Light conversion adhesive film containing benzophenone light conversion material

Abstract

The invention provides a light conversion adhesive film containing a benzophenone light conversion material, which is characterized in that the light conversion adhesive film comprises a compound represented by a formula I and a substrate transparent to visible light, the definition of each group in the formula I is described in the specification, and the mass fraction of the compound represented by the formula I in the light conversion adhesive film is 0.001-3%. The light conversion adhesive film can be used for a solar cell so as to enhance the efficiency and the stability of the solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell materials and relates to a light-converting film containing benzophenone-based light-converting materials that can be used in solar cell modules. Background Technology

[0002] Ultraviolet (UV) radiation accounts for approximately 5% of the total energy of sunlight. In silicon-based solar cells, UV radiation is typically not effectively utilized due to the band gap of silicon, limiting the cell's maximum efficiency. Furthermore, the high energy of UV photons can trigger degradation of cell materials, leading to device deterioration. Therefore, converting UV radiation into a wavelength usable by silicon-based solar cells helps improve both cell efficiency and lifespan. This conversion can be achieved by introducing light-converting materials into the cell that absorb in the UV region and emit in the visible light region. Currently, films containing light-converting materials are being increasingly widely incorporated into solar cells.

[0003] The light-converting materials in existing technologies are typically organic fluorescent materials, rare earth materials, or quantum dot materials. For example, Hanwha Total Co., Ltd. uses films containing pyrene fluorescent materials (CN114335353A); Nitto Denko Corporation (CN103339221A) and Zhejiang Foster New Materials Research Institute Co., Ltd. (CN117431022A) use films containing triazole fluorescent materials; Hunan Normal University (CN102268261A), Panasonic Intellectual Property Co., Ltd. (CN116997633A), and Zhijing Technology Co., Ltd. (CN116970346A) use films containing rare earth metals such as Eu and Ce; Dalian Institute of Chemical Physics (CN113035990A) and Suzhou Hongdao New Materials Co., Ltd. (CN 117229728A) use films containing quantum dots such as ZnS and CdS.

[0004] However, while existing organic fluorescent materials exhibit high photoluminescence quantum efficiency (PLQY), their Stokes shift (the redshift of the emission spectrum compared to the absorption spectrum) is typically small, limiting their conversion of ultraviolet light to deep blue light (<450nm), which is still far from the wavelength range where silicon-based solar cells achieve the highest utilization efficiency. Alternatively, the absorption of organic fluorescent materials may significantly overlap with the absorption of silicon solar cells, impacting cell efficiency. Rare-earth materials, although possessing large Stokes shifts, have narrow emission peaks and typically low PLQY, making it difficult to efficiently convert ultraviolet light into visible light. Quantum dot materials are expensive, pose environmental risks, and large-scale production technologies are not yet fully developed.

[0005] Therefore, there is a need in the art for a light-converting film containing organic fluorescent materials that can effectively improve the efficiency and lifetime of solar cells. Summary of the Invention

[0006] This invention addresses the aforementioned problems in existing technologies by proposing a light-converting film containing benzophenone-based light-converting materials, which can be used in solar cells to improve their efficiency and stability. This invention uses benzophenone-based thermally activated delayed fluorescence (TADF) materials as the light-converting material in the film. TADF materials have an electron donor-aryl-electron acceptor structure, therefore the corresponding excited states are typically charge-transfer (CT) excited states. The structure of the molecule in the CT state usually differs significantly from its ground state structure, resulting in a large Stokes shift; simultaneously, the molecular structure in the CT excited state is relatively relaxed, thus the emission spectral width of the material is significantly greater than that of traditional fluorescent materials and rare-earth materials. Furthermore, benzophenone itself is a commonly used ultraviolet absorber, further ensuring the light absorption effect of the corresponding material. Therefore, the benzophenone-based TADF material used in this invention can efficiently absorb ultraviolet light and convert it into a wavelength band with high battery utilization efficiency, improving battery efficiency and lifespan.

