Method for producing solar cell

Abstract

A method for producing a solar cell is provided in which a photoelectric conversion element including a perovskite compound is sealed with a sealing layer and a sealing film, the method making it possible to ensure adhesion between the sealing layer and the sealing film. The method for producing a solar cell seals a photoelectric conversion element comprising an electrode substrate, a photosensitive layer containing a perovskite compound, and a second electrode, and includes a stacking step in which a sealing layer and a sealing film are stacked in this order on the second electrode side of the photoelectric conversion element. The sealing film comprises a resin support and a sealing-layer adhesion layer disposed on the sealing layer side of the resin support. The sealing-layer adhesion layer is formed when producing the resin support. The sealing-layer adhesion layer contains particles having a diameter which is more than one time the thickness of the sealing-layer adhesion layer but not more than two times the thickness thereof.

Description

Solar cell manufacturing method

[0001] The present invention relates to a method for manufacturing a solar cell.

[0002] In solar cells currently in practical use, a solid inorganic semiconductor such as silicon is used in the photosensitive layer of the photoelectric conversion element. However, solar cells using a solid inorganic semiconductor in the photosensitive layer have low flexibility and poor conformability, which limits their range of application. Therefore, there is a demand for solar cells using an organic semiconductor as the photosensitive layer (hereinafter referred to as organic solar cells), which have high conformability and a wide range of applications.

[0003] Among organic solar cells, solar cells using perovskite compounds in the photosensitive layer have attracted attention as they have higher photoelectric conversion efficiency. While solar cells using perovskite compounds have high photoelectric conversion efficiency, their performance deteriorates due to moisture adsorption. Therefore, in solar cells using perovskite compounds, it is necessary to suppress moisture adsorption in the photoelectric conversion element (photosensitive layer).

[0004] In response to this, it has been proposed to seal a photoelectric conversion element using a perovskite compound using a sealing film such as a sealing layer and a gas barrier film.

[0005] For example, Patent Document 1 describes a solar cell module encapsulant sheet having a barrier layer laminate including a substrate film, an oxide barrier layer vapor-deposited on the substrate film, and a film laminated on the oxide barrier layer via an adhesive layer. Patent Document 1 describes that a power generation element (photoelectric conversion element) is encapsulated by laminating, in this order, an encapsulating layer made of a resin material and a solar cell module encapsulant sheet on the power generation element.

[0006] Japanese Patent Application Laid-Open No. 2016-063126

[0007] In a configuration in which a sealing layer and a sealing film are laminated in this order on a photoelectric conversion element to seal it, if the adhesion between the sealing layer and the sealing film is low, peeling occurs at the interface between the sealing layer and the sealing film. Therefore, Patent Document 1 describes providing an easy-adhesion layer on the surface of the sealing film on the sealing layer side to improve the adhesion between the sealing film and the sealing layer.

[0008] However, according to the investigations of the present inventors, it has been found that the adhesion between the sealing layer and the sealing film is not sufficient when the sealing layer and the sealing film are simply attached via an easy-adhesion layer.

[0009] In view of the above circumstances, an object of the present invention is to provide a method for manufacturing a solar cell in which a photoelectric conversion element using a perovskite compound is sealed with a sealing layer and a sealing film, wherein the method can ensure adhesion between the sealing layer and the sealing film.

[0010] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following configuration.

[0011] [1] A method for manufacturing a solar cell that encapsulates a photoelectric conversion element having an electrode substrate, a photosensitive layer containing a perovskite compound, and a second electrode, the method comprising: a lamination step of laminating a sealing layer and a sealing film on the second electrode side of the photoelectric conversion element; the sealing film having a resin support and a sealing layer adhesion layer disposed on the sealing layer side of the resin support; the sealing layer adhesion layer being formed during the manufacturing of the resin support; and the sealing layer adhesion layer containing particles, the diameter of the particles being more than 1 time and not more than 2 times the thickness of the sealing layer adhesion layer. [2] The method for manufacturing a solar cell according to [1], wherein the sealing layer is a crosslinkable resin. [3] The method for manufacturing a solar cell according to [1] or [2], wherein the lamination step comprises: a first lamination step of laminating a sealing layer on the second electrode side of the photoelectric conversion element; and a second lamination step of laminating a sealing film on the surface of the sealing layer opposite the photoelectric conversion element, with the sealing layer adhesion layer facing the sealing layer side. [4] The method for manufacturing a solar cell according to any of [1] to [3], wherein the lamination step is performed by roll-to-roll. [5] The method for manufacturing a solar cell according to any one of [1] to [4], wherein the resin support is a polyester resin. [6] The method for manufacturing a solar cell according to any one of [1] to [5], wherein the resin component contained in the sealing layer adhesion layer is a urethane resin.

[0012] According to the present invention, there is provided a method for manufacturing a solar cell in which a photoelectric conversion element using a perovskite compound is sealed with a sealing layer and a sealing film, wherein the method can ensure adhesion between the sealing layer and the sealing film.

[0013] Fig. 1 is a diagram conceptually showing an example of a solar cell produced by the solar cell manufacturing method of the present invention. Fig. 2 is a diagram conceptually showing another example of a solar cell produced by the solar cell manufacturing method of the present invention. Fig. 3 is a diagram for explaining an example of a solar cell manufacturing method of the present invention. Fig. 4 is a diagram for explaining an example of a solar cell manufacturing method of the present invention. Fig. 5 is a diagram for explaining an example of a solar cell manufacturing method of the present invention. Fig. 6 is a diagram for explaining another example of a solar cell manufacturing method of the present invention. Fig. 7 is a diagram for explaining another example of a solar cell manufacturing method of the present invention.

