Light conversion adhesive film containing phenanthroimidazole-based light conversion material

Abstract

Disclosed in the present invention is a light conversion adhesive film usable for sunlight wavelength conversion. The light conversion adhesive film comprises a compound of formula I and a matrix. The definitions of various groups in formula I are as described herein, and the mass fraction of the compound of formula I in the light conversion adhesive film is 0.001%-3%. The light conversion adhesive film of the present invention can be used in a solar cell to enhance the efficiency and stability of the solar cell.

Description

Light conversion adhesive film containing phenanthroimidazole light conversion material TECHNICAL FIELD

[0001] The present application belongs to the field of solar cell materials, and relates to a light conversion adhesive film containing a phenanthroimidazole light conversion material for solar wavelength conversion. BACKGROUND

[0002] About 5% of the total energy of sunlight radiated to the ground is ultraviolet light with a wavelength shorter than 400 nm. Limited by the energy band structure of silicon itself, these ultraviolet rays cannot be effectively utilized by silicon-based solar cells, which limits the maximum efficiency of the cell. On the other hand, due to the high energy of ultraviolet photons, it may cause degradation of cell materials and deterioration of devices. Therefore, converting ultraviolet light into a wavelength range that can be utilized by silicon-based solar cells helps to improve both the efficiency and the life of the cell. This conversion can be achieved by introducing a light conversion material with an absorption spectrum in the ultraviolet region and an emission spectrum in the visible region into the cell.

[0003] Existing light conversion materials can be divided into three categories: quantum dot materials, rare earth materials, or organic fluorescent materials. For example, CN113035990A and CN117229728A disclose adhesive films using materials containing ZnS, CdS, etc. quantum dots. CN102268261A, CN116997633A, and CN116970346A disclose adhesive films using materials containing Eu, Ce, etc. rare earth metals. CN114335353A discloses an adhesive film using a fluorescent material containing pyrene, and CN117431022A and CN103339221A disclose adhesive films using triazole fluorescent materials.

[0004] However, each of the existing light conversion materials has some shortcomings. For example, quantum dot materials are expensive, have environmental concerns, and the technology for large-scale production of stable quantum dots is not yet perfect. Although rare earth materials have a large Stokes shift (red shift of the emission spectrum compared to the absorption spectrum), their luminescence peak is very narrow, and the PLQY (photoluminescence quantum efficiency) is usually low, which cannot efficiently convert ultraviolet light into visible light. The fluorescent materials used in the prior art have a high PLQY, but the Stokes shift is usually small, which results in their ability to convert ultraviolet light into only deep blue light (<450 nm), which cannot be efficiently utilized by silicon-based solar cells.

[0005] Therefore, there is a need in the art for a light conversion adhesive film containing organic fluorescent materials that can effectively improve the efficiency and life of solar cells. SUMMARY

[0006] The present application is directed to the above-mentioned problems existing in the prior art, and proposes a light conversion film containing phenanthroimidazole light conversion material, which can be used to improve the efficiency and stability of silicon-based solar cells. The present application uses phenanthroimidazole compounds with hybrid local excitation-charge transfer excitation (HLCT) characteristics as light conversion materials in the film. The charge transfer (CT) characteristics of HLCT materials have a large Stokes shift; at the same time, the molecular structure is relatively relaxed under the CT excited state, so the emission spectrum width of HLCT materials is significantly larger than that of traditional fluorescent materials and rare earth materials; and the local excitation (LE) characteristics guarantee the high PLQY of the material. Therefore, the phenanthroimidazole HLCT material can efficiently absorb ultraviolet light and convert it into a band with higher utilization efficiency for silicon-based solar cells, thereby improving the efficiency of the battery. At the same time, the phenanthroimidazole compound has strong absorption to ultraviolet rays of 300-400 nm, thereby improving the service life of the battery.

