport holes, and can be appropriately selected according to the intended purpose. Examples thereof include electrolytes (wherein the redox pair is dissolved in an organic solvent), gel electrolytes (wherein the polymer matrix is ​​impregnated with a liquid obtained by dissolving the redox pair in an organic solvent), molten salts containing redox pairs, solid electrolytes, inorganic hole transport materials, and organic hole transport materials. In the above examples, solid electrolytes are preferred, and organic hole transport materials are more preferred. The above examples can be used alone or in combination.

[0061] The hole transport layer preferably contains a lithium salt and the anion in the lithium salt has an asymmetric structure. The asymmetric structure means that the left and right sides of the anion molecular structure are different from the lithium ion located in the center. The lithium salt having an asymmetric structure is preferably a lithium salt represented by the following general formula (1).

[0062]

[0063] In the general formula (1), A and B are each a substituent selected from F, CF3, C2F5, C3F7 and C4F9, and the substituent A and the substituent B are different from each other.

[0064] The inventors have found that, in particular, when a lithium salt having an asymmetric structure is included in the hole transport layer, the light durability of the photoelectric conversion element can be significantly improved. The reason for the improvement in light durability is believed to be that the lithium salt has an asymmetric structure, which increases the solubility of the lithium salt in the solvent, thereby reducing the possibility of phase separation in the hole transport layer.

[0065] The lithium salt having a symmetrical structure helps to form a see-island structure rich in anions, thereby causing phase separation during the evaporation of the solvent after the hole transport layer is formed. The lithium salt is water-soluble and has low compatibility with other components forming the hole transport layer. Therefore, it is speculated that the anions are easily unevenly distributed in the hole transport layer. In addition, another reason for the poor durability of the photoelectric conversion element seems to be that the amount of lithium salt added is limited due to the low solubility of the lithium salt in the solvent.

[0066] The lithium salt with an asymmetric structure used in the present invention improves the solubility in the solvent and reduces the possibility of causing phase separation in the hole transport layer, thereby reducing the area with low transport performance in the hole transport layer to stabilize the hole transport performance. In addition, it is believed that by improving the solubility of the lithium salt, the amount of lithium salt added can be increased, so that a synergistic effect of both high output and high durability can be achieved.

[0067] The lithium salt represented by the general formula (1) participates in the transfer of charges, and excellent photoelectric conversion characteristics can be achieved by adding the lithium salt.

[0068] Examples of the lithium salt represented by the general formula (1) include lithium (fluorosulfonyl) (trifluoromethanesulfonyl) imide (Li-FTFSI), lithium (fluorosulfonyl) (pentafluoroethanesulfonyl) imide (Li-FPFSI), lithium (fluorosulfonyl) (nonafluorobutanesulfonyl) imide (Li-FNFSI), lithium (nonafluorobutanesulfonyl) (trifluoromethanesulfonyl) imide (Li-NFTFSI), and lithium (pentafluoroethanesulfonyl) (trifluoromethanesulfonyl) imide (Li-PFTFSI). Among the above examples, lithium (fluorosulfonyl) (trifluoromethanesulfonyl) imide (Li-FTFSI) is particularly preferred.

[0069] Specific examples of the structural formula of the lithium salt are as follows.

[0070]

[0071] For example, when a coating liquid is formed by coating a hole transport layer containing a lithium salt, the lithium salt in the formed film is not necessarily a salt state in which anions and cations are combined, but may be a state in which lithium cations and anions are separated. Specifically, the inventors found that when a hole transport layer containing a lithium salt is used to form a coating liquid to form a hole transport layer, and the amount of lithium cations contained in the electron transport layer is more than the amount of lithium cations contained in the hole transport layer, the lithium cations migrate into the electron transport layer. The inventors also found that although some anions migrate, the amount of anions contained in the hole transport layer is greater than the amount of anions contained in the electron transport layer.

[0072] In the present invention, it is preferred that the cations and anions of the lithium salt are separated, and the cations and anions form different distribution states. Since the cations and anions of the lithium salt are contained in the photoelectric conversion layer, the obtained photoelectric conversion element achieves high output with low illumination light under various temperature environments, and can further improve the excellent output retention effect.

[0073] In addition to the lithium salt represented by the general formula (1), the hole transport layer of the photoelectric conversion layer may also include lithium salts with different structures. In addition to the above-mentioned lithium salts, the lithium salt may be a lithium salt with a symmetrical anion species. Examples thereof include lithium bis(fluorosulfonyl)imide (Li-FSI), lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), lithium bis(pentafluoroethanesulfonyl)imide (Li-BETI) and lithium bis(nonafluorobutanesulfonyl)imide. In addition, other examples may include cyclic imides, such as (cyclohexafluoropropane) (disulfone) imide lithium.

[0074] However, the above lithium salts cannot be added in large amounts due to their symmetrical anions and low solubility. Therefore, when any of the above lithium salts is added, it is preferred to add a small amount.

[0075] The content of the lithium salt is preferably 5 mol% or more but 50 mol% or less, more preferably 20 mol% or more but 35 mol% or less, relative to the hole transport material. When the amount of the lithium salt is within the above range, high output of low-illuminance light is achieved, output retention is improved, and high durability is achieved.

[0076] The organic solvent contained in the hole transport layer may be any solvent known in the art as long as the solvent can dissolve various materials to be contained, such as lithium salt and the hole transport material described later. The organic solvent may be appropriately selected depending on the intended purpose.

[0077] Examples of the organic solvent include ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, nitrile solvents, and hydrocarbon solvents.

[0078] Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetophenone.

[0079] Examples of the ester solvent include ethyl formate, ethyl acetate, n-butyl acetate, and methyl benzoate.

[0080] Examples of the ether solvent include anisole, diisopropyl ether, dibutyl ether, dimethoxyethane, diethoxyethane, ethoxybenzene, tetrahydrofuran, dioxolane and dioxane.

[0081] Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0082] Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene and 1-chloronaphthalene.

[0083] Examples of the nitrile solvent include acetonitrile, propionitrile and methacrylonitrile.

[0084] Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.

[0085] The above examples may be used alone or in combination.

[0086] Among the above solvents, halogenated hydrocarbon solvents, ether solvents and nitrile solvents are preferred.

[0087] The boiling point of the organic solvent is not particularly limited and can be appropriately selected according to the intended purpose. The boiling point is preferably 70°C or higher but 150°C or lower. When an organic solvent having a boiling point in the above range is used, the porous electron transport layer tends to be filled with the hole transport layer to avoid excess solvent. The amount of solvent can be reduced by heating and drying the hole transport layer after applying the hole transport layer. However, when the hole transport layer is heated and dried at too high a temperature or for too long a time, even if the amount of solvent can be reduced, high output may not be achieved, or the durability of the resulting photoelectric conversion element may be significantly reduced. Therefore, the choice of solvent is also important. In the present invention, among the above solvents, chlorobenzene or a mixed solvent including chlorobenzene is preferably used.

[0088] The average thickness of the hole transport layer is not particularly limited and can be appropriately selected according to the intended purpose. The hole transport layer preferably has a structure of fine pores penetrating the porous electron transport layer, and the average thickness of the hole transport layer provided on the electron transport layer is preferably 0.01 μm or more but 20 μm or less, more preferably 0.1 μm or more but 10 μm or less, and further preferably 0.2 μm or more but 2 μm or less.

[0089] The hole transport layer may be directly formed on the electron transport layer to which the photosensitive compound is adsorbed, which will be described later.

[0090] The method for producing the hole transport layer is not particularly limited as long as the amount (residual amount) of the solvent after forming the photoelectric conversion element is 30 μg / mm 3 or less, and can be appropriately selected according to the intended purpose. Examples of the production method include a method of forming a thin film in a vacuum, such as a vacuum evaporation method, and a wet film forming method. Among the above examples, the wet film forming method is particularly preferred in consideration of the manufacturing cost, and the method of applying on the electron transport layer is preferred.

[0091] In the case of using a wet film-forming method, the coating method is not particularly limited and can be carried out according to known methods. For example, various methods such as dip coating, spray coating, wire rod coating, spin coating, roller coating, scraper coating, gravure coating, die coating, and wet printing methods such as relief printing, offset printing, gravure printing, intaglio printing, rubber plate printing and screen printing can be used.

[0092] In addition, the film of the hole transport layer can be formed in a supercritical fluid or a subcritical fluid having a temperature and pressure below the critical point. The supercritical fluid is not particularly limited, as long as the supercritical fluid exists as a non-condensing high-density fluid in a temperature and pressure region exceeding the limit (critical point) at which gas and liquid can coexist, the supercritical fluid will not condense even if it is compressed, and the supercritical fluid is also a fluid in a state equal to or greater than the critical temperature and critical pressure. The supercritical fluid can be appropriately selected according to the intended purpose. The supercritical fluid is preferably a supercritical fluid with a low critical temperature.

[0093] Examples of the supercritical fluid include carbon monoxide, carbon dioxide, ammonia, nitrogen, water, alcohol solvents, hydrocarbon solvents, halogen solvents, and ether solvents.

[0094] Examples of the alcohol solvent include methanol, ethanol and n-butanol.

[0095] Examples of the hydrocarbon solvent include ethane, propane, 2,3-dimethylbutane, benzene, and toluene.

[0096] Examples of the halogen solvent include dichloromethane and chlorotrifluoromethane.

[0097] Examples of the ether solvent include dimethyl ether.

[0098] The above examples may be used alone or in combination.

[0099] Among the above examples, carbon dioxide is preferred because the critical pressure of carbon dioxide is 7.3 MPa and the critical temperature is 31° C., so a supercritical state of carbon dioxide can be easily produced, and a supercritical fluid of carbon dioxide is easy to handle due to its non-flammability.

[0100] The subcritical fluid is not particularly limited as long as it exists as a high-pressure liquid in the temperature and pressure region near the critical point. The subcritical fluid can be appropriately selected according to the intended purpose. The compounds listed as supercritical fluids can be appropriately used as subcritical fluids.

[0101] The critical temperature and critical pressure of the subcritical fluid are not particularly limited and can be appropriately selected depending on the intended purpose. The critical temperature of the subcritical fluid is preferably -273°C or higher but 300°C or lower, more preferably 0°C or higher but 200°C or lower.

[0102] Furthermore, in addition to the supercritical fluid or subcritical fluid, an organic solvent or an entrainer may be used in combination. The solubility in the supercritical fluid can be easily adjusted by adding an organic solvent or an entrainer.

[0103] The organic solvent is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the organic solvent include ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.

[0104] Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0105] Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.

[0106] Examples of the ether solvent include diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxolane and dioxane.

[0107] Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0108] Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene and 1-chloronaphthalene.

[0109] Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.

[0110] The above examples may be used alone or in combination.

[0111] In addition, the method for producing the hole transport layer is preferably a method of coating a hole transport layer forming material containing a material for forming the hole transport layer on the electron transport layer adsorbed with the photosensitive compound, and then controlling by drying before forming the second electrode. Heating and drying are particularly preferred.

[0112] The pressure as a heating and drying condition is not particularly limited. Heating and drying are preferably performed under ambient pressure.

[0113] The temperature as the heating and drying conditions is preferably 30° C. or higher but 130° C. or lower, more preferably 50° C. or higher but 100° C. or lower.

[0114] The treatment time as the heat drying condition is preferably 10 minutes or longer but 24 hours or shorter, more preferably 30 minutes or longer but 2 hours or shorter.

[0115] In addition, a hole transport material layer may be provided on the electron transport layer adsorbing the photosensitive compound, and then a pressing process may be performed. As the pressing process is performed, the hole transport material adheres more closely to the electron transport layer as a porous electrode, thereby improving efficiency.

[0116] The method of the press treatment is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include press molding using a flat plate such as an IR pellet mold and roll pressing using a roll.

[0117] The pressure is preferably 10 kgf / cm 2 or more, more preferably 30kgf / cm 2 or larger.

[0118] The time of the press treatment is not particularly limited and can be appropriately selected according to the intended purpose. The time is preferably 1 hour or less. In addition, heat can be applied during the press treatment. During the press treatment, a release agent can be provided between the press and the electrode.

[0119] Examples of the release agent include fluorine resins such as polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, perfluoroalkoxy fluorine resin, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polyvinyl fluoride. The above examples may be used alone or in combination.

[0120] After the press treatment but before the second electrode is provided, a metal oxide may be provided between the hole transport material and the second electrode.

[0121] Examples of metal oxides include molybdenum oxide, tungsten oxide, vanadium oxide and nickel oxide. The above examples can be used alone or in combination. Among the examples listed above, molybdenum oxide is preferred.

[0122] The method for providing the metal oxide on the hole transport layer is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the method include a method of forming a thin film in a vacuum (such as sputtering and vacuum vapor deposition) and a wet film formation method.

[0123] The wet film forming method preferably prepares a paste dispersed with metal oxide powder or sol, and applies the paste to the hole transport layer. When the wet film forming method is used, the coating method is not particularly limited, and any method known in the art can be used for coating. For example, various methods such as dip coating, spray coating, wire rod coating, spin coating, roller coating, scraping, gravure coating, die coating and wet printing methods (e.g., relief printing, offset printing, gravure printing, gravure printing, rubber printing and screen printing) can be used.

[0124] The average thickness of the coating metal oxide is preferably 0.1 nm or more but 50 nm or less, and more preferably 1 nm or more but 10 nm or less.

[0125] In the photoelectric conversion element of the present invention, the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less, preferably 25 μg / mm 3 or less, more preferably 20 μg / mm 3 When the amount of solvent per unit volume of the hole transport layer is 30 μg / mm3 or less, the light durability of the hole transport layer can be improved.

[0126] When a lithium salt having a symmetrical structure is used, a large amount of solvent may be used to maintain compatibility, or phase separation may occur due to a reduction in the amount of solvent. Therefore, a lithium salt having a symmetrical structure does not achieve an improvement in durability. When a lithium salt having an asymmetrical structure used in the present invention is used, on the contrary, the lithium salt itself has high compatibility, so the amount of solvent may be reduced, and due to a synergistic effect with a lithium salt having an asymmetrical structure, an improvement in durability may be achieved.

[0127] The measurement of the amount of the solvent per unit volume of the hole transport layer is performed in the following manner.

[0128] [Method for measuring the amount of solvent]

[0129] After the manufactured photoelectric conversion element was immersed in liquid nitrogen, it was crushed by a hummer, and the crushed photoelectric conversion element was transferred to a vial.

[0130] The sample collected in the vial was heated on a hot plate heated to 150° C. for 1 hour, and the gas in the vial was collected. From the collected gas, 100 μL of the gas was sampled and analyzed according to gas chromatography-mass spectrometry.

[0131] Gas chromatography-mass spectrometry (GCMS) was performed under the following conditions.

[0132] -equipment-

[0133] SION-TQ (GCMS), purchased from BRUKER

[0134] UNITY2 (TD), purchased from MARKES

[0135] -Measurement conditions-

[0136] Chromatographic column: SGE GC chromatographic column

[0137] Sol-wax

[0138] L=30.0m

[0139] ID=0.25mm ID

[0140] Film = 0.25 μm

[0141] Column heating: 40°C (hold for 5 minutes) to <20°C / min> to 260°C (hold for 5 minutes)

[0142] Carrier gas: He

[0143] Nozzle: 200℃

[0144] Column flow rate: 1.00mL / min (constant)

[0145] Ionization method: Electron ionization (EI) (70eV)

[0146] Injection mode: 1:10 separation

[0147] Measurement mode: Total ion chromatography (TIC) (m / z = 33 to 600)

[0148] Injection volume: 100μL (gas)

[0149] The same sample was measured at 3 points (N=3), and the average value thereof was provided as the measured value. The area value of each component was calculated from the specific spectrum. In the example, since chlorobenzene was used as the solvent of the hole transport layer, the measurement was performed at m / z=112.