[0014] The present invention will be described in detail below. The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0015] In addition, in this specification, for each component, a substance corresponding to the component may be used alone or in combination of two or more. Here, when two or more substances for each component are used in combination, the content of the component refers to the total content of the substances used in combination, unless otherwise specified.

[0016] [Method for manufacturing solar cell] The method for manufacturing a solar cell of the present invention is a method for manufacturing a solar cell that encapsulates a photoelectric conversion element having an electrode substrate, a photosensitive layer containing a perovskite compound, and a second electrode, and includes a lamination step of laminating a sealing layer and a sealing film in this order on the second electrode side of the photoelectric conversion element, wherein the sealing film has a resin support and a sealing layer adhesion layer that is disposed on the sealing layer side of the resin support, the sealing layer adhesion layer is formed during the manufacturing of the resin support, and the sealing layer adhesion layer contains particles, the diameter of which is more than 1 time and not more than 2 times the thickness of the sealing layer adhesion layer.

[0017] A solar cell manufactured by the solar cell manufacturing method of the present invention (hereinafter also referred to as the manufacturing method of the present invention) will be described with reference to FIG.

[0018] The solar cell 10 shown in FIG. 1 includes a photoelectric conversion element 12 having an electrode substrate 32, a photosensitive layer 30, and a second electrode 34, a sealing layer 16, a resin support 20, and a sealing film 18 having a sealing layer adhesion layer 22.

[0019] 1 , the sealing layer 16 is laminated on the second electrode 34 side of the photoelectric conversion element 12, and the sealing film 18 is laminated on the surface of the sealing layer 16 opposite the photoelectric conversion element 12. The sealing film 18 is laminated on the sealing layer 16 with the sealing layer adhesion layer 22 facing the sealing layer 16 side.

[0020] 1 , the sealing layer adhesion layer 22 contains particles 24, and the diameter of the particles 24 is larger than the thickness of the sealing layer adhesion layer 22. Specifically, the diameter of the particles 24 is more than one time and not more than two times the thickness of the sealing layer adhesion layer 22.

[0021] As will be described in detail later, the sealing layer adhesion layer 22 is formed when the resin support body 20 is manufactured.

[0022] In the solar cell 10 produced by the production method of the present invention, the encapsulating layer adhesion layer 22 is formed during the production of the resin support 20, thereby enhancing adhesion between the encapsulating layer adhesion layer 22 and the resin support 20. Furthermore, because the encapsulating layer adhesion layer 22 contains particles 24 whose diameter is larger than its thickness, the adhesion to the encapsulating layer 16 is enhanced by a so-called anchor effect. This enhances adhesion between the encapsulating layer 16 and the sealing film 18, preventing peeling at the interface between the encapsulating layer 16 and the sealing film 18. This prevents moisture-induced deterioration of the photoelectric conversion element 12 (photosensitive layer 30) using a perovskite compound.

[0023] <Photoelectric Conversion Element> The photoelectric conversion element 12 converts light energy into electrical energy, and is not limited to any particular type as long as it has a photosensitive layer 30 containing a perovskite compound. As an example, the photoelectric conversion element 12 has the photosensitive layer 30 provided on an electrode substrate 32, a hole transport layer provided on the photosensitive layer 30, and a second electrode 34 provided on the hole transport layer.

[0024] [Electrode Substrate] The electrode substrate 32 is not particularly limited as long as it is conductive and can support the photosensitive layer 30, etc. The electrode substrate 32 is preferably made of a conductive material, such as a metal, or has a glass or plastic support and a transparent electrode as a conductive film formed on the surface of the support.

[0025] Among these, an electrode substrate (conductive support) in which a transparent electrode film is formed by coating a conductive metal oxide on the surface of a glass or plastic support is more preferred. Examples of supports formed from plastic include the transparent polymer film described in paragraph 0153 of JP-A-2001-291534. In addition to glass and plastic, ceramics (JP-A-2005-135902) and conductive resins (JP-A-2001-160425) can also be used as materials for forming the support. Tin oxide (TO) is preferred as the metal oxide, and indium-tin oxide (tin-doped indium oxide; ITO) and fluorine-doped tin oxide such as fluorine-doped tin oxide (FTO) are more preferred. In this case, the amount of metal oxide to be applied is determined based on the surface area of ​​the support (1 m). 2 A preferred amount is 0.1 to 100 g per unit.

[0026] The electrode substrate 32 is preferably substantially transparent. In the present invention, "substantially transparent" means that the transmittance of light (wavelength 300 to 1200 nm) is 10% or more, preferably 50% or more, and more preferably 80% or more. The thickness of the support and electrode substrate 32 is not particularly limited and is set to an appropriate thickness. For example, it is preferably 0.01 μm to 10 mm, more preferably 0.1 μm to 5 mm, and even more preferably 0.3 μm to 4 mm. When a transparent electrode is provided, the film thickness of the transparent electrode is not particularly limited and is, for example, preferably 0.01 to 30 μm, more preferably 0.02 to 25 μm, and even more preferably 0.025 to 20 μm.

[0027] The electrode substrate 32 or the support may have a light management function on its surface. For example, the surface of the electrode substrate 32 or the support may have an antireflection film formed by alternately laminating high-refractive-index films and low-refractive-index oxide films as described in JP-A-2003-123859, or may have a light guide function as described in JP-A-2002-260746.

[0028] The photoelectric conversion element 12 may also have a blocking layer (short-circuit prevention layer) on the surface of the electrode substrate 32. In the photoelectric conversion element 12, for example, when the photosensitive layer 30 or the hole transport layer is electrically connected to a transparent electrode or the like, a reverse current occurs. The blocking layer functions to prevent this reverse current. The blocking layer can also function as a scaffold for supporting a light absorber. This blocking layer may also be provided when the photoelectric conversion element 12 has an electron transport layer. Blocking layers are described in WO 2019 / 053967, etc.

