Solar cell element coating composition, solar cell module and method for manufacturing same

Abstract

Provided is a solar cell element coating composition containing (A) an organopolysiloxane represented by the following average unit formula (1) (R1R32SiO1 / 2) 2 (Ar2SiO2 / 2) a (R22SiO2 / 2) b (1) [in the formula, R1 is an alkenyl group, R2 is a monovalent saturated hydrocarbon group, R3 is a monovalent saturated hydrocarbon group or aryl group, and Ar is an aryl group. A is an integer of 1-100, b is an integer of 0-1000, and a / (a + b) is a number of 0.01-1.0. (B) an organosilicon compound having, in one molecule, at least two hydrogen atoms bonded to a silicon atom; and (C) a platinum group metal catalyst activated by light having a wavelength of 200-500 nm. The composition can be directly applied to a solar cell element in an organic thin film solar cell, a perovskite solar cell, or the like.

Description

Technical Field

[0001] The present invention relates to a solar cell element coating composition and a solar cell module and a method for producing the same. Background Art

[0002] In recent years, research and development has been underway on flexible solar cells that emphasize cost reduction and design, transparent solar cells, lightweight and easy-to-handle organic thin-film solar cells, and solar cells with perovskite compounds in the power generation layer that achieve both low prices and high efficiency (hereinafter referred to as "perovskite solar cells") .

[0003] Perovskite solar cells can be manufactured cheaply and have high power generation efficiency compared to crystalline silicon solar cells. Perovskite solar cell elements are obtained by stacking a light-transmitting substrate or a light-transmitting film, a transparent conductive film, an electron transport layer, a power generation layer, a hole transport layer, and a back electrode in sequence from the light-receiving side. In the so-called modular process of sealing the above-mentioned elements, a structure in which a sealing material is applied to the further back side of the back electrode and the backmost side is sealed with a substrate, a film, etc. is studied. Various structures have been proposed, such as a structure in which a light-transmitting substrate on the light-receiving side and a substrate on the backmost side are used for glass, a light-transmitting film is used on the light-receiving side, and a flexible structure in which a film is used on the backmost side.

[0004] On the other hand, perovskite compounds are not resistant to water vapor, and solar cells are exposed to a harsh environment outdoors for a long time, so perovskite solar cell modules are required to block water vapor at a high level.

[0005] For such electronic devices that are not resistant to water vapor, various technologies have been introduced for pre-setting a water vapor barrier layer on the component before the sealing process. For example, Patent Document 1 introduces a barrier coating technology comprising three layers of silicon, oxygen, and carbon. This is a technology for forming a water vapor barrier film with flexibility and mechanical strength using a plasma chemical vapor growth (CVD) method. However, the plasma CVD method uses a CVD device to form the device under vacuum, and the device is arranged in a vacuum chamber. It needs to be processed in a vacuum environment, so it is difficult to scale up the device. Furthermore, since both vacuum and atmospheric open processes are involved, it is inevitable that the process will be complicated and the cost will increase.

[0006] In addition, a technique for forming a ZnO-SiO2-Al2O3 film by direct current (DC) sputtering is introduced in Patent Document 2. The DC sputtering method also requires a vacuum environment and has the same problem in that the process is complicated.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2014-100806

[0010] Patent Document 2: Japanese Patent Application Publication No. 2013-147710 Summary of the invention

[0011] Problems to be solved by the invention

[0012] The present invention has been completed in view of the above-mentioned actual situation, and its purpose is to provide a solar cell element coating composition that can be directly coated on a solar cell element in an organic thin-film solar cell, a perovskite solar cell, etc., and cured under atmospheric pressure to form a protective film with high water vapor barrier properties.

[0013] Means for solving problems

[0014] The present inventors have conducted intensive studies to solve the above problems and have found that the following solar cell element coating composition can be directly coated on a solar cell element and cured under atmospheric pressure to form a protective film with high water vapor barrier properties, thereby completing the present invention.

[0015] That is, the present invention provides:

[0016] 1. A solar cell element coating composition comprising:

[0017] (A) an organopolysiloxane represented by the following average unit formula (1)

[0018] (R 1 R 3 2SiO 1 / 2 )2(Ar2SiO 2 / 2 ) a (R 2 2SiO 2 / 2 ) b (1)

[0019] In the formula, R 1 are each independently alkenyl, R 2 are each independently a substituted or unsubstituted monovalent saturated hydrocarbon group, R 3 are each independently a substituted or unsubstituted monovalent saturated hydrocarbon group, or a substituted or unsubstituted aryl group, Ar is a substituted or unsubstituted aryl group, a is an integer of 1 to 100, b is an integer of 0 to 1000, a / (a+b) is a number of 0.01 to 1.0,

