Light conversion film based on benzotriazole compound, preparation method therefor, and use thereof

Abstract

Provided in the present invention are a light conversion film based on a benzotriazole compound, a preparation method therefor, and a use thereof. Specifically provided in the present invention is a light conversion agent having a structure represented in the following formula I, wherein the definitions of R1-R5, Ar1, and Ar2 are as described in any embodiment herein. Also provided in the present invention are a light conversion film comprising the light conversion agent, and a preparation method therefor. Compared with the existing light conversion films, in one or more embodiments of the present invention, the introduction of an unsaturated bond in the light conversion film can prevent light conversion agent migration. The absorption spectrum and the emission spectrum of the light conversion film in the present invention can be effectively regulated. In one or more embodiments of the present invention, the light conversion agent is a novel light conversion molecule designed on the basis of benzotriazole, and the molecular structure thereof is stable.

Description

Benzotriazole-based light-conversion films, their preparation methods, and applications Technical Field

[0001] This invention belongs to the field of solar cell materials, specifically relating to a light-converting film based on benzotriazole compounds, its preparation method, and its application. Background Technology

[0002] Heterojunction silicon (HJT) cells have garnered significant attention in the photovoltaic industry in recent years due to their high efficiency and excellent temperature coefficient. However, the sensitivity of HJT cells to ultraviolet (UV) radiation is a major concern. High-energy UV photons easily cause photodegradation on the surface of HJT cells, leading to a gradual decline in cell performance. To address this issue, light-converting films are widely used in HJT cells. These films absorb high-energy UV photons and convert them into low-energy visible light photons, thus mitigating the direct impact of UV radiation on the cell. This conversion process not only protects the cell surface materials but also effectively improves the cell's photoelectric conversion efficiency, as the converted photons are more readily absorbed and utilized by the cell. To save costs, the commonly used encapsulation scheme for photovoltaic HJT cells currently involves using a light-converting film on the front and a high-transparency film on the back. The dispersion of the light-converting agent in the film is a physical dispersion. Under heating conditions, the concentration difference between the front and back films causes the agent to migrate from the front of the cell to the back, resulting in a decrease in the concentration of the agent on the front and failing to effectively protect the cell.

[0003] Patent application CN117700442A (applicant is Changzhou Baijia Niandai Thin Film Technology Co., Ltd.) discloses a light conversion agent prepared by the following method. This patent application introduces trimethyl(oxy)silane at the N position of benzotriazole, but the reaction of siloxane requires the formation of a double bond, resulting in low reaction efficiency.

[0004] Patent application CN117801412A (applicant is Ningbo Jizhi Technology Co., Ltd.) discloses a light-converting agent prepared by the following method. This patent application utilizes other light-converting conjugate structures to achieve the light-converting function, but the conjugate structure is unstable.

[0005] The light-converting agents currently used are physically dispersed in the film. In this case, the light-converting agents are easily subjected to thermal motion when heated, which causes the concentration of the light-converting agents in the film to migrate to the film components that do not contain the light-converting agents, thus reducing the content of the light-converting agents in the film. Summary of the Invention

[0006] The purpose of this invention is to provide a light-converting film based on benzotriazole compounds, its preparation method, and its application.

[0007] In a first aspect, the present invention provides a light-converting agent having the structure shown in Formula I.

[0008] In formula I,

[0009] R1 and R2 are each independently selected from C1-C20 alkyl groups optionally substituted with halogens, C1-C20 alkoxy groups optionally substituted with halogens, halogens, hydroxyl groups, cyano groups, and nitro groups.

[0010] Ar1 and Ar2 are each independently selected from C6-C14 arylene and 5-14 heteroarylene, wherein the heteroarylene contains 1, 2, 3 or 4 heteroatoms selected from N, O, S and Se;

[0011] R3 and R4 are each independently selected from C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C10 cycloalkyl, C1-C20 alkoxy, hydroxyl and -NR′R″, R′ and R″ are each independently selected from H, C1-C10 alkyl and C6-C14 aryl, and R3 and R4 are each independently substituted by 0, 1, 2, 3 or 4 substituents selected from C1-C20 alkyl and C1-C20 alkoxy.