[0007] Specifically, one aspect of the present application provides a light conversion film for solar wavelength conversion, which comprises a compound of formula I and a matrix:

[0008] In formula I, i and j are each independently selected from an integer from 0 to 10, and Ar1 and Ar2 are each independently selected from C6-C10 arylene;

[0009] R1 and R2 satisfy characteristics (1), (2) or (3):

[0010] (1) R1 is an electron-donating group, and R2 is a hydrogen atom or an electron-withdrawing group;

[0011] (2) R1 is an electron-withdrawing group, and R2 is a hydrogen atom or an electron-donating group;

[0012] (3) R1 is a hydrogen atom, and R2 is an electron-donating group or an electron-withdrawing group;

[0013] The electron-donating group is selected from C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C2-C10 amido, C2-C10 ester, C3-C11 cycloalkyl, C6-C14 aryl, 9H-carbazol-9-yl, diphenylamine and 4-(diphenylamine)phenyl, and the C6-C14 aryl, 9H-carbazol-9-yl, diphenylamine and 4-(diphenylamine)phenyl as the electron-donating group can be substituted by one or more C1-C10 alkyl; the electron-withdrawing group is selected from cyano, cyanophenyl, trifluoromethyl and 1-phenyl-1H-benzo[d]-imidazol-2-yl;

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

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

[0016] In one or more embodiments, i and j are each independently selected from 0 and 1, and Ar1and Ar2are phenylene.

[0017] In one or more embodiments, the electron-donating group is selected from 9H-carbazol-9-yl and diphenylamine group.

[0018] In one or more embodiments, the electron-withdrawing group is selected from cyano and 1-phenyl-1H-benzo[d]-imidazol-2-yl.

[0019] In one or more embodiments, the compound of Formula I is selected from one or more of the compounds of Formula II and Formula III:

[0020] In Formula II, R3and R4satisfy characteristics (a), (b), or (c):

[0021] (a) R3is an electron-donating group, and R4is a hydrogen atom or an electron-withdrawing group;

[0022] (b) R3is an electron-withdrawing group, and R4is a hydrogen atom or an electron-donating group;

[0023] (c) R3is a hydrogen atom, and R4is an electron-donating group or an electron-withdrawing group;

[0024] In Formula III, R5and R6satisfy characteristics (A), (B), or (C):

[0025] (A) R5is an electron-donating group, and R6is a hydrogen atom or an electron-withdrawing group;

[0026] (B) R5is an electron-withdrawing group, and R6is a hydrogen atom or an electron-donating group;

[0027] (C) R5is a hydrogen atom, and R6is an electron-donating group or an electron-withdrawing group.

[0028] 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:

[0029] In one or more embodiments, 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-absorbing agent; 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-absorbing agent.

[0030] In one or more embodiments, the thickness of the light conversion adhesive film is 0.1-1.0 mm;

[0031] In one or more embodiments, the substrate can be one or more selected from the group consisting of polyethylene terephthalate, polyvinyl butyral, ethylene-vinyl acetate copolymer, polyethylene, ethylene polytetrafluoroethylene, polyimide, polycarbonate, polystyrene, polyurethane, polyacrylate, silicone sol, silicone gel, and polyolefin elastomer.

[0032] In one or more embodiments, the substrate has a refractive index of 1.4-1.7.

[0033] The present application also provides a method for preparing the light-conversion adhesive film as described in any of the embodiments herein, which comprises: uniformly mixing the components of the light-conversion adhesive film, melt-extruding into a film, and cooling and shaping to obtain the light-conversion adhesive film.

[0034] The present application also provides a solar cell module comprising the light-conversion adhesive film as described in any of the embodiments herein.

[0035] In one or more embodiments, 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.

[0036] The present application also provides a method for enhancing the efficiency and stability of a solar cell, which comprises: introducing the light-conversion adhesive film as described in any of the embodiments herein into the solar cell.

[0037] In one or more embodiments, 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. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is an absorption-emission spectrum diagram of compound 1, compound 2, compound 3, and compound 4 in the present application.

[0039] Figure 2 is an absorption-emission spectrum diagram of compound 1 and the triazole material used in comparative example 2 in the present application. DETAILED DESCRIPTION

[0040] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in this document. Unless otherwise specified, all technical and scientific words used in this document have the usual meaning understood by those skilled in the art of the present application, and in the event of a conflict, the definition in this specification shall prevail.

[0041] Theories and mechanisms described and disclosed herein, whether correct or not, should not be considered limiting of the scope of the present application, which is defined by the claims. The present application can be implemented in ways other than those specifically set forth herein without departing from the scope of the present application.

[0042] In this document, "comprise", "include", "contain", and similar words are used in a broad sense, and encompass "consist essentially of" and "consist of", for example, when this document discloses that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0043] In this document, all features defined by numerical ranges or percentage ranges, such as values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0044] In this document, unless otherwise specified, percentages refer to mass percentages, and ratios refer to mass ratios.

[0045] In this document, the sum of the percentages of the components of a composition is 100%.