[0020] (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule, and

[0021] (C) a platinum group metal catalyst activated by light with a wavelength of 200 to 500 nm;

[0022] 2. The solar cell element coating composition according to 1, wherein the component (B) is at least one selected from the following (i) to (iii),

[0023] (i) an organohydrogenpolysiloxane represented by the following average composition formula (2):

[0024] R 4 c H d SiO (4-c-d) / 2 (2)

[0025] In the formula, R 4 Each is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms other than an alkenyl group, c and d are numbers satisfying 0.7≤c≤2.1, 0.01≤d≤1, and 0.8≤c+d≤2.7,

[0026] (ii) an addition reaction product of vinyl norbornene and / or diallyl bisphenol A and a cyclic organohydrogenpolysiloxane,

[0027] (iii) silane compounds containing SiH groups;

[0028] 3. The solar cell element coating composition according to 1 or 2, wherein the component (C) comprises (η 5 -cyclopentadienyl)trialiphatic platinum compounds or bis(β-diketonate)platinum compounds;

[0029] 4. A solar cell module comprising: a solar cell element, and a water vapor barrier layer composed of a cured product of the solar cell element coating composition according to any one of 1 to 3;

[0030] 5. The solar cell module according to 4, wherein the solar cell element is an organic thin film type or a perovskite type solar cell element;

[0031] 6. A method for producing a solar cell module, comprising: bringing the solar cell element coating composition according to any one of 1 to 3 into contact with a solar cell element directly or via at least one other layer, irradiating the composition with light having a wavelength of 200 to 500 nm under atmospheric pressure, and then curing the composition by heating.

[0032] Effects of the Invention

[0033] The solar cell element coating composition of the present invention can be directly coated on a solar cell element, and can be cured under atmospheric pressure to form a cured product having high water vapor barrier properties.

[0034] The solar cell element coating composition of the present invention having such characteristics can be used as a protective film for organic thin-film solar cells, perovskite solar cells, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic longitudinal sectional view showing an example of a perovskite solar cell module according to the present invention.

[0036] Figure 2 This is a schematic longitudinal cross-sectional view showing a perovskite solar cell unit produced in an example.

[0037] Figure 3 This is a schematic longitudinal cross-sectional view showing a perovskite solar cell module produced in an example. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below.

[0039] [1] Coating composition

[0040] (1)(A)Component

[0041] The component (A) in the solar cell element coating composition of the present invention is an organopolysiloxane represented by the following average unit formula (1).

[0042] (R 1 R 3 2SiO 1 / 2 )2(Ar2SiO 2 / 2 ) a (R 2 2SiO 2 / 2 ) b (1)

[0043] In the formula, R 1 are each independently alkenyl, R 2 are each independently a substituted or unsubstituted monovalent saturated hydrocarbon group, R 3 Each is independently a substituted or unsubstituted monovalent saturated hydrocarbon group, or a substituted or unsubstituted aryl group, and each Ar is independently a substituted or unsubstituted aryl group.

[0044] As R 1 The alkenyl group is preferably an alkenyl group having 2 to 10 carbon atoms, and more preferably an alkenyl group having 2 to 6 carbon atoms. Specific examples thereof include vinyl, allyl, butenyl, pentenyl, hexenyl and the like, and vinyl is particularly preferred.

[0045] As R 2The monovalent saturated hydrocarbon group is preferably a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, more preferably a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms, and further preferably a monovalent saturated hydrocarbon group having 1 to 3 carbon atoms, and may be any of a linear, branched, or cyclic group. Specific examples thereof include linear or branched alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, and n-heptyl; and cycloalkyl groups such as cyclohexyl. In addition, a part or all of the hydrogen atoms of these groups may be substituted by halogen atoms such as chlorine, fluorine, and bromine. Specific examples thereof include halogenated alkyl groups such as chloromethyl, 3-chloropropyl, and 3,3,3-trifluoropropyl.

[0046] Among these, a methyl group is preferred from the viewpoint of heat resistance.

[0047] As R 3 The monovalent saturated hydrocarbon group is preferably a monovalent saturated hydrocarbon group having 1 to 12 carbon atoms, more preferably a monovalent saturated hydrocarbon group having 1 to 6 carbon atoms, and further preferably a monovalent saturated hydrocarbon group having 1 to 3 carbon atoms, and may be any of a linear, branched, or cyclic type. Specific examples thereof include: 2 The same groups as exemplified in .