[0012] R5 is selected from C2-C20 alkenyl groups optionally substituted with 1, 2, or 3 -OC(=O)-R6, C2-C20 alkynyl groups optionally substituted with 1, 2, or 3 -OC(=O)-R6, and C1-C20 alkyl groups substituted with 1, 2, or 3 substituents selected from C2-C20 alkenyl groups, C2-C20 alkynyl groups, and -OC(=O)-R6, and R6 is a C1-C20 hydrocarbon group containing at least one -C=C- structure.

[0013] In a second aspect, the present invention provides a light-converting film comprising an adhesive film and a light-converting agent as described in the first aspect of the present invention; wherein the mass ratio of the light-converting agent to the adhesive film is (1-20):1000.

[0014] A third aspect of the present invention provides a method for preparing the light-converting film described in the second aspect of the present invention, the method comprising mixing the mixture of the film particles and the light-converting agent.

[0015] In a fourth aspect, the present invention provides a solar cell comprising the light-converting film described in the second aspect of the present invention.

[0016] In one or more embodiments, the solar cell is an HJT cell. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the transconverter migration experiment.

[0018] Figure 2 shows the form in which the light conversion agent molecules exist in the film before lamination.

[0019] Figure 3 shows the form in which the light conversion agent molecules exist in the film after lamination. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0025] 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 defined by the claims.

[0026] 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.

[0027] As used herein, "hydrocarbon group" refers to a group containing only carbon and hydrogen atoms, generally referring to the group remaining after a corresponding hydrocarbon loses a hydrogen atom (H). In this document, hydrocarbon groups include alkyl, alkenyl, and alkynyl groups. Alkyl, alkenyl, and alkynyl groups are as described in any embodiment herein.

[0028] As used herein, "alkyl" refers to a straight-chain or branched monovalent saturated hydrocarbon group having a specified number of carbon atoms. Specifically, alkyl groups are those having 1 to 20 carbon atoms ("C1-C20 alkyl"), typically containing 1 to 16 carbon atoms (C1-C16 alkyl), preferably containing 1 to 10 carbon atoms (C1-C10 alkyl), and more preferably containing 1 to 6 carbon atoms (C1-C6 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, etc. In some embodiments, the alkyl group suitable for use in this invention can be C1-C20 alkyl, such as C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, C9 alkyl, C10 alkyl, C11 alkyl, C12 alkyl, C13 alkyl, C14 alkyl, C15 alkyl, C16 alkyl, C17 alkyl, C18 alkyl, C19 alkyl, and C20 alkyl.

[0029] As used herein, as part of a group or other group, the term "alkenyl" refers to a straight-chain or branched hydrocarbon chain group consisting only of carbon and hydrogen atoms and containing at least one double bond, which is linked by a single bond to the rest of the molecule. In some embodiments, the alkenyl group contains 2 to 20 carbon atoms ("C2-C20 alkenyl"), preferably 2 to 10 carbon atoms ("C2-C10 alkenyl"), and more preferably 2 to 6 carbon atoms ("C2-C6 alkenyl"). Non-limiting examples of alkenyl groups include, but are not limited to, vinyl, propenyl, allyl, butenyl, but-1-enyl, but-2-enyl, pentenyl, pent-1-enyl, pentadienyl, pent-1,4-dienyl, etc. Unless otherwise specifically specified in this specification, the alkenyl group may optionally be substituted. In some embodiments, the alkenyl groups suitable for use in this invention can be C2-C10 alkenyl groups, such as C2 alkenyl, C3 alkenyl, C4 alkenyl, C5 alkenyl, C6 alkenyl, C7 alkenyl, C8 alkenyl, C9 alkenyl, and C10 alkenyl groups.

