Perovskite solar cells

Abstract

To provide a highly durable perovskite solar cell that prevents moisture and oxygen from entering a device.SOLUTION: A solar cell includes a support 11, a solar cell element 12 provided on the support, an adhesive layer 13 covering the entire solar cell element, a sealant layer 14 covering the entire adhesive layer, and a sealing portion 15 provided in the edge region of the sealing agent layer and covering the edge region, and the solar cell element includes a transparent electrode, a photoelectric conversion layer containing a perovskite compound, and a backside electrode in that order, and the distance (d1) between the edge of the solar cell element and the edge of the adhesive layer is 0.5 mm or more and 2 cm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to perovskite solar cells. [Background technology]

[0002] Perovskite solar cells are vulnerable to water, and creating a device structure that prevents water from entering the device is a challenge. WO2018 / 052032 describes a structure that seals the entire side of the organic insulating layer that covers the entire perovskite solar cell. Since this device is prone to water penetration through the organic insulating layer located between the flexible substrate made of metal foil and the transparent electrode, the organic insulating layer is sealed with a barrier layer. However, the problem of water penetration from the interface between the barrier layer and the transparent electrode has not been resolved. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2018 / 052032 publication Summary of the Invention [Problem to be solved by the invention]

[0004] One of the objects of this invention is to provide a highly durable perovskite solar cell. [Means for solving the problem]

[0005] The solar cell described in this specification includes a support, a solar cell element provided on the support, an adhesive layer covering the solar cell element, a sealant layer covering the adhesive layer, and a sealing portion provided in an end region of the sealant layer and covering the end region. The solar cell element includes, in this order, an electrode, a photoelectric conversion layer containing a perovskite compound, and a back electrode.

[0006] In the above solar cell, the distance (d1) between the end of the solar cell element and the end of the adhesive layer is preferably 0.5 mm or more and 2 cm or less.

[0007] In the above solar cell, the distance (d2) between the end of the adhesive layer and the end of the sealant layer is preferably 0.2 mm or more and 1 cm or less.

[0008] In the above solar cell, the distance (d3) between the edge of the sealant layer and the edge of the sealing portion is preferably 0.5 mm or more and 1.5 cm or less.

[0009] In the above solar cell, the sealing portion is preferably opaque. [Effects of the Invention]

[0010] According to this invention, it is possible to provide a highly durable perovskite solar cell that can prevent water intrusion. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a conceptual diagram showing an example of a cross-sectional view of a solar cell of the present invention. [Figure 2] FIG. 2 is a conceptual diagram showing an example of a top view of the solar cell of the present invention. [Figure 3] FIG. 3 is a conceptual diagram showing an example of a cross-sectional view of a solar cell of the present invention. [Figure 4] FIG. 4 is a conceptual diagram showing an example of a cross-sectional view of a solar cell of the present invention. [Figure 5] FIG. 5 is a conceptual diagram showing an example of the structure of a perovskite solar cell element (normal type). [Figure 6] FIG. 6 is a conceptual diagram showing an example of the structure of a perovskite solar cell element (inverted type). [Figure 7] FIG. 7 is a conceptual diagram showing a cross section of a solar cell in an experimental example. [Figure 8] FIG. 8 is a conceptual diagram showing a top view of the solar cell of the experimental example. [Figure 9]FIG. 9 is a conceptual diagram showing an example of a cross section of a solar cell in an experimental example. [Figure 10] FIG. 10 is a conceptual diagram showing an example of a cross section of a solar cell in an experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes embodiments of the present invention with reference to the drawings. The present invention is not limited to the embodiments described below, and also includes appropriate modifications of the embodiments below within the scope obvious to those skilled in the art.

[0013] solar cells The first invention relates to a solar cell. Figures 1, 3, and 4 are cross-sectional views of a solar cell, and Figure 2 is a conceptual diagram showing the solar cell shown in Figure 1 as seen from above. As shown in Figures 1 to 4, the solar cells 1, 2, and 3 have first supports 11, 21, and 31, (perovskite) solar cell elements 12, 22, and 32, adhesive layers 13, 23, and 33, sealant layers (main body portions) 14, 24, and 34 that cover the entire adhesive layers, and sealing portions 15, 25, and 35.

[0014] Supports 11, 21, 31 As the supports 11, 21, and 31, known substrates for organic solar cells and organic EL elements can be used as appropriate. Examples of substrates include glass, plastic plates, plastic films, and inorganic crystals. Substrates having at least one film of a metal film, a semiconductor film, a conductive film, and an insulating film formed on part or all of their surfaces can also be suitably used. In particular, for the purpose of reducing thickness and weight, it is preferable that the support be a flexible substrate.