[0048] As R 3 The aryl group is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 10 carbon atoms. Specific examples thereof include phenyl, naphthyl, tolyl, xylyl, mesityl, etc. In addition, examples include halogen-substituted aryl groups such as chlorophenyl groups in which a part or all of the hydrogen atoms of these groups are substituted with halogen atoms such as chlorine, fluorine, and bromine.

[0049] Among these, a methyl group or a phenyl group is preferred.

[0050] The aryl group of Ar is preferably an aryl group having 6 to 20 carbon atoms, and more preferably an aryl group having 6 to 10 carbon atoms. Specific examples thereof include 3 The same groups as those exemplified in , preferably phenyl.

[0051] All hydrocarbon groups (R 1 , R 2 , R 3 The content of methyl groups in Ar) is preferably 20 to 99 mol%, more preferably 40 to 97 mol%, and particularly preferably 60 to 95 mol%. Within such a range, a cured product having excellent heat resistance can be obtained.

[0052] a is an integer of 1 to 100, preferably an integer of 1 to 50, more preferably an integer of 20 to 40, b is an integer of 0 to 1000, preferably an integer of 1 to 1000, more preferably an integer of 1 to 500, further preferably an integer of 100 to 400, and a / (a+b) is a number of 0.01 to 1.0, preferably a number of 0.01 to 0.4, more preferably a number of 0.05 to 0.3.

[0053] The molecular weight of the component (A) is not particularly limited, but the weight average molecular weight (Mw) calculated based on standard polystyrene measured by gel permeation chromatography (GPC) using a THF solvent is preferably 500 to 100,000, more preferably 700 to 50,000, and particularly preferably 1,000 to 30,000.

[0054] As specific examples of component (A), for example, substances represented by the following formula can be listed, but are not limited to these. It should be noted that in the following formula, Me represents a methyl group, Ph represents a phenyl group, and Vi represents a vinyl group (hereinafter the same). Component (A) can be used alone or in combination of two or more.

[0055] (ViMe2SiO 1 / 2 )2(Ph2SiO 2 / 2 ) a (Me2SiO 2 / 2 ) b

[0056] (ViMePhSiO 1 / 2 )2(Ph2SiO 2 / 2 ) a (Me2SiO 2 / 2 ) b

[0057] (ViMe2SiO 1 / 2 )2(Ph2SiO 2 / 2 ) a

[0058] (ViMePhSiO 1 / 2 )2(Ph2SiO 2 / 2 ) a

[0059] (Where a and b are the same as above.)

[0060] (2) (B) Component

[0061] The component (B) in the solar cell element coating composition of the present invention is an organic silicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule. The SiH group in the component (B) is added by a hydrosilylation reaction with the addition-reactive carbon-carbon double bond in the component (A) to form a cured product with a three-dimensional network structure. As the component (B), for example, the following substances (i) to (iii) can be used.

[0062] (i) an organohydrogenpolysiloxane represented by the following average composition formula (2)

[0063] R 4 c H d SiO (4-c-d) / 2 (2)

[0064] In the formula, R 4 Each is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms, particularly 1 to 6 carbon atoms, other than an alkenyl group; c and d are numbers satisfying 0.7≤c≤2.1, 0.01≤d≤1, and 0.8≤c+d≤2.7.

[0065] In the above average composition formula (2), R 4 The monovalent hydrocarbon group having 1 to 12 carbon atoms may be any of linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl and sec-hexyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, o-tolyl, m-tolyl and p-tolyl; aralkyl groups such as benzyl and 2-phenylethyl; and haloalkyl groups such as chloromethyl, 3-chloropropyl and 3,3,3-trifluoropropyl in which one or more hydrogen atoms bonded to a carbon atom in these groups are substituted with a halogen atom, a cyano group or a group containing an epoxy ring; 2-cyanoethyl; 3-glycidoxypropyl and the like.

[0066] Among these, a methyl group or a phenyl group is particularly preferred from the viewpoint of easy industrial production and availability.

[0067] c is a number satisfying 0.7≤c≤2.1, and preferably 1≤c≤1.8.

[0068] d is a number satisfying 0.01≤d≤1, preferably 0.02≤d≤1, and more preferably 0.1≤d≤1.

[0069] In addition, c+d is a number satisfying 0.8≤c+d≤2.7, preferably 1≤c+d≤2.4, and more preferably 1.6≤c+d≤2.2.

[0070] The kinematic viscosity of the component (i) is not particularly limited, but is preferably 0.1 to 100,000 mm / s at 23° C. as measured by an Ostwald viscometer. 2 / s, more preferably 0.5 to 500 mm 2 / s.

[0071] Specific examples of the component (i) include those represented by the following formulae, but the present invention is not limited to these.