[0150] The measured value obtained by GCMS was compared with the above calibration curve to determine the quantitative value on the calibration curve, and the quantitative value was converted using the volume of the hole transport layer according to the following formula to calculate the quantitative value of chlorobenzene per unit volume of the hole transport layer. The above hole transport layer refers to a region of a film having a thickness, which exists independently as a layer, and the hole transport layer does not include a region of a porous layer that penetrates the electron transport layer.

[0151] Quantitative value (μg / mm 3 ) = quantitative value on the calibration curve (μg) / hole transport layer area × film thickness (mm 3 )

[0152] The solvent for forming the calibration curve was prepared as follows. The solvent was used to form the calibration curve.

[0153] -Preparation of solutions for forming a calibration curve and formation of a calibration curve-

[0154] Standard chlorobenzene was diluted with methanol.

[0155] The obtained solution (1 μL) was transferred to a vial, the vial was heated on a hot plate at 150° C., 100 μL of gas collected from the gas generated from the vial was introduced into the above GCMS apparatus, and the amount of chlorobenzene was measured in the same manner as the above method.

[0156] The hole transport layer preferably includes a p-type semiconductor material, a pyridine compound, and an oxidant.

[0157] The hole transport layer includes a p-type semiconductor material so as to impart a function of transporting holes.

[0158] -P-type semiconductor material-

[0159] The p-type semiconductor material is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include inorganic p-type semiconductor materials and organic p-type semiconductor materials.

[0160] The inorganic p-type semiconductor material is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include CuSCN, CuI, CuBr, NiO, V2O5 and graphene oxide. Among the above-mentioned examples, organic p-type semiconductor materials are preferred.

[0161] The organic p-type semiconductor material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, any organic p-type semiconductor material known in the art may be used.

[0162] Examples of organic p-type semiconductor materials known in the art include oxadiazole compounds, triphenylmethane compounds, pyrazoline compounds, hydrazine compounds, tetraarylbenzidine compounds, stilbene compounds and spiro compounds. The above examples can be used alone or in combination. Among the above examples, spiro compounds are preferred.

[0163] The spiro compound is preferably a compound represented by the following general formula (10).

[0164]

[0165] In the general formula (10), R 31 To R 34 Each is independently a substituted amino group, such as dimethylamino, diphenylamino and naphthyl-4-toluidinyl.

[0166] Specific examples of the spiro compound include, but are not limited to, the following (D-1) to (D-22).

[0167]

[0168]

[0169]

[0170] In addition, as the spiro compound used as the hole transport material, a compound represented by the following general formula (4) is particularly preferably used.

[0171]

[0172] In the general formula (4), R3 is a hydrogen atom or an alkyl group.

[0173] For example, among (D-1) to (D-20), the compound represented by the general formula (4) is (D-7) or (D-10).

[0174] Because the spiro compounds listed above have high hole mobility, and two benzidine skeleton molecules are spirally combined together, thus forming an approximately spherical electron cloud, and due to excellent jumping conductivity between molecules, excellent photoelectric conversion characteristics are exhibited. In addition, spiro compounds are dissolved in various organic solvents due to their high solubility. Since spiro compounds are amorphous (amorphous substances without crystalline structure), spiro compounds are often densely filled in porous electron transport layers. In addition, spiro compounds do not absorb 450nm or longer light, so light is effectively absorbed by photosensitive compounds, which is particularly preferred for solid dye-sensitized solar cell units.

[0175] When the molar amount of the lithium salt in the hole transport layer is determined as X, and the molar amount of the organic p-type semiconductor material in the hole transport layer is determined as Y, the molar ratio X / Y of the lithium salt to the organic p-type semiconductor material is 0.35 or more but 0.65 or less, and more preferably 0.5 or more but 0.6 or less. When the molar ratio X / Y of the lithium salt to the organic p-type semiconductor material is 0.35 or more but 0.65 or less, light durability can be improved.

[0176] The hole transport layer may have a single layer structure formed of a single material, or have a laminated structure including multiple compounds. When the hole transport layer has a laminated structure, in all the layers of the laminate of the hole transport layer, the polymer material is preferably used for the layer close to the second electrode described below. It is advantageous to use a polymer material with excellent film forming properties because the surface of the porous electron transport layer can be flattened and the photoelectric conversion characteristics can be improved. Since the polymer material easily penetrates the porous electron transport layer, the polymer material provides excellent coverage on the surface of the porous electron transport layer, so that the effect of preventing short circuit can be obtained when the electrode is set.

[0177] The polymer material used for the hole transport layer is not particularly limited, and examples thereof include hole transport polymer materials known in the art.

[0178] Examples of the hole transport polymer material include polythiophene compounds, polyphenylenevinylene compounds, polyfluorene compounds, polyphenylene compounds, polyarylamine compounds, and polythiadiazole compounds.

[0179] Examples of the polythiophene compound include poly(3-n-hexylthiophene), poly(3-n-octyloxythiophene), poly(9,9′-dioctylfluorene-co-bithiophene), poly(3,3″′-didodecylquaternary thiophene), poly(3,6-dioctylthiophene[3,2-b]thiophene), poly(2,5-bis(3-decylthiophen-2-yl)thiophene[3,2-b]thiophene), poly(3,4-didecylthiophene-co-thiophene[3,2-b]thiophene), poly(3,6-dioctylthiophene[3,2-b]thiophene-co-thiophene[3,2-b]thiophene), poly(3,6-dioctylthiophene[3,2-b]thiophene-co-thiophene) and poly(3,6-dioctylthiophene[3,2-b]thiophene-co-bithiophene).

[0180] Examples of the polyphenylene vinylene compounds include poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylene vinylene], and poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene)-co-(4,4′-biphenylene vinylene)].

[0181] Examples of the polyfluorene compounds include poly(9,9′-docosylfluorenyl-2,7-diacyl), poly[(9,9-dioctyl-2,7-divinylfluorene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylfluorene)-alt-co-(4,4′-biphenylene)], poly[(9,9-dioctyl-2,7-divinylfluorene)-alt-co-2-methoxy-5-(2-ethylhexyl)-1,4-dioctyl)-phenylene], and poly[(9,9-dioctyl-2,7-diacyl)-co-(1,4-(2,5-dihexyloxy)benzene)).

[0182] Examples of the polyphenylene compound include poly[2,5-dioctyloxy-1,4-phenylene] and poly[2,5-di(2-ethylhexyloxy-1,4-phenylene].

[0183] Examples of the polyarylamine compound include poly[(9,9-dioctylfluorenyl-2,7-diacyl)-alt-co-(N,N'-diphenyl)-N,N'-di(p-hexylphenyl)-1,4-diaminobenzene], poly[(9,9-dioctylfluorenyl-2,7-diacyl)-alt-co-(N,N'-bis(4-octyloxyphenyl)benzidine-N,N'-(1,4-diphenylene)], poly[(N,N'-bis(4-octyloxyphenyl)benzidine-N,N'-(1,4 -biphenylene)], poly[(N,N'-bis(4-(2-ethylhexyloxy)phenyl)benzidine-N,N'-(1,4-biphenylene)], poly[phenylimino-1,4-phenyleneethylene-2,5-dioctyloxy-1,4-phenyleneethylene-1,4-phenylene], poly[p-tolueneimino-1,4-phenyleneethylene-2,5-di(2-ethylhexyloxy)-1,4-phenyleneethylene-1,4-phenylene], and poly[4-(2-ethylhexyloxy)phenylimino-1,4-phenylene].

[0184] Examples of the polythiadiazole compound include poly[(9,9-dioctylfluorenyl-2,7-diacyl)-alt-co-(1,4-benzo(2,1′,3)thiadiazole] and poly(3,4-didecylthiophene-co-(1,4-benzo(2,1′,3)thiadiazole).

[0185] Among the above-mentioned embodiments, polythiophene compounds and polyarylamine compounds are preferred in view of their carrier mobility and ionization potential.

[0186] -Pyridine compounds-

[0187] It is assumed that the pyridine compound exists near the interface of the electron transport layer to prevent reverse transfer of electrons from the electron transport layer (ie, transfer of electrons from the electron transport layer to the hole transport layer).

[0188] The pyridine compound is preferably a pyridine compound represented by the general formula (A) or the general formula (B), and more preferably a tertiary amine compound represented by the general formula (A1) or the general formula (B1). It is advantageous to add the pyridine compound represented by the general formula (A) or the general formula (B) to the hole transport layer because a high open circuit voltage is obtained and high photoelectric conversion performance is obtained. When the hole transport layer includes a tertiary amine compound represented by the general formula (A1) or the general formula (B1), high photoelectric conversion performance with low illumination light and stability over time can be achieved.

[0189]

[0190] In the general formula (A), R1 and R2 are each independently an alkyl group or an aromatic hydrocarbon group, wherein R1 and R2 are the same group or different groups, or may be combined together to form a heterocyclic group including a nitrogen atom.

[0191]

[0192] In the general formula (B), R1 and R2 are each independently an alkyl group or an aromatic hydrocarbon group, wherein R1 and R2 are the same group or different groups, or may be combined together to form a heterocyclic group including a nitrogen atom.

[0193]

[0194] In the general formula (A1) and the general formula (B1), Ar1 and Ar2 are each an aromatic group which may have a substituent, wherein Ar1 and Ar2 may be the same or different, or may be bonded together.

[0195] Specific exemplary compounds of the pyridine compounds represented by the general formula (A) and the general formula (B) will be listed below, but the pyridine compound used in the present invention is not limited to the following exemplary compounds.

[0196]

[0197]

[0198] Next, the following exemplary compounds C-1 to C-20 are listed as specific examples of the tertiary amine compounds represented by the general formula (A1) and the general formula (B1), but the tertiary amine compounds are not limited to the exemplary compounds C-1 to C-20. The above examples may be used alone or in combination.

[0199]

[0200]

[0201]

[0202]

[0203] The amount of the pyridine compound in the hole transport layer is preferably 20 mol% or more but 65 mol% or less, and more preferably 35 mol% or more but 50 mol% or less relative to the hole transport material. When the amount of the pyridine compound is within the above 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 when used for a long time in various environments (especially low temperature environments).

[0204] When the molar amount of the pyridine compound in the photoelectric conversion layer is determined as a, and the molar amount of the lithium salt in the photoelectric conversion layer is determined as b, furthermore, the molar ratio a / b of the pyridine compound to the lithium salt in the photoelectric conversion layer is preferably 2.0 or less, more preferably 1.8 or less, and even more preferably 1.7 or less.

[0205] A molar ratio a / b of 2.0 or less can result in that when light of low illuminance is emitted in a low-temperature environment, high output can be maintained for a longer period of time, and the durability of the photoelectric conversion element can be further improved.

[0206] The molecular weight of the pyridine compound is preferably 140 g / mol or more. When the molecular weight of the pyridine compound is 140 g / mol or more, physical and electrical contact between the electron transport layer and the hole transport layer can be prevented to further reduce reverse electron transfer, because the pyridine compound exists near the interface of the electron transport layer, and therefore, low illumination light can exhibit high photoelectric conversion characteristics.

[0207] -Oxidants-

[0208] The hole transport layer preferably includes an oxidant. Since the hole transport layer includes an oxidant, part of the organic hole transport material becomes a radical cation, and thus the conductivity is improved to enhance the durability and stability of output characteristics.

[0209] Since the organic hole transport material is oxidized by the oxidant, the organic hole transport material exhibits excellent hole conductivity and can be prevented from releasing (reducing) the oxidized state due to the influence of the surrounding environment of the photoelectric conversion layer. Therefore, excellent stability can be obtained over time.

[0210] The oxidizing agent is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include tris(4-bromophenyl)aluminum hexachloroantimonate, silver hexafluoroantimonate, nitrosammonium tetrafluoroborate, silver nitrate and metal complexes. The above-mentioned examples can be used alone or in combination. Among the above-mentioned examples, metal complexes are preferred.

[0211] Examples of the metal complex include a metal complex having a structure consisting of a metal cation, a ligand, and an anion.

[0212] The metal cation is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include cations of chromium, manganese, zinc, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium, osmium, iridium, vanadium, gold, platinum, etc. Among the examples listed above, cations of manganese, zinc, iron, cobalt, nickel, copper, ruthenium, silver and vanadium are preferred, and cobalt complexes are more preferred.

[0213] The ligand preferably includes a five-membered heterocyclic ring and / or a six-membered heterocyclic ring containing at least one nitrogen, and may include a substituent. Specific examples thereof include, but are not limited to, the following compounds.

[0214]

[0215]

[0216] Examples of anions include hydride ions (H - ), fluoride ion (F - ), chloride ion (Cl - ), bromide ion (Br - ), iodide ion (I - ), hydroxide ion (OH - ), cyanide ion (CN - ), nitrate ion (NO3 - ), nitrite ion (NO2 - ), hypochlorite ion (ClO - ), chlorite ion (ClO2 - ), chlorate ion (ClO3 - ), perchlorate ion (ClO4 - ), permanganate ion (MnO4 - ), acetate ion (CH3COO - ), bicarbonate ion (HCO3 - ), dihydrogen phosphate ion (H2PO4 - ), hydrogen sulfate ion (HSO4 - ), hydrogen sulfide ion (HS - ), thiocyanate ion (SCN - ), tetrafluoroborate ion (BF4 - ), hexafluorophosphate ion (PF6 - ), tetracyanoborate ion (B(CN)4 - ), dicyandiamide ion (N(CN)2 - ), p-toluenesulfonate ion (TsO - ), trifluoromethanesulfonate ion (CF3SO2 - ), bis(trifluoromethanesulfonyl)ammonium ion (N(SO2CF3)2 - ), tetrahydroaluminate ion ([Al(OH)4] - or [Al(OH)4(H2O)2] - ), dicyanosilver(I) ion ([Ag(CN)2] - ), tetrahydrochromate(III) ion ([Cr(OH)4] - ), tetrachloroaurate(III) ion ([AuCl4] - ), oxide ions (O 2- ), sulfide ion (S 2- ), peroxide ions (O2 2- ), sulfate ion (SO4 2- ), sulfite ion (SO3 2- ), thiosulfate (S2O3 2-), carbonate ion (CO3 2- ), chromate ion (CrO4 2- ), dichromate ion (Cr2O7 2- ), hydrogen phosphate ion (HPO4 2- ), tetrahydrozincate (II) ion ([Zn(OH)4] 2- ), tetracyanozincate (II) ion ([Zn(CN)4] 2- ), tetrachlorocuprate(II) ion ([CuCl4] 2- ), phosphate ion (PO4 3- ), hexacyanoferrate (III) ion ([Fe(CN)6] 3- ), bis(thiosulfate)silver(I) ion ([Ag(S2O3)2] 3- ) and ferrocyanide(II) ions ([Fe(CN)6] 4- ). Among the above-mentioned examples, tetrafluoroborate ion, hexafluorophosphate ion, tetracyanoborate ion, bis(trifluoromethanesulfonyl)amide ion and perchlorate ion are preferred.

[0217] As the metal complex, a trivalent cobalt complex is particularly preferably added. When the trivalent cobalt complex is added as an oxidant, the hole transport material can be oxidized to stabilize the hole transport material, thereby improving the hole transport performance.

[0218] For example, in the present invention, a trivalent cobalt complex is preferably used as the cobalt complex to be added to the hole transport layer forming coating liquid, but the hole transport layer of the photoelectric conversion element obtained using the hole transport layer forming coating liquid preferably includes a divalent cobalt complex. This is because the trivalent cobalt complex is mixed with the hole transport material to oxidize the hole transport material, so the cobalt complex becomes divalent. In other words, in the present invention, the photoelectric conversion layer preferably further includes a divalent cobalt complex.