[0046] In this document, when describing embodiments or examples, it should be understood that they are not intended to limit the present application to these embodiments or examples. On the contrary, all alternatives, modifications, and equivalents of the methods and materials described herein that are within the scope of the present application are to be included herein.

[0047] In this document, for the sake of brevity, not all possible combinations of the technical features in each embodiment or example are described. Therefore, as long as the combinations of the technical features do not contradict each other, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered to be within the scope of the present specification.

[0048] The ideal light conversion material in the light conversion adhesive film of the silicon-based solar cell should have strong absorption for wavelengths below 400 nm, large Stokes shift, wide emission spectrum, and high PLQY. The present application introduces a light conversion adhesive film containing phenanthroimidazole HLCT material into the solar cell to enhance the efficiency and stability of the cell. Such materials have high PLQY, large Stokes shift, and emission spectrum matching the absorption band of the silicon-based cell, which helps to improve the light conversion efficiency. In addition, the phenanthroimidazole and other building blocks have high light stability, so the corresponding materials themselves have high stability, and continuously absorb ultraviolet light below 300-400 nm, thus effectively avoiding damage to the cell by ultraviolet light.

[0049] The present application provides a light conversion adhesive film that can be used for solar wavelength conversion, which includes a phenanthroimidazole light conversion material. The mass fraction of the light conversion material in the light conversion adhesive film can be 0.001% to 3%. In some preferred embodiments, the mass fraction of the light conversion material in the light conversion adhesive film is 0.001% to 0.5%, more preferably 0.01% to 0.5%, further preferably 0.05% to 0.5%, for example 0.1%, 0.2%, 0.3%, 0.4%. Controlling the amount of light conversion material selected in the present application in the light conversion adhesive film within the preferred range is beneficial to the effect of the light conversion material on improving the efficiency and stability of the cell.

[0050] Compound of formula I

[0051] In the present application, the structure of the compound of formula I used as a light conversion material is as follows:

[0052] In formula I, i and j are each independently selected from an integer from 0 to 10, and Ar1 and Ar2 are each independently selected from a C6-C10 arylene group;

[0053] R1 and R2 satisfy characteristics (1), (2) or (3):

[0054] (1) R1 is an electron-donating group, and R2 is a hydrogen atom or an electron-withdrawing group;

[0055] (2) R1 is an electron-withdrawing group, and R2 is a hydrogen atom or an electron-donating group;

[0056] (3) R1 is a hydrogen atom, and R2 is an electron-donating group or an electron-withdrawing group.

[0057] In the present application, the compound of formula I is characterized in that R1 and R2 are not simultaneously a hydrogen atom, not simultaneously an electron-donating group, and not simultaneously an electron-withdrawing group. This is beneficial to the effect of the compound of formula I on improving the efficiency and stability of the cell.

[0058] In the present application, the electron-donating group can be selected from the group consisting of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C2-C10 amido, C2-C10 ester, C3-C11 cycloalkyl, C6-C14 aryl, 9H-carbazol-9-yl, diphenylamine, and 4-(diphenylamine)phenyl. The C6-C14 aryl, 9H-carbazol-9-yl, diphenylamine, and 4-(diphenylamine)phenyl as the electron-donating group can be substituted with one or more C1-C10 alkyl. In some embodiments, the electron-donating group is selected from the group consisting of 9H-carbazol-9-yl and diphenylamine.

[0059] In the present application, the electron-withdrawing group can be selected from the group consisting of cyano, cyanophenyl, trifluoromethyl, and 1-phenyl-1Hbenzo[d]-imidazol-2-yl. In some embodiments, the electron-withdrawing group is selected from the group consisting of cyano and 1-phenyl-1Hbenzo[d]-imidazol-2-yl.

[0060] In some embodiments, R1 is 9H-carbazol-9-yl or diphenylamine, and R2 is a hydrogen atom, cyano, or 1-phenyl-1Hbenzo[d]-imidazol-2-yl.

[0061] In some embodiments, R1 is cyano or 1-phenyl-1Hbenzo[d]-imidazol-2-yl, and R2 is a hydrogen atom, 9H-carbazol-9-yl, or diphenylamine.

[0062] In some embodiments, R1 is a hydrogen atom, and R2 is 9H-carbazol-9-yl, diphenylamine, cyano, or 1-phenyl-1Hbenzo[d]-imidazol-2-yl.