[0072] (Me3SiO 1 / 2 )2(HMeSiO 2 / 2 ) 45 (Me2SiO 2 / 2 ) 17

[0073] (HMe2SiO 1 / 2 )2(HMeSiO 2 / 2 )2(Ph2SiO 2 / 2 )2

[0074] (ii) Addition reaction product of vinyl norbornene and / or diallyl bisphenol A and cyclic organohydrogen polysiloxane

[0075] As the component (B), for example, an addition reaction product obtained by hydrosilylation reaction of vinyl norbornene or diallylbisphenol A and cyclic organohydrogenpolysiloxane represented by the following structural formula (3) or (4) can be used.

[0076] [Chemistry 1]

[0077]

[0078] In the formula, Z is a group represented by the following structural formula (5), (6) or (7) or a group represented by the following structural formula (10), and Z' is a group represented by the following structural formula (8) or (9) or a group represented by the following structural formula (11). s is an integer of 0 to 100, preferably an integer of 1 to 10, t is an integer of 1 to 100, preferably an integer of 1 to 20, q and r are each independently an integer of 0 to 3, and the total of q and r in each cyclic siloxane moiety is independently 2 or 3.

[0079] [Chemistry 2]

[0080]

[0081] (In formulae (5) to (9), the asterisk (*) indicates the bonding site to the silicon atom, and the stereo configuration of each asymmetric carbon may be either cis (exo) or trans (endo).)

[0082] [Chemistry 3]

[0083]

[0084] (In the formula, the asterisk (*) indicates the bonding site to the silicon atom.)

[0085] The viscosity of the component (ii) is not particularly limited, but the viscosity at 25° C. measured using a rotational viscometer is preferably 10 to 100,000 mPa·s, more preferably 100 to 10,000 mPa·s.

[0086] The compound represented by formula (3) or (4) can be obtained by subjecting 5-vinylbicyclo[2.2.1]hept-2-ene and / or diallylbisphenol A represented by the following structural formula (12) to an addition reaction with a cyclic siloxane represented by the following formula (13) in the presence of a hydrosilylation reaction catalyst. The compound represented by the following structural formula (12) may be a single-structure compound or a mixture of two or more isomers.

[0087] [Chemistry 4]

[0088]

[0089] (In the formula, q and r are the same as above.)

[0090] As the hydrosilylation reaction catalyst, a known hydrosilylation reaction catalyst can be used. For example, platinum-based catalysts such as carbon powder loaded with platinum metal, platinum black, platinum chloride, chloroplatinic acid, reaction products of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, and platinum-based catalysts such as bisacetoacetic acid; palladium-based catalysts; platinum-based metal-based catalysts such as rhodium-based catalysts, etc. In addition, there are no particular restrictions on the addition reaction conditions, the use of solvents, etc., and the reaction can be carried out under known conditions.

[0091] In the above reaction, the amount of diallylbisphenol A and the cyclic siloxane represented by the above formula (13) used is preferably an amount that is 1.05 times the number of moles of the cyclic siloxane represented by the above formula (13) relative to the number of moles of allyl groups contained in diallylbisphenol A. When 5-vinylbicyclo[2.2.1]hept-2-ene is used, the amount of the cyclic siloxane represented by the above formula (13) used is preferably an amount that is 1.05 times the number of moles of the olefin contained in 5-vinylbicyclo[2.2.1]hept-2-ene.

[0092] (iii) Silane compounds containing SiH groups

[0093] As the component (B), in addition to the components (i) and (ii), the following silane compounds can also be used.

[0094] [Chemistry 5]

[0095]

[0096] The kinematic viscosity of the component (iii) is not particularly limited, but is preferably 0.1 to 100,000 mm2 at 23°C as measured by an Ostwald viscometer. 2 / s, more preferably 0.5 to 500 mm 2 / s.

[0097] The (B) component of the present invention may be used alone or in combination of two or more.

[0098] The amount of component (B) to be incorporated is not particularly limited, but is preferably 0.5 to 2.0 mol, more preferably 0.8 to 1.5 mol, of hydrogen atoms bonded to silicon atoms per 1 mol of addition-reactive carbon-carbon double bonds of component (A) in the composition of the present invention.

[0099] (3) (C) Component

[0100] The platinum group metal catalyst for the hydrosilylation reaction of the component (C) is a platinum catalyst that is inactive when shielded from light and becomes active when irradiated with light of a wavelength of 200 to 500 nm, and is a catalyst for promoting the hydrosilylation reaction of the addition-reactive carbon-carbon double bonds in the component (A) and the hydrogen atoms bonded to the silicon atoms in the component (B).