[0219] It is particularly preferred that the trivalent cobalt complex hardly remains, especially in the hole transport layer of the photoelectric conversion element, and almost all of the cobalt complex is converted into a divalent cobalt complex. As a result, the hole transport performance is improved and stabilized, the high output and output retention rate are improved, and the effect can be manifested in different temperature environments.

[0220] For example, the valence state of the cobalt complex contained in the hole transport layer can be determined by XAFS spectroscopy. XAFS spectroscopy is an abbreviation for X-ray absorption fine structure spectroscopy. For example, a sample is irradiated with X-rays, and its absorption is measured to obtain an XAFS spectrum.

[0221] In the XAFS spectrum, the structure close to the absorption edge is called the S-ray absorption near-edge structure (XANES), and the wide-range X-ray absorption fine structure that appears on the energy side of about 100 eV or more higher than the absorption edge is called the extended X-ray absorption fine structure (EXAFS). Information related to the valence state of the target atom or its structure can be mainly obtained from the aforementioned XANES. In this case, for example, the XAFS spectrum of the divalent cobalt complex powder and the XAFS spectrum of the trivalent cobalt complex powder are measured respectively. By comparing the XAFS spectrum of the cobalt complex contained in the hole transport layer with the XAFS spectra of the divalent and trivalent cobalt complex powder samples, the valence state of the cobalt complex contained in the hole transport layer can be determined.

[0222] Fig.18 FIG. 2 shows an XAFS spectrum of a photoelectric conversion module (photoelectric conversion module of Example 1) using an example of the photoelectric conversion element of the present invention obtained in the above manner. Fig.18 As shown, the cobalt complex included in the hole transport layer of the photoelectric conversion module using the example of the photoelectric conversion element of the present invention matches the spectrum of the divalent cobalt complex powder well, and does not have a region that matches the spectrum of the trivalent cobalt complex powder. Therefore, it can be judged that almost all of the cobalt complex included is a divalent cobalt complex.

[0223] The trivalent cobalt complex added to the hole transport layer forming coating liquid is preferably a cobalt complex represented by the structural formula (4) or the structural formula (5).

[0224]

[0225] In the structural formulas (4) and (5), R8 to R 10 are respectively a hydrogen atom, a methyl group, an ethyl group, a tert-butyl group or a trifluoromethyl group, and X is any one of the structural formulas (6) to (9).

[0226] BF4 structure (6)

[0227] PF6 Structure (7)

[0228]

[0229] In the structural formulae (6) to (9), X is more preferably the structural formula (8). X represented by the structural formula (8) is advantageous because the hole transport material is stably maintained in an oxidized state.

[0230] Specific examples of the above-mentioned cobalt complex include, but are not limited to, the following (F-1) to (F-24).

[0231]

[0232]

[0233]

[0234] The amount of the oxidant is preferably 0.5 parts by mass or more but 50 parts by mass or less, and more preferably 5 parts by mass or more but 30 parts by mass or less, relative to 100 parts by mass of the hole transport material. The entire portion of the hole transport material does not need to be oxidized by adding the oxidant. As long as at least a portion of the hole transport material is oxidized, the addition of the oxidant is effective.

[0235] In addition, the lithium cations of the lithium salt represented by the general formula (1) may migrate to the electron transport layer. For example, half or more of the lithium ions may be included in the electron transport layer described below.

[0236] The inner region below the electron transport layer is more preferably filled with the hole transport layer used in the present invention because the output can be further improved. In this case, the hole transport layer provided inside the electron transport layer is also treated as the hole transport layer.

[0237] <<Electron Transport Layer>>

[0238] The photoelectric conversion element includes an electron transport layer including a photosensitive compound.

[0239] The electron transport layer is preferably disposed between the first electrode and the photosensitive compound.

[0240] The purpose of forming the electron transport layer is to transport the electrons generated by the photosensitive compound to the first electrode or the hole blocking layer. Therefore, the electron transport layer is preferably disposed close to the first electrode or the hole blocking layer.

[0241] The structure of the electron transport layer is not particularly limited and can be appropriately selected according to the intended purpose. When at least two photoelectric conversion elements are arranged adjacent to each other, the electron transport layer of one photoelectric conversion element may extend to the electron transport layer of another photoelectric conversion element, but the electron transport layer of one photoelectric conversion element is preferably arranged not to extend from the electron transport layer of another photoelectric conversion element. In addition, the structure of the electron transport layer may be a single-layer structure or a multilayer structure in which a plurality of layers are laminated.

[0242] The electron transport layer includes an electron transport material, and may further include other materials as necessary.

[0243] The electron transport material is not particularly limited and can be appropriately selected depending on the intended purpose. The electron transport material is preferably a semiconductor material.

[0244] The semiconductor material is preferably in the form of particles, which are combined together to form a porous film. The photosensitive compound is adsorbed on the surface of the semiconductor particles constituting the porous electron transport layer by chemical or physical means.

[0245] The semiconductor material is not particularly limited, and any semiconductor material known in the art may be used. Examples thereof include elemental semiconductors, compound semiconductors, and compounds having a perovskite structure.

[0246] Examples of semiconductor elements include silicon and germanium.

[0247] Examples of compound semiconductors include metal sulfide compounds. Specific examples thereof include oxide semiconductors such as titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc., sulfide semiconductors such as cadmium, zinc, lead, silver, antimony, bismuth, etc., selenide semiconductors such as cadmium, lead, etc., telluride semiconductors such as cadmium, and other compound semiconductors. Examples of the above-mentioned other compound semiconductors include phosphide semiconductors such as zinc, gallium, indium, cadmium, etc., gallium arsenide, copper indium selenide semiconductors, and copper indium sulfide semiconductors.

[0248] Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.

[0249] Among the examples listed above, oxide semiconductors are preferred, and titanium oxide, zinc oxide, tin oxide, and niobium oxide are more preferred. It is advantageous to use titanium oxide as an electron transport material for an electron transport layer because a high open circuit voltage is obtained due to the high conduction band of titanium oxide, thereby achieving excellent photoelectric conversion performance.

[0250] The examples listed above may be used alone or in combination. In addition, the crystal type of the semiconductor material is not particularly limited and may be appropriately selected depending on the intended purpose. The semiconductor material may be single crystal, polycrystalline or amorphous.

[0251] The average grain diameter of the primary particles of semiconductor material is not particularly limited, and can be suitably selected according to the intended purpose.Its average grain diameter is preferably 1nm or larger but 100nm or smaller, and more preferably 5nm or larger but 50nm or smaller.In addition, the semiconductor material with particle diameter greater than the above-mentioned average grain diameter can be mixed or laminated, and this may cause the raising of conversion efficiency due to the influence of scattered incident light.In this case, the number average grain diameter with the semiconductor material of larger particle diameter is preferably 50nm or larger but 500nm or smaller.

[0252] The average thickness of the electron transport layer is not particularly limited and can be appropriately selected according to the intended purpose. Its average thickness is preferably 50 nm or more but 100 μm or less, more preferably 100 nm or more but 50 μm or less, and even more preferably 120 nm or more but 10 μm or less. The average thickness of the electron transport layer within the above preferred range is advantageous because a sufficient amount of photosensitive compound can be ensured per unit projected area, a high light capture rate can be maintained, the dispersion distance of injected electrons tends not to increase, and the charge loss due to recombination can be reduced.

[0253] The production method of the electron transport layer is not particularly limited and can be appropriately selected according to the intended purpose. Examples include: a method of forming a thin film in a vacuum (e.g., sputtering), a wet film formation method, and a wet printing method. In the above-mentioned embodiments, considering the production cost, the wet film formation method is preferred, and more preferably, a paste (a dispersion of a semiconductor material) in which a powder or sol of a semiconductor material is dispersed is prepared, and the paste is applied to a first electrode or a hole blocking layer used as an electron collector electrode substrate.

[0254] The wet film forming method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include dip coating, spray coating, wire bar coating, spin coating, roll coating, blade coating, gravure coating, and die coating.

[0255] As the wet printing method, various methods such as relief printing, offset printing, gravure printing, intaglio printing, flexographic printing, and screen printing can be used.

[0256] Examples of methods for producing a dispersion of a semiconductor material include a method of mechanically pulverizing the material by a grinding device known in the art. According to the above method, a single particulate semiconductor material or a mixture of a semiconductor and a resin is dispersed in water or a solvent to produce a dispersion of a semiconductor material.

[0257] Examples of the resin include polymers or copolymers of vinyl compounds (e.g., styrene, vinyl acetate, acrylate, and methacrylate), silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, cellulose ester resins, cellulose ether resins, polyurethane resins, phenolic resins, epoxy resins, polycarbonate resins, polyacrylate resins, polyamide resins, and polyimide resins. The above-listed examples may be used alone or in combination.

[0258] Examples of the solvent include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.

[0259] Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol and α-terpineol.

[0260] Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0261] Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.

[0262] Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane and dioxane.

[0263] Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0264] Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, iodomethane, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene and 1-chloronaphthalene.

[0265] Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.

[0266] The above-listed examples may be used alone or in combination.

[0267] The dispersion liquid including the semiconductor material or the paste including the semiconductor material obtained by the sol-gel method may include an acid, a surfactant, or a chelating agent to prevent re-aggregation of particles.

[0268] Examples of the acid include hydrochloric acid, nitric acid, and acetic acid.

[0269] Examples of the surfactant include polyoxyethylene octylphenyl ether.

[0270] Examples of the chelating agent include acetylacetone, 2-aminoethanol and ethylenediamine.

[0271] Furthermore, in order to improve film-forming properties, it is also advantageous to add a thickener.

[0272] Examples of thickeners include polyethylene glycol, polyvinyl alcohol and ethylcellulose.

[0273] After applying the semiconductor material, sintering or irradiation with microwaves, electron beams or lasers may be performed to electrically connect particles of the semiconductor material to improve film strength or adhesion to the substrate. One of the above treatments may be performed alone, or two or more of the above treatments may be performed in combination.

[0274] When firing of an electron transport layer including a semiconductor material is performed, the firing temperature is not particularly limited and can be appropriately selected according to the intended purpose. When the firing temperature is too high, the resistance of the substrate may increase, or the substrate may melt. Therefore, the firing temperature is preferably 30°C or higher but 700°C or lower, and more preferably 100°C or higher but 600°C or lower. In addition, the firing time is not particularly limited and can be appropriately selected according to the intended purpose. The firing time is preferably 10 minutes or longer, but 10 hours or shorter.

[0275] When the electron transport layer formed by the semiconductor material is subjected to microwave irradiation, the irradiation time is not particularly limited and can be appropriately selected according to the intended purpose. The irradiation time is preferably 1 hour or less. The irradiation can be performed from the side where the electron transport layer is formed, or from the other side where the electron transport layer is not formed.

[0276] In order to increase the surface area of ​​the electron transport layer or improve the electron injection efficiency of the photosensitive compound described below, for example, after firing the electron transport layer formed of the semiconductor material, chemical plating can be performed using an aqueous solution of titanium tetrachloride or a mixed solution with an organic solvent, or electrochemical plating can be performed using an aqueous solution of titanium trichloride.

[0277] The film obtained by firing semiconductor material particles with a diameter of tens of nanometers forms a porous state. The film with a porous nanostructure has a very large surface area, and its surface area can be expressed by a roughness factor. The roughness factor is a numerical value representing the actual area of ​​the inner side of the hole relative to the area of ​​the semiconductor particles applied on the first substrate. Therefore, the larger the roughness coefficient, the better. Considering the relationship with the average thickness of the electron transport layer, the roughness factor is preferably 20 or more.

[0278] Furthermore, a photosensitive compound may be disposed between the electron transport layer and the hole transport layer.

[0279] <<Photosensitive Compounds>>

[0280] In the present invention, in order to further improve the conversion efficiency, it is preferred that the photosensitive compound is adsorbed on the surface of the electron transport semiconductor of the electron transport layer.

[0281] The photosensitizing compound is not particularly limited as long as the photosensitizing compound is a compound that is excited by excitation light to be used, and can be appropriately selected depending on the intended purpose. Examples thereof include: a Japanese translation of PCT International Application Publication No. 07-500630, Japanese Unexamined Patent Application Publication No. 10-233238, Japanese Unexamined Patent Application Publication No. 2000-26487, Japanese Unexamined Patent Application Publication No. 2000-323191, and a metal complex disclosed in Japanese Unexamined Patent Application Publication No. 2001-59062, a coumarin compound disclosed in Japanese Unexamined Patent Application Publication No. 10-93118, Japanese Unexamined Patent Application Publication No. 2002-164089, Japanese Unexamined Patent Application Publication No. 2004-95450 and J. Phys. Chem. C, 7224, Vol. 111 (2007), Japanese Unexamined Patent Application Publication No. 2004-95450 and Chem. Commun., 4887 (2 007), Japanese Unexamined Patent Application Publication No. 2003-264010, Japanese Unexamined Patent Application Publication No. 2004-63274, Japanese Unexamined Patent Application Publication No. 2004-115636, Japanese Unexamined Patent Application Publication No. 2004-200068, Japanese Unexamined Patent Application Publication No. 2004-235052, J. Am. Chem. Soc., 12218, Vol. 126 (2004), Chem. Commun., 3036 (2003) and Angew. Chem. Int. Ed., 1923, Vol. 47 (2008), indoline compounds disclosed in J. Am. Chem. Soc., 16701, Vol. 128 (2006) and J. Am. Chem. Soc., 14256, Vol. 128 (2006), thiophene compounds disclosed in Japanese Unexamined Patent Application Publication No. 11-86916, Japanese Unexamined Patent Application Publication No. 11-214730, Japanese Unexamined Patent Application Publication No. 2000-106224, Japanese Unexamined Patent Application Publication No. 2001-76773 and Japanese Unexamined Patent Application Publication No. 2003-7359, cyanine dyes disclosed in Japanese Unexamined Patent Application Publication No. The merocyanine dyes disclosed in Japanese Unexamined Patent Application Publication No. 11-214731, Japanese Unexamined Patent Application Publication No. 11-238905, Japanese Unexamined Patent Application Publication No. 2001-52766, Japanese Unexamined Patent Application Publication No. 2001-76775 and Japanese Unexamined Patent Application Publication No. 2003-7360, Japanese Unexamined Patent Application Publication No. 10-92477, Japanese Unexamined Patent Application Publication No. 11-273754, Japanese 9-arylxanthene compounds disclosed in Japanese Unexamined Patent Application Publication No. 11-273755 and Japanese Unexamined Patent Application Publication No. 2003-31273, triarylmethane compounds disclosed in Japanese Unexamined Patent Application Publication No. 10-93118 and Japanese Unexamined Patent Application Publication No. 2003-31273, Japanese Unexamined Patent Application Publication No. 09-199744, Japanese Unexamined Patent Application Publication No. 10-2332 38. Phthalocyanine compounds and polyporphyrin compounds disclosed in Japanese Unexamined Patent Application Publication No. 11-204821, Japanese Unexamined Patent Application Publication No. 11-265738, J. Phys. Chem., 2342, Vol. 91 (1987), J. Phys. Chem. B, 6272, Vol. 97 (1993), Electroanal. Chem., 31, Vol. 537 (2002), Japanese Unexamined Patent Application Publication No. 2006-032260, J. Porphyrins Phthalocyanines, 230, Vol. 3 (1999), Angew. Chem. Int. Ed., 373, Vol. 46 (2007), and Langmuir, 5436, Vol. 24 (2008).