[0029] The photoelectric conversion element 12 may have a porous layer on the electrode substrate 32. When a blocking layer is provided, the porous layer is preferably formed on the blocking layer. The porous layer functions as a scaffold supporting the photosensitive layer 30 on its surface. In order to increase the light absorption efficiency of a solar cell, it is preferable to increase the surface area of ​​at least the portion that receives light such as sunlight, and it is preferable to increase the overall surface area of ​​the porous layer.

[0030] The porous layer is preferably a microparticle layer having pores in which microparticles of the material forming the porous layer are deposited or adhered to each other. The porous layer may be a microparticle layer in which two or more types of microparticles are deposited. When the porous layer is a microparticle layer having pores, the amount of light absorber carried (adsorption amount) can be increased. Porous layers are described in WO 2019 / 053967 and the like.

[0031] The photoelectric conversion element 12 preferably has an electron transport layer on the surface of the electrode substrate 32. The electron transport layer has the function of transporting electrons generated in the photosensitive layer 30 to the electrode substrate 32. The electron transport layer is formed of an electron transport material that can fulfill this function. Any conventionally known material can be used as the material for the electron transport layer.

[0032] [Photosensitive Layer] The photosensitive layer 30 is made of a material selected from materials that efficiently realize a photoelectric conversion process in which, after excitons (electron-hole pairs) are generated upon exposure to light such as sunlight, the excitons dissociate into electrons and holes, and the electrons are transported to the negative electrode side and the holes are transported to the positive electrode side. In the present invention, the photosensitive layer 30 contains a perovskite compound. A perovskite compound is a compound that has a perovskite structure. As the perovskite compound, an organic-inorganic perovskite compound is preferred.

[0033] Perovskite compounds that can be used as the photosensitive layer 30 of the photoelectric conversion element 12 are described in JP 2017-017166 A, WO 2019 / 053967 A, JP 2015-191916 A, and the like.

[0034] The photosensitive layer 30 is preferably provided on the surface of each of the above layers so that excited electrons flow to the electrode substrate 32 or the second electrode 34. In this case, the photosensitive layer 30 may be provided on the entire surface of each of the above layers, or on a part of the surface.

[0035] The thickness of the photosensitive layer 30 is appropriately set depending on the embodiment in which the photosensitive layer 30 is disposed on the electrode substrate 32, and is not particularly limited. Typically, the thickness is, for example, preferably 0.001 to 100 μm, more preferably 0.01 to 10 μm, and even more preferably 0.01 to 5 μm. When a porous layer is disposed, the total thickness including the thickness of the porous layer is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.3 μm or more. Furthermore, the total thickness is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. The total thickness can be within a range that appropriately combines the above values. Here, when the photosensitive layer 30 is a thin film, the thickness of the photosensitive layer 30 refers to the distance from the interface with the porous layer to the interface with the hole transport layer along the direction perpendicular to the surface of the porous layer. When the photoelectric conversion element 12 has a porous layer, the total thickness of the porous layer, photosensitive layer 30, and hole transport layer is not particularly limited, and is, for example, preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and particularly preferably 0.3 μm or more. Furthermore, this total thickness is preferably 200 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and particularly preferably 5 μm or less. The total thickness can be within a range that appropriately combines the above values. In the present invention, when the photosensitive layer 30 is provided as a thick film, this photosensitive layer may also function as a hole transport layer.

[0036] The photosensitive layer 30 may contain a light-absorbing component such as a metal complex dye or an organic dye in addition to the perovskite compound.

[0037] The photoelectric conversion element 12 preferably has a hole transport layer between the electrode substrate 32 and the second electrode 34. In this embodiment, the hole transport layer is preferably in contact with (laminated on) the photosensitive layer 30. The hole transport layer is preferably provided between the photosensitive layer 30 and the second electrode 34. The hole transport layer has a function of replenishing electrons in the photosensitive layer 30, and is preferably a solid layer (solid hole transport layer). Hole transport layers are described in WO 2019 / 053967, etc.

[0038] [Second Electrode] The second electrode 34 functions as a positive electrode in the photoelectric conversion element 12. There are no particular limitations on the second electrode 34 as long as it is conductive, and it can have the same configuration as the electrode substrate 32. If sufficient strength is maintained, a support is not necessarily required. The structure of the second electrode 34 is preferably one that has a high current collection effect. In order for light to reach the photosensitive layer 30, at least one of the electrode substrate 32 and the second electrode 34 must be substantially transparent. In the present invention, it is preferable that the electrode substrate 32 is transparent so that sunlight, etc., is incident from the support side. In this case, it is even more preferable that the second electrode 34 has light-reflecting properties.

[0039] Examples of materials for forming the second electrode 34 include metals such as platinum (Pt), gold (Au), nickel (Ni), copper (Cu), silver (Ag), indium (In), ruthenium (Ru), palladium (Pd), rhodium (Rh), iridium (Ir), osnium (Os), and aluminum (Al), the aforementioned conductive metal oxides, carbon materials, and conductive polymers. Carbon materials may be any conductive material formed by bonding carbon atoms, such as fullerenes, carbon nanotubes, graphite, and graphene. The second electrode 34 is preferably a thin film (including a thin film formed by vapor deposition) of a metal or conductive metal oxide, or a glass or plastic substrate having such a thin film. The glass or plastic substrate is preferably glass having a thin film of gold or platinum, or glass having platinum vapor-deposited thereon.