[0015] Solar cell elements 12, 22, 32 A solar cell element refers to an element that receives light such as sunlight and generates electricity. A solar cell element preferably has a shape in which a perovskite layer (light absorption layer / photoelectric conversion layer) is sandwiched between an electron transport layer and a hole transport layer. The perovskite layer is preferably a perovskite layer made of an organic-inorganic hybrid compound. As shown in FIG. 5, the solar cell element may have a normal structure in which, from the transparent electrode 40 side, an electron transport layer 46, a perovskite layer 47, a hole transport layer 48, and a back electrode 49 are formed. Alternatively, as shown in FIG. 6, the solar cell element may have an inverted structure in which, from the transparent electrode 50 side, a hole transport layer 58, a perovskite layer 57, an electron transport layer 56, and a back electrode 59 are formed.

[0016] electrode 40,50 The electrodes are preferably transparent electrodes for transmitting light. The transparent electrodes serve as a support for the electron transport layer and also function to extract electrons from the perovskite layer (light absorption layer / photoelectric conversion layer). The electrodes are formed on supports 11, 21, and 31. The transparent electrodes are formed from a conductor, specific examples of which include a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In2O3) film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide (FTO) film, a laminated film formed by laminating these, gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, and cobalt. These may be used alone or in combination, and may be in either a single layer or a laminated form. These films may function, for example, as a diffusion prevention layer. The thickness of these electrodes is not particularly limited, and it is generally preferable to adjust the sheet resistance to 5 to 15 Ω / □ (per unit area). The electrodes can be obtained by known film formation methods depending on the material to be formed. These electrodes may be in the form of a film or a lattice such as a mesh. A known method for forming electrodes on a support is used, and vacuum film formation such as vacuum deposition or sputtering is preferred. Transparent electrodes may also be used that have been patterned, and examples of such methods include immersion in a laser or etching solution, and patterning using a mask during vacuum film formation. Any method is acceptable for the present invention.

[0017] Electron transport layer46,56 The electron transport layers 46 and 56 are preferably made of electron-transporting semiconductors, such as oxides of titanium, tin, zinc, iron, tungsten, zirconium, indium, cerium, yttrium, aluminum, magnesium, vanadium, and niobium, and metal chalcogenides such as cadmium, zinc, lead, silver, antimony, and bismuth sulfide, cadmium and lead selenide, and cadmium telluride. Of these, oxides are particularly preferred. Zinc oxide, tin oxide, and titanium oxide are particularly preferred. The electron transport layer may be a single layer or a multilayer. In the case of a multilayer structure, the layer may be porous, with semiconductor particles of different particle sizes coated in multiple layers. In the case of a porous structure, the particle size of the semiconductor particles is preferably 3 to 100 nm, more preferably 5 to 70 nm. The film thickness is preferably 5 to 1,000 nm, more preferably 10 to 500 nm.

[0018] The method for forming the electron transport layer is not particularly limited, and may be either a vacuum film formation method such as sputtering or ion plating, or a wet film formation method such as sol-gel.

[0019] Hole transport layer 48, 58 The hole transport layers 48, 58 are layers that have the function of transporting charges. For example, conductors, semiconductors, organic hole transport materials, etc. can be used for the hole transport layers. These materials can function as hole transport materials that receive holes from the perovskite layer (light absorption layer) and transport the holes. Examples of such conductors and semiconductors include compound semiconductors containing monovalent copper, such as CuI, CuInSe2, and CuS; and compounds containing metals other than copper, such as GaP, NiO, CoO, FeO, Bi2O3, MoO2, and Cr2O3. Among these, semiconductors containing monovalent copper are preferred, and CuI is more preferred, from the viewpoint of more efficiently receiving only holes and achieving higher hole mobility. Examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyethylenedioxythiophene (PEDOT); fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD); carbazole derivatives such as polyvinylcarbazole; triphenylamine derivatives such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA); diphenylamine derivatives; polysilane derivatives; polyaniline derivatives, etc. Among these, triphenylamine derivatives and fluorene derivatives are preferred, with PTAA and Spiro-OMeTAD being more preferred, from the viewpoint of more efficiently receiving only holes and achieving higher hole mobility.

[0020] In order to further improve the hole transport properties, the hole transport layer may contain an oxidizing agent such as lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethylsulfonyl)imide, trifluoromethylsulfonyloxysilver, NOSbF6, SbCl5, SbF5, or tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide]. The hole transport layer may also contain a basic compound such as t-butylpyridine (TBP), 2-picoline, or 2,6-lutidine. The contents of the oxidizing agent and basic compound may be the amounts conventionally used. The thickness of the hole transport layer is preferably 50 to 800 nm, and more preferably 100 to 600 nm, from the viewpoint of more efficiently receiving only holes and achieving higher hole mobility. The method for forming the hole transport layer is not particularly limited, and can be performed according to a known method. For example, wet film formation methods such as dipping, spraying, spin coating, and blade coating, and vacuum film formation methods such as sputtering can be mentioned.