[0282] Among the examples listed above, metal complex compounds, coumarin compounds, polyene compounds, indoline compounds and thiophene compounds are preferred, and compounds represented by the following structural formulas (1), (2) and (3) available from Mitsubishi Paper Mills Limited are also preferably used.

[0283]

[0284]

[0285] Examples of the photosensitizing compound to be more preferably used include compounds represented by the following general formula (5).

[0286]

[0287] In the general formula (5), X 11 and X 12 Each is independently an oxygen atom, a sulfur atom or a selenium atom.

[0288] R 11 is a methane group which may have a substituent. Specific examples of the substituent include an aryl group (eg, a phenyl group and a naphthyl group) and a heterocyclic ring (eg, a thienyl group and a furfuryl group).

[0289] R 12 is an alkyl group, an aryl group or a heterocyclic group, which may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a 2-propyl group and a 2-ethylhexyl group. Examples of the aryl group and examples of the heterocyclic group are as described above.

[0290] R 13 It is an acid group, such as carboxylic acid, sulfonic acid, phosphonic acid, boric acid and phenol. 13 The number can be one, two or more.

[0291] Z1 and Z2 are each independently a substituent constituting a cyclic structure. Examples of Z1 include condensed hydrocarbon compounds (e.g., benzene rings and naphthalene rings) and heterocycles (e.g., thiophene rings and furan rings), each of which may have a substituent. Specific examples of substituents include the above-mentioned alkyl and alkoxy (e.g., methoxy, ethoxy and 2-isopropyl). Specific examples of Z2 include the following (A-1) to (A-22).

[0292] Note that m is an integer from 0 to 2.

[0293]

[0294] Among the compounds listed above, the compounds represented by the general formula (6) are more preferably used.

[0295]

[0296] In the general formula (6), n is an integer of 0 or 1; R3 is an aryl group which may have a substituent, or a substituent represented by any of the following three structural formulas.

[0297]

[0298] Specific examples of the photosensitizing compounds represented by the general formulae (5) and (6) include, but are not limited to, the following (B-1) to (B-41).

[0299]

[0300]

[0301]

[0302]

[0303]

[0304] Furthermore, examples of the photosensitive compound preferably used include compounds represented by the general formula (7).

[0305]

[0306] In the general formula (7), Ar1 and Ar2 are each an aryl group which may have a substituent; R1 and R2 are each a C4 to C10 straight chain or branched alkyl group; and X is a substituent represented by any of the following structural formulas.

[0307]

[0308] Among the photosensitizing compounds represented by the general formula (7), the compounds represented by the general formula (8) are more preferably used.

[0309]

[0310] In the general formula (7), Ar4 and Ar5 are each a phenyl group which may have a substituent or a naphthyl group which may have a substituent; and Ar6 is each a phenyl group which may have a substituent or a thienyl group which may have a substituent.

[0311] Specific example compounds of the photosensitizing compounds represented by the general formulae (7) and (8) will be listed below, but the photosensitizing compound used in the present invention is not limited to the following example compounds.

[0312]

[0313]

[0314]

[0315]

[0316]

[0317] Among the photosensitive compounds listed above, one of the photosensitive compounds can be used, or two or more photosensitive compounds can be used in combination. As an LED light source, light sources of different hues, such as warm colors, cool colors, and white colors, are used, and their spectra are different depending on the hue. For example, a light source with a color temperature of 3000K has a relatively strong hue in the 600nm region and emits red light. The light emitted by a light source with a color temperature of 5000K is daytime white and is balanced as a whole. A light source with a color temperature greater than 6500K has a relatively strong hue in the 450nm region and emits light of a blue daylight color. Therefore, it is preferred to maintain high output even when the color temperature of the LED used changes. In this case, it is advantageous to mix different photosensitive compounds because the output variation caused by the color temperature may be reduced.

[0318] As a method of adsorbing the first photosensitive compound on the surface of the semiconductor material of the electron transport layer, available methods are a method of immersing the electron transport layer containing the semiconductor material in a solution or dispersion of the photosensitive compound, and a method of applying the solution or dispersion of the photosensitive compound to the electron transport layer to allow the photosensitive compound to be adsorbed thereon. When the electron transport layer containing the semiconductor material is immersed in the solution or dispersion of the photosensitive compound, immersion, dipping, roller coating, or air knife coating can be used.

[0319] When the photosensitive compound is adsorbed on the electron transport layer by applying a solution or dispersion of the photosensitive compound to the electron transport layer, wire bar coating, slide hopper coating, extrusion coating, curtain coating, spin coating or spray coating may be used. In addition, carbon dioxide or the like may be used for adsorption in a supercritical fluid.

[0320] When the photosensitive compound is allowed to be adsorbed on the semiconductor material, a condensing agent may be used.

[0321] The condensation polymerization agent may be an agent that exhibits a catalytic effect to physically or chemically bind the photosensitive compound to the surface of the semiconductor material, or an agent that exhibits a stoichiometric effect to favorably shift the chemical equilibrium. In addition, a thiol or hydroxyl compound may be further added as a condensation auxiliary agent.

[0322] Examples of the solvent for dissolving or dispersing the photosensitive compound include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.

[0323] Examples of the alcohol solvent include methanol, ethanol, and isopropanol.

[0324] Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0325] Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.

[0326] Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane and dioxane.

[0327] Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0328] Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, iodomethane, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene and 1-chloronaphthalene.

[0329] Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.

[0330] The above-listed examples may be used alone or in combination.

[0331] When the aggregation between particles of each compound is prevented, the photosensitive compound can function more effectively, although it depends on the photosensitive compound used. Therefore, an aggregation dissociation agent can be used in combination. Examples of the aggregation dissociation agent include steroidal compounds (such as cholic acid and chenodeoxycholic acid), long-chain alkyl carboxylic acids, and long-chain alkyl phosphonic acids.

[0332] The amount of the aggregation dissociation agent is preferably 0.5 mol parts or more but 100 mol parts or less, and more preferably 10 mol parts or more but 50 mol parts or less, relative to 1 mol parts of the photosensitive compound.

[0333] Preferably, the temperature at which the photosensitive compound or the combination of the photosensitive compound and the aggregation dissociation agent is adsorbed on the surface of the semiconductor material constituting the electron transport layer is -50°C or higher, but 200°C or lower. The adsorption time is preferably 5 seconds or longer but 1000 hours or shorter, more preferably 10 seconds or longer but 500 hours or shorter, and even more preferably 1 minute or longer but 150 hours or shorter. The adsorption is preferably carried out in the dark. In addition, the adsorption can be carried out in a static or stirring state.

[0334] The stirring method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include methods using a stirrer, a ball mill, a paint conditioner, a sand mill, a grinder, a disperser, or ultrasonic dispersion.

[0335] In addition, the photoelectric conversion element of the present invention may include a perovskite layer. It is advantageous to use a perovskite layer in a photoelectric conversion element. The perovskite layer is a layer including perovskite and is configured to absorb light to sensitize the electron transport layer. Therefore, the perovskite layer is preferably arranged close to the electron transport layer.

[0336] The perovskite compound is a composite material of an organic compound and an inorganic compound, and is represented by the following general formula (9).

[0337] X α Y β M γ General formula (9)

[0338] In the general formula (9), the ratio of α:β:γ is 3:1:1, and β and γ are both integers greater than 1. For example, X may be a halogen ion, Y may be an alkylamine compound ion, and M may be a metal ion.

[0339] X in the general formula (9) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include halogen ions such as chloride ion, bromide ion and iodide ion. The above-listed examples may be used alone or in combination.

[0340] Examples of Y in the general formula (9) include alkylamine compound ions (e.g., methylamine ion, ethylamine ion, n-butylamine ion, and formamidine ion), cesium, potassium, and rubidium. In addition, for the lead halide-methylammonium perovskite compound, when the halogen ion is Cl, the peak λ of the light absorption spectrum is max About 350nm, when the halogen ion is Br, the peak value of the light absorption spectrum is λ max is about 410nm. When the halogen ion is I, the peak value of the light absorption spectrum is λ max is about 540nm. Due to the peak λ of the light absorption spectrum max Moving to the longer wavelength side in sequence, the available spectral width (bandwidth) therefore differs.

[0341] M in the general formula (9) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include metals such as lead, indium, antimony, tin, copper and bismuth.

[0342] Furthermore, the perovskite layer preferably has a layered perovskite structure in which layers each formed of a halide metal and layers each formed of a pair of quasi-organic cation molecules are alternately laminated.

[0343] The method for forming the perovskite layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a method of dissolving or dispersing a metal halide or an alkylamine halide to prepare a solution, applying the solution, and drying the applied solution.

[0344] Furthermore, examples of a method for forming a perovskite layer include a two-step precipitation method of applying a solution obtained by dissolving or dispersing a metal halide and drying, and immersing the product in a solution obtained by dissolving an alkylamine halide to form a perovskite compound.

[0345] In addition, examples of the method for forming the perovskite layer include a method of applying a solution obtained by dissolving or dispersing a metal halide and a halide alkylamine with the addition of a poor solvent for the perovskite compound (a solvent having a low solubility for the perovskite compound) to precipitate crystals. In addition, examples of the method for forming the perovskite layer include depositing a metal halide by vapor deposition in an atmosphere filled with a gas containing methylamine.

[0346] Among the examples listed above, preferred is a method of precipitating crystals by adding a poor solvent for the perovskite compound to dissolve or disperse a metal halide and an alkylamine halide to obtain a solution.

[0347] The method for applying the solution is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include dipping, spin coating, spray coating, dip coating, roller coating, and air knife coating. In addition, the method for applying the solution may be a method of precipitating in a supercritical fluid using carbon dioxide or the like.

[0348] In addition, the perovskite layer may include a photosensitizing compound. The sensitizing dye used as the photosensitizing compound is not particularly limited as long as the sensitizing dye is a compound excited by the excitation light used, and can be appropriately selected according to the intended purpose. Examples thereof include the photosensitizing compounds listed above.

[0349] The method for forming the perovskite layer including the sensitizing dye is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include a method of mixing a perovskite compound with a photosensitive compound and a method of adsorbing a photosensitive compound after forming the perovskite layer.

[0350] <Second Electrode>

[0351] The second electrode may be formed on the hole transport layer, or on the metal oxide of the hole transport layer. In addition, the second electrode may be the same as the first electrode. When the strength of the resulting photoelectric conversion element is sufficiently maintained, it is not necessary to provide a second substrate.

[0352] Examples of the second electrode material include metals, carbon compounds, conductive metal oxides, and conductive polymers.

[0353] Examples of metals include platinum, gold, silver, copper, and aluminum.

[0354] Examples of carbon compounds include graphite, fullerene, carbon nanotube, and graphene.

[0355] Examples of the conductive metal oxide include ITO, FTO, and ATO.

[0356] Examples of conductive polymers include polythiophene and polyaniline.

[0357] The above-listed examples may be used alone or in combination.

[0358] The second electrode may be formed on the hole transport layer by an appropriate method such as coating, lamination, vapor deposition, CVD, or bonding, depending on the material used or the type of the hole transport layer.

[0359] In the photoelectric conversion element of the present invention, at least one of the first electrode and the second electrode is preferably substantially transparent. A preferred embodiment is that the side of the first electrode is transparent and allows incident light to enter from the side of the first electrode. In this case, the material reflecting light is preferably used for the side of the second electrode. As the material reflecting light, it is preferred to use metal, glass or a plastic or thin metal film on which a conductive oxide is deposited by vapor deposition. In addition, it is also effective to set an anti-reflection layer on the incident light side.

[0360] <Second Substrate>

[0361] The second substrate is not particularly limited. Any substrate known in the art can be used as the second substrate. Examples thereof include substrates such as glass, plastic film and ceramic. In order to improve the adhesion of the contact area between the second substrate and the sealing member, a rough surface texture (convex-concave shape) can be imparted.

[0362] The method of imparting a rough surface texture is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include sandblasting, water blasting, polishing, chemical etching, and laser processing.

[0363] As a method for improving the adhesion between the second substrate and the sealing member, for example, organic matter deposited on the surface of the second substrate can be removed, or the hydrophilicity of its surface can be improved. The method for removing organic matter deposited on the surface of the second substrate is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include UV ozone washing and enzyme ion treatment.

[0364] <Sealing member>>

[0365] The sealing member can be used for the photoelectric conversion element of the present invention, and the use of the sealing member is effective. The sealing member can seal at least the electron transport layer and the hole transport layer to separate from the external environment of the photoelectric conversion element. In other words, the photoelectric conversion element of the present invention preferably also includes a sealing member, which is configured to seal the photoelectric conversion layer and separate from the external environment of the photoelectric conversion element.

[0366] Any member known in the art can be used as a sealing member, as long as the sealing member is a member that can inhibit excessive moisture or oxygen from entering the inside of the sealing member from the external environment. In addition, the sealing member has the effect of preventing mechanical damage that may be caused when the photoelectric conversion element is pressed from the outside. As long as this effect can be applied, any member known in the art can be used as a sealing member.

[0367] The sealing system is roughly divided into "frame sealing" and "plane sealing". In the "frame sealing", the sealing member is arranged on the peripheral area of ​​the power generation area (which is composed of the photoelectric conversion layer of the photoelectric conversion layer of the photoelectric conversion element) and bonded to the second substrate, and in the "plane sealing", the sealing member is arranged on the entire plane of the power generation area and bonded to the second substrate. The former "frame sealing" can form a hollow part in the sealing member, and the water content or oxygen content in the sealing member can be appropriately adjusted. In addition, the second electrode does not contact the sealing member, which leads to the effect of reducing the possibility of the second electrode being peeled off. At the same time, the latter "plane sealing" has an excellent effect of preventing excessive water or oxygen from entering from the outside, and can ensure a large contact area with the sealing member. Therefore, a high sealing strength can be obtained, and when a flexible substrate is used as the first substrate, the plane sealing is particularly suitable.

[0368] The type of sealing member is not particularly limited and can be appropriately selected according to the intended purpose. Examples thereof include curing resins and low melting point glass resins. Curing resins are not particularly limited as long as the curing resin is a resin that can be cured with light or heat and can be appropriately selected according to the intended purpose. Among light-curing or heat-curing resins, acrylic resins and epoxy resins are preferably used.

[0369] As the cured product of the acrylic resin, any material known in the art may be used as long as the cured product is a product obtained by curing a monomer or an oligomer containing an acrylic group in its molecule.

[0370] As the cured product of the epoxy resin, any material known in the art may be used as long as the cured product is a product obtained by curing a monomer or an oligomer containing an epoxy group in its molecule.

[0371] Examples of epoxy resins include water-dispersible epoxy resins, non-solvent epoxy resins, solid epoxy resins, heat-curing epoxy resins, curing agent mixed epoxy resins, and UV-curing epoxy resins. Among the examples listed above, heat-curing epoxy resins and UV-curing epoxy resins are preferred, and UV-curing epoxy resins are more preferred. The UV-curing epoxy resin may be heated. Even after the UV-curing epoxy resin is cured with UV radiation, it is preferably heated.

[0372] Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, novolac epoxy resins, alicyclic epoxy resins, long-chain aliphatic epoxy resins, glycidylamine epoxy resins, glycidylether epoxy resins, and glycidylester epoxy resins. The above-listed examples may be used alone or in combination.

[0373] The epoxy resin is preferably mixed with a curing agent or various additives as necessary.

[0374] The curing agent is classified into amine-based curing agents, acid anhydride-based curing agents, polyamide-based curing agents and other curing agents, and can be appropriately selected according to the intended purpose.