[0040] The film thickness of the second electrode 34 is not particularly limited, but is preferably 0.01 to 100 μm, more preferably 0.01 to 10 μm, and even more preferably 0.01 to 1 μm.

[0041] In the present invention, in order to prevent contact between the electrode substrate 32 and the second electrode 34, a spacer and / or a separator can be used in place of the blocking layer or together with the blocking layer 14. Also, a hole blocking layer can be provided between the second electrode 34 and the hole transport layer.

[0042] Each layer of the photoelectric conversion element 12 can be formed by a known manufacturing method described in, for example, International Publication No. 2019 / 053967, J. Am. Chem. Soc., 2009, 131 (17), pp. 6050-6051, Science, 338, p. 643 (2012), etc.

[0043] <Sealing layer> The sealing layer (sealing layer) 16 is a layer for bonding the sealing film 18 to the photoelectric conversion element 12, and seals the photoelectric conversion element 12 together with the sealing film 18 to prevent moisture from reaching the photoelectric conversion element 12 (photosensitive layer 30).

[0044] The sealing layer 16 is not particularly limited, and known materials can be suitably used. The sealing layer 16 may be made of known materials used for bonding sheet-like materials in optical devices and optical elements, such as optically clear adhesive (OCA), optically clear double-sided tape, ultraviolet-curable resin, epoxy-based thermosetting resin, silicone-based adhesive resin, ethylene-vinyl acetate copolymer (EVA), and polyolefin elastomer (POE). The sealing layer 16 is preferably made of a material having a polar functional group, such as an ultraviolet-curable resin or an epoxy-based thermosetting resin.

[0045] Among these, the sealing layer 16 is preferably made of a cross-linkable resin, specifically, an epoxy-based thermosetting resin.

[0046] The thickness of the sealing layer 16 is not particularly limited, but is preferably 1 to 200 μm, more preferably 3 to 150 μm, and even more preferably 5 to 100 μm.

[0047] <Sealing Film> The sealing film 18 seals the photoelectric conversion element 12 to prevent moisture from reaching the photoelectric conversion element 12 (photosensitive layer 30).

[0048] The sealing film 18 has at least a resin support 20 and a sealing layer adhesion layer 22. Here, in the sealing film 18, the resin support 20 itself may have gas barrier properties (water vapor barrier properties), or as shown in Fig. 2, the sealing film 18 may have a barrier layer 26 having gas barrier properties on the surface of the resin support 20 opposite to the sealing layer adhesion layer 22. That is, in the sealing film 18, the barrier layer 26 is formed on the surface of the resin support 20 opposite to the surface that becomes the sealing layer 16 side when the photoelectric conversion element 12 is sealed.

[0049] [Resin Support Body] When the resin support body 20 itself has gas barrier properties, the resin support body 20 can be made of a resin material with high gas barrier properties, such as ethylene vinyl alcohol copolymer resin (EVOH) or polyvinyl alcohol (PVA).

[0050] Alternatively, when the resin support 20 itself has gas barrier properties, a resin support having an inorganic filler mixed in a resin layer can be used as the resin support 20. In this case, examples of the inorganic filler include silica (silicon dioxide), alumina (aluminum oxide), aluminum nitride, magnesium oxide, silicon nitride, zinc oxide, and boron nitride. The shape of the inorganic filler is not particularly limited, and any of spherical, plate-like, fibrous, rod-like, amorphous, hollow, and other shapes can be preferably used.

[0051] When the sealing film 18 has a barrier layer 26, the resin support 20 can be a known sheet-like material (film, plate-like material) that is used as a support in known gas barrier films, known laminated functional films, etc., as long as it can support the barrier layer 26.

[0052] The material of the resin support body 20 is not limited, and various materials can be used as long as they can form the barrier layer 26. A highly transparent material is preferable as the material of the resin support body 20, and various resin materials can be exemplified. Examples of materials for the resin support body 20 include polyethylene (PE), polyethylene naphthalate (PEN), polyamide (PA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyacrytonitrile (PAN), polyimide (PI), transparent polyimide, polymethyl methacrylate resin (PMMA), polycarbonate (PC), polyacrylate, polymethacrylate, polypropylene (PP), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), cycloolefin copolymer (COC), cycloolefin polymer (COP), triacetyl cellulose (TAC), and ethylene-vinyl alcohol copolymer (EVOH).

[0053] Among these, polyester resins such as PET and PEN are preferred from the viewpoint of heat resistance.

[0054] The thickness of the resin support body 20 may be set appropriately depending on the application, forming material, etc. The thickness of the resin support body 20 is preferably 5 to 150 μm, more preferably 10 to 100 μm. By setting the thickness of the resin support body 20 within the above range, the mechanical strength of the sealing film 18 is sufficiently ensured, and it is preferable in terms of reducing the weight, thickness, flexibility, etc. of the sealing film 18.

[0055] In addition, the resin support 20 may be provided with functional layers (functional films) for obtaining various functions, such as a protective layer, an adhesive layer, a light-reflecting layer, an anti-reflection layer, a light-shielding layer, a planarizing layer, a buffer layer, a stress relaxation layer, an easy-adhesion layer, an adhesion layer, and a sliding layer.

[0056] [Barrier Layer] The sealing film 18 preferably has a barrier layer 26. As the barrier layer 26, a barrier layer used in a known gas barrier film can be used.

[0057] As the barrier layer 26, for example, a resin barrier layer such as the above-mentioned EVOH or other resin layer having high gas barrier properties, or a resin layer mixed with an inorganic filler can be used.