[0030] As used herein, as part of a group or other group, the term "alkynyl" refers to a straight-chain or branched hydrocarbon chain group consisting only of carbon and hydrogen atoms, having one or more carbon-carbon triple bonds (-C≡C-), which are connected by single bonds to the rest of the molecule. In some embodiments, the alkynyl group contains 2 to 20 carbon atoms ("C2-C20 alkynyl"), preferably 2 to 10 carbon atoms ("C2-C10 alkynyl"), and more preferably 2 to 6 carbon atoms ("C2-C6 alkynyl"). Non-limiting examples of alkynyl groups include ethynyl, 1-propynyl, 1-methyl-2-propynyl, 2-propynyl, 1-butynyl, and 2-butynyl. Unless otherwise specifically specified in this specification, the alkynyl group may optionally be substituted. In some embodiments, the alkynyl group suitable for use in this invention can be a C2-C10 alkynyl group, such as C2 alkynyl, C3 alkynyl, C4 alkynyl, C5 alkynyl, C6 alkynyl, C7 alkynyl, C8 alkynyl, C9 alkynyl, or C10 alkynyl.

[0031] As used herein, "cycloalkyl" or "carbocyclic" refers to a saturated cyclic hydrocarbon having 3 to 10 ring carbon atoms, comprising one ring such as cyclohexyl or multiple rings such as adamantyl. Cycloalkyl groups comprising more than one ring can be fused, spirocyclic, bridged, or combinations thereof. Preferred cycloalkyl groups are saturated cyclic hydrocarbons having 3 to 8 ring carbon atoms ("C3-C8 cycloalkyl"). In some embodiments, the cycloalkyl group has 4 to 6 ring carbon atoms ("C4-C6 cycloalkyl"). Examples of cycloalkyl groups include adamantyl, decahydronaphthyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

[0032] As used herein, "alkoxy" refers to alkyl-O-, and preferred alkoxy groups are C1-C20 alkoxy groups, such as C1-C16 alkoxy, C1-C10 alkoxy, C1-C8 alkoxy, C1-C6 alkoxy, and C1-C4 alkoxy groups, including, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, 1,2-dimethylbutoxy, etc.

[0033] As used herein, "halogenated" or "halogen" refers to elements in Group 17 with atomic numbers 9 to 85. "Halogen" or "halogen atom" refers to F, Cl, Br, and I. "Halogenated" means substituted by an atom selected from F, Cl, Br, and I.

[0034] As used in this article, "nitro" refers to -NO2.

[0035] As used in this article, "hydroxyl group" refers to the -OH group.

[0036] As used in this article, "cyano" refers to -CN.

[0037] As used herein, "aryl" refers to an unsaturated aromatic carbocyclic monovalent group having a single ring (e.g., phenyl) or multiple fused rings (e.g., naphthyl or anthracene), wherein the fused rings may or may not be aromatic. In one variation, the aryl group comprises 6 to 14 ring carbon atoms ("C6-C14 aryl"), preferably C6-C10 aryl. Aryl groups having more than one ring, wherein at least one ring is non-aromatic, may be attached to the parent structure at an aromatic ring position or at a non-aromatic ring position. Examples of aryl groups include phenyl, naphthyl, phenanthryl, anthracene, indyl, azulel, biphenyl, biphenylene, and geniyl. As used herein, "arylene" refers to an unsaturated aromatic carbocyclic divalent group having a single ring (e.g., phenyl) or multiple fused rings (e.g., naphthyl or anthracene), wherein the fused rings may or may not be aromatic. A arylene is a divalent group of an aryl group. In one variant, the arylene comprises 6 to 14 cyclic carbon atoms (“C6-C14 arylene”), preferably C6-C10 arylene.

[0038] As used herein, "heteroaryl" refers to a monovalent group containing 5-14, preferably 5-10, ring atoms, and having 6, 10, or 14 π electrons shared in the ring system. As used herein, "hybridaryl" refers to a divalent group containing 5-14, preferably 5-10, ring atoms, and having 6, 10, or 14 π electrons shared in the ring system. The ring atoms contained in heteroaryl or hybridaryl groups are carbon atoms and 1, 2, 3, or 4 heteroatoms selected