[0375] Examples of amine-based curing agents include aliphatic polyamines (eg, diethylenetriamine and triethylenetetramine) and aromatic polyamines (eg, m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone).

[0376] Examples of the acid anhydride-based curing agent include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnaphthalic anhydride, pyromellitic anhydride, HET anhydride, and dodecenylsuccinic anhydride.

[0377] Examples of other curing agents include imidazoles and polythiol. The above-listed examples may be used alone or in combination.

[0378] Examples of additives include fillers, gap fillers, polymerization initiators, desiccants (moisture absorbents), curing accelerators, coupling agents, flexibilizers, colorants, flame retardant aids, antioxidants, and organic solvents. Among the examples listed above, fillers, gap fillers, curing accelerators, polymerization initiators, and desiccants (moisture absorbents) are preferred, and fillers and polymerization initiators are more preferred.

[0379] Fillers can effectively prevent the ingress of moisture and oxygen, reduce volume shrinkage during curing, reduce the amount of waste gas generated during curing or heating, improve mechanical strength, control thermal conductivity or fluidity, and are very effective in maintaining stable production under various environments. In particular, the output characteristics and durability of photoelectric conversion elements are affected not only by the ingress of moisture or oxygen, but also by the waste gas generated during the curing or heating of the sealing member. When the photoelectric conversion element is stored in a high-temperature environment, the waste gas generated during the heating process can significantly affect the output characteristics.

[0380] In this case, a filler, a caulking agent, or a desiccant is added to the sealing member. As a result, such additives themselves can inhibit the entry of moisture or oxygen, and the amount of the sealing member to be used can be reduced, so the generation of waste gas can be reduced. Adding such additives is effective not only for curing, but also when the photoelectric conversion element is stored in a high temperature environment.

[0381] Filler is not particularly limited and can be appropriately selected according to the intended purpose. For example, inorganic fillers are preferably used, such as crystalline or amorphous silica, talc, aluminum oxide, aluminum nitride, silicon nitride, calcium silicate and calcium carbonate. The examples listed above can be used alone or in combination. The average primary particle size of the filler is preferably 0.1 μm or larger but 10 μm or smaller, and more preferably 1 μm or larger but 5 μm or smaller. When the average primary particle diameter is within the above-mentioned preferred range, the entry of moisture or oxygen can be fully suppressed, the appropriate viscosity of the sealing member can be obtained, the adhesion to the substrate and the defoaming property can be improved, the sealing width can be controlled, and the ideal processing performance can be obtained.

[0382] The amount of the filler is preferably 10 parts by mass or more but 90 parts by mass or less relative to 100 parts by mass of the entire sealing member, and more preferably 20 parts by mass or more but 70 parts by mass or less. When the amount of the filler is within the above range, the entry of moisture or oxygen can be fully suppressed, the appropriate viscosity of the sealing member can be obtained, and ideal adhesion and processing properties can be obtained.

[0383] The gap filler, also called a gap control agent or a spacer, can control the gap formed in the sealing area. When the sealing member is applied to the first substrate or the first electrode, the second substrate is placed thereon, and the stacked structure is sealed, the gap at the sealing area matches the size of the gap filler because the epoxy resin includes the gap filler. As a result, the gap in the sealing area can be easily controlled.

[0384] Any material known in the art can be used as a filler, as long as the material is a particle having a uniform particle size and high solvent resistance or heat resistance. The material of the filler is preferably a material having a high affinity for epoxy resin and being a spherical particle. Specific examples thereof include glass beads, silica particles, and organic resin particles. The above-listed examples can be used alone or in combination.

[0385] The particle size of the caulking agent can be selected according to the gap of the sealing area to be provided, and the particle size is preferably 1 μm or more but 100 μm or less, and more preferably 5 μm or more but 50 μm or less.

[0386] Examples of the polymerization initiator include a thermal polymerization initiator that initiates polymerization with heat and a photopolymerization initiator that initiates polymerization with light.

[0387] A thermal polymerization initiator is a compound that generates an active substance such as a free radical or a cation when heated, and specifically, an azo compound such as 2,2'-azobisbutyronitrile (AIBN) or a peroxide such as benzoyl peroxide (BPO) is used as a thermal polymerization initiator. As a cationic thermal polymerization initiator, a benzene sulfonate or an alkyl sulfonate can be used. As a photopolymerization initiator, a cationic photopolymerization initiator is preferably used in the case of epoxy resin. When the cationic photopolymerization initiator is mixed with an epoxy resin and irradiated with light, the cationic photopolymerization initiator decomposes to generate a strong acid, which induces polymerization of the epoxy resin to perform a curing reaction. The cationic photopolymerization initiator has the advantages of small volume shrinkage during curing, no oxygen inhibition, and high storage stability.

[0388] Examples of the cationic photopolymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, metallocene compounds, and silanol-aluminum complexes.

[0389] In addition, a photoacid generator capable of generating an acid under light irradiation may be used. The function of the photoacid generator is similar to that of the acid that initiates cationic polymerization. Examples thereof include onium salts, such as onium salts based on ionic sulfonium salts and onium salts based on ionic iodonium salts, including a cationic portion and an ionic portion. The examples listed above may be used alone or in combination.

[0390] The amount of the polymerization initiator may vary depending on the material used. Relative to 100 parts by mass of the entire sealing member, the amount of the polymerization initiator is preferably 0.5 parts by mass or more but 10 parts by mass or less, and more preferably 1 part by mass or more but 5 parts by mass or less. The amount of the polymerization initiator within the above range is effective because the curing process is appropriate, the amount of uncured residues can be reduced, and excessive generation of waste gas can be prevented.

[0391] Desiccant, also known as hygroscopic agent, is a material that has the function of physically or chemically adsorbing or absorbing moisture. Adding desiccant to sealing components is effective because, in some cases, moisture resistance can be further improved and the impact of exhaust gas can be reduced.

[0392] The desiccant is preferably a particle. 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 zeolites. Among the examples listed above, zeolite or calcium oxide is preferred because zeolite or calcium oxide absorbs a large amount of moisture. The examples listed above can be used alone or in combination.

[0393] Curing accelerators are also called curing catalysts and are used to speed up the curing process. Curing accelerators are mainly used for heat-curing epoxy resins.

[0394] Examples of curing accelerators include tertiary amines or tertiary amine salts, such as 1,8-diazacyclo(5,4,0)-undecene-7 (DBU) and 1,5-diazacyclo(4,3,0)-nonene-5 (DBN), imidazole compounds, such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, and phosphine or phosphine salts, such as triphenylphosphine and tetraphenylphosphine tetraphenylborate. The above-listed examples can be used alone or in combination.

[0395] The coupling agent has the effect of enhancing the intermolecular bonding force, and examples thereof include silane coupling agents. Specific examples thereof include: silane coupling agents such as 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl methyl dimethoxysilane, 3-glycidyloxypropyl methyl dimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, N-(2-aminoethyl) 3-aminopropyl methyl dimethoxysilane, N-(2-aminoethyl) 3-aminopropyl methyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, vinyl trimethoxysilane, N-(2-(vinylbenzylamino)ethyl) 3-aminopropyl trimethoxysilane hydrochloride and 3-methacryloxypropyl trimethoxysilane. The above examples can be used alone or in combination.

[0396] As sealing member, known commercial resin composition as sealing material, sealing material or adhesive, and can be effectively used in the present invention.In the above-mentioned example, there is developed and commercial epoxy resin composition for solar cell or organic EL element, and can be effectively used especially in the present invention.The available product of epoxy resin comprises product name: TB3118, TB3114, TB3124 and TB3125F (all can be purchased from ThreeBond), WorldRock 5910, World Rock 5920 and World Rock 8723 (all can be purchased from Kyoritsu Chemical & Co., Ltd.) and WB90US (P) (can be purchased from MORESCO).

[0397] After applying the low-melting-point glass resin, the resin is fired at about 550°C to decompose the resin component, and the resin is melted using an infrared laser or the like to adhere to the glass substrate. At this time, the glass component with a low melting temperature diffuses into the metal oxide layer and physically connects, thereby obtaining high sealing performance. In addition, since the resin component disappears, the offgas seen with acrylic resin or epoxy resin is not generated, thereby preventing the degradation of the photoelectric conversion element.

[0398] In the present invention, a sheet-like sealing material can be used as a sealing member. For example, the sheet-like sealing material is a thin sheet on which an epoxy resin layer is formed in advance, wherein the thin sheet is glass or a film with high gas barrier properties, and corresponds to the second substrate of the present invention. By bonding the sheet-like sealing material to the second electrode and then curing it, a sealing member and a second substrate can be formed immediately. The use of a sheet-like sealing material is effective because a structure including a hollow portion can be created according to the formation pattern of the epoxy resin layer formed on the sheet. When the resin layer is formed over the entire area of ​​the plate, the sealing realizes "surface sealing". When the resin layer is formed according to the formation pattern of the resin layer to include a hollow portion inside the photoelectric conversion element, the sealing realizes "frame sealing".

[0399] The formation method of the sealing member is not particularly limited, and the sealing member can be formed by a known method. For example, various methods such as dispersion, wire rod coating, spin coating, roller coating, scraping, gravure coating, relief printing, offset printing, gravure printing, rubber plate printing and screen printing can be used.

[0400] In addition, a passivation layer may be provided between the sealing member and the second electrode. The passivation layer is not particularly limited as long as the passivation layer is provided so that the sealing member does not contact the second electrode, and may be appropriately selected according to the intended purpose. As the passivation layer, aluminum oxide, silicon nitride or silicon oxide is preferably used.

[0401] Since the hole transport function of the hole transport layer can be stably maintained for a long time, introducing oxygen into the hollow portion inside the seal may be effective for improving the durability of the photoelectric conversion element. In the present invention, it is preferred to introduce oxygen into the hollow portion inside the seal, wherein the hollow portion is formed by sealing. The oxygen concentration therein is more preferably 10.0% (by volume) or more but 21.0% (by volume) or less.

[0402] By sealing inside the glove box where the oxygen concentration is adjusted, the oxygen concentration in the hollow portion can be controlled. The oxygen concentration can be adjusted by a method using a gas cylinder containing a gas having a predetermined oxygen concentration or a method using a nitrogen generator. The oxygen concentration in the glove box can be measured by a commercial oxygen meter or an oxygen monitor.

[0403] For example, the oxygen concentration in the hollow portion formed by the seal can be measured by internal vapor analysis (IVA). Specifically, IVA is a method in which a photoelectric conversion element is installed in a highly vacuumed area, and a hole is formed in the photoelectric conversion element to generate gas or moisture, and the generated gas or moisture is subjected to mass spectrometry. According to the above method, the oxygen concentration contained in the sealed photoelectric conversion element can be determined. As a mass spectrometer, there are quadrupole mass spectrometers and time-of-flight mass spectrometers. Time-of-flight mass spectrometers make the measurement more sensitive.

[0404] The gas other than oxygen included in the sealed photoelectric conversion element is preferably an inert gas, more preferably nitrogen gas or argon gas.

[0405] When sealing, it is preferred to control the oxygen concentration and the dew point in the glove box. Adjusting the dew point is effective in improving the output or durability of the photoelectric conversion element. The dew point refers to the temperature at which gases including water vapor begin to condense when cooled.

[0406] The dew point is not particularly limited. The dew point is preferably 0°C or lower, and more preferably -20°C or lower. The lower limit of the dew point is preferably -50°C or higher.

[0407] <<Hole blocking layer>>

[0408] It is preferred to further form a hole blocking layer, which is very effective for increasing output and improving the sustainability of output. The hole blocking layer is formed between the first electrode and the electron transport layer. In other words, the photoelectric conversion element of the present invention preferably further includes a hole blocking layer disposed between the first electrode and the photoelectric conversion layer.

[0409] The hole blocking layer can transfer electrons generated by the photosensitive compound and transferred to the electron transport layer to the first electrode and prevent contact with the hole transport layer. As a result, the hole blocking layer can prevent holes from flowing into the first electrode and can prevent the output from being reduced due to the recombination of electrons and holes. Compared with the wet photoelectric conversion element using an electrolytic solution, the recombination rate between the holes in the hole transport material in the solid photoelectric conversion element provided with the hole transport layer and the electrons on the electrode surface is faster. Therefore, the effect obtained by forming the hole blocking layer is significant.

[0410] The material of the hole blocking layer is not particularly limited as long as the material is transparent to visible light and has electron transport capability, and can be appropriately selected according to the intended purpose. Examples of the material include elemental semiconductors (such as silicon and germanium), compound semiconductors (such as metal chalcogenides), and compounds having a perovskite structure.

[0411] Examples of metal chalcogenides include oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc., sulfides of cadmium, zinc, lead, silver, antimony, bismuth, etc., selenides of cadmium, lead, etc., and tellurium compounds of cadmium, etc. Examples of other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc., gallium arsenide, copper indium selenide, and copper indium sulfide.

[0412] Examples of the compound having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.

[0413] Among the materials listed above, oxide semiconductors are preferred, titanium oxide, niobium oxide, magnesium oxide, aluminum oxide, zinc oxide, tungsten oxide, and tin oxide are more preferred, and titanium oxide is more preferred.

[0414] The examples listed above can be used alone or in combination. The hole blocking layer can be a single layer or a multilayer. In addition, the crystal type of the above semiconductor is not particularly limited and can be appropriately selected according to the intended purpose. The semiconductor can be single crystal, polycrystalline or amorphous.

[0415] The production method of the hole blocking layer is not particularly limited and can be appropriately selected depending on the intended purpose. Examples of the production method thereof include a method for forming a thin film in a vacuum (vacuum film forming method) and a wet film forming method.

[0416] Examples of the vacuum film formation method include sputtering, pulsed laser deposition (PLD), ion beam sputtering, ion-assisted deposition, ion plating, vacuum vapor deposition, atomic layer deposition (ALD), and chemical vapor deposition (CVD).

[0417] Examples of wet film forming methods include sol-gel methods. According to the sol-gel method, the solution is subjected to chemical reactions such as hydrolysis, polymerization and condensation to form a gel, and then heat-treated to accelerate the densification of the gel. When the sol-gel method is used, the coating method of the sol solution is not particularly limited and can be appropriately selected according to the intended purpose. Examples of coating methods include dip coating, spray coating, wire rod coating, spin coating, roller coating, blade coating and gravure coating. In addition, wet printing can be used as a coating method. Examples of wet printing methods include relief printing, offset printing, gravure printing, gravure printing, rubber printing and screen printing. In addition, the temperature of the heat treatment performed after applying the sol solution is preferably 80°C or higher, and more preferably 100°C or higher.

[0418] The average thickness of the hole blocking layer is not particularly limited and can be appropriately selected according to the intended purpose. The average thickness of the hole blocking layer is preferably 5 nm or more but 1 μm or less. In the case of wet film formation, the average thickness is more preferably 500 nm or more but 700 nm or less. In the case of dry film formation, the average thickness is more preferably 5 nm or more but 30 nm or less.

[0419] The examples of the photoelectric conversion element of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. For example, the number of the following components, the position of the following components, and the shape of the following components (which will not be described in the following embodiments) are also included in the scope of the present invention.

[0420] <First Embodiment>

[0421] Figure 1is a schematic diagram showing an example of the photoelectric element of the first embodiment. Figure 1 The photoelectric conversion element 101 of the first embodiment includes a first electrode 2 formed on a first substrate 1. An electron transport layer 4 is formed on the first electrode 2, and a photosensitive compound 5 is adsorbed on the surface of an electron transport material constituting the electron transport layer 4. On the upper part and inside of the electron transport layer 4, a hole transport layer 6 is formed. A second electrode 7 is formed on the hole transport layer 6. A second substrate 9 is disposed above the second electrode 7. The second substrate 9 is fixed to the first electrode 2 by a sealing member 8. The sealing member 8 may also be adhered to the first substrate 1 instead of the first electrode 2, which can effectively enhance the sealing property.