[0007] Specifically, one aspect of the present invention provides a light-converting film comprising a compound of formula I and a matrix transparent to visible light:

[0008]

[0009] In Formula I, R1, R2, and R3 are each independently selected from hydrogen atoms, D1 groups, substituted D1 groups, D2 groups, and substituted D2 groups, and at most one of R1, R2, and R3 is a hydrogen atom. The structures of the D1 and D2 groups are as follows:

[0010]

[0011] In groups D1 and D2, * indicates the position where the group is attached to other parts of the compound of formula I; X in group D2 is an oxygen atom, a sulfur atom, a methylene group, or a substituted methylene group;

[0012] As the substituted D1 group and the substituted D2 group, one or more hydrogen atoms on the D1 group and the D2 group may be replaced by a group selected from halogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, cyano, trifluoromethyl, 9H-carbazole-9-yl and 9H-carbazole-9-yl derivatives; said 9H-carbazole-9-yl derivatives include: 9H-carbazole-9-yl, α-carblinyl, β-carblinyl, γ-carblinyl substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, carbazoleyl and diphenylamineyl, α-carblinyl, β-carblinyl, γ-carblinyl, and cyclic derivatives of 9H-carbazole-9-yl with one or more groups selected from indole, benzothiophene and benzofuran;

[0013] When X in the D2 group is a substituted methylene group, one or two hydrogen atoms on the methylene group can be replaced by a group selected from C1-C10 alkyl, C3-C11 cycloalkyl and C6-C14 aryl groups;

[0014] The mass fraction of the compound of formula I in the optical transfer film is 0.001% to 3%.

[0015] In one or more embodiments, the mass fraction of the compound of formula I in the light-converting film is 0.001% to 0.5%.

[0016] In one or more embodiments, the compound of formula I is selected from compounds of formula II and formula III:

[0017]

[0018] In Formula II, R1 and R2 are each independently selected from D1 group, substituted D1 group, D2 group and substituted D2 group;

[0019] In Formula III, R2 and R3 are each independently selected from D1 group, substituted D1 group, D2 group and substituted D2 group.

[0020] In one or more embodiments, the substituted D1 group is an E1 group: In the E1 group, * indicates the position where the group is attached to other parts of the compound of formula I. R4 and R5 are each independently selected from hydrogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl and 9H-carbazole-9-yl, and at most one of R4 and R5 is a hydrogen atom.

[0021] In one or more embodiments, the substituted D2 group is an E2 group: In the E2 group, * indicates the position where the group is attached to other parts of the compound of formula I. R6 and R7 are each independently selected from hydrogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl and 9H-carbazole-9-yl, and at most one of R6 and R7 is a hydrogen atom.

[0022] In one or more embodiments, the compound of formula I is selected from one or more of the following compounds: compound 1, compound 2, compound 3, and compound 4:

[0023]

[0024] In one or more embodiments, the thickness of the light-converting adhesive film is 0.1-1.0 mm.

[0025] In one or more embodiments, the matrix may be one or more selected from polyethylene terephthalate, polyvinyl butyral, ethylene-vinyl acetate copolymer, polyethylene, ethylene polytetrafluoroethylene, polyimide, polycarbonate, polystyrene, polyurethane, polyacrylate, siloxane sol, siloxane gel and polyolefin elastomer.

[0026] In one or more embodiments, the refractive index of the matrix is ​​1.4-1.7.

[0027] In one or more embodiments, the light-converting film further includes one or more additives selected from crosslinking agents, co-crosslinking agents, plasticizers, antioxidants, and water-absorbing agents; preferably, the light-converting film includes crosslinking agents and co-crosslinking agents, and optionally further includes one or more additives selected from plasticizers, antioxidants, and water-absorbing agents.

[0028] The present invention also provides a method for preparing the light-converting adhesive film according to any embodiment of the present invention, the method comprising: mixing the components of the light-converting adhesive film evenly, melting and extruding them into a film, and cooling and shaping them to obtain the light-converting adhesive film.

[0029] The present invention also provides a solar cell module, the solar cell module comprising the light-converting adhesive film described in any embodiment herein.