[0021] Perovskite layer (light absorption layer / photoelectric conversion layer) 47, 57 The perovskite layers (light absorption layers and photoelectric conversion layers) 47 and 57 are layers that absorb light and perform photoelectric conversion by transferring excited electrons and holes. The perovskite compound in the present invention is preferably a composite material of an organic compound and an inorganic compound. The perovskite compound preferably exhibits a layered perovskite structure in which layers made of metal halide and layers in which organic cation molecules are arranged are alternately stacked, and is represented by the following general formula (1): XαYβMγ · · General formula (1) In the above general formula (1), X represents a halogen atom, Y represents an alkylamine compound, M represents at least one metal ion selected from lead, tin, indium, antimony, and bismuth, the ratio of α:β:γ is 3:1:1, and β and γ represent integers greater than 1. X can be a halogen atom such as chlorine, bromine, or iodine, which can be used alone or as a mixture. Y can be an alkylamine compound such as methylamine, ethylamine, n-butylamine, or formamidine.

[0022] Furthermore, the flatness of the perovskite layer is preferably such that the difference in height is 50 nm or less (-25 nm to +25 nm) within a 500 nm x 500 nm area in the horizontal direction of the surface as measured by a scanning electron microscope, and more preferably the difference in height is 40 nm or less (-20 nm to +20 nm). This makes it easier to balance the light absorption efficiency and the exciton diffusion length, and further improves the absorption efficiency of light reflected by the electrode.

[0023] Examples of methods for forming a perovskite layer include a one-step precipitation method in which a solution in which metal halides and halogenated alkylamines are dissolved or dispersed in a solvent is applied to the electron transport layer or hole transport layer and dried, or a two-step precipitation method in which a solvent in which metal halides are dissolved or dispersed is applied to the electron transport layer or hole transport layer, dried, and then immersed in a solution in which halogenated alkylamines are dissolved in the solvent.In addition, in the one-step precipitation method, it is also possible to add a solvent that does not dissolve the perovskite compound before complete application to promote crystallization all at once.

[0024] After forming the perovskite compound layer, a solution of a halogenated amine compound may be applied onto the perovskite layer. Examples of the halogenated amine compound include phenylethylamine bromide, phenylethylamine iodide, n-hexyltrimethylamine bromide, n-octadecylamine iodide, and 5-ammonium valerate iodide, and these compounds may be used alone or in combination.

[0025] Back electrode 49, 59 Examples of the back electrodes 49, 59 include metals such as platinum, gold, silver, copper, aluminum, rhodium, nickel, cobalt, iron, palladium, and indium; carbon-based compounds such as graphite, graphene, and carbon nanotubes; conductive metal oxides such as ITO, indium-doped zinc oxide (IZO), and antimony-doped tin oxide (ATO); and conductive polymers such as polythiophene and polyaniline. These may be used alone or in combination of two or more. The back electrodes may be transparent electrodes. The thickness of the back electrodes is not particularly limited, and they may be a single film of the above-mentioned materials or a mixture or laminate of two or more of them. The back electrodes can be formed by coating, laminating, vacuum deposition, CVD, bonding, or other methods on the hole transport layer, depending on the type of material used and the type of hole transport layer.

[0026] Adhesive layer 13,23,33 The adhesive layer is a layer that covers the solar cell element. The adhesive layer may cover the entire solar cell element, or may cover only a portion of the solar cell element. The adhesive layer is a layer that is placed between the support and the sealant layer (main body). The adhesive layer is used to bond the support and the sealant layer, as well as to bond the solar cell element on the support and the sealant layer. However, when the adhesive layer covers the entire solar cell element, it also has the function of sealing the solar cell element. There are no particular restrictions on the material of the adhesive, and it can be selected appropriately depending on the purpose. For example, hardened acrylic resin or epoxy resin can be used. Any known material can be used as the cured acrylic resin, provided that it is a cured monomer or oligomer having an acrylic group in the molecule, and any known material can be used as the cured epoxy resin, provided that it is a cured monomer or oligomer having an epoxy group in the molecule.

[0027] Epoxy resins include water-dispersed, solvent-free, solid, heat-cured, curing agent-mixed, and UV-cured resins. Among these, heat-cured and UV-cured resins are preferred, with UV-cured resins being more preferred. UV-cured resins can also be heated, and it is preferable to heat them even after UV curing. Specific examples of epoxy resins include bisphenol A, bisphenol F, novolac, cyclic aliphatic, long-chain aliphatic, glycidyl amine, glycidyl ether, and glycidyl ester resins. These may be used alone or in combination. It is also preferable to mix a curing agent or various additives with the epoxy resin as needed. Commercially available epoxy resin compositions can be used in the present invention. Among these, there are commercially available epoxy resin compositions developed for solar cells and organic EL devices, which can be particularly effectively used in the present invention. Commercially available epoxy resin compositions include, for example, TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond Co., Ltd.), World Rock 5910, World Rock 5920, World Rock 8723 (manufactured by Kyoritsu Chemical Industries Co., Ltd.), and WB90US(P) (manufactured by MORESCO Corporation).