[0422] Figure 1 The photoelectric conversion element 101 of the first embodiment has a hollow portion 10 between the second electrode 7 and the second substrate 9. Since the hollow portion 10 is provided, the moisture content or oxygen concentration inside the hollow portion can be controlled. As a result, the power generation performance or durability of the photoelectric conversion element can be improved. Since the second electrode 7 and the second substrate 9 are not in contact with each other, the separation or breakage of the second electrode 7 can be prevented. The oxygen concentration in the hollow portion is not particularly limited and can be freely controlled. The oxygen concentration in the hollow portion is preferably 10% or more but 21% or less.

[0423] Although not shown, each of the first electrode 2 and the second electrode 7 has a conduction path to an electrode extraction terminal.

[0424] <Second Embodiment>

[0425] Figure 2 is a schematic diagram showing an example of a photoelectric conversion element according to the second embodiment. Figure 2 The photoelectric conversion element 101 of the second embodiment includes a hole blocking layer 3 between the first substrate 1 and the electron transport layer 4. The formation of the hole blocking layer 3 is effective in improving the power generation performance because recombination between electrons and holes can be prevented. Figure 1 similar, Figure 2 The photoelectric conversion element shown in FIG. 1 has a hollow portion 10 between the second electrode 7 and the second substrate 9 .

[0426] <Third Embodiment>

[0427] Figure 3 is a schematic diagram showing an example of a photoelectric conversion element according to the third embodiment. Figure 3 The photoelectric conversion element 101 of the third embodiment is Figure 2Photoelectric conversion element, wherein the hollow part 10 is covered with a sealing member 8 to seal the entire surface. For example, the sealing member 8 can be formed by applying the sealing member 8 to the entire surface of the second electrode 7, and then arranging the second substrate 9 on the sealing member 8, or by using the above-mentioned sheet-like sealing material. In this case, the passivation layer 11 can be arranged between the second electrode 7 and the sealing member 8, and the formation of the passivation layer 11 can effectively prevent the peeling of the second electrode. As described above, the mechanical strength of the photoelectric conversion element can be enhanced by coring almost the entire surface using a sealing member.

[0428] (Production method of photoelectric conversion element)

[0429] The method for producing a photoelectric conversion element of the present invention comprises forming a photoelectric conversion layer including a hole transport layer on a first electrode, and controlling the amount of solvent in the hole transport layer. The amount of solvent per unit volume of the hole transport layer can be adjusted to 30 μg / mm 3 Or smaller. According to need, the method may further include other steps.

[0430] The method for producing a photoelectric conversion element of the present invention includes forming a first electrode on a first substrate, forming a photoelectric conversion layer on the first electrode, and forming a second electrode on the photoelectric conversion layer. It may also include the step of forming other components as needed, such as a hole blocking layer and a sealing component.

[0431] In the method for producing the photoelectric conversion element of the present invention, the first electrode, the photoelectric conversion layer, the second electrode, and other members and layers are the same as those described in the photoelectric conversion element of the present invention.

[0432] <Photoelectric Conversion Layer Formation Step>

[0433] The photoelectric conversion layer forming step is a step including forming a photoelectric conversion layer including a hole transport layer on the first electrode.

[0434] The photoelectric conversion layer forming step is a step including forming a photoelectric conversion layer according to the method described for the photoelectric conversion layer of the photoelectric conversion element of the present invention.

[0435] <Solvent Amount Control Step>

[0436] The solvent amount control step is a step including controlling the amount of solvent contained in the produced photoelectric conversion element. For example, the solvent amount control step includes heating after forming the hole transport layer.

[0437] When the solvent amount control step is performed, the solvent component contained is evaporated to adjust the amount of the solvent contained in the produced photoelectric conversion element to 30 μg / mm per unit volume of the hole transport layer. 3 or less.

[0438] In the solvent amount control step, any method for drying known in the art can be used, such as a method of heating and drying after forming a layer, a method of naturally drying in a room temperature environment, and a method of blowing. Among the examples listed above, a method of heating and drying that can control the amount of solvent in a short time is preferably used.

[0439] As the drying conditions in the solvent amount control step, it is preferred to dry for 10 minutes or longer but 24 hours or shorter at an ambient pressure of 20°C or higher but 130°C or lower, and more preferably to dry for 30 minutes or longer but 2 hours or shorter at an ambient pressure of 50°C or higher but 100°C or lower.

[0440] The method for heating and drying is not particularly limited as long as the above-mentioned heating and drying conditions are achieved, and can be appropriately selected according to the intended purpose. Examples thereof include the following methods. Specifically, any method known in the art can be used as long as the method is a method in which the solvent in the hole transport layer can be evaporated by heating using an oven, a dryer, a constant temperature chamber or a heating plate.

[0441] (Photoelectric conversion module)

[0442] The photoelectric conversion module of the present invention includes a plurality of photoelectric conversion elements of the present invention, wherein the photoelectric conversion elements disposed adjacent to each other are electrically connected in series or in parallel.

[0443] For example, the photoelectric conversion module of the present invention has a photoelectric conversion element arrangement region in which a plurality of photoelectric conversion elements are arranged adjacent to each other and connected in series or in parallel. The photoelectric conversion module includes photoelectric conversion elements, in each of which a photoelectric conversion layer includes an electron transport layer and a hole transport layer formed between a first electrode and a second electrode.

[0444] The photoelectric conversion module of the present invention includes a plurality of photoelectric conversion elements. In addition, the photoelectric conversion elements may be connected in series and / or in parallel, or may include a photoelectric conversion element that is independently provided and not connected to other photoelectric conversion elements.

[0445] The structure of each layer of the photoelectric conversion module of the present invention may be the same as the structure of each layer of the photoelectric conversion element.

[0446] The structure of the photoelectric conversion module of the present invention is not particularly limited and can be appropriately selected according to the intended purpose. In at least two photoelectric conversion elements arranged adjacent to each other, the first electrode, electron transport layer and second electrode of one photoelectric conversion element are separated from the first electrode, electron transport layer and second electrode of another photoelectric conversion element. In at least two photoelectric conversion elements arranged adjacent to each other, at the same time, the hole transport layer of one photoelectric conversion element can be separated from the hole transport layer of another photoelectric conversion element, or the hole transport layer of one photoelectric conversion element and the hole transport layer of another photoelectric conversion element can extend to each other to form a continuous layer.

[0447] The photoelectric conversion module of the present invention includes at least two photoelectric conversion elements disposed adjacent to each other, and a first electrode of one photoelectric conversion element and a second electrode of another photoelectric conversion element are electrically connected via a conductive portion penetrating the photoelectric conversion layer.

[0448] In addition, the photoelectric conversion module of the present invention may have a structure in which a pair of substrates are provided, a photoelectric conversion element alignment region is provided between the pair of substrates, the photoelectric conversion elements are connected in series or in parallel, and a sealing member is provided between the pair of substrates. In particular, the photoelectric conversion module of the present invention preferably includes a sealing member configured to seal the photoelectric conversion layer of the photoelectric conversion element in the photoelectric conversion module from the external environment of the photoelectric conversion module.

[0449] The following will describe examples of the photoelectric conversion module of the present invention with reference to the accompanying drawings. However, the following embodiments should not be construed as limiting the scope of the present invention. For example, the number of the following components, the position of the following components, and the shape of the following components (which will not be described in the following embodiments) are also included in the scope of the present invention.

[0450] <Fourth Embodiment>

[0451] Figure 4 : is a schematic diagram showing an example of a photoelectric conversion module of the present invention, and the example shows a cross section of a part of a photoelectric conversion element, in which a plurality of photoelectric conversion elements are included and the photoelectric conversion elements are connected in series.

[0452] like Figure 4 As shown, after forming the hole transport layer 6, the through hole 12 is formed, and then the second electrode 7 is formed. As a result, the second electrode material is introduced into the through hole 12 to be electrically connected to the first electrode 2b of the adjacent cell. Figure 4 Although not shown in the figure, the first electrode 2a and the second electrode 7b each have a path electrically connected to an electrode of an adjacent photoelectric conversion element or to an output extraction terminal.

[0453] The through hole 12 may penetrate the first electrode 2 to reach the first substrate 1. Alternatively, when the through hole 12 reaches the inside of the first electrode 2, the process may be stopped so that the through hole 12 does not reach the first substrate 1.

[0454] When the shape of the through hole 12 is a hole that penetrates the first electrode 2 to reach the first substrate 1, and the total opening area of ​​the holes is too large relative to the area of ​​the through hole 12, the resistance value increases as the cross-sectional film area of ​​the first electrode 2 decreases, which may reduce the photoelectric conversion efficiency. Therefore, relative to the area of ​​the through hole 12, the total opening area of ​​the holes is preferably 5 / 100 or more, but 60 / 100 or less.

[0455] The method for forming the through hole 12 is not particularly limited and can be appropriately selected according to the intended purpose. Examples include sandblasting, water jetting, polishing, chemical etching and laser processing. Among the examples listed above, laser processing is preferred. According to laser processing, fine pores can be formed without using sand, etching or resist, and processing can be performed cleanly with good reproducibility. In addition, when the through hole 12 is formed, at least one selected from the group consisting of the hole blocking layer 3, the electron transport layer 4, the hole transport layer 6 and the second electrode 7 can be removed by impact stripping of laser processing. Therefore, it is not necessary to set a mask when laminating the layers, and the removal of the layers and the formation of the fine through hole 12 can be easily performed at one time.

[0456] <Fifth Embodiment>

[0457] Figure 5 Schematic diagram showing an example of a photoelectric conversion module of the present invention. Figure 4 Differently, the hole transport layer 6 is separated from the adjacent photoelectric conversion element, and the hole transport layer of each photoelectric conversion element has an independent layer structure. As a result, the diffusion of electrons can be suppressed to reduce the leakage of current, so the durability of the photoelectric conversion module can be further improved. Therefore, the photoelectric conversion module with such a layer structure is effective.

[0458] (Electronic equipment)

[0459] The electronic device of the present invention includes the photoelectric conversion element of the present invention or the photoelectric conversion module of the present invention and a device driven by the power generated by the photoelectric conversion performed by the photoelectric conversion element or the photoelectric conversion module. The electronic device may further include other devices as required.

[0460] In addition, the electronic device of the present invention includes the photoelectric conversion element of the present invention or the photoelectric conversion module of the present invention, a battery unit capable of storing electric energy generated by photoelectric conversion performed by the photoelectric conversion element or the photoelectric conversion module, and a device driven by the electric power stored in the battery unit. The electronic device may also include other devices as needed.

[0461] (Power Module)

[0462] The power module of the present invention includes the photoelectric conversion module of the present invention and a power integrated circuit (IC). The power module may also include other devices as required.

[0463] Next, specific embodiments of electronic equipment including the photoelectric conversion module of the present invention and a device driven by power generated by the photoelectric conversion module will be described.

[0464] Figure 6 : is a block diagram showing a mouse of a personal computer as an example of the electronic device of the present invention.

[0465] like Figure 6 As shown, the photoelectric conversion module is combined with the power IC and the electric storage device, and the electric energy provided is connected to the power supply of the mouse control circuit. As a result, when the mouse is not in use, the electric storage device can be charged, and the charged electricity can be used to drive the mouse, so a mouse that does not require wiring or battery replacement can be obtained. In addition, the weight of the mouse can be reduced because there is no need to install a battery. Therefore, the mouse as an electronic device of the present invention is effective.

[0466] Figure 7 It shows Figure 6 A schematic external view of an example of a mouse.

[0467] like Figure 7 As shown, the photoelectric conversion module, the power IC and the electrical storage device are installed inside the mouse, but the upper part of the photoelectric conversion element is covered with a transparent shell to allow light to reach the photoelectric conversion element of the photoelectric conversion module. The arrangement of the photoelectric conversion element is not limited to Figure 7 For example, the photoelectric conversion element may be disposed at a position where the photoelectric conversion element can be irradiated with light even when the mouse is covered by a hand, and such an arrangement may be preferable in some cases.

[0468] Next, another embodiment of an electronic device including the photoelectric conversion module of the present invention and a device driven by the power generated by the photoelectric conversion module will be described.

[0469] Figure 8 is a block diagram showing a keyboard of a personal computer as an example of the electronic device of the present invention.

[0470] like Figure 8As shown, the photoelectric conversion element of the photoelectric conversion module is combined with the power IC and the electric storage device, and the electric energy provided can be transmitted to the power supply of the keyboard control circuit. As a result, when the keyboard is not in use, the electric storage device can be charged, and the charged electricity can be used to drive the keyboard, so a keyboard that does not require wiring or battery replacement can be obtained. In addition, the weight of the keyboard can be reduced because there is no need to install a battery. Therefore, the keyboard as an electronic device of the present invention is effective.

[0471] Fig. 9 It shows Figure 8 A schematic external view of an example of a keyboard is shown.

[0472] like Fig. 9 As shown, the photoelectric conversion element, power IC and electrical storage device of the photoelectric conversion module are installed inside the keyboard, but the upper part of the photoelectric conversion element is covered with a transparent shell to allow light to reach the photoelectric conversion element. In addition, the entire shell of the keyboard can be formed of a transparent resin. The arrangement of the photoelectric conversion element is not limited to Fig. 9 In the case of a small keyboard with a small space for mounting a photoelectric conversion element, such as Fig.10 As shown, the photoelectric conversion element can be embedded as a part of the key, and this arrangement is effective.

[0473] Next, still another embodiment of an electronic device including the photoelectric conversion module of the present invention and a device driven by the power generated by the photoelectric conversion module will be described.

[0474] Fig.11 is a block diagram showing a sensor as an example of the electronic device of the present invention.

[0475] like Fig.11 As shown, the photoelectric conversion element of the photoelectric conversion module is combined with a power supply IC and an electrical storage device, and the provided electrical energy is transmitted to the power supply of the sensor circuit. As a result, the sensor module can be constructed without connecting an external power supply and without replacing the battery. The sensing target can be temperature and humidity, illumination, human motion, CO2, acceleration, UV, noise, geomagnetism or pressure. The sensor module can be applied to various sensors with good effects. Fig.12 As shown, the sensor module is configured to sense a target to be measured periodically and transmit the read data to a personal computer (PC) or a smart phone through wireless communication.

[0476] With the advent of the Internet of Things (IoT) society, the use of sensors is expected to increase significantly. Replacing the batteries of multiple sensors one by one is time-consuming and unrealistic. In addition, the installation of sensors in locations such as ceilings and walls where it is not easy to replace batteries also leads to poor operability. In addition, providing power through photoelectric conversion elements is also a significant advantage. In addition, the photoelectric conversion module of the present invention has the advantage that high output can be obtained with light of low illumination, and since the output has a low dependence on the incident angle of light, a high degree of freedom in installation can be achieved.

[0477] Next, still another embodiment of an electronic device including the photoelectric conversion module of the present invention and a device driven by the power generated by the photoelectric conversion module will be described.

[0478] Fig.12 is a block diagram showing a turntable as an example of the electronic equipment of the present invention.

[0479] like Fig.12 As shown, the photoelectric conversion element is combined with a power IC and an electric storage device, and the supplied electric energy is transmitted to the power supply of the turntable circuit. Therefore, the turntable can be constructed without connecting an external power supply or replacing batteries.

[0480] For example, the turntable is used in a display cabinet for displaying products. The wiring of the power supply degrades the appearance of the display screen, and the displayed products need to be removed when replacing the battery unit, which is very time-consuming. The use of the photoelectric conversion module of the present invention is effective because the above problems can be solved.