[0063] In some preferred embodiments, R1 is an electron-withdrawing group, and R2 is a hydrogen atom or an electron-donating group. More preferably, R1 is an electron-withdrawing group (e.g., cyano), and R2 is an electron-donating group (e.g., diphenylamine). This is advantageous for exerting the effect of the compound of formula I to improve the efficiency of a battery.

[0064] In some preferred embodiments, R1 is a hydrogen atom, and R2 is an electron-withdrawing group (e.g., 1-phenyl-1Hbenzo[d]-imidazol-2-yl) or an electron-donating group (e.g., 9H-carbazol-9-yl). This is advantageous for exerting the effect of the compound of formula I to improve the efficiency and stability of a battery.

[0065] In some embodiments, i and j are each independently selected from the group consisting of 0 and 1, for example, i is 0 and j is 1, or i is 1 and j is 0.

[0066] In some embodiments, Ar1 and Ar2 are phenylene, for example, 1,4-phenylene.

[0067] In the present application, a hydrocarbon group refers to a monovalent saturated or unsaturated group having a straight chain or branched chain structure composed of carbon atoms and hydrogen atoms.

[0068] In the present application, alkyl refers to a monovalent saturated group consisting of carbon and hydrogen atoms having a straight chain or branched chain structure. In the present application, the number of Cs preceding a group indicates the number of carbon elements contained in the group, for example, C1 alkyl indicates an alkyl group containing 1 carbon atom, i.e., methyl. Alkyl groups suitable for use in the present application can be C1-C10 alkyl, for example, C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl, C10 alkyl.

[0069] In the present application, alkenyl refers to a monovalent unsaturated group consisting of carbon and hydrogen atoms having a straight chain or branched chain structure and containing a carbon-carbon double bond. Alkenyl groups can contain one or more carbon-carbon double bonds. In some embodiments, alkenyl groups contain one carbon-carbon double bond. Alkenyl groups suitable for use in the present application can be C2-C10 alkenyl, for example, C2 alkenyl, C3 alkenyl, C4 alkenyl, C5 alkenyl, C6 alkenyl, C7 alkenyl, C8 alkenyl, C9 alkenyl, C10 alkenyl.

[0070] In the present application, alkynyl refers to a monovalent unsaturated group consisting of carbon and hydrogen atoms having a straight chain or branched chain structure and containing a carbon-carbon triple bond. Alkynyl groups can contain one or more carbon-carbon triple bonds. In some embodiments, alkynyl groups contain one carbon-carbon triple bond. Alkynyl groups suitable for use in the present application can be C2-C10 alkynyl, for example, C2 alkynyl, C3 alkynyl, C4 alkynyl, C5 alkynyl, C6 alkynyl, C7 alkynyl, C8 alkynyl, C9 alkynyl, C10 alkynyl.

[0071] In the present application, amido refers to a group formed by replacing one or more hydrocarbylene groups (e.g., alkylene) in a hydrocarbyl group (e.g., alkyl) with a -CONH- group. Amido groups can contain one or more -CONH- groups. In some embodiments, amido groups contain one -CONH- group. Amido groups suitable for use in the present application can be C2-C10 amido, for example, C2 amido, C3 amido, C4 amido, C5 amido, C6 amido, C7 amido, C8 amido, C9 amido, C10 amido.

[0072] In the present application, ester refers to a group formed by replacing one or more hydrocarbylene groups (e.g., alkylene) in a hydrocarbyl group (e.g., alkyl) with a -COO- group. Ester groups can contain one or more -COO- groups. In some embodiments, ester groups contain one -COO- group. Ester groups suitable for use in the present application can be C2-C10 ester, for example, C2 ester, C3 ester, C4 ester, C5 ester, C6 ester, C7 ester, C8 ester, C9 ester, C10 ester.

[0073] In the present application, cycloalkyl refers to a monovalent, saturated radical having a ring structure composed of carbon and hydrogen atoms, and the cycloalkyl group is attached to the rest of the molecule through a carbon atom on the ring. Cycloalkyl groups suitable for use in the present application can be C3-C11 cycloalkyl groups, such as C3 cycloalkyl, C4 cycloalkyl, C5 cycloalkyl, C6 cycloalkyl, C7 cycloalkyl, C8 cycloalkyl, C9 cycloalkyl, C10 cycloalkyl, C11 cycloalkyl.

[0074] In the present application, aryl refers to a monovalent radical composed of carbon and hydrogen atoms having an aromatic ring structure, and the aryl group is attached to the rest of the molecule through a carbon atom on the aromatic ring. Aryl groups suitable for use in the present application can be C6-C14 aryl groups, including but not limited to C6 aryl (e.g., phenyl), C10 aryl (e.g., naphthyl), C14 aryl (e.g., anthryl, phenanthryl).