[0028] The curing agent is not particularly limited and can be selected appropriately depending on the purpose. Examples include amine-based, acid anhydride-based, polyamide-based, and other curing agents. Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, PEG-4 anhydride, and dodecenyl succinic anhydride. Other curing agents include imidazoles and polymercaptan. These may be used alone or in combination of two or more.

[0029] The additives are not particularly limited and can be selected appropriately depending on the purpose. Examples include fillers, gap agents, polymerization initiators, desiccants (moisture absorbers), curing accelerators, coupling agents, flexibilizers, colorants, flame retardant aids, antioxidants, and organic solvents. Among these, fillers, gap agents, curing accelerators, polymerization initiators, and desiccants (moisture absorbers) are preferred, with fillers and polymerization initiators being more preferred. The inclusion of fillers as additives can suppress the penetration of moisture and oxygen, and can also provide effects such as reduced volumetric shrinkage during curing, reduced outgassing during curing or heating, improved mechanical strength, and control of thermal conductivity and fluidity. Therefore, including fillers as additives is highly effective in maintaining stable output in various environments. Additives may be added to the sealant layer or sealing portion.

[0030] Furthermore, with regard to the output characteristics and durability of solar cell elements, not only are the effects of moisture and oxygen intrusion significant, but the effects of outgassing generated when the sealing material hardens or is heated cannot be ignored. In particular, the effects of outgassing generated when heated have a significant impact on output characteristics when stored in a high-temperature environment. By incorporating fillers, gap agents, and desiccants into the adhesive layer, sealant layer, and sealing part, these themselves can suppress the penetration of moisture and oxygen, and by reducing the amount of adhesive and sealant used, the effect of reducing outgassing can be achieved. Incorporating fillers, gap agents, and desiccants into the adhesive layer, sealant layer, and sealing part is effective not only during hardening, but also when storing solar cell elements in a high-temperature environment.

[0031] The filler is not particularly limited and can be selected appropriately depending on the purpose. Examples include crystalline or amorphous silica, silicate minerals such as talc, and inorganic fillers such as alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate. Among these, hydrotalcite is particularly preferred. These may be used alone or in combination of two or more types.

[0032] The average primary particle size of the filler is preferably 0.1 μm or more and 10 μm or less, and more preferably 1 μm or more and 5 μm or less. When the average primary particle size of the filler is within the above preferred range, the effect of suppressing the penetration of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, adhesion to the substrate and degassing properties are improved, and it is also effective in controlling the width of the sealing part and workability.

[0033] The content of the filler is preferably 10 to 90 parts by mass, and more preferably 20 to 70 parts by mass, relative to the total (100 parts by mass) of the adhesive layer, etc. When the content of the filler is within the above preferred range, the effect of suppressing the penetration of moisture and oxygen is sufficiently obtained, the viscosity is appropriate, and adhesion and workability are also good.

[0034] Gap agents are also called gap control agents or spacer agents. By including a gap agent as an additive, it becomes possible to control the gap in the sealing portion. For example, when an adhesive layer is applied on a first substrate or a first electrode, and a second substrate is placed on top of that to seal, the gap in the sealing portion is aligned to the size of the gap agent because the adhesive layer or sealing material layer contains a gap agent, making it easy to control the gap in the sealing portion. There are no particular restrictions on the gap agent, as long as it is granular, has a uniform particle size, and has high solvent resistance and heat resistance, and it can be selected appropriately depending on the purpose. As a gap agent, one that has high affinity with epoxy resin and has a spherical particle shape is preferred. Specifically, glass beads, silica microparticles, organic resin microparticles, etc. are preferred. These may be used alone or in combination of two or more types. The particle size of the gap agent can be selected according to the gap of the sealing portion to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0035] There are no particular restrictions on the polymerization initiator as long as it uses heat or light to initiate polymerization, and it can be selected appropriately depending on the purpose. Examples include thermal polymerization initiators and photopolymerization initiators. Thermal polymerization initiators are compounds that generate active species such as radicals and cations when heated, and examples include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). Benzene sulfonate esters and alkyl sulfonium salts are used as thermal cationic polymerization initiators. On the other hand, in the case of epoxy resins, photocationic polymerization initiators are preferably used as photopolymerization initiators. When a photocationic polymerization initiator is mixed with epoxy resin and irradiated with light, the photocationic polymerization initiator decomposes, generating acid, which then causes the epoxy resin to polymerize and the curing reaction to proceed. Photocationic polymerization initiators have the advantages of causing little volume shrinkage during curing, not being inhibited by oxygen, and having high storage stability.