[0481] The above describes the photoelectric conversion module of the present invention, the electronic device including the device driven by the power generated by the photoelectric conversion module and the power module, but the above embodiments are only part of the present invention, and the application of the photoelectric conversion module of the present invention is not limited to the above embodiments.

[0482] <Application>

[0483] The photoelectric conversion module of the present invention can be used as a self-sustaining power source, and the device can be driven by the power generated by the photoelectric conversion performed by the photoelectric conversion module. The photoelectric conversion module of the present invention can generate electrical energy under the irradiation of light. Therefore, the electronic device does not need to be connected to a power source or replace the battery. Therefore, the electronic device can be driven in a place where there is no power supply facility, the electronic device can be worn or carried, and the electronic device can be driven without replacing the battery unit even in a place where it is not easy to replace the battery unit. In addition, when a dry cell battery unit is used, the electronic device becomes heavier due to the weight of the dry cell battery unit, or the electronic device becomes larger due to the size of the dry cell battery unit. Therefore, there may be problems when installing the electronic device on the wall or ceiling or transporting the electronic device. Since the photoelectric conversion module of the present invention is thin and light, it can be freely installed and can be worn and carried, which is advantageous.

[0484] As described above, the photoelectric conversion module of the present invention can be used as a self-sustaining power source and can be used in combination with various electronic devices. For example, the photoelectric conversion module of the present invention can be used in combination with display devices (e.g., electronic desktop calculators, watches, mobile phones, electronic notepads, and electronic paper), accessory devices of personal computers (e.g., mice and keyboards), various sensor devices (e.g., temperature and humidity sensors and human detection sensors), transmitters (e.g., beacons and global positioning systems (GPS)), and many electronic devices (e.g., auxiliary lights and remote controls).

[0485] The photoelectric conversion module of the present invention is widely used because the photoelectric conversion element can generate electric energy under low illumination light, and can generate electric energy indoors and in dim or dark places. In addition, the photoelectric conversion element is highly safe because liquid leakage in the case of a dry cell battery unit does not occur, and accidental ingestion does not occur in the case of a button battery unit. In addition, the photoelectric conversion module can be used as an auxiliary power source to extend the continuous operating time of a rechargeable or dry cell type electronic device. As described above, by combining the photoelectric conversion module of the present invention and a device driven by electric power generated by photoelectric conversion, an electronic device that is lightweight, easy to use, has a high degree of freedom in installation, does not require replacement of battery cells, is highly safe, and effectively reduces environmental load can be obtained.

[0486] Fig.13 The basic structure diagram of an electronic device is shown, in which there is a photoelectric conversion module of the present invention and a device driven by the power generated by the photoelectric conversion. When the photoelectric conversion module is irradiated with light, the electronic device can generate electric energy and can extract electric energy. The circuit of the device can be driven by the generated electric energy.

[0487] Since the output of the photoelectric conversion element varies depending on the circumferential illumination, it may not be driven stably in some cases. Fig.13 In this case, if Fig.14 As shown, a power supply IC for a photoelectric conversion element can be integrated between the photoelectric conversion element and the circuit of the device in order to supply a stable voltage to one side of the circuit, and this arrangement is effective.

[0488] However, the photoelectric conversion element of the photoelectric conversion module has the following problem. That is, when light with sufficient illumination is not applied, the desired electric energy cannot be obtained, although the photoelectric conversion element can generate electric energy as long as light with sufficient illumination is applied. In this case, Fig.15As shown, an electric storage device such as a capacitor is installed between the power supply IC and the device circuit to store excess electric energy from the photoelectric conversion element in the electric storage device. As a result, even when the illumination of light is too low or light is not applied to the photoelectric conversion element, the electricity stored in the electric storage device can be supplied to the device circuit, and the electronic device can be driven stably, and the advantages obtained by the photoelectric conversion element can be maximized.

[0489] Meanwhile, the photoelectric conversion module of the present invention can also be used as a power module, and it is effective to use the photoelectric conversion module as a power module. Fig.16 As shown, when the photoelectric conversion module of the present invention is connected to a power supply IC for a photoelectric conversion element, the DC power supply module can supply the power supply IC with electric energy generated by photoelectric conversion performed by the photoelectric conversion element of the photoelectric conversion module at a constant voltage level.

[0490] like Fig.17 As shown, in addition, the electric storage device is combined with the power supply IC. As a result, the electric energy generated by the photoelectric conversion element of the photoelectric conversion module can be stored in the electric storage device, which makes it possible to constitute a power supply module that can supply power even when the illumination of light is too low or light is not applied to the photoelectric conversion element.

[0491] Fig.16 and 17 The power module of the present invention shown can be used as a power module that does not require replacement of battery units, which is different from mainstream battery units known in the art.

[0492] Example

[0493] The present invention will be described below by way of examples, but should not be construed as being limited to these examples in any way.

[0494] (Example 1)

[0495] <Production of Photoelectric Conversion Modules>

[0496] On a glass substrate used as a first substrate, an indium-doped tin oxide (ITO) film and a niobium-doped tin oxide (NTO) film were sequentially formed by sputtering as a first electrode. Subsequently, a dense titanium oxide layer (average thickness: 20 nm) was formed on the first electrode by sputtering through reaction with oxygen as a hole blocking layer.

[0497] Next, titanium oxide paste (18NR-T, available from Greatcell Solar Materials) was applied to the hole blocking layer by screen printing to have an average thickness of about 1.2 μm. The applied paste was dried at 120°C and then fired in air at 570°C for 30 minutes to form a porous electron transport layer. Then, the ITO / NTO layer, the hole blocking layer, and the electron transport layer were separated into 8 units by laser processing.

[0498] The glass substrate having the electron transport layer formed thereon was immersed in a solution obtained by adding an acetonitrile / tert-butanol mixture (volume ratio: 1:1) to the photosensitive compound represented by B-5 above (0.2 mM) and stirring, and then allowed to stand in the dark for 1 hour to allow the photosensitive compound to be adsorbed on the surface of the electron transport layer.

[0499] Next, 86.9 mM of lithium (fluorosulfonyl) (trifluoromethanesulfonyl) imide (Li-FTFSI) (available from KISHIDA CHEMICAL Co., Ltd.) used as lithium salt b, 143.1 mM of pyridine compound a represented by H-1, 159.0 mM of organic hole transport material (HTM) represented by D-7 (SHT-263, available from Merck KGaA) and 12.7 mM of cobalt complex represented by F-11 (available from Greatcell Solar Materials Pty Ltd.) were added to the chlorobenzene solution and dissolved to prepare a hole transport layer coating liquid. The molar ratio a / b of the pyridine compound a to the lithium salt b was 1.65.

[0500] The molar ratio X / Y of the lithium salt to the organic p-type semiconductor material is 0.55, wherein X is the molar amount of the lithium salt in the hole transport layer, and Y is the molar amount of the organic p-type semiconductor material in the hole transport layer.

[0501] Next, a hole transport layer coating liquid was applied onto the electron transport layer, and a photosensitive compound was adsorbed on the electron transport layer by die coating to form a hole transport layer having a thickness of about 500 nm.

[0502] After the hole transport layer coating liquid was applied onto the electron transport layer on which the photosensitive compound was adsorbed, the applied hole transport layer coating liquid was heated and dried in an oven at 60° C. under ambient pressure for 60 minutes.

[0503] After that, the edge of the glass substrate where the sealing member is to be set and the gap between the cells are etched by laser processing, and through holes for connecting the ITO / NTO layer are formed by laser processing. These through holes will become the terminal extraction parts. In addition, through holes for connecting the cells in series are also formed.

[0504] After setting a mask between the edge of the glass substrate and the cell, silver was deposited by vacuum vapor deposition to form a second electrode with a thickness of about 70 nm.

[0505] A UV curable resin (World Rock No. 5910, available from Kyoritsu Chemical & Co., Ltd.) was applied to the edge of the glass substrate by a dispenser (2300N, available from SAN-EI TECH Ltd) to surround the power generation area. Thereafter, the final product was moved into a glove box, the dew point therein was adjusted to -40°C, a mixed gas of nitrogen and oxygen (oxygen concentration: 10% volume fraction) was introduced, a cover glass sheet was placed on the UV curable resin as a second substrate, the UV curable resin was cured by UV radiation, and then heated at 80°C for 60 minutes. As described above, the power generation area was sealed. Finally, a UV cutting film was bonded to the light receiving surface, thereby producing a Figure 5 The photoelectric conversion module 102 is shown.

[0506] (Example 2)

[0507] Photoelectric conversion module 2 was manufactured in the same manner as Example 1, except that after the hole transport layer coating liquid was applied onto the electron transport layer, the hole transport layer coating liquid was heated and dried in an oven at 90° C. under ambient pressure for 30 minutes.

[0508] (Example 3)

[0509] Photoelectric conversion module 3 was manufactured in the same manner as Example 1, except that the amount of lithium salt was changed to 95.6 mM, the amount of pyridine compound was changed to 141.9 mM, the amount of organic hole transport material was changed to 157.7 mM, and the amount of cobalt complex was changed to 12.6 mM.

[0510] (Example 4)

[0511] Photoelectric conversion module 4 was manufactured in the same manner as in Example 1, except that the amount of lithium salt was changed to 84.0 mM, the amount of pyridine compound was changed to 138.4 mM, the organic hole transport material was changed to 153.7 mM of the organic hole transport material represented by D-10, and the amount of cobalt complex was changed to 12.3 mM.

[0512] (Example 5)

[0513] Photoelectric conversion module 5 was manufactured in the same manner as in Example 1, except that the amount of lithium salt was changed to 103.3 mM, the amount of pyridine compound was changed to 140.8 mM, the amount of organic hole transport material was changed to 156.5 mM, the amount of cobalt complex was changed to 12.5 mM, and the drying conditions were changed to drying at 50° C. for 90 minutes.

[0514] (Comparative Example 1)

[0515] The photoelectric conversion module 6 was manufactured in the same manner as in Example 1, except that after the hole transport layer coating liquid was applied onto the electron transport layer, the production process continued with sequential steps without heating and drying the hole transport layer coating liquid.

[0516] (Comparative Example 2)

[0517] Photoelectric conversion module 7 was manufactured in the same manner as Example 1, except that after the hole transport layer coating liquid was applied onto the electron transport layer, the coated hole transport layer coating liquid was heated and dried in an oven at 40° C. under ambient pressure for 15 minutes.

[0518] (Comparative Example 3)

[0519] A photoelectric conversion module 8 was manufactured in the same manner as in Example 1, except that the amount of the lithium salt was changed to 86.9 mM, the amount of the pyridine compound was changed to 143.1 mM, the amount of the organic hole transport material was changed to 159.0 mM, the amount of the cobalt complex was changed to 12.7 mM, and the drying conditions were changed to drying at 50° C. for 3 minutes.

[0520] (Comparative Example 4)

[0521] Photoelectric conversion module 9 was manufactured in the same manner as in Example 1, except that no lithium salt was added, the amount of the pyridine compound was changed to 155.5 mM, the amount of the organic hole transport material was changed to 172.8 mM, and the amount of the cobalt complex was changed to 13.8 mM.

[0522] (Example 6)

[0523] The photoelectric conversion module 10 was manufactured in the same manner as in Example 1, except that the amount of the lithium salt was changed to 80.2 mM, the amount of the pyridine compound was changed to 144.4 mM, the amount of the organic hole transport material was changed to 160.4 mM, and the amount of the cobalt complex was changed to 12.5 mM.

[0524] (Example 7)

[0525] A photoelectric conversion module 11 was manufactured in the same manner as in Example 1, except that the amount of the lithium salt was changed to 75.2 mM, the amount of the pyridine compound was changed to 145.1 mM, the amount of the organic hole transport material was changed to 161.2 mM, and the amount of the cobalt complex was changed to 12.6 mM.

[0526] (Example 8)

[0527] The photoelectric conversion module 12 was manufactured in the same manner as in Example 1, except that the amount of the lithium salt was changed to 65.1 mM, the amount of the pyridine compound was changed to 146.5 mM, the amount of the organic hole transport material was changed to 162.8 mM, and the amount of the cobalt complex was changed to 12.7 mM.

[0528] (Example 9)

[0529] A photoelectric conversion module 13 was manufactured in the same manner as in Example 1, except that the amounts of the lithium salt were changed to 54.8 mM, the pyridine compound to 148.0 mM, the organic hole transport material to 164.4 mM, and the cobalt complex to 12.8 mM.

[0530] (Example 10)

[0531] A photoelectric conversion module 14 is produced in the same manner as in Example 1, except that the photosensitizing compound is changed to a photosensitizing compound represented by B-51, the lithium salt is changed to 86.7 mM of lithium (fluorosulfonyl)(pentafluoroethanesulfonyl)imide (Li-FPFSI), the amount of the pyridine compound is changed to 142.8 mM, the amount of the organic hole transport material is changed to 158.6 mM, and the oxidant is changed to 11.6 mM of an oxidant represented by F-23.

[0532] (Example 11)

[0533] A photoelectric conversion module 15 was produced in the same manner as in Example 10, except that the drying conditions were changed to 75° C. for 45 minutes.

[0534] (Example 12)

[0535] The photoelectric conversion module 16 was manufactured in the same manner as in Example 1, except that the photosensitizing compound was changed to the photosensitizing compound represented by B-51, the lithium salt was changed to 85.3 mM of lithium (pentafluoroethanesulfonyl)(trifluoromethanesulfonyl)imide (Li-PFTFSI), the amount of the pyridine compound was changed to 140.4 mM, the amount of the organic hole transport material was changed to 156.0 mM, and the oxidant was changed to 11.4 mM of the oxidant represented by F-23.

[0536] (Example 13)

[0537] The photoelectric conversion module 17 was manufactured in the same manner as in Example 12, except that the drying conditions were changed to 75° C. for 45 minutes.

[0538] (Example 14)

[0539] The photoelectric conversion module 18 was manufactured in the same manner as in Example 1, except that the photosensitizing compound was changed to a photosensitizing compound represented by B-51, the amount of the lithium salt was changed to 94.3 mM, the organic hole transport material was changed to 146.6 mM of an organic hole transport material represented by D-10, the pyridine compound was changed to 141.4 mM of a pyridine compound represented by H-3, and the oxidant was changed to 15.7 mM of an oxidant represented by F-23.

[0540] (Example 15)

[0541] The photoelectric conversion module 19 was manufactured in the same manner as in Example 14, except that the drying conditions were changed to 75° C. for 45 minutes.

[0542] (Comparative Example 5)

[0543] The photoelectric conversion module 20 was manufactured in the same manner as in Example 1, except that the lithium salt was changed to 70.1 mM lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), the amount of the pyridine compound was changed to 145.7 mM, the amount of the organic hole transport material was changed to 161.9 mM, and the oxidant was changed to 11.9 mM of an oxidant represented by F-23.

[0544] (Comparative Example 6)

[0545] The photoelectric conversion module 21 was manufactured in the same manner as in Example 1, except that the lithium salt was changed to 89.6 mM lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), the amount of the pyridine compound was changed to 142.3 mM, the amount of the organic hole transport material was changed to 158.1 mM, and the oxidant was changed to 11.6 mM of an oxidant represented by F-23.

[0546] (Comparative Example 7)

[0547] The photoelectric conversion module 22 was manufactured in the same manner as in Example 1, except that the lithium salt was changed to 72.1 mM lithium bis(fluorosulfonyl)imide (Li-FSI), the amount of the pyridine compound was changed to 149.7 mM, the amount of the organic hole transport material was changed to 166.4 mM, and the oxidant was changed to 12.2 mM of an oxidant represented by F-23.