[0075] In the present application, aryl refers to a monovalent radical composed of carbon and hydrogen atoms having an aromatic ring structure, and the aryl group is attached to the rest of the molecule through a carbon atom on the aromatic ring. Aryl groups suitable for use in the present application can be C6-C14 aryl groups, including but not limited to C6 aryl (e.g., phenyl), C10 aryl (e.g., naphthyl), C14 aryl (e.g., anthryl, phenanthryl).

[0076] Compounds of Formula II, Compounds of Formula III

[0077] In some embodiments, the compounds of Formula I used in the present application are selected from one or more of the following:

[0078] In Formula II, R3 and R4 satisfy characteristics (a), (b), or (c):

[0079] (a) R3 is an electron-donating group, and R4 is a hydrogen atom or an electron-withdrawing group;

[0080] (b) R3 is an electron-withdrawing group, and R4 is a hydrogen atom or an electron-donating group;

[0081] (c) R3 is a hydrogen atom, and R4 is an electron-donating group or an electron-withdrawing group;

[0082] In Formula III, R5 and R6 satisfy characteristics (A), (B), or (C):

[0083] (A) R5 is an electron-donating group, and R6 is a hydrogen atom or an electron-withdrawing group;

[0084] (B) R5 is an electron-withdrawing group, and R6 is a hydrogen atom or an electron-donating group;

[0085] (C) R5 is a hydrogen atom, and R6 is an electron-donating group or an electron-withdrawing group;

[0086] wherein the electron-donating group and the electron-withdrawing group are as previously described.

[0087] In some preferred embodiments, in Formula II, R3 is hydrogen, and R4 is an electron-withdrawing group (e.g., 1-phenyl-1H-benzo[d]-imidazol-2-yl) or an electron-donating group (e.g., 9H-carbazol-9-yl). This is advantageous for exerting the effect of the compound of Formula II to enhance the efficiency and stability of a battery.

[0088] In some embodiments, in Formula III, R5 is an electron-donating group, and R6 is an electron-withdrawing group, or R5 is an electron-withdrawing group, and R6 is an electron-donating group. More preferably, R5 is an electron-withdrawing group (e.g., cyano), and R6 is an electron-donating group (e.g., diphenylamine). This is advantageous for exerting the effect of the compound of Formula III to enhance the efficiency of a battery.

[0089] Compound 1, Compound 2, Compound 3, and Compound 4

[0090] In some preferred embodiments, the light conversion adhesive film of the present application includes, as the light conversion material, one or more of Compound 1, Compound 2, Compound 3, and Compound 4 selected from the group consisting of:

[0091] This is advantageous for exerting the effect of the light conversion adhesive film to enhance the efficiency and stability of a battery.

[0092] In some preferred embodiments, the light conversion adhesive film of the present application includes, as the light conversion material, one or more of Compound 1, Compound 2, and Compound 3, more preferably one or both of Compound 1 and Compound 2, and more preferably Compound 1. This is advantageous for exerting the effect of the light conversion adhesive film to enhance the efficiency and stability of a battery.

[0093] In the present application, the hydrogen atom in the compound of Formula I, the compound of Formula II, the compound of Formula III, and Compound 1 to Compound 4 as the light conversion material can be protium or deuterium.

[0094] Source of the compound

[0095] In the present application, the compound of formula I, compound 2 to compound 10 as light conversion material can be prepared by known methods, for example, the methods in the following references can be referred to: Tian, X.; et al. A Novel Deep Blue LE-Dominated HLCT Excited State Design Strategy and Material for OLED. https: / / doi.org / 10.3390 / molecules26154560; Tan, Y.; et al. A novel bipolar D-H-A type phenanthroimidazole / carbazole hybrid material for high efficiency nondoped deep-blue organic light-emitting diodes with NTSC CIEy and low efficiency roll-off. https: / / doi.org / 10.1039 / c7tc04089j; Chen, W.-C.; et al. Highly efficient deep-blue electroluminescence from a charge-transfer emitter with stable donor skeleton. https: / / doi.org / 10.1021 / ascami.6b14638.

[0096] The compound of formula I, compound of formula II, compound of formula III, compound 1 to compound 4 can also be purchased by commercially available routes.