[0101] Specific examples of such component (C) include (η 5 -cyclopentadienyl) trialiphatic platinum compounds, their derivatives, and the like.

[0102] Among these, particularly preferred substances are cyclopentadienyltrimethylplatinum complex, methylcyclopentadienyltrimethylplatinum complex, and cyclopentadienyl-modified derivatives thereof.

[0103] Furthermore, bis(β-diketonate)platinum compounds are also listed as preferred examples of the component (C), and among these, bis(acetylacetonate)platinum compounds and derivatives thereof modified with an acetylacetonate group are particularly preferred.

[0104] The amount of component (C) to be added is not limited as long as it is an amount that promotes the curing (hydrosilylation reaction) of the present composition. The amount of platinum group metal atoms in this component is preferably 0.01 to 500 ppm by mass, more preferably 0.05 to 100 ppm, and even more preferably 0.01 to 50 ppm, based on the total mass of components (A) and (B) of the present composition.

[0105] The above-mentioned (C) component may be used alone or in combination of two or more.

[0106] (4) (D) Component

[0107] In the solar cell element coating composition of the present invention, a reaction control agent as the component (D) may be added as needed in order to prevent thickening and gelation before heat curing when the composition is prepared or applied to a substrate.

[0108] Specific examples thereof include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, ethynylmethyldecylmethanol, 3-methyl-3-trimethylsiloxy-1-butyn, 3-methyl-3-trimethylsiloxy-1-pentyn, 3,5-dimethyl-3-trimethylsiloxy-1-hexyn, 1-ethynyl-1-trimethylsiloxycyclohexane, bis(2,2-dimethyl-3-butynyloxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, and 1,1,3,3-tetramethyl-1,3-divinyldisiloxane.

[0109] Among these, 1-ethynylcyclohexanol, ethynylmethyldecylmethanol, 3-methyl-1-butyn-3-ol, and bis(2,2-dimethyl-3-butynyloxy)dimethylsilane are preferred.

[0110] When the component (D) is added, its amount is preferably 0.01 to 2.0 parts by mass, more preferably 0.01 to 0.1 parts by mass, based on 100 parts by mass of the total of the components (A) and (B). Within this range, the reaction control effect is fully exerted.

[0111] (5) Other ingredients

[0112] The solar cell element coating composition of the present invention may contain other components exemplified below, in addition to the above-mentioned components (A) to (C) and the component (D) used as required, unless the purpose of the present invention is impaired.

[0113] For example, there can be listed adhesion-imparting agents having one or more functional groups including alkenyl, (meth)acryloyl, carbonyl, epoxy, alkoxysilyl, and amide in one molecule; thixotropy control agents such as fumed silica; reinforcing agents such as crystalline silica; antioxidants such as hindered phenols and hindered amines; light stabilizers; heat resistance improving agents such as metal oxides and metal hydroxides; colorants such as titanium oxide; thermal conductivity-imparting fillers such as aluminum oxide and crystalline silica; viscosity modifiers such as non-reactive silicone oils having no reactive functional groups; conductivity-imparting agents such as metal powders such as silver and gold; pigments and dyes for coloring, etc.

[0114] The solar cell element coating composition of the present invention has excellent light transmittance and is easy to obtain a thin film cured product, so it is suitable as a transparent protective material for organic thin film solar cell elements, perovskite solar cell elements, etc. By using the solar cell element coating composition of the present invention, for example, a cured product with a total light transmittance of 90% or more measured by the method according to JIS K7361-1:1997 can be produced with a thickness of 50 μm.

[0115] [2] Solar cell module

[0116] Next, one embodiment of a solar cell module according to the present invention will be described with reference to the drawings. Figure 1 An example of a perovskite solar cell module according to one embodiment of the present invention is shown in FIG.

[0117] The perovskite solar cell module 10 includes a light-transmitting substrate or a light-transmitting film 1 on a light-receiving surface, a perovskite solar cell element 2 stacked on its reverse surface, a water vapor barrier layer 3 formed on its back side in a manner covering the solar cell element 2, a sealing material 4 formed on its back side in a manner covering the water vapor barrier layer 3, and a back side substrate or a back side film 5 stacked on the sealing material 4 at the backmost part.

[0118] Among them, the light-receiving surface light-transmitting substrate or the light-receiving surface light-transmitting film 1 is a transparent member on the side where sunlight is incident, and it is necessary to have transparency, weather resistance, impact resistance, and a long-term reliable performance for outdoor use. As a specific example of the light-receiving surface light-transmitting substrate 1, transparent glass can be listed, preferably blue plate glass and white plate tempered glass. In addition, as the light-receiving surface light-transmitting film 1, resin films can be listed, and it is preferred to use a light-transmitting film with high water vapor barrier properties.