[0036] Examples of photocationic polymerization initiators include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, methacerone compounds, and silanol-aluminum complexes. Photoacid generators, which have the function of generating acid upon irradiation with light, can also be used as polymerization initiators. Photoacid generators act as acids that initiate cationic polymerization, and examples include onium salts such as ionic sulfonium salts and iodonium salts, which consist of a cationic moiety and an anionic moiety. These may be used alone or in combination of two or more types.

[0037] The amount of polymerization initiator to be added may vary depending on the material used, but is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, relative to the entire sealing member (100 parts by mass). By keeping the amount added within the above preferred range, curing proceeds properly, the amount of uncured material remaining can be reduced, and excessive outgassing can be prevented.

[0038] A desiccant (also known as a moisture absorbent) is a material that has the ability to physically or chemically adsorb and absorb moisture, and by incorporating it into a sealing material, it is possible to further increase moisture resistance and reduce the effects of outgassing. There are no particular limitations on the desiccant, and it can be selected appropriately depending on the purpose, but particulate desiccants are preferred, and examples include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, and zeolite. Among these, zeolite, which has a high moisture absorption capacity, is preferred. These may be used alone or in combination of two or more types.

[0039] A curing accelerator (also called a curing catalyst) is a material that accelerates the curing rate and is mainly used in thermosetting epoxy resins. The curing accelerator is not particularly limited and can be selected appropriately depending on the purpose. For example, tertiary amines or tertiary amine salts such as DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5), 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole are suitable. Examples include imidazoles such as tetraphenylphosphine, phosphine or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate. These may be used alone or in combination of two or more.

[0040] The coupling agent is not particularly limited as long as it is a material that has the effect of enhancing molecular bonding strength and can be appropriately selected depending on the purpose, and examples thereof include silane coupling agents. Specific examples include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, and 3-methacryloxypropyltrimethoxysilane. These may be used alone or in combination of two or more types.

[0041] In the present invention, a sheet-like adhesive can be used. A sheet-like adhesive is a sheet on which a resin layer is formed in advance, and the sheet can be made of glass or a film with high gas barrier properties. The sheet may also be made of resin only. The sheet-like adhesive can also be attached to a sealing film. It is also possible to create a structure with a hollow portion on the sealing film and then attach it to a device.

[0042] The distance (d1) between the edge of the solar cell element and the edge of the adhesive layer is preferably 0.5 mm or more and 2 cm or less. The edge of the solar cell element refers to the outer part of the solar cell element. For example, if the solar cell element is rectangular, the part on the edge of the rectangle constitutes the edge of the solar cell element. The edge of the adhesive layer refers to the outermost edge of the adhesive layer. d1 refers to the closest one between the edge of the solar cell element and the edge of the adhesive layer (the edge on the opposite side from the solar cell element). d1 is preferably 1 mm or more, and more preferably 2 mm or more. However, d1 may be adjusted appropriately depending on the size of the solar cell element. If the solar cell element is rectangular and the length of its long side is l, d1 may be 0.01 l or more and 0.5 l or less, or 0.05 l or more and 0.2 l or less.

[0043] Sealant layer (main body) 14, 24, 34 The sealant layer (main body portion) is formed to cover the adhesive layer and refers to a layer that prevents water and the like from penetrating into the solar cell element. In this specification, it is referred to as the sealant layer or the main body portion to distinguish it from the sealing portion. The sealant layer preferably covers the solar cell element and the adhesive layer. The sealant layer is, for example, arranged opposite the support so as to sandwich the solar cell element including the photoelectric conversion layer and the electrode. The sealant layer may be composed of a sealant film. There are no particular restrictions on the shape, structure, size, or type (material) of the sealant layer, and they can be selected appropriately depending on the purpose. The sealant layer may be in the form of a thin film or a film.

[0044] The material constituting the sealant layer may be the same as the material of the adhesive layer. Other examples of sealant layer materials include a resin substrate having a barrier layer formed on its surface to prevent the passage of moisture and oxygen. The barrier layer may be formed on one or both sides of the substrate. In the latter case, the material of the resin substrate is not particularly limited, but examples include polyolefin-based resins such as homopolymers or copolymers of ethylene, propylene, butene, etc.; amorphous polyolefin-based resins such as cyclic polyolefins; polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide-based resins such as nylon 6, nylon 66, nylon 12, and copolymer nylon; ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide-based resins, polyetherimide-based resins, polysulfone-based resins, polyethersulfone-based resins, polyetheretherketone-based resins, polycarbonate-based resins, polyvinyl butyral-based resins, polyarylate-based resins, fluororesins, acrylic resins, and biodegradable resins. Among these, polyester resins are preferred, with polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) being particularly preferred, from the viewpoint of film properties such as heat resistance and transparency. The resin substrate may be made of one type of resin material, or may be made of two or more types of resin materials.