[0058] Furthermore, an inorganic barrier layer including an inorganic layer made of a metal material such as aluminum, or an inorganic material such as silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, etc. may be used as the barrier layer 26. Furthermore, an organic-inorganic laminated barrier layer in which inorganic layers and organic layers serving as base layers for the inorganic layers are alternately laminated, as described in JP-A-2015-171798, JP-A-2014-024602, etc., may also be used as the barrier layer 26.

[0059] The method for forming the barrier layer 26 may be selected appropriately depending on the material for forming the barrier layer 26. For example, when the barrier layer 26 is an organic barrier layer, the organic barrier layer may be formed by applying a resin material that will become the organic barrier layer onto the resin support 20. When a resin material with high gas barrier properties is used for the organic barrier layer, a laminated film may be produced by laminating the resin support and the organic barrier layer by co-extrusion with the resin material that will become the resin support.

[0060] Furthermore, when the barrier layer 26 is an inorganic barrier layer, it can be formed by a known inorganic layer forming method such as vapor deposition, sputtering, plasma CVD, or atomic layer deposition (ALD).

[0061] Furthermore, when the barrier layer 26 is an organic / inorganic laminated barrier layer, it can be formed by the methods described in JP-A-2015-171798, JP-A-2014-024602, and the like.

[0062] The thickness of the barrier layer 26 may be appropriately set depending on the material from which the barrier layer 26 is formed so as to exhibit the desired gas barrier properties.

[0063] [Sealing Layer Adhesion Layer] The sealing layer adhesion layer 22 is disposed on the surface of the resin support 20 facing the sealing layer 16, and is a layer for improving adhesion between the sealing layer 16 and the sealing film 18. The sealing layer adhesion layer 22 contains particles in a resin material serving as a base material.

[0064] Examples of resin materials that serve as the base material of the sealing layer adhesion layer 22 include urethane resin, acrylic resin, and polyester resin.

[0065] Among these, urethane resins are preferred from the viewpoint of ensuring adhesion between the sealing layer and the resin support.

[0066] The particles 24 contained in the sealing layer adhesion layer 22 are not particularly limited and may be inorganic or organic particles. Examples of inorganic particles include silica (SiO2) and zirconia. Examples of organic particles include cross-linked acrylic and cross-linked styrene.

[0067] The shape of the particles 24 is not particularly limited, but is preferably spherical, and the closer to a perfect sphere the more preferable.

[0068] Here, the diameter (particle size) of particles 24 is more than 1 time and not more than 2 times the thickness of sealing layer adhesion layer 22. That is, sealing layer adhesion layer 22 has a configuration in which particles 24 protrude from the surface of the resin layer serving as the base material. Note that, in the present invention, the thickness of sealing layer adhesion layer 22 refers to the thickness of sealing layer adhesion layer 22 (the resin layer serving as the base material) at positions in the in-plane direction where particles 24 are not present.

[0069] By making the diameter (particle size) of the particles 24 more than one time the thickness of the sealing layer adhesion layer 22, the adhesion between the sealing layer adhesion layer 22 and the sealing layer 16 can be improved by a so-called anchor effect. Furthermore, if the diameter (particle size) of the particles 24 is too large relative to the thickness of the sealing layer adhesion layer 22, gaps may be generated when the particles 24 are laminated on the sealing layer 16, causing bubbles to form at the interface between the sealing layer adhesion layer 22 and the sealing layer 16, which may result in a decrease in adhesion. Therefore, by making the diameter (particle size) of the particles 24 no more than two times the thickness of the sealing layer adhesion layer 22, the generation of bubbles can be suppressed, and the adhesion between the sealing layer adhesion layer 22 and the sealing layer 16 can be improved.

[0070] From the viewpoint of adhesion between the sealing layer adhesion layer 22 and the sealing layer 16, the ratio of the diameter (particle size) of the particles 24 to the thickness of the sealing layer adhesion layer 22 is preferably 1.25 to 1.88 times.

[0071] The thickness of the sealing layer adhesion layer 22 and the particle diameter of the particles 24 are measured by cutting the sealing layer adhesion layer 22 with a microtome or the like and observing it with a transmission electron microscope (TEM) at a magnification that allows the particle shape to be confirmed. The thickness of the sealing layer adhesion layer 22 and the particle diameter of the particles 24 are each measured at three points and their average values ​​are used.

[0072] From the viewpoint of adhesion between the sealing film 18 and the sealing layer 16, the thickness of the sealing layer adhesion layer 22 is preferably 0.01 μm to 10 μm, more preferably 0.03 μm to 7 μm, and even more preferably 0.05 μm to 5 μm. As will be described later, in the present invention, the sealing layer adhesion layer 22 is formed during the production of the resin support 20, and therefore can be thinner than when formed by coating or the like.

[0073] From the viewpoint of adhesion between the sealing film 18 and the sealing layer 16, the average particle size of the particles 24 is preferably 0.01 μm to 20 μm, more preferably 0.015 μm to 15 μm, and even more preferably 0.02 μm to 10 μm.

[0074] Furthermore, from the viewpoint of adhesion between the sealing film 18 and the sealing layer 16, the concentration of the particles 24 in the sealing layer adhesion layer 22 is preferably 0.1 wt % to 5 wt %, and more preferably 0.5 wt % to 3 wt %. Here, the concentration [wt %] of the particles 24 is the weight percentage of the particles 24 relative to the weight of the base material.

[0075] In the present invention, the sealing layer adhesion layer 22 is formed during the production of the resin support body 20. This will be described in detail later.

[0076] The manufacturing method of the present invention will be described below.

[0077] The manufacturing method of the present invention includes a sealing layer adhesion layer forming step of forming a sealing layer adhesion layer 22 during manufacturing of a resin support body 20, and a lamination step of laminating a sealing layer 16 and a sealing film 18 on the second electrode 34 side of a photoelectric conversion element 12 having an electrode substrate 32, a photosensitive layer 30 containing a perovskite compound, and a second electrode 34.