[0119] The perovskite solar cell element 2 generally has a structure in which an electron transport layer, a power generation layer formed of a perovskite compound, a hole transport layer, and a back electrode are stacked on a light-transmitting substrate or a light-transmitting film 1 on the light-receiving side. However, the structure is not limited to this.

[0120] The water vapor barrier layer 3 is preferably formed by coating the solar cell element coating composition of the present invention on the back side of the perovskite solar cell element 2 so as to cover the solar cell element 2 without a gap, and is well adhered to the light-receiving surface light-transmissive substrate or light-receiving surface light-transmissive film 1 and the perovskite solar cell element 2.

[0121] The sealing material 4 provided on the back side of the perovskite solar cell element 2 is preferably flexible and transparent to obtain durability.

[0122] As the back substrate 5 , white plate glass, blue plate glass, or the like can be used.

[0123] Examples of the back film 5 include films with controlled water vapor transmission, such as a laminated film combining a fluororesin film and a polyethylene terephthalate (PET) film, a laminated film combining a metal thin film and a PET film, and a film obtained by vapor-depositing a thin metal layer on a polyethylene naphthalate (PEN) film.

[0124] When the back substrate or the back film 5 has light transmittance, the obtained solar cell module becomes a transparent type, and the application range can be expanded.

[0125] [3] Method for manufacturing solar cell module

[0126] The water vapor barrier layer can be formed by directly contacting the solar cell element coating composition of the present invention with the solar cell element and curing it through a curing step. The contact method of the solar cell element coating composition is not particularly limited, and can be, for example, a dispensing method, a casting method, a dipping method, a roller coating method, a spraying method, a screen printing method, etc. It should be noted that the film thickness of the water vapor barrier layer is not particularly limited. For example, when applied to an organic thin film solar cell and a perovskite solar cell, it is preferably 1 to 3000 μm, more preferably 10 to 1000 μm, and further preferably 20 to 500 μm.

[0127] In addition, the solar cell element coating composition of the present invention can be applied via other layers formed on the solar cell element, such as SiO, SiN, AlO and other inorganic layers, as needed. When multiple layers are stacked on the solar cell element, the cured product of the solar cell element coating composition of the present invention can also be used between the layers as a buffer film. Furthermore, the film bonding method obtained by curing the solar cell element coating composition of the present invention can be used.

[0128] When curing the solar cell element coating composition of the present invention, the platinum group metal catalyst is activated by irradiating light with a wavelength of 200 to 500 nm, preferably 200 to 370 nm. For light irradiation, a UV-LED lamp, a metal halide lamp, a mercury lamp, etc. can be used.

[0129] From the viewpoint of the curing speed of the composition and the prevention of discoloration, the irradiation intensity is preferably 30 to 2000 mW / cm 2 The irradiation dose is preferably 3000 to 100000 mJ / cm 2 The temperature during irradiation is not particularly limited as long as it does not adversely affect the solar cell element, but is preferably 10 to 60°C, more preferably 20 to 40°C.

[0130] After the light irradiation, the solar cell element may be heated within a range that does not adversely affect the solar cell element, and the heating temperature is preferably 50 to 80° C., more preferably 50 to 70° C. The heating time is preferably 1 to 60 minutes, more preferably 10 to 30 minutes.

[0131] Example

[0132] The present invention is specifically described below with reference to the following examples and comparative examples, but the present invention is not limited to the following examples. It should be noted that in the following examples, Me represents a methyl group, Ph represents a phenyl group, and Vi represents a vinyl group. In addition, the kinematic viscosity is a measured value obtained by using an Ostwald viscometer, and the viscosity is a measured value obtained by using a rotational viscometer.

[0133] [1] Preparation of coating composition

[0134] [Examples 1-1 to 1-5, Comparative Examples 1-1 to 1-3]

[0135] The following components (A) to (D) were mixed in the amounts (parts by mass) shown in Table 1 to prepare a solar cell element coating composition.