[0045] The resin substrate may contain other materials such as inorganic fillers to improve the durability of the solar cell module. There are no particular limitations on the inorganic fillers, but examples include silica, mica, talc, clay, bentonite, montmorillonite, kaolinite, wollastonite, calcium carbonate, titanium oxide, alumina, barium sulfate, potassium titanate, and glass fiber. The inorganic filler mixed into the resin substrate may be one type, or two or more types.

[0046] The barrier layer is composed primarily of metal oxides, metals, mixtures formed from polymers and metal alkoxides, and examples thereof include aluminum oxide, silicon oxide, and aluminum. Polymers include polyvinyl alcohol, polyvinylpyrrolidone, and methyl cellulose. Metal alkoxides include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

[0047] The barrier layer may be transparent or opaque. The barrier layer may be a single layer made from a combination of the above materials, or may have a multi-layer structure. The barrier layer may be formed by a known method, such as vacuum film formation (e.g., sputtering), dipping, roll coating, screen printing, spraying, or gravure printing. The thickness of the sealant layer main body may be within the range generally used in this technology. For example, it may be set appropriately within the range of 0.05 to 1 mm.

[0048] The sealant layer preferably covers the entire adhesive layer, and is preferably larger than the adhesive layer to prevent the intrusion of water and oxygen. The distance (d2) between the end of the adhesive layer and the end of the sealant layer is preferably 0.2 mm or more and 1 cm or less. The end of the adhesive layer is as explained above. The end of the sealant layer means the outermost edge of the sealant layer. The distance between the end of the adhesive layer and the end of the sealant layer means the distance at which the end of the adhesive layer and the end of the sealant layer are the shortest. d2 is preferably 0.5 mm or more, and more preferably 1 mm or more. Furthermore, although the upper limit varies depending on the size and use of the solar cell, if it is too large, the solar cell (device) itself will become too large, or parts other than the solar cell element will become too large and wasteful, so d2 is preferably 1 cm or less, more preferably 5 mm or less, and more preferably 4 mm or less.

[0049] Sealing parts 15, 25, 35 The sealing portions 15, 25, and 35 are provided in the edge regions of the sealant layer and are portions that cover the edge regions. The edge regions of the sealant layer refer to the outer edge portions of the sealant layer. The sealing portions are provided to more firmly isolate the outer periphery of the sealant layer from water and oxygen. The sealing portions are formed separately from the sealant layer. The sealant material may be the same as that of the sealant layer, or may be the same as that of the adhesive. The shape of the sealing portions is not particularly limited. An example of the shape of the sealing portion is one that is installed so as to cover the contact point between the edge of the sealant layer and the support. The sealing portion can be formed by known methods, such as coating, depending on the material.

[0050] The sealing portion overlaps and protrudes from the upper part of the sealant layer, and may be somewhat large to prevent the intrusion of moisture and oxygen. The width of the sealing portion (the distance from the center of the solar cell element toward the outside) is preferably 2 mm or more, more preferably 3 mm or more. It may also be 3 cm or less, 2 cm or less, 1.5 cm or less, or 5 mm or less.

[0051] The distance (d3) between the end of the sealant layer and the end of the sealing portion is preferably 0.5 mm or more and 1.5 cm or less. The end of the sealant layer is as explained above. The end of the sealing portion refers to the outer edge of the sealing portion (the side opposite the solar cell element). The distance between the end of the sealant layer and the end of the sealing portion refers to the closest distance between the end of the sealant layer and the end of the sealing portion. d3 is preferably 1 mm or more, more preferably 1.5 mm or more, to prevent the intrusion of moisture and oxygen and to adhere closely to the sealant body to prevent peeling. Furthermore, if the solar cell (device) becomes too large or if parts other than the solar cell element become too large, this will cause waste, so it is preferably 1.5 cm or less, more preferably 1 cm or less, and more preferably 5 mm or less.

[0052] Furthermore, it is preferable that the sealing portion be made opaque, since this makes it easier to distinguish it from the sealant layer (main body portion). Methods for making the sealing portion opaque in this manner are not particularly limited, but include a method of incorporating a filler that can be used in the adhesive layer or sealant layer (main body portion), or incorporating a known pigment or dye. In the cross-sectional view, the cross-sectional shape of the sealing portion is rounded. However, the cross-sectional shape of the sealing portion may be a flat shape parallel to the support. The thickness of the sealing portion may be equal to or less than the thickness of the sealant layer. [Example]