[0097] Matrix

[0098] In the present application, the matrix is preferably transparent to visible light. The transmittance of the matrix to visible light is ≥ 0.85, at which time the matrix is considered to be transparent to visible light.

[0099] The material of the matrix can be one or more selected from polyethylene terephthalate, polyvinyl butyral, ethylene-vinyl acetate copolymer (EVA for short), polyethylene, ethylene polytetrafluoroethylene, polyimide, polycarbonate, polystyrene, polyurethane, polyacrylate, silicone sol, silicone gel and polyolefin elastomer. In some embodiments, the material of the matrix is EVA.

[0100] The refractive index of the matrix is preferably 1.4-1.7, for example 1.5, 1.6. This is conducive to improving the effect of light conversion adhesive film on enhancing the efficiency and stability of the battery.

[0101] The matrix can be present in the light conversion adhesive film in a mass fraction of 80% to 99.8%, for example 90%, 95%, 96%, 97%, 98%, 98.5%, 99%, 99.5%.

[0102] Auxiliary agent

[0103] Further, the light conversion adhesive film of the present application optionally or preferably can include an auxiliary agent. Suitable auxiliary agents for use in the present application include, but are not limited to, those selected from the group consisting of cross-linking agents, co-cross-linking agents, plasticizers, antioxidants, and water-absorbing agents, etc. In some embodiments, the light conversion adhesive film of the present application consists of a light conversion material, a matrix, and an optional auxiliary agent.

[0104] In some preferred embodiments, the auxiliary agent includes a cross-linking agent, for example, t-butyl peroxy isopropyl carbonate. The cross-linking agent is preferably present in the light conversion adhesive film in a mass fraction of 0.1% to 1%, for example 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. This is advantageous for improving the effect of the light conversion adhesive film in enhancing the efficiency and stability of the battery.

[0105] In some preferred embodiments, the auxiliary agent includes a co-cross-linking agent, for example, trimethylolpropane tetraacrylate. The co-cross-linking agent is preferably present in the light conversion adhesive film in a mass fraction of 0.1% to 1%, for example 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. This is advantageous for improving the effect of the light conversion adhesive film in enhancing the efficiency and stability of the battery.

[0106] In some preferred embodiments, the matrix is EVA, the cross-linking agent is t-butyl peroxy isopropyl carbonate, and the co-cross-linking agent is trimethylolpropane tetraacrylate. This is advantageous for improving the effect of the light conversion adhesive film in enhancing the efficiency and stability of the battery.

[0107] In the present application, the plasticizer, antioxidant, and water-absorbing agent are optionally or preferably added to the light conversion adhesive film, and the amount thereof can be conventional.

[0108] Method for preparing the light conversion adhesive film

[0109] The light conversion adhesive film of the present application can be prepared by uniformly mixing the components of the light conversion adhesive film, melt-extruding the mixture into a film, and then cooling and setting the film.

[0110] The temperature for melt-extrusion can be 80 to 120°C, for example 90°C, 100°C, 110°C. The cooling and setting can be performed at room temperature (for example 25°C).

[0111] Solar cell module

[0112] In a high temperature and negative pressure environment, the light conversion adhesive film of the present application is laminated and packaged on a back plate (such as a glass plate) as a front adhesive film together with a solar cell (such as a single crystal silicon solar cell) and a back adhesive film (the material can be pure EVA), after cooling the assembly, the light conversion adhesive film becomes the front surface of the assembly, and the back adhesive film becomes the back surface of the assembly, to obtain a solar cell assembly.

[0113] The present application has the following beneficial technical effects:

[0114] In the present application, the light conversion material in the adhesive film is a phenanthroimidazole HLCT material with a more matched emission spectrum and absorption wavelength band of silicon-based solar cells, which improves the quantum efficiency of silicon-based cells; such material also effectively absorbs ultraviolet light below 400 nm, especially the absorption of short-wave ultraviolet light around 300 nm is stronger than that of traditional triazole light conversion materials, which is beneficial to improve the service life of the device.

[0115] The present application will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present application. The methods, reagents and materials used in the examples and comparative examples are conventional in the art unless otherwise specified. The raw material compounds in the examples and comparative examples can be purchased through commercial channels.

[0116] Example 1

[0117] This example provides an adhesive film using compound 1 as a light conversion material and a corresponding device. Compound 1 is purchased from Zhengzhou Alpha Chemical Co., Ltd.