[0030] In one or more embodiments, the solar cell module includes one or more of the following devices: PN junction devices containing group III-V or II-IV elements, Cu-In-Ga-Se thin film devices, organic sensitizer devices, organic thin film devices, quantum dot thin film devices, amorphous silicon solar cell devices, microcrystalline silicon solar cell devices, and crystalline silicon solar cell devices.

[0031] The present invention also provides a method for enhancing the efficiency and stability of a solar cell, the method comprising: introducing a light-converting adhesive film as described in any embodiment herein into the solar cell.

[0032] In one or more embodiments, the solar cell includes one or more of the following devices: PN junction devices containing group III-V or II-IV elements, Cu-In-Ga-Se thin film devices, organic sensitizer devices, organic thin film devices, quantum dot thin film devices, amorphous silicon solar cell devices, microcrystalline silicon solar cell devices, and crystalline silicon solar cell devices. Attached Figure Description

[0033] Figure 1 The above are the absorption-emission spectra of compounds 1, 2, 3, and 4 in this invention.

[0034] Figure 2The images show the absorption-emission spectra of the triazole materials used in Compound 2 and Comparative Example 2 in this invention. Detailed Implementation

[0035] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0036] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0037] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0038] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0039] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0040] In this article, the sum of the percentages of all components in the composition is 100%.

[0041] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0042] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0043] Ideally, the light-converting material in the film should exhibit strong absorption at wavelengths below 400 nm, a large Stokes shift, a broad emission spectrum, and high PLQY. In this invention, the benzophenone-based light-converting material in the film is a TADF material whose emission spectrum more closely matches the absorption band of silicon-based solar cells. Introducing this type of material improves the quantum efficiency of silicon-based cells; this material also effectively absorbs ultraviolet light below 400 nm, thereby extending the device lifetime.

[0044] This invention provides a light-converting film for sunlight wavelength conversion, comprising a benzophenone-based light-converting material. The mass fraction of the light-converting material in the film can be 0.001% to 3%. In some preferred embodiments, the mass fraction of the light-converting material in the film is 0.001% to 0.5%, more preferably 0.01% to 0.5%, and even more preferably 0.05% to 0.5%, for example 0.1%, 0.2%, 0.3%, and 0.4%. Controlling the amount of the light-converting material selected in this invention within the aforementioned preferred range is beneficial for maximizing the effect of the light-converting material in improving battery efficiency and stability.

[0045] Furthermore, the light-converting film of the present invention may optionally or preferably include additives. Available additives include, but are not limited to, crosslinking agents, co-crosslinking agents, plasticizers, antioxidants, and water-absorbing agents.

[0046] In some embodiments, the light-converting film of the present invention comprises a light-converting material, a matrix, and optional additives.

[0047] Formula I compound

[0048] The light-converting film of the present invention comprises a compound of formula I as a light-converting material and a matrix:

[0049] In Formula I, R1, R2, and R3 are each independently selected from hydrogen atoms, D1 groups, substituted D1 groups, D2 groups, and substituted D2 groups, and at most one of R1, R2, and R3 is a hydrogen atom. The structures of the D1 and D2 groups are as follows:

[0050]

[0051] In groups D1 and D2, * indicates the position where the group is attached to other parts of the compound of formula I; X in group D2 is an oxygen atom, a sulfur atom, a methylene group, or a substituted methylene group;

[0052] As the substituted D1 group and the substituted D2 group, one or more hydrogen atoms on the D1 group and the D2 group can be replaced by a group selected from halogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, cyano, trifluoromethyl, 9H-carbazole-9-yl and 9H-carbazole-9-yl derivatives.

[0053] When X in the D2 group is a substituted methylene group, one or two hydrogen atoms on the methylene group can be replaced by groups selected from C1-C10 alkyl, C3-C11 cycloalkyl and C6-C14 aryl groups.

[0054] In this invention, 9H-carbazole-9-yl is as shown in the following formula: The asterisk (*) indicates the position where the 9H-carbazole-9-yl group is attached to other parts of the compound.