[0548] (Comparative Example 8)

[0549] The photoelectric conversion module 23 was manufactured in the same manner as in Example 1, except that the lithium salt was changed to 68.3 mM of lithium bis(pentafluoroethanesulfonyl)imide (Li-BETI), the amount of the pyridine compound was changed to 141.8 mM, the amount of the organic hole transport material was changed to 157.6 mM, and the oxidant was changed to 11.6 mM of an oxidant represented by F-23.

[0550] Next, the sealed oxygen concentration, the valence state of the cobalt complex, and the chlorobenzene content were measured for each produced photoelectric conversion module, and the performance of the photoelectric conversion module (initial maximum output power Pmax1 and Pmax retention rate) was evaluated. The results are shown in Table 1.

[0551] <Sealed oxygen concentration>

[0552] By opening the sealed part (sample) of the photoelectric conversion module in a highly vacuum atmosphere, the oxygen concentration inside the sealed photoelectric conversion module is measured according to IVA, and the released moisture or gas is quantified by a flight mass spectrometer (IVA: semiconductor internal gas analyzer, available from Oki Engineering Co., Ltd (OEG)), detector: quadruple mass spectrometer (QM1422 / QMA-125, available from PFEIFFERVACUUM) for mass spectrometry analysis.

[0553] As a result, it was confirmed that the oxygen concentration in the sealing portion of each of the produced photoelectric conversion modules was almost the same as the set oxygen concentration (10% by volume).

[0554] <Valence of Cobalt Complex>

[0555] The valence state of the cobalt complex in each photoelectric conversion module was analyzed by X-ray absorption fine structure spectroscopy (XAFS). The valence state of the cobalt complex in the photoelectric conversion module was measured by opening the seal of the photoelectric conversion module and keeping the state of the electrode setting. In addition, the XAFS spectra of the divalent cobalt complex powder and the XAFS spectra of the trivalent cobalt complex powder were measured separately.

[0556] Then, the valence state of the cobalt complex in the hole transport layer was determined by comparing the XAFS spectrum of the cobalt complex in the hole transport layer with the XAFS spectrum of the sample. Fig.18 2 shows the XAFS analysis results of the photoelectric conversion module of Example 1.

[0557] exist Fig.18 The spectrum of the photoelectric conversion module of Example 1 almost matches the spectrum of the divalent cobalt complex powder sample. From the above results, it can be confirmed that a trivalent cobalt complex is added when producing the photoelectric conversion element and the photoelectric conversion module of the present invention, but most of the cobalt complex contained in the produced photoelectric conversion element and the photoelectric conversion module becomes a divalent cobalt complex.

[0558] <Measurement of Chlorobenzene Content>

[0559] After the produced photoelectric conversion element was immersed in liquid nitrogen, the photoelectric conversion element was crushed by hammering, and the crushed photoelectric conversion element was transferred to a vial.

[0560] The sample collected in the vial was heated on a hot plate heated to 150° C. for 1 hour, and the gas in the vial was collected. From the collected gas, 100 μL of the gas was sampled and analyzed according to gas chromatography-mass spectrometry.

[0561] Gas chromatography-mass spectrometry analysis was performed under the following conditions.

[0562] -equipment-

[0563] SION-TQ (GCMS), purchased from BRUKER

[0564] UNITY2 (TD), purchased from MARKES

[0565] -Measurement conditions-

[0566] Chromatographic column: SGE GC chromatographic column

[0567] Sol-wax

[0568] L=30.0m

[0569] ID=0.25mm ID

[0570] Film = 0.25 μm

[0571] Column heating: 40°C (hold for 5 minutes) to <20°C / min> to 260°C (hold for 5 minutes)

[0572] Carrier gas: He

[0573] Nozzle: 200℃

[0574] Column flow rate: 1.00mL / min (constant)

[0575] Ionization method: Electron ionization (EI) (70eV)

[0576] Injection mode: 1:10 separation

[0577] Measurement mode: Total ion chromatography (TIC) (m / z = 33 to 600)

[0578] Injection volume: 100μL (gas)

[0579] The same sample was measured at 3 points (N=3), and the average value thereof was provided as the measured value. The area value of each component was calculated from the specific spectrum. In the examples, since chlorobenzene was used as a solvent for the hole transport layer, the measurement was performed at m / z=112.

[0580] The measured value obtained by GCMS was compared with the above calibration curve to determine the quantitative value on the calibration curve, and the quantitative value was converted using the volume of the hole transport layer according to the following formula to calculate the quantitative value of chlorobenzene per unit volume of the hole transport layer. The above hole transport layer refers to a region of a film having a thickness, which exists independently as a layer, and the hole transport layer does not include a region of a porous layer that penetrates the electron transport layer.

[0581] Quantitative value (μg / mm 3 ) = quantitative value on the calibration curve (μg) / hole transport layer area × film thickness (mm 3 )

[0582] The solvent for forming the calibration curve was prepared as follows. The solvent was used to form the calibration curve.

[0583] -Preparation of solutions for forming a calibration curve and formation of a calibration curve-

[0584] Standard chlorobenzene was diluted with methanol.

[0585] The obtained solution (1 μL) was transferred to a vial, the vial was heated on a hot plate at 150° C., 100 μL of gas collected from the gas generated from the vial was introduced into the above GCMS apparatus, and the amount of chlorobenzene was measured in the same manner as the above method.

[0586] <Performance evaluation of photoelectric conversion module>

[0587] The obtained photoelectric conversion module was installed in a constant temperature chamber with an opening at the top, and light from a 5000K white LED was applied from the opening into the constant temperature chamber to adjust the illuminance on the photoelectric conversion module to 200 lux. In addition, wiring connected to the terminals of the photoelectric conversion module was extended to the outside of the constant temperature chamber so that the IV characteristics were measured in a state where the photoelectric conversion module was set in the constant temperature chamber.

[0588] Thereafter, the constant temperature chamber was set to 60°C, and the IV characteristics at 60°C were measured by a solar cell test system (As-510-PV03, available from NFCORPORATION) to determine the initial maximum output power Pmax1 (μW). After standing for 750 hours in the same state, the IV characteristics were measured again to determine the maximum output power Pmax2 (μW), and the Pmax retention rate at 60°C was determined according to the following formula: [(Pmax2 / Pmax1) x 100] (%). The results are shown in Table 1.

[0589] The thermostatic chamber was set to -30°C, and the Pmax retention rate at -30°C was measured according to the formula: [(Pmax2 / Pmax1) x 100] (%) in the same manner as the Pmax retention rate at 60°C. The results are shown in Table 1.

[0590] Table 1-1

[0591]

[0592] Table 1-2

[0593]

[0594] Table 1-3

[0595]

[0596] It can be clearly seen from the examples of the present invention that the initial Pmax is high and remains stable even in different temperature environments of 60°C and -30°C, when the hole transport layer contains a lithium salt having an asymmetric structure and the amount of the solvent contained in the photoelectric conversion element is controlled to 30 μg / mm per unit volume of the hole transport layer. 3 or less, excellent durability was obtained. The durability test of Comparative Example 4 was suspended due to the low initial Pmax; the test of Comparative Example 6 was suspended because the material was not dissolved in the composition of Comparative Example 6 and a photoelectric conversion element could not be produced.

[0597] For example, the present invention is implemented as follows.

[0598] <1> A photoelectric conversion element, comprising:

[0599] The first electrode,

[0600] a photoelectric conversion layer, and

[0601] a second electrode;

[0602] The photoelectric conversion layer includes a hole transport layer, the hole transport layer includes a lithium salt with an asymmetric structure, and the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less.

[0603] <2> according to <1> A photoelectric conversion element, wherein the amount of solvent per unit volume of the hole transport layer is 25 μg / mm 3 or less.

[0604] <3> according to <1> or <2> A photoelectric conversion element, wherein the lithium salt having an asymmetric structure is represented by the following general formula (1),

[0605]

[0606] In the general formula (1), A and B are each a substituent selected from F, CF3, C2F5, C3F7 and C4F9, and A and B are different substituents from each other.

[0607] <4> according to <1> to <3> The photoelectric conversion element according to any one of the preceding claims, wherein the lithium salt is lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide.

[0608] <5> according to <1> to <4> The photoelectric conversion element of any one of the above, wherein the hole transport layer further comprises an organic p-type semiconductor material, and the organic p-type semiconductor material is a compound represented by the following general formula (4):

[0609]

[0610] In the general formula (4), R3 is a hydrogen atom or an alkyl group.

[0611] <6> according to <5> A photoelectric conversion element, wherein the molar ratio X / Y of the lithium salt to the organic p-type semiconductor material is 0.35 or greater but 0.65 or less, X is the molar amount of the lithium salt in the hole transport layer, and Y is the molar amount of the organic p-type semiconductor material in the hole transport layer.

[0612] <7> according to <1> to <6> The photoelectric conversion element according to any one of the preceding claims, wherein the hole transport layer further comprises a pyridine compound.

[0613] <8> according to <7> A photoelectric conversion element, wherein the molar ratio a / b of the pyridine compound to the lithium salt is less than 2.0.

[0614] <9> according to <1> to <8> The photoelectric conversion element according to any one of the preceding claims, wherein the hole transport layer further comprises a divalent cobalt complex.

[0615] <10> according to <1> to <9> The photoelectric conversion element of any one of the items further includes a hole blocking layer, wherein the first electrode, the photoelectric conversion layer and the second electrode are arranged in this order, and the hole blocking layer is arranged between the first electrode and the photoelectric conversion layer.

[0616] <11> according to <1> to <10> The photoelectric conversion element of any one of , further including a sealing member configured to seal the photoelectric conversion layer from an external environment of the photoelectric conversion element.

[0617] <12> A photoelectric conversion module, comprising a plurality of <1> to <11> The photoelectric conversion element of any one of the above, wherein the photoelectric conversion elements arranged adjacent to each other are electrically connected in series or in parallel.

[0618] <13> according to <12> A photoelectric conversion module, wherein at least two photoelectric conversion elements are arranged adjacent to each other in the photoelectric conversion module, and a first electrode in one of the photoelectric conversion elements and a second electrode in another photoelectric conversion element are electrically connected via a conductive portion passing through the photoelectric conversion layer.

[0619] <14> according to <12> or <13> The photoelectric conversion module further includes a sealing member configured to seal the photoelectric conversion layer of the photoelectric conversion element in the photoelectric conversion module to be separated from the external environment of the photoelectric conversion module.

[0620] <15> An electronic device comprising: <1> to <11> The photoelectric conversion element according to any one of <12> to <14> A photoelectric conversion module according to any one of the above and a device driven by electric power generated by photoelectric conversion performed by a photoelectric conversion element or a photoelectric conversion module.

[0621] <16> An electronic device, comprising:

[0622] according to <1> to <11> The photoelectric conversion element according to any one of <12> to <14> The photoelectric conversion module of any one of the above,

[0623] a storage battery unit capable of storing electric energy generated by photoelectric conversion performed by a photoelectric conversion element or a photoelectric conversion module, and

[0624] A device powered by electricity stored in a battery cell.

[0625] <17> A method for producing a photoelectric conversion element, the method comprising:

[0626] forming a photoelectric conversion layer including a hole transport layer on the first electrode, and

[0627] Controlling the amount of solvent in the hole transport layer;

[0628] The amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less.

[0629] according to <1> to <11> The photoelectric conversion element according to any one of <12> to <14> The photoelectric conversion module according to any one of <15> or <16> Electronic equipment and <17> The method for producing a photoelectric conversion element can solve the above-mentioned various problems existing in the art and achieve the purpose of the present invention.

Claims

1. A photoelectric conversion element comprising a first electrode, a photoelectric conversion layer and a second electrode; in, The photoelectric conversion layer includes a hole transport layer, The hole transport layer includes a lithium salt having an asymmetric structure, and the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less, The hole transport layer further comprises an organic p-type semiconductor material, and the organic p-type semiconductor material is a compound represented by the following general formula (4): In the general formula (4), R3 is a hydrogen atom or an alkyl group, The molar ratio X / Y of lithium salt to organic p-type semiconductor material is 0.50 or more but 0.65 or less, and X is the molar amount of lithium salt in the hole transport layer, and Y is the molar amount of organic p-type semiconductor material in the hole transport layer.

2. The photoelectric conversion element according to claim 1, wherein The amount of solvent per unit volume of the hole transport layer is 25 μg / mm 3 or less.

3. The photoelectric conversion element according to claim 1, wherein The lithium salt having an asymmetric structure is represented by the following general formula (1): In the general formula (1), A and B are each a substituent selected from F, CF3, C2F5, C3F7 and C4F9, and A and B are different substituents from each other.

4. The photoelectric conversion element according to claim 1, wherein The lithium salt is lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide.

5. The photoelectric conversion element according to claim 1, wherein The hole transport layer also includes a pyridine compound.

6. The photoelectric conversion element according to claim 5, wherein The molar ratio a / b of the pyridine compound to the lithium salt is less than 2.

0.

7. The photoelectric conversion element according to claim 1, wherein The hole transport layer also includes a divalent cobalt complex.

8. The photoelectric conversion element according to claim 1, wherein A hole blocking layer is also included, and the first electrode, the photoelectric conversion layer and the second electrode are arranged in this order, and the hole blocking layer is arranged between the first electrode and the photoelectric conversion layer.

9. The photoelectric conversion element according to any one of claims 1 to 8, wherein A sealing member configured to seal the photoelectric conversion layer from an external environment of the photoelectric conversion element is also included. 10 . A photoelectric conversion module, comprising a plurality of the photoelectric conversion elements according to claim 1 , wherein the photoelectric conversion elements adjacent to each other are electrically connected in series or in parallel.

11. The photoelectric conversion module according to claim 10, wherein: At least two photoelectric conversion elements are disposed adjacent to each other in the photoelectric conversion module, and a first electrode in one of the photoelectric conversion elements and a second electrode in another photoelectric conversion element are electrically connected via a conductive portion passing through the photoelectric conversion layer.

12. The photoelectric conversion module according to claim 10 or 11, wherein: A sealing member is also included, the sealing member being configured to seal the photoelectric conversion layer of the photoelectric conversion element in the photoelectric conversion module to be separated from an external environment of the photoelectric conversion module.

13. An electronic device comprising: The photoelectric conversion element according to any one of claims 1 to 9 or the photoelectric conversion module according to any one of claims 10 to 12, and A device driven by electricity generated by photoelectric conversion performed by a photoelectric conversion element or a photoelectric conversion module.

14. An electronic device comprising: The photoelectric conversion element according to any one of claims 1 to 9 or the photoelectric conversion module according to any one of claims 10 to 12, a storage battery unit capable of storing electric energy generated by photoelectric conversion performed by a photoelectric conversion element or a photoelectric conversion module, and A device powered by electricity stored in a battery cell.

15. A method for producing a photoelectric conversion element, the method comprising: forming a photoelectric conversion layer including a hole transport layer on the first electrode, and Controlling the amount of solvent in the hole transport layer; Furthermore, the hole transport layer includes a lithium salt having an asymmetric structure, and the amount of solvent per unit volume of the hole transport layer is 30 μg / mm 3 or less, The hole transport layer further comprises an organic p-type semiconductor material, and the organic p-type semiconductor material is a compound represented by the following general formula (4): In the general formula (4), R3 is a hydrogen atom or an alkyl group, The molar ratio X / Y of lithium salt to organic p-type semiconductor material is 0.50 or more but 0.65 or less, and X is the molar amount of lithium salt in the hole transport layer, and Y is the molar amount of organic p-type semiconductor material in the hole transport layer.

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