[0118] This example manufactures a light conversion adhesive film by the following method:

[0119] According to the total mass of the light conversion adhesive film, 98.8%wt of EVA, 0.5%wt of tert-butyl peroxy isopropyl carbonate as a crosslinking agent, 0.5%wt of trimethylolpropane tetraacrylate as a co-crosslinking agent and 0.2%wt of compound 1 are uniformly mixed, then melted and extruded into a film at 100℃, and the extruded adhesive film is cooled and shaped at 25℃ to obtain a light conversion adhesive film with a thickness of 0.3mm.

[0120] This example manufactures a solar cell assembly by the following method:

[0121] The packaging glass, the above light conversion adhesive film, the 182mm HJT solar cell of Huasheng New Energy Technology Co., Ltd., pure EVA and glass back plate are laminated and packaged at 130℃ in a negative pressure environment, and the light conversion adhesive film is used as the front surface of the cell to obtain the solar cell assembly of Example 1.

[0122] Example 2

[0123] The light conversion adhesive film and solar module of Example 2 were prepared in a similar manner as Example 1, except that Compound 1 was replaced by an equivalent mass fraction of Compound 2. Compound 2 was used in the light conversion adhesive film. Compound 2 was purchased from Zhengzhou Alpha Chemical Co., Ltd.

[0124] Example 3

[0125] The light conversion adhesive film and solar module of Example 3 were prepared in a similar manner as Example 1, except that Compound 1 was replaced by an equivalent mass fraction of Compound 3. Compound 3 was used in the light conversion adhesive film. Compound 3 was purchased from Zhengzhou Alpha Chemical Co., Ltd.

[0126] Example 4

[0127] The light conversion adhesive film and solar module of Example 4 were prepared in a similar manner as Example 1, except that Compound 1 was replaced by an equivalent mass fraction of Compound 4. Compound 4 was used in the light conversion adhesive film. Compound 4 was purchased from Zhengzhou Alpha Chemical Co., Ltd.

[0128] Comparative Example 1

[0129] The adhesive film and solar module of Comparative Example 1 were prepared in a similar manner as Example 1, except that no light conversion material was added, and the film components were 99.0%wt EVA, 0.5%wt tert-butyl peroxy isopropyl carbonate, and 0.5%wt trimethylolpropane tetraacrylate.

[0130] Comparative Example 2

[0131] The light conversion adhesive film and solar module of Comparative Example 2 were prepared in a similar manner as Example 1, except that Compound 1 was replaced by an equivalent mass fraction of a triazole material with the molecular structure: The fluorescent material was purchased from Shanghai Bide Pharmaceutical Technology Co., Ltd.

[0132] Test Example

[0133] I. Photophysical property test: The light conversion materials in each example and comparative example were subjected to photophysical test using an ultraviolet-visible spectrometer, a fluorescence spectrometer, and an integrating sphere. The absorption spectrum of the light conversion material was determined by an Agilent Cary 3500 ultraviolet-visible spectrometer, and the emission spectrum and PLQY were determined by a Horiba spectrometer FL-3 and its integrating sphere accessory. The results are shown in FIG. 1, FIG. 2, and Table 1.

[0134] From Table 1, Figure 1 and Figure 2, it can be found that the Stokes shift and the half-peak width of the HLCT material based on phenanthroimidazole are superior to those of the triazole material, and the PLQY (0.8-0.9) is also comparable to that of the triazole material. It is particularly noteworthy that the absorbance of the phenanthroimidazole light conversion material at about 300 nm is significantly stronger than that of the triazole material, which is caused by the side band of the strong absorption peak of the group in the short wave region. Since the shorter the wavelength, the greater the damage to the material, the strong absorption of the phenanthroimidazole light conversion material at this point is more conducive to the protection of the battery material. In addition, from Examples 1 and 2, it can be found that the connection of phenanthroimidazole with donor or acceptor groups can achieve better light-emitting efficiency and Stokes shift, which can be attributed to the good bipolar characteristics of phenanthroimidazole. In contrast, Examples 3 and 4 can be found that when phenanthroimidazole is connected with both electron donor (aniline) and electron acceptor (cyanobenzene), the isomer 3 with the N end connected to the electron acceptor emits a redder light. This can be due to the lone pair of electrons of N can produce a stronger CT characteristic with the acceptor, which can be further verified by the relatively strong absorption side band of compound 3 at 400-420 nm.