[0053] An ITO-coated glass substrate (25mm x 24.5mm, Geomatec) was ultrasonically cleaned for 15 minutes each using 2-propanol, acetone, Semicoclean 56 (a cleaning solution for displays, product name: Furuuchi Chemical Co., Ltd.), water, and 2-propanol, in that order, followed by plasma treatment. Next, 300μL of an aqueous SnO2 colloidal solution (a 15% SnO2 colloidal solution diluted 1:1 with pure water and passed through a PTFE filter) was dropped onto the substrate as an electron transport layer, and a film was formed using spin coating (3000 rpm, 20 seconds), followed by heating and drying at 150°C for 30 minutes. The substrate was transferred to a glove box, and a 1.05 M perovskite precursor solution was prepared by dissolving CsI, MABr (methylammonium bromide, CHN·HBr), PbBr2, PbI2, and FAI (formamidine hydroiodide, CH4N2·HI) in a 10:3 volumetric ratio mixture of DMF and DMSO. After filtering the solution through a PTFE filter, 190 μL of the solution was applied to the substrate with the electron transport layer by spin coating (1000 rpm with a slope of 1 s for 10 s, then 3000 rpm with a slope of 5 s for 20 s). 300 μL of chlorobenzene was added dropwise during the spin coating process. The resulting device was then heated at 150 °C for 10 min. Next, a solution of 72.3 mg of the hole-transporting material Spiro-OMeTAD, 13.5 mg of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)] (FK209, Fujifilm Wako Pure Chemical Industries, Ltd.), 28.8 μL of 4-t-butylpyridine, and 9.1 mg of LiTFSI in 1 mL of chlorobenzene was stirred for 30 minutes, filtered through a PTFE filter, and 90 μL of the solution was spin-coated onto the perovskite layer (4000 rpm for 30 seconds with a slope of 4 seconds, followed by a slope of 4 seconds and a stop), followed by heating and drying at 70 °C for 30 minutes. Finally, 80 nm of gold was deposited by vacuum deposition to obtain a perovskite solar cell.

[0054] An adhesive mixture of 1.0 g of hydrotalcite and Epoch epoxy resin (E-01-001 base: 4.0 g, hardener: 2.0 g) was applied to the perovskite solar cell element using spin coating (1000 rpm, 120 seconds), and the unnecessary portion was removed with acetone. Next, an aluminum oxide-deposited PET film (product name: Barialocks, product of Toray Industries, Inc.) cut to a size larger than the adhesive application area was attached and heated at 80°C for 1 hour.

[0055] A one-component epoxy adhesive (Nagase ChemteX UV Resin XNR5516Z-B1) was applied to the outer periphery of this film by screen printing and cured by UV irradiation to form a sealing part, producing a solar cell device as shown in Figure 1. The width of the sealing part was 3.3 mm (same width in both the vertical and horizontal directions), with d1 being 2.0 mm, d2 being 0.3 mm, and d3 being 1.0 mm. This solar cell device was placed in a solar simulator (Bunkokeiki Co., Ltd. SM-250PV, light intensity: 100 mW / cm 2 The solar cell characteristics were measured using the device. The results were an open circuit voltage of 1.10 V and a short circuit current density of 22.1 mA / cm. 2 A form factor of 0.72 and a conversion efficiency of 17.5% were obtained. Next, this solar cell device was placed in a constant temperature and humidity tester at 60°C and 90% RH to carry out a durability test. After 500 hours, the retention rate of the initial characteristics was 91%. [Experimental Example 1]

[0056] A solar cell device was fabricated in the same manner as in Example 1, except that no sealing resin was provided on the outer periphery of the film, and the solar cell characteristics were evaluated. As a result, the open circuit voltage was 1.10 V and the short circuit current density was 22.0 mA / cm 2 The result was a form factor of 0.72 and a conversion efficiency of 17.4%, confirming performance equivalent to that of Example 1. Next, a durability test was conducted in a constant temperature and humidity chamber in the same manner as in Example 1, and the retention rate after 500 hours was measured, resulting in 42%, demonstrating that the device structure of the present invention has excellent durability. [Example]

[0057] In Example 1, an adhesive layer (first layer) of the same size as the part where the perovskite solar cell element was formed was formed on the element, and then the top of that was covered with a sealant layer (first layer), and an adhesive layer was formed on top of that so that the entire top was again covered with the same adhesive (second layer), and the top of that was then covered with a sealant layer the same as the first layer (second layer). A sealing material was applied to the outer periphery of this second layer in the same manner as in Example 1 and cured to produce a solar cell device as shown in FIG. The width of the sealing portion was 3.4 mm (same width in both the vertical and horizontal directions), with d1 being 1.9 mm, d2 being 0.4 mm, and d3 being 1.1 mm. The solar cell characteristics of this device were measured, revealing an open circuit voltage of 1.09 V and a short circuit current density of 22.2 mA / cm. 2 A form factor of 0.72 and a conversion efficiency of 17.4% were obtained. Next, a durability test was conducted in a constant temperature and humidity chamber in the same manner as in Example 1, and the retention rate after 500 hours was measured, resulting in 92%, which clearly demonstrated that the device structure of the present invention has excellent durability. [Example]