[0055] In this invention, the 9H-carbazole-9-yl derivative includes: 9H-carbazole-9-yl groups substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, carbazole, and diphenylamine groups; α-carbolinyl, β-carbolinyl, γ-carbolinyl groups; and cyclic derivatives of 9H-carbazole-9-yl groups substituted with one or more groups selected from indole, benzothiophene, and benzofuran. In some preferred embodiments, the 9H-carbazole-9-yl derivative is a 9H-carbazole-9-yl group substituted with one or two substituents selected from C1-C10 alkyl and C6-C14 aryl groups.

[0056] In this invention, alkyl refers to a monovalent saturated group consisting of carbon atoms and hydrogen atoms, having a straight-chain or branched structure. In this invention, the number of carbon atoms preceding the group indicates the number of carbon atoms contained in the group; for example, C1 alkyl represents an alkyl group containing one carbon atom, i.e., methyl. Alkyl groups suitable for this invention can be C1-C10 alkyl groups, such as C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl, and C10 alkyl. Examples of C4 alkyl groups include tert-butyl (t-Bu).

[0057] In this invention, alkylene refers to a divalent saturated group composed of carbon and hydrogen atoms with a straight-chain or branched structure. For example, methylene is -CH2-.

[0058] In this invention, cycloalkyl refers to a monovalent saturated group with an aliphatic ring structure composed of carbon atoms and hydrogen atoms, and the cycloalkyl group is connected to other parts of the molecule through carbon atoms on the aliphatic ring. The cycloalkyl groups suitable for this invention can be C3-C11 cycloalkyl groups, such as C3, C4, C5, C6, C7, C8, C9, C10, and C11 cycloalkyl groups.

[0059] In this invention, aryl refers to a monovalent group with an aromatic ring structure composed of carbon atoms and hydrogen atoms, and the aryl group is connected to other parts of the molecule through the carbon atoms on the aromatic ring. The aryl groups suitable for this invention can be C6-C14 aryl groups, including but not limited to C6 aryl (e.g., phenyl), C10 aryl (e.g., naphthyl), and C14 aryl (e.g., anthraceneyl, phenanthrene).

[0060] In this invention, halogens include fluorine, chlorine, bromine, and iodine.

[0061] In some preferred embodiments, the compound of formula I is selected from compounds of formula II and formula III:

[0062]

[0063] R1, R2, and R2 are as described in any of the preceding embodiments. This is beneficial for improving the effect of the light-converting adhesive film on enhancing battery efficiency and stability.

[0064] In some preferred embodiments, in Formula II, R1 and R2 are each independently selected from a D1 group, a substituted D1 group, a D2 group, and a substituted D2 group. For example, in Formula II, R1 and R2 can each be independently selected from a D1 group, a D1 group substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl, a D2 group substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl. This is beneficial for improving the efficiency and stability of the cell enhanced by the light-converting film.

[0065] In some preferred embodiments, in Formula III, R2 and R3 are each independently selected from a D1 group, a substituted D1 group, a D2 group, and a substituted D2 group. For example, in Formula III, R2 and R3 can each be independently selected from a D1 group, a D1 group substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl, a D2 group substituted with one or two substituents selected from C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl. This is beneficial for improving the efficiency and stability of the cell enhanced by the light-converting film.

[0066] In some preferred embodiments, the substituted D1 group is an E1 group: In the E1 group, * indicates the position where the group is attached to other parts of the compound of formula I. R4 and R5 are each independently selected from hydrogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl, and at most one of R4 and R5 is a hydrogen atom. In some embodiments, R4 is a hydrogen atom, and R5 is selected from hydrogen atoms, C1-C10 alkyl, C3-C11 cycloalkyl, C6-C14 aryl, and 9H-carbazole-9-yl. Preferably, R5 is selected from C1-C10 alkyl (e.g., tert-butyl (t-Bu)) and 9H-carbazole-9-yl. This is beneficial for improving the effect of the light transfer film on enhancing battery efficiency and stability.

[0067] In some preferred embodiments, the substituted D2 group is an E2 group: In the E2 group, * indicates the position where the group is attached to other parts of the compound of formula I. R6 and R7 are each independently selected from hydrogen atoms, C1-C10 alkyl groups, C3-C11 cycloalkyl groups, C6-C14 aryl groups, and 9H-carbazole-9-yl groups, and at most one of R6 and R7 is a hydrogen atom. In some embodiments, R6 and R7 are each independently selected from C1-C10 alkyl groups (e.g., C1-C4 alkyl groups). This is beneficial for improving the effect of the light transfer film on enhancing battery efficiency and stability.