[0136] (A)Ingredients

[0137] (A-1) an organopolysiloxane represented by the following average unit formula (14) (Mw: 28000)

[0138] (ViMe2SiO 1 / 2 )2(Me2SiO 2 / 2 ) 300 (Ph2SiO 2 / 2 ) 30 (14)

[0139] (A-2) an organopolysiloxane represented by the following average unit formula (15) (Mw: 11200)

[0140] (ViMe2SiO 1 / 2 )2(Me2SiO 2 / 2 ) 68 (Ph2SiO 2 / 2 ) 30 (15)

[0141] (A-3) Organopolysiloxane represented by the following average unit formula (16) (Mw: 905)

[0142] (ViMePhSiO 1 / 2 )2(Ph2SiO 2 / 2 )3(16)

[0143] (B) Ingredients

[0144] (B-1) A compound represented by the following average unit formula (17) (kinematic viscosity at 23°C: 45 mm 2 / s, content of hydrogen atoms bonded to silicon atoms: 0.0112 mol / g)

[0145] (Me3SiO 1 / 2 )2(HMeSiO 2 / 2 ) 45 (Me2SiO 2 / 2 ) 17 (17)

[0146] (B-2) A compound represented by the following average unit formula (18) (kinematic viscosity at 23°C: 21 mm 2 / s, content of hydrogen atoms bonded to silicon atoms: 0.0061 mol / g)

[0147] (HMe2SiO 1 / 2 )2(HMeSiO 2 / 2 )2(Ph2SiO 2 / 2 )2(18)

[0148] (B-3) A siloxane compound represented by the following structural formula (19) (kinematic viscosity at 25° C.: 1000 mPa·s, content of hydrogen atoms bonded to silicon atoms: 0.0066 mol / g)

[0149] [Chemistry 6]

[0150]

[0151] (B-4) A compound represented by the following structural formula (20) (kinematic viscosity at 23°C: 1.8 mm 2 / s, content of hydrogen atoms bonded to silicon atoms: 0.0092 mol / g)

[0152] [Chemistry 7]

[0153]

[0154] (C) Ingredients

[0155] (C-1) Toluene solution of methylcyclopentadienyltrimethylplatinum complex (platinum concentration: 0.5 mass%)

[0156] (C'-2) Toluene solution of platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (platinum concentration: 0.5 mass%)

[0157] (D) Ingredients

[0158] (D-1) 1.0 mass % toluene solution of bis(2,2-dimethyl-3-butynyloxy)dimethylsilane

[0159] (D-2) Bis(2,2-dimethyl-3-butynyloxy)dimethylsilane

[0160] [Table 1]

[0161]

[0162] [2] Manufacturing of solar cell modules

[0163] [Examples 2-1 to 2-5, Comparative Examples 2-1 to 2-3]

[0164] Using the solar cell element coating compositions obtained in Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-3, solar cell modules were produced according to the following procedures.

[0165] like Figure 2 As shown, a transparent conductive film, an electron transport layer, a perovskite layer, and a hole transport layer are stacked in sequence on a glass substrate (size 50×50 mm, thickness 3.2 mm) serving as a light-receiving surface light-transmitting substrate 1, and a perovskite solar cell element 2 having a positive electrode is stacked on the hole transport layer in a manner of being located in the center of the light-receiving surface light-transmitting substrate 1 (size 25×25 mm), thereby obtaining a perovskite solar cell unit 11 for evaluation.

[0166] Secondly, if Figure 3 As shown, a fluororesin adhesive tape (0.25 mm thick, 3×3 mm wide, produced by Chunghwa Chemical Industries, Ltd.) is provided as a dam material 6 on the outer periphery of the light-transmitting substrate 1 on the light-receiving surface. Then, the solar cell element coating composition is applied to the perovskite solar cell element 2 in a manner to a thickness of 0.1 mm.

[0167] In Examples 1-1 to 1-5, after the solar cell element coating composition was applied to the perovskite solar cell element 2, a metal halide lamp (HANDY UV-100, manufactured by ORC Manufacturing Co., Ltd. (OCR)) was used to irradiate the perovskite solar cell element 2 from above at 25°C with an ultraviolet light intensity of 100 mW / cm 2 The cumulative irradiation dose is 3000mJ / cm 2 Then, the solar cell element coating composition was cured by heating at 60° C. for 1 hour to obtain a water vapor barrier layer 3 .

[0168] Then, a glass (size 50×50 mm, thickness 3.2 mm) as the back substrate 5 was placed on the upper part of the cofferdam material 6, and the back side was fixed with a polyimide tape 7 so that the back substrate 5 would not fall off, thereby obtaining a perovskite solar cell module 12 for evaluation.

[0169] In Comparative Examples 1-1 to 1-3, after the solar cell element coating composition was applied on the perovskite solar cell element 2, the solar cell element coating composition was cured by heating at 100°C for 1 hour.

[0170] Then, a glass substrate (size 50×50 mm, thickness 3.2 mm) serving as the back substrate 5 is placed on the upper part of the cofferdam material 6, and the back side is fixed with a polyimide tape 7 so that the back substrate 5 does not fall off, thereby obtaining a perovskite solar cell module 12 for evaluation.