[0058] On the perovskite solar cell element in Example 1, an adhesive layer (first layer) of the same size as the part where the element was formed was formed, and a sealant layer (first layer) was formed on top of that, and then an adhesive layer (second layer) was formed to cover the entire top of that again with the same adhesive, and then the top of that was covered with a sealant layer the same as the first layer (second layer). A sealing material was applied to the outer periphery of this second layer film in the same manner as in Example 1 and cured to produce a solar cell device as shown in FIG. The width of the sealing portion was 3.9 mm (same width in both the vertical and horizontal directions), with d1 being 2.0 mm, d2 being 0.7 mm, and d3 being 1.2 mm. The solar cell characteristics of this device were measured, revealing an open circuit voltage of 1.09 V and a short circuit current density of 22.1 mA / cm. 2A form factor of 0.72 and a conversion efficiency of 17.3% were obtained. Next, a durability test was conducted in a constant temperature and humidity chamber in the same manner as in Example 1, and the retention rate after 500 hours was measured, resulting in 93%, which clearly demonstrated that the device structure of the present invention has excellent durability. [Experimental Example 2]

[0059] A solar cell device was fabricated in the same manner as in Example 2, except that no sealing resin was provided on the outer periphery of the film in Example 2, and the solar cell characteristics were evaluated. As a result, the open circuit voltage was 1.09 V and the short circuit current density was 22.0 mA / cm 2 The result was a form factor of 0.72 and a conversion efficiency of 17.3%, confirming performance equivalent to that of Example 2. Next, a durability test was conducted in a constant temperature and humidity chamber in the same manner as in Example 1, and the retention rate after 500 hours was measured, resulting in 51%, demonstrating that the device structure of the present invention has excellent durability. [Experimental Example 3]

[0060] A solar cell device was fabricated in the same manner as in Example 3, except that no sealing resin was provided on the outer periphery of the film, and the solar cell characteristics were evaluated. As a result, the open circuit voltage was 1.10 V and the short circuit current density was 22.0 mA / cm 2 The result was a form factor of 0.71 and a conversion efficiency of 17.2%, confirming performance equivalent to that of Example 3. Next, a durability test was conducted in a constant temperature and humidity chamber in the same manner as in Example 1, and the retention rate after 500 hours was measured, resulting in 48%, demonstrating that the device structure of the present invention has excellent durability. [Example]

[0061] Except for mixing carbon black into the sealing portion, solar cells were manufactured in the same manner as in Example 1. The sealing portion turned black, and it was possible to clearly see that the sealing portion was formed and covered the edge of the sealing layer without any gaps.

[0062] As described above, by using the sealing structure of the present invention, it is possible to manufacture a highly durable device. [Industrial Applicability]

[0063] This invention can be used in fields such as solar cells. [Explanation of symbols]

[0064] 1,2,3,6,7,8 solar cells 4,5 Perovskite solar cell elements 11,21,31,61,71,81 Support 12,22,32,62,72,82 Perovskite solar cell elements 13,23,33,63,73,83 Adhesive layer 14,24,34,64,74,84 Sealant layer 15, 25, 35 Sealing part 40,50 transparent electrode 46,56 Electron transport layer 47,57 Photoelectric conversion layer (perovskite layer) 48,58 Hole transport layer 49,59 Back electrode

Claims

1. A support; a solar cell element provided on the support; an adhesive layer covering the solar cell element and the surface of the support outside the periphery of the solar cell element; a film-like sealant layer that covers the adhesive layer and forms a contact point facing the surface of the support in an end region outside the periphery of the adhesive layer; a sealing portion that is provided annularly along the end region of the sealant layer so as to cover a contact point between the end of the sealant layer and the support, and that covers the surface of the support outside the portion where the end region of the sealant layer faces the surface of the support and the end region of the sealant layer, The solar cell element is An electrode, a photoelectric conversion layer containing a perovskite compound; a back electrode, in this order; Solar cell.

2. The solar cell according to claim 1, A solar cell, wherein the distance (d1) between the end of the solar cell element and the end of the adhesive layer is 0.5 mm or more and 2 cm or less.

3. The solar cell according to claim 1, A solar cell, wherein a distance (d2) between an end of the adhesive layer and an end of the sealant layer is 0.2 mm or more and 1 cm or less.

4. The solar cell according to claim 1, A solar cell, wherein a distance (d3) between an end of the sealant layer and an end of the sealing portion is 0.5 mm or more and 1.5 cm or less.

5. The solar cell according to claim 1, The solar cell, wherein the sealing portion is opaque.

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