[0068] Compound 1, Compound 2, Compound 3 and Compound 4

[0069] In some preferred embodiments, the light-converting film of the present invention comprises one or more light-converting materials and a matrix selected from compound 1, compound 2, compound 3 and compound 4:

[0070]

[0071] This helps to improve the efficiency and stability of the battery by enhancing the effect of the light transfer film.

[0072] In some preferred embodiments, the light-converting material is selected from one or more of compound 2, compound 3, and compound 4, more preferably from one or two of compound 2 and 4, and even more preferably from compound 2. This is beneficial for improving the effect of the light-converting film on enhancing battery efficiency and stability.

[0073] In this invention, the hydrogen atoms in compounds of formula I, formula II, formula III, and compounds 1 to 4, which are used as light-converting materials, can be protium or deuterium.

[0074] Source of compounds

[0075] In this invention, the compounds of formula I, formula II, formula III, and compounds 1 to 4, which serve as light-converting materials, can be prepared using known methods, for example, by referring to the methods described in the following literature: Zhang, Q.; et al. Nearly 100% Internal Quantum Efficiency in Undoped Electroluminescent Devices Employing Pure Organic Emitters. https: / / doi.org / 10.1002 / adma.201405474; Lee, SY; et al. Luminous Butterflies: Efficient Exciton Harvesting by Benzophenone Derivatives for Full-Color Delayed Fluorescence OLEDs. https: / / doi.org / 10.1002 / anie.201402992; Rajamali, P.; et al. A New Molecular Design Based on Thermally Activated Delayed Fluorescence for Highly Efficient Organic Light Emitting Diodes. https: / / doi.org / 10.1021 / jacs.5b10950.

[0076] Compounds of Formula I, Formula II, Formula III, and Compounds 1 through 4 are also available through commercial channels.

[0077] matrix

[0078] In this invention, the substrate is preferably transparent to visible light. A substrate with a visible light transmittance ≥ 0.85 is considered transparent to visible light.

[0079] The matrix material can be one or more selected from polyethylene terephthalate, polyvinyl butyral, ethylene-vinyl acetate copolymer (EVA), polyethylene, ethylene polytetrafluoroethylene, polyimide, polycarbonate, polystyrene, polyurethane, polyacrylate, siloxane sol, siloxane gel, and polyolefin elastomer. In some embodiments, the matrix material is EVA.

[0080] The refractive index of the matrix is ​​preferably 1.4-1.7, such as 1.5 or 1.6. This is beneficial for improving the efficiency and stability of the solar cell by enhancing the light transfer film.

[0081] The matrix can account for 80% to 99.8% of the mass of the light-converting film, for example, 90%, 95%, 96%, 97%, 98%, 98.5%, 99%, and 99.5%.

[0082] Additives

[0083] The additives applicable to this invention include, but are not limited to, those selected from crosslinking agents, co-crosslinking agents, plasticizers, antioxidants, and water-absorbing agents.

[0084] In some preferred embodiments, the additives include crosslinking agents, such as tert-butyl peroxyisopropyl carbonate. The crosslinking agent preferably accounts for 0.1%-1% of the mass fraction of the light-converting film, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or 0.9%. This is beneficial for improving the effectiveness of the light-converting film in enhancing battery efficiency and stability.

[0085] In some preferred embodiments, the additives include a co-crosslinking agent, such as trimethylolpropane tetraacrylate. The crosslinking agent preferably accounts for 0.1%-1% of the mass fraction of the light-converting film, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or 0.9%. This is beneficial for improving the effectiveness of the light-converting film in enhancing battery efficiency and stability.

[0086] In some preferred embodiments, the matrix is ​​EVA, the crosslinking agent is tert-butyl peroxyisopropyl carbonate, and the co-crosslinking agent is trimethylolpropane tetraacrylate. This is beneficial for improving the effect of the light transfer film on enhancing battery efficiency and stability.