[0171] [Initial output maintenance rate]

[0172] The obtained perovskite solar cell evaluation body was irradiated with light from the surface direction of the light-transmitting substrate 1 using a simulated sunlight irradiation device, and the output (W1) of the evaluation perovskite solar cell module 12 was measured.

[0173] The output (W1) of the evaluation perovskite solar cell module 12 and the output (W c ), and the initial output maintenance rate (%) was calculated. The case where the initial output maintenance rate was 95% or more was evaluated as 0, and the case where it was less than 95% was evaluated as ×. The results are shown in Table 2.

[0174] Initial output maintenance rate (%) = (W1 / W c )×100

[0175] [Output maintenance rate after humidity test]

[0176] In addition, the output (W2) of the evaluation perovskite solar cell module 12 after exposure to an environment of 60°C and 90% RH for 500 hours was measured by the same method as above, and the output maintenance rate (%) after the humidity test was calculated. The output maintenance rate after the humidity test was evaluated as 0 when it was 80% or more, and as × when it was less than 80%. The results are shown in Table 2.

[0177] Output maintenance rate after humidity test (%) = (W2 / W c )×100

[0178] [Table 2]

[0179]

[0180] As shown in Table 2, the perovskite solar cells having a water vapor barrier layer composed of the cured products of the solar cell element coating compositions of Examples 1-1 to 1-5 showed good output maintenance even when exposed to an environment of 60° C. and 90% RH for 500 hours.

[0181] On the other hand, the perovskite solar cells using the compositions of Comparative Examples 1-1 to 1-3 had low initial output maintenance rates and failed the humidity resistance test. This is believed to be because the heat-sensitive perovskite solar cell elements were damaged by heating to 100° C. during the formation of the water vapor barrier layer, resulting in reduced output.

[0182] Description of Reference Numerals

[0183] 1 Light-receiving surface light-transmitting substrate / light-receiving surface light-transmitting film

[0184] 2 Perovskite solar cell elements

[0185] 3 Water vapor barrier

[0186] 4 Sealing materials

[0187] 5 Back substrate / back side film

[0188] 6 Cofferdam materials

[0189] 7 Polyimide tape

[0190] 10 Perovskite solar cell module

[0191] 11 Evaluation of perovskite solar cell

[0192] 12 Evaluation of perovskite solar cell modules

Claims

1. A solar cell element coating composition comprising: (A) an organopolysiloxane represented by the following average unit formula (1) (R 1 R 3 2SiO 1 / 2 )2(Ar2SiO 2 / 2 ) a (R 2 2SiO 2 / 2 ) b (1) In the formula, R 1 are each independently alkenyl, R 2 are each independently a substituted or unsubstituted monovalent saturated hydrocarbon group, R 3 are each independently a substituted or unsubstituted monovalent saturated hydrocarbon group, or a substituted or unsubstituted aryl group, Ar is a substituted or unsubstituted aryl group, a is an integer of 1 to 100, b is an integer of 0 to 1000, a / (a+b) is a number of 0.01 to 1.0, (B) an organosilicon compound having at least two hydrogen atoms bonded to silicon atoms in one molecule, and (C) A platinum group metal catalyst activated by light with a wavelength of 200 to 500 nm.

2. The solar cell element coating composition according to claim 1, wherein The component (B) is at least one selected from the following (i) to (iii), (i) an organohydrogenpolysiloxane represented by the following average composition formula (2): R 4 c H d SiO (4-c-d) / 2 (2) In the formula, R 4 Each is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 12 carbon atoms other than an alkenyl group, c and d are numbers satisfying 0.7≤c≤2.1, 0.01≤d≤1, and 0.8≤c+d≤2.7, (ii) an addition reaction product of vinyl norbornene and / or diallyl bisphenol A and a cyclic organohydrogenpolysiloxane, (iii) Silane compounds containing SiH groups.

3. The solar cell element coating composition according to claim 1 or 2, wherein The component (C) comprises (η 5 -cyclopentadienyl)trialiphatic platinum compounds or bis(β-diketonate)platinum compounds. 4 . A solar cell module comprising: a solar cell element; and a water vapor barrier layer composed of a cured product of the solar cell element coating composition according to claim 1 .

5. The solar cell module according to claim 4, wherein: The solar cell element is an organic thin film type or a perovskite type solar cell element.

6. A method for producing a solar cell module, comprising: bringing the solar cell element coating composition according to any one of claims 1 to 3 into contact with a solar cell element directly or via at least one other layer, irradiating the composition with light having a wavelength of 200 to 500 nm under atmospheric pressure, and then curing the composition by heating.

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