[0078] <Sealing Layer Adhesion Layer Forming Step> The sealing layer adhesion layer forming step is a step of forming the sealing layer adhesion layer 22 during the production of the resin support body 20 .

[0079] Specifically, when an unstretched sheet that will become resin support body 20 is stretched to form resin support body 20, a composition that will become sealing layer adhesion layer 22 containing particles 24 is applied to the unstretched sheet before stretching the unstretched sheet, and the unstretched sheet is stretched simultaneously with the composition that will become sealing layer adhesion layer 22, thereby forming sealing layer adhesion layer 22 together with resin support body 20 (see FIG. 3 ). In this way, by forming sealing layer adhesion layer 22 before the stretching of resin support body 20 is completed, the thickness of sealing layer adhesion layer 22 becomes thin, and the adhesion between resin support body 20 and sealing layer adhesion layer 22 becomes extremely strong.

[0080] In addition, when stretching is performed multiple times during the production of resin support 20, a composition that will become sealing layer adhesion layer 22 can be applied and stretched on resin support 20 (unstretched sheet) at least before the final stretching. For example, when resin support 20 is formed by biaxial stretching, first, an unstretched sheet is stretched in the longitudinal direction (MD), then a composition that will become sealing layer adhesion layer 22 is applied to the unstretched sheet, and then the unstretched sheet is stretched in the width direction (TD). As a result, the composition applied to the unstretched sheet is also stretched, and sealing layer adhesion layer 22 is formed on resin support 20.

[0081] After stretching, a heat treatment or the like may be carried out as necessary.

[0082] Furthermore, in the case where the sealing film 18 has a configuration including the barrier layer 26, after the sealing layer adhesion layer forming step, a step of forming the barrier layer 26 is carried out on the resin support 20 on which the sealing layer adhesion layer 22 has been formed. The method of forming the barrier layer 26 is as described above.

[0083] The sealing layer adhesion layer 22 may be formed on at least one of the main surfaces of the resin support body 20, but may also be formed on both main surfaces of the resin support body 20.

[0084] Furthermore, in a configuration in which the sealing layer adhesion layer 22 is formed on both main surfaces of the resin support 20 and the sealing film 18 has a barrier layer 26, the sealing layer adhesion layer 22 may be provided between the resin support 20 and the barrier layer 26. In a configuration in which the sealing layer adhesion layer 22 is provided between the resin support 20 and the barrier layer 26, an organic barrier layer or an organic-inorganic laminated barrier layer can be used as the barrier layer 26.

[0085] <Lamination Step> The lamination step is a step of laminating the sealing layer 16 and the sealing film 18 on the second electrode 34 side of the photoelectric conversion element 12 having the electrode substrate 32, the photosensitive layer 30 containing a perovskite compound, and the second electrode 34.

[0086] For example, the lamination process includes a first lamination process of laminating a sealing layer 16 on the second electrode 34 side of the photoelectric conversion element 12, as shown in Figure 4, and a second lamination process of laminating a sealing film 18 on the surface of the sealing layer 16 opposite the photoelectric conversion element 12, with the sealing layer adhesion layer 22 facing the sealing layer 16 side, as shown in Figure 5.

[0087] Alternatively, the lamination process may include a third lamination process of laminating the sealing layer 16 on the sealing layer adhesion layer 22 side of the sealing film 18, as shown in Figure 6, and a fourth lamination process of laminating a laminate of the sealing layer 16 and the sealing film 18 on the second electrode 34 side of the photoelectric conversion element 12, as shown in Figure 7.

[0088] The method for forming the sealing layer 16 may be appropriately set depending on the type of sealing layer 16. For example, when the sealing layer 16 is made of a cross-linkable resin, in the first lamination step, a paint to become the sealing layer 16 may be applied to the second electrode 34 of the photoelectric conversion element 12, and in the second lamination step, the sealing film 18 may be laminated on the applied paint film and then cured to form the sealing layer 16. Alternatively, in the third lamination step, the paint to become the sealing layer 16 may be applied to the sealing layer adhesion layer 22 of the sealing film 18, and in the fourth lamination step, the photoelectric conversion element 12 may be laminated on the applied paint film and then cured to form the sealing layer 16.

[0089] As a method for applying the paint that will become the sealing layer 16, various conventionally known application methods can be used.

[0090] Furthermore, when the sealing layer 16 is a cross-linkable resin, the method for curing (cross-linking, polymerization) the coating film that becomes the sealing layer 16 may be a conventionally known method such as ultraviolet irradiation or heating, depending on the type of resin material that becomes the sealing layer 16.

[0091] The lamination process produces a solar cell 10 in which an electrode substrate 32, a photosensitive layer 30 containing a perovskite compound, a photoelectric conversion element 12 having a second electrode 34, a sealing layer 16, and a sealing film 18 having a sealing layer adhesion layer 22 and a resin support 20 are laminated in this order.

[0092] Here, in the manufacturing method of the present invention, the lamination step may be performed by roll-to-roll. For example, the photoelectric conversion element 12 is formed using a long electrode substrate 32, and while the long electrode substrate 32 is transported in the longitudinal direction, a coating material that will become the sealing layer 16 is applied to the second electrode 34 of the photoelectric conversion element 12 (first lamination step), and a long sealing film 18 is laminated on the applied coating film (second lamination step). Thereafter, if necessary, the coating film is cured to form the sealing layer 16. When laminating the sealing film 18, for example, the photoelectric conversion element 12 on which the coating film has been formed and the sealing film 18 are sandwiched between a pair of pressure rolls to perform the lamination.