[0087] In this invention, plasticizers, antioxidants, and water-absorbing agents are optionally or preferably added to the light-converting film, and their dosage can be conventional.

[0088] Preparation method of light transfer film

[0089] The light-converting adhesive film of the present invention can be obtained by mixing the components of the light-converting adhesive film evenly, melting and extruding them into a film, and then cooling and shaping it.

[0090] The melt extrusion temperature can be 80–120°C, for example, 90°C, 100°C, or 110°C. Cooling and setting can be carried out at room temperature (e.g., 25°C).

[0091] Solar cell modules

[0092] Under high temperature and negative pressure conditions, the light-converting adhesive film of the present invention is laminated and encapsulated on a back sheet (e.g., a glass plate) as a front adhesive film with a solar cell (e.g., a monocrystalline silicon solar cell) and a back adhesive film (the material can be pure EVA). After the module is cooled, the light-converting adhesive film becomes the front surface of the module, and the back adhesive film becomes the back surface of the module, thus obtaining a solar cell module.

[0093] The present invention achieves the following beneficial technical effects:

[0094] This invention introduces a light-conversion film containing benzophenone-based TADF materials into solar cells to enhance cell efficiency and stability. These materials have a high photoluminescence efficiency (PLQY) and an emission peak in the 430-510 nm range, matching the absorption band of silicon-based solar cells and thus contributing to improved light conversion efficiency. Furthermore, the benzophenone / carbazole building blocks exhibit high photostability, resulting in inherently high stability for the materials themselves. They also provide continuous absorption of light below 420 nm, with benzophenone exhibiting particularly strong absorption at 300 nm, effectively preventing UV damage to the cell.

[0095] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0096] Example 1

[0097] This embodiment provides a method using compound 1 This refers to the film and corresponding devices for light-converting materials. Compound 1 was purchased from Xi'an Sunlight Energy Technology Co., Ltd.

[0098] This embodiment manufactures the light-converting adhesive film using the following method:

[0099] Based on the total mass of the light-converting adhesive film, 98.8% wt of EVA, 0.5% wt of tert-butyl peroxyisopropyl carbonate as a crosslinking agent, 0.5% wt of trimethylolpropane tetraacrylate as a co-crosslinking agent, and 0.2% wt of compound 1 were mixed evenly and then melt-extruded at 100°C to form a film. The extruded film was then cooled and set at 25°C to obtain a light-converting adhesive film with a thickness of 0.3 mm.

[0100] This embodiment manufactures solar cell modules in the following manner:

[0101] Under a negative pressure environment at 130°C, the encapsulation glass, the above-mentioned light-converting adhesive film, the 182mm HJT solar cell from Huasheng New Energy Technology Co., Ltd., pure EVA, and glass backsheet were laminated and encapsulated, with the light-converting adhesive film serving as the front surface of the cell, to obtain the solar cell module of Example 1.

[0102] Example 2

[0103] The light-converting film and solar cell module of Example 2 were prepared using a method similar to that of Example 1, except that compound 1 was replaced with an equal mass fraction of compound 2. It is used in light-converting films. Compound 2 was purchased from Xi'an Sunlight Energy Technology Co., Ltd.

[0104] Example 3

[0105] The light-converting adhesive film and solar cell module of Example 3 were prepared using a method similar to that of Example 1, except that compound 1 was replaced with an equal mass fraction of compound 3. It is used in light-converting films. Compound 3 was purchased from Xi'an Sunlight Energy Technology Co., Ltd.

[0106] Example 4

[0107] The light-converting adhesive film and solar cell module of Example 4 were prepared using a method similar to that of Example 1, except that compound 1 was replaced with an equal mass fraction of compound 4. It is used in light-converting films. Compound 4 was purchased from Xi'an Sunlight Energy Technology Co., Ltd.

[0108] Comparative Example 1

[0109] The encapsulant film and solar cell module of Comparative Example 1 were prepared using a method similar to that of Example 1, but the difference was that no light-converting material was added. The encapsulant film composition was 99.0% wt of EVA, 0.5% wt of tert-butyl peroxyisopropyl carbonate, and 0.5% wt of trimethylolpropane tetraacrylate.