[0135] Table 1: Comparison of the photophysical properties of the light conversion materials in each example and comparative example

[0136] II. Device performance test: In order to evaluate the performance of the solar cell assembly to illustrate the effect of the present application, the power test and UV aging test of the solar cell assembly in each example and comparative example were carried out. The power test used ANPA1000 tester of Shandong Aino Instrument Co., Ltd., and the UV aging used 142W multiple UV aging box at 70°C for 120kWh / m 2 UV aging, the results are shown in Table 2.

[0137] Table 2 shows that the phenanthroimidazole light conversion material can effectively improve the device efficiency and inhibit the degradation of the device, especially the inhibition of the device degradation is significantly superior to that of the triazole material. As mentioned earlier, this can be attributed to the HLCT characteristics of the phenanthroimidazole light conversion material, which makes its spectral width and Stokes shift relatively larger, and can more effectively absorb short wave ultraviolet light.

[0138] Table 2: Comparison of the efficiency and decay rate of the device in different examples and comparative examples

Claims

1. A light-converting adhesive film that can be used for wavelength conversion of sunlight, characterized in that, The light-converting film comprises a compound of formula I and a matrix: In Equation I, i and j are each independently selected from integers from 0 to 10, and Ar1 and Ar2 are each independently selected from C6-C10 arylene groups; R1 and R2 satisfy features (1), (2) or (3): (1) R1 is an electron-donating group, and R2 is a hydrogen atom or an electron-withdrawing group; (2) R1 is an electron-withdrawing group, and R2 is a hydrogen atom or an electron-donating group; (3) R1 is a hydrogen atom, and R2 is an electron-donating or electron-withdrawing group; The electron-donating group is selected from C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C2-C10 amide, C2-C10 ester, C3-C11 cycloalkyl, C6-C14 aryl, 9H-carbazole-9-yl, diphenylamino, and 4-(diphenylamino)phenyl-yl. The C6-C14 aryl, 9H-carbazole-9-yl, diphenylamino, and 4-(diphenylamino)phenyl-yl electron-donating groups may be substituted by one or more C1-C10 alkyl groups. The electron-withdrawing group is selected from cyano, cyanophenyl, trifluoromethyl, and 1-phenyl-1H benzo[d]-imidazol-2-yl. The mass fraction of the compound of formula I in the optical transfer film is 0.001% to 3%.

2. The light-converting adhesive film as described in claim 1, characterized in that, The mass fraction of the compound of formula I in the optical transfer film is 0.001% to 0.5%.

3. The light-converting adhesive film as described in claim 1, characterized in that, The compound of formula I has one or more of the following characteristics: i and j are each independently selected from 0 and 1, and Ar1 and Ar2 are phenylene; The electron-donating group is selected from 9H-carbazole-9-yl and diphenylamino; The electron-withdrawing group is selected from cyano and 1-phenyl-1H benzo[d]-imidazol-2-yl.

4. The light-converting adhesive film as described in claim 1, characterized in that, The compound of formula I is selected from one or more of the compounds of formula II and formula III: In Equation II, R3 and R4 satisfy characteristics (a), (b), or (c): (a) R3 is an electron-donating group, and R4 is a hydrogen atom or an electron-withdrawing group; (b) R3 is an electron-withdrawing group, and R4 is a hydrogen atom or an electron-donating group; (c) R3 is a hydrogen atom, and R4 is an electron-donating or electron-withdrawing group; In Equation III, R5 and R6 satisfy characteristics (A), (B), or (C): (A) R5 is an electron-donating group, and R6 is a hydrogen atom or an electron-withdrawing group; (B) R5 is an electron-withdrawing group, and R6 is a hydrogen atom or an electron-donating group; (C) R5 is a hydrogen atom, and R6 is an electron-donating or electron-withdrawing group.

5. The light-converting adhesive film as described in claim 1, characterized in that, The compound of formula I is selected from one or more of the following compounds: compound 1, compound 2, compound 3 and compound 4:

6. The light-converting adhesive film as described in claim 1, characterized in that, 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 also includes one or more additives selected from plasticizers, antioxidants, and water-absorbing agents.

7. The light-converting adhesive film as described in claim 1, characterized in that, The light-converting adhesive film has one or more of the following characteristics: The thickness of the light-converting adhesive film is 0.1-1.0 mm; 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. The refractive index of the matrix is ​​1.4-1.

7.

8. A method for preparing the light-transfer adhesive film according to any one of claims 1-7, characterized in that, The method includes: mixing the components of the light-converting adhesive film evenly, melting and extruding them into a film, and cooling and shaping it to obtain the light-converting adhesive film.

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

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

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