[0093] Alternatively, for example, while the long sealing film 18 is transported in the longitudinal direction, a coating material to become the sealing layer 16 is applied to the sealing layer adhesive layer 22 of the sealing film 18 (third lamination step), and the long photoelectric conversion element 12 is laminated on the applied coating film (fourth lamination step). Thereafter, the coating film is cured as necessary.

[0094] The method for manufacturing a solar cell of the present invention has been described in detail above, but the present invention is not limited to the above examples, and various improvements and modifications may be made within the scope of the present invention.

[0095] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0096] [Example 1] <Preparation of sealing film> (Formation of resin support and sealing layer adhesion layer) Terephthalic acid and ethylene glycol were directly reacted and esterified, and then the polyester raw material obtained by a continuous polymerization device was supplied to an extruder, melt-kneaded, extruded through a melt die, and cast onto a cooling drum to obtain an unstretched sheet that would become the resin support.

[0097] This unstretched sheet was stretched in the longitudinal direction (MD) by sequential biaxial stretching, and then fed to a subsequent tenter. The following composition A, which would become a sealing layer adhesion layer, was applied to both sides of the unstretched sheet by bar coating. The thickness of the applied composition film was adjusted so that the thickness of the sealing layer adhesion layer after stretching would be 0.05 μm. Then, the unstretched sheet was stretched in the width direction (TD) together with the composition film. Further, after that, a heat treatment was performed to obtain a 100 μm thick PET film (resin support) with a sealing layer adhesion layer laminated on both sides.

[0098] Composition A ------------------------------------------------- Binder (base material): Elastron H3DF (urethane resin, manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) 46.52 mg / m 2 Hardener: WM44-L70 (manufactured by Asahi Kasei Corporation) 5.44 mg / m 2 Particles: PL-7 (average particle size 75 nm) manufactured by Fuso, 1.50 mg / m 2 ----------------------------------------------------------------------------------

[0099] (Formation of Barrier Layer) An organic / inorganic laminated barrier layer was formed on one surface of the resin support having the sealing layer adhesive layer in the following manner.

[0100] A UV-curable resin (TMPTA manufactured by Daicel Cytec) and a photopolymerization initiator (ESACURE KTO46 manufactured by Lamberti) were weighed out to a weight ratio of 95:5, and these were dissolved in methyl ethyl ketone (MEK) to prepare a coating solution with a solids concentration of 15%. The coating solution was applied roll-to-roll onto a resin support (sealing layer adhesion layer) using an E-type Giesser, dried, and then UV-cured to form an organic layer. Then, an inorganic layer (SiN film) was formed on the organic layer by plasma CVD to form an organic-inorganic laminated barrier layer. Thus, a sealing film was produced. The inorganic layer was formed as follows.

[0101] An inorganic layer (silicon nitride layer) was formed on the surface of the organic layer using a roll-to-roll CVD apparatus. Silane gas (flow rate 160 sccm: 0°C, standard conditions of 1 atmosphere, same below), ammonia gas (flow rate 370 sccm), hydrogen gas (flow rate 590 sccm), and nitrogen gas (flow rate 240 sccm) were used as source gases. A high-frequency power source with a frequency of 13.56 MHz was used as the power source. The film formation pressure was 40 Pa, and the final film thickness was 50 nm. In this way, an inorganic layer was laminated on the surface of the organic layer.

[0102] The produced sealing film was cut using a microtome or the like and observed under a transmission electron microscope (TEM JEM2100F manufactured by JEOL) at a magnification sufficient to confirm the particle shape, and the thickness of the sealing layer adhesive layer and the particle diameter of the particles were measured. The thickness of the sealing layer adhesive layer was 0.04 μm (40 nm). The particle diameter of the particles was 75 nm.

[0103] <Fabrication of Photoelectric Conversion Element> A long photoelectric conversion element having a photosensitive layer containing a perovskite compound was fabricated with reference to Example 1 of JP-A No. 2022-117248.

[0104] <Lamination Step> A coating material for forming a sealing layer was prepared by mixing 108 parts by mass of an epoxy resin ("TOPR-300" manufactured by Nippon Steel Chemical & Material Co., Ltd.), 7.5 parts by mass of a curing accelerator ("U-CAT3512T" manufactured by San-Apro Co., Ltd.), and 163 parts by mass of a phenoxy resin solution ("YX7200B35" manufactured by Mitsubishi Chemical Corporation, solvent (MEK), non-volatile component 35%).

[0105] While conveying the long photoelectric conversion element in the longitudinal direction, the coating material prepared above was applied to the surface of the second electrode side with a gravure roll, and the long sealing film prepared above was attached to the coating film side and pressed with a pair of pressure rolls to attach the sealing film to the coating film on the photoelectric conversion element. Thereafter, the coating film was cured by heating to form a sealing layer.

[0106] In this way, a solar cell was fabricated.

[0107] Example 2 A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, the sealing adhesive layer was produced using the following composition B, and the particle size was set to 0.045 μm.

[0108] Composition B ------------------------------------------------- Binder (base material): Elastron H3DF (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 46.52 mg / m 2 Hardener: WM44-L70 (manufactured by Asahi Kasei Corporation) 5.44 mg / m 2 Particles: PL-3 (average particle size 45 nm) manufactured by Fuso, 1.50 mg / m 2 ----------------------------------------------------------------------------------

[0109] [Comparative Example 1] A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, the sealing layer adhesion layer was formed after the production of the resin support, the sealing layer adhesion layer was produced using the following composition C, and the thickness of the sealing layer adhesion layer was 450 μm.