[0110] Comparative Example 2

[0111] The light-converting film and solar cell module of Comparative Example 2 were prepared using a method similar to that of Example 1, except that compound 1 was replaced with an equal mass fraction of triazole material, the molecular structure of which is as follows: This fluorescent material is produced by Shanghai BIDE Pharmaceutical Technology Co., Ltd.

[0112] Test case

[0113] I. Photophysical Properties Testing: Photophysical tests were performed on the light-converting materials in each example and comparative example using a UV-Vis spectrometer, a fluorometer, and an integrating sphere. The absorption spectra of the light-converting materials were measured using an Agilent Cary 3500 UV-Vis spectrophotometer, and the emission spectra and PLQY of the light-converting materials were measured using a Horiba FL-3 spectrometer and its integrating sphere accessory. The results are as follows: Figure 1 , Figure 2 As shown in Table 1.

[0114] Comparison Table 1 Figure 1 and Figure 2 Compared to triazole materials, benzophenone-based TADF materials exhibit a larger Stokes shift (>100 nm), a broader emission spectrum (FWHM>60 nm), and higher PLQY (~0.9). The large Stokes shift and broad emission spectrum originate from the charge-transfer excited-state characteristics between benzophenone and carbazole. Specifically, from... Figure 2 It can be observed that the absorption intensity of triazole materials at 350 nm is much greater than that at 300 nm, while the absorbance of benzophenone materials near 350 nm is relatively close to that near 300 nm. Since shorter wavelengths of ultraviolet light cause greater damage to devices, benzophenone-based light-converting materials are more effective in protecting devices, which is one reason why these devices have a longer lifespan.

[0115] Table 1: Comparison of photophysical properties of optical transfer materials in each embodiment and comparative example

[0116]

[0117]

[0118] II. Device Performance Testing: To evaluate the performance of the solar cell modules and illustrate the effectiveness of the present invention, power tests and UV aging tests were conducted on the solar cell modules in each embodiment and comparative example. Power tests were performed using an ANPA1000 tester from Shandong Aino Instruments Co., Ltd., and UV aging was carried out using a 142W multi-expansion UV aging chamber at 70°C for 120 hours. The results are shown in Table 2.

[0119] Table 2 shows that benzophenone-based light-converting materials can effectively improve device efficiency and suppress device degradation. As mentioned earlier, this can be attributed to the large Stokes shift, wide emission spectrum, and strong absorption of benzophenone-based light-converting materials, which enable them to convert ultraviolet light into a wavelength band with higher utilization efficiency in silicon-based solar cells, thus resulting in higher efficiency in the corresponding cells.

[0120] Table 2: Comparison of device efficiency and attenuation rate in different embodiments and comparative examples

[0121]

Claims

1. A light conversion adhesive film, characterized in that, The light conversion adhesive film comprises a compound of Formula I and a substrate transparent to visible light: In Formula I, R1, R2, and R3 are each independently selected from a hydrogen atom, a D1 group, a substituted D1 group, a D2 group, and a substituted D2 group, and at most one of R1, R2, and R3 is a hydrogen atom, wherein the structures of the D1 group and the D2 group are as follows: In the D1 group and the D2 group, * indicates the position at which the group is connected to the other part of the compound of Formula I; X in the D2 group is an oxygen atom, a sulfur atom, a methylene group, or a substituted methylene group; As the substituted D1 group and the substituted D2 group, one or more hydrogen atoms in the D1 group and the D2 group can be substituted with a group selected from a halogen atom, a C1-C10 alkyl group, a C3-C11 cycloalkyl group, a C6-C14 aryl group, a cyano group, a trifluoromethyl group, a 9H-carbazol-9-yl group, and a 9H-carbazol-9-yl derivative; the 9H-carbazol-9-yl derivative includes: a 9H-carbazol-9-yl group substituted with 1 or 2 substituents selected from a C1-C10 alkyl group, a C3-C11 cycloalkyl group, a C6-C14 aryl group, a carbazolyl group, and a diphenylamine group, an α-carboline group, a β-carboline group, a γ-carboline group, and a 9H-carbazol-9-yl group in a fused ring derivative with one or more groups selected from an indole group, a benzothiophene group, and a benzofuran group; When X in the D2 group is a substituted methylene group, one or both hydrogen atoms in the methylene group can be substituted with a group selected from a C1-C10 alkyl group, a C3-C11 cycloalkyl group, and a C6-C14 aryl group; The mass fraction of the compound of Formula I in the light conversion adhesive film is 0.001% to 3%.