[0110] Composition C ------------------------------------------------- Binder (base material): A-520 (polyester resin, manufactured by Takamatsu Oil & Fat Co., Ltd.) 302 mg / m 2 Hardener: Carbodilite V-02-L2 (manufactured by Nisshinbo) 15.9 mg / m 2Particles: Cross-linked acrylic particles MR2G (average particle size 1 μm) manufactured by Soken Chemical & Engineering Co., Ltd. 2.2 mg / m 2 ----------------------------------------------------------------------------------

[0111] Comparative Example 2 A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, the sealing layer adhesion layer was produced using the following composition D, which did not contain particles.

[0112] Composition D ------------------------------------------------- Binder (base material): Elastron H3DF (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 46.52 mg / m 2 Hardener: WM44-L70 (manufactured by Asahi Kasei Corporation) 5.44 mg / m 2 ----------------------------------------------------------------------------------

[0113] Comparative Example 3 A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, the sealing adhesive layer was produced using the following composition E, and the particle size was set to 0.015 μm.

[0114] Composition E ------------------------------------------------- Binder (base material): Elastron H3DF (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 46.52 mg / m 2 Hardener: WM44-L70 (manufactured by Asahi Kasei Corporation) 5.44 mg / m 2 Particles: PL-1 (average particle size 15 nm) manufactured by Fuso, 1.50 mg / m 2 ----------------------------------------------------------------------------------

[0115] Comparative Example 4 A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, the sealing adhesive layer was produced using the following composition F, and the particle size was set to 0.090 μm.

[0116] Composition F ------------------------------------------------- Binder (base material): Elastron H3DF (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) 46.52 mg / m 2 Hardener: WM44-L70 (manufactured by Asahi Kasei Corporation) 5.44 mg / m 2 Particles: Fuso PL-10H (average particle size 90 nm) 1.50 mg / m 2 ----------------------------------------------------------------------------------

[0117] [Comparative Example 5] A solar cell was produced in the same manner as in Example 1, except that in the production of the sealing film, a sealing layer adhesion layer was formed after the production of a resin support, the sealing layer adhesion layer was produced using the following composition G, the thickness of the sealing layer adhesion layer was set to 450 μm, and the particle diameter was set to 0.8 μm.

[0118] Composition G ------------------------------------------------- Binder (base material): A-520 (polyester resin, manufactured by Takamatsu Oil & Fat Co., Ltd.) 302 mg / m 2 Hardener: Carbodilite V-02-L2 (manufactured by Nisshinbo) 15.9 mg / m 2 Particles: Cross-linked acrylic particles MX-80H3wT (average particle size 0.8 μm) manufactured by Soken Chemical & Engineering Co., Ltd., 2.2 mg / m 2 ----------------------------------------------------------------------------------

[0119] [Evaluation] The fabricated solar cells were left for 24 hours at a temperature of 30°C and a humidity of 70% RH (durability test). The appearance and adhesion of the solar cells were visually inspected before and after the durability test, and evaluated according to the following criteria. The sealing surface refers to the interface between the sealing layer and the sealing layer adhesive layer, and the interface between the sealing layer adhesive layer and the resin support. A: No bubbles were present on the sealing surface of the solar cell, and there was no problem with the adhesion between the sealing layer and the sealing film. B: Bubbles were present on the sealing surface of the solar cell, and there was a problem with the adhesion between the sealing layer and the sealing film.

[0120] The results are shown in Table 1.

[0121]

[0122] From Table 1, it can be seen that the examples of the present invention have higher adhesion between the sealing layer and the sealing film than the comparative examples.

[0123] In Comparative Example 1, bubbles (peeling) were observed at both the interface between the sealing layer and the sealing layer adhesive layer and the interface between the sealing layer adhesive layer and the resin support. In Comparative Examples 2 to 4, bubbles (peeling) were observed at the interface between the sealing layer and the sealing layer adhesive layer. In Comparative Example 5, bubbles (peeling) were observed at the interface between the sealing layer adhesive layer and the resin support.

[0124] The above results clearly demonstrate the effectiveness of the present invention.

[0125] REFERENCE SIGNS LIST 10 solar cell 12 photoelectric conversion element 16 sealing layer 18 sealing film 20 resin support 22 sealing layer adhesion layer 24 particles 26 barrier layer 30 photosensitive layer 32 electrode substrate 34 second electrode

Claims

1. A method for manufacturing a solar cell that encapsulates a photoelectric conversion element having an electrode substrate, a photosensitive layer containing a perovskite compound, and a second electrode, the method comprising a lamination step of laminating a sealing layer and a sealing film on the second electrode side of the photoelectric conversion element, the sealing film having a resin support and a sealing layer adhesion layer that is disposed on the sealing layer side of the resin support, the sealing layer adhesion layer being formed during the manufacture of the resin support, and the sealing layer adhesion layer containing particles, the diameter of the particles being more than 1 time and not more than 2 times the thickness of the sealing layer adhesion layer.

2. The method for producing a solar cell according to claim 1, wherein the sealing layer is a crosslinkable resin.

3. A method for manufacturing a solar cell as described in claim 1 or 2, wherein the lamination process includes a first lamination process of laminating the sealing layer on the second electrode side of the photoelectric conversion element, and a second lamination process of laminating the sealing film on the surface of the sealing layer opposite the photoelectric conversion element, with the sealing layer adhesion layer facing the sealing layer side.

4. The method for producing a solar cell according to claim 1 or 2, wherein the lamination step is carried out by roll-to-roll.

5. The method for producing a solar cell according to claim 1 or 2, wherein the resin support is a polyester resin.

6. The method for manufacturing a solar cell according to claim 1 or 2, wherein the resin component contained in the sealing layer adhesion layer is a urethane resin.

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