2. The light conversion film according to claim 1, wherein The mass fraction of the compound of Formula I in the light conversion adhesive film is 0.001% to 0.5%.

3. The light conversion film according to claim 1, wherein The compound of Formula I is selected from a compound of Formula II and a compound of Formula III: In Formula II, R1 and R2 are each independently selected from a D1 group, a substituted D1 group, a D2 group, and a substituted D2 group; In Formula III, R2 and R3 are each independently selected from a D1 group, a substituted D1 group, a D2 group, and a substituted D2 group.

4. The light conversion adhesive film according to claim 1, wherein substituted D1group is an E1group: In the E1group, * indicates the position at which the group is attached to the remainder of the compound of formula I, and R4and R5are each independently selected from the group consisting of a hydrogen atom, a C1-C10alkyl group, a C3-C11cycloalkyl group, a C6-C14aryl group, and a 9H-carbazol-9-yl group, and no more than one of R4and R5is a hydrogen atom; The substituted D2group is an E2group: In the E2group, * indicates the position at which the group is attached to the remainder of the compound of formula I, and R6and R7are each independently selected from the group consisting of a hydrogen atom, a C1-C10alkyl group, a C3-C11cycloalkyl group, a C6-C14aryl group, and a 9H-carbazol-9-yl group, and no more than one of R6and R7is a hydrogen atom.

5. The light conversion film according to claim 1, wherein The compound of Formula I is selected from one or more of Compound 1, Compound 2, Compound 3, and Compound 4 as follows:

6. The light-converting adhesive film as described in claim 1, characterized in that, The light conversion adhesive film has one or more of the following characteristics: The thickness of the light conversion adhesive film is 0.1-1.0 mm; The substrate can be one or more selected from polyethylene terephthalate, polyvinyl butyral, ethylene-vinyl acetate copolymer, polyethylene, ethylene polytetrafluoroethylene, polyimide, polycarbonate, polystyrene, polyurethane, polyacrylate, silicone sol, silicone gel, and polyolefin elastomer; The refractive index of the substrate is 1.4-1.

7.

7. The light converting film of claim 1, wherein the light converting film has a thickness of 0.5 to 5 microns. The light conversion adhesive film further comprises one or more auxiliary agents selected from a crosslinking agent, a co-crosslinking agent, a plasticizer, an antioxidant, and a water absorbent; preferably, the light conversion adhesive film comprises a crosslinking agent and a co-crosslinking agent, and optionally further comprises one or more selected from a plasticizer, an antioxidant, and a water absorbent.

8. A method of preparing the light conversion adhesive film according to any one of claims 1 to 7, characterized in that, The method comprises: mixing the components of the light conversion adhesive film uniformly, then melt-extruding into a film, and cooling and setting to obtain the light conversion adhesive film.

9. A solar cell module characterized by comprising: The solar cell module comprises the light conversion adhesive film according to any one of claims 1-7. Preferably, the solar cell module comprises one or more of the following devices: a PN junction device containing III-V or II-IV group elements, a Cu-In-Ga-Se thin film device, an organic sensitizer device, an organic thin film device, a quantum dot thin film device, an amorphous silicon solar cell device, a microcrystalline silicon solar cell device, and a crystalline silicon solar device.

10. A method of enhancing the efficiency and stability of a solar cell, characterized by, The method comprises: introducing the light conversion adhesive film according to any one of claims 1-7 into a solar cell. Preferably, the solar cell comprises one or more of the following devices: a PN junction device containing III-V or II-IV group elements, a Cu-In-Ga-Se thin film device, an organic sensitizer device, an organic thin film device, a quantum dot thin film device, an amorphous silicon solar cell device, a microcrystalline silicon solar cell device, and a crystalline silicon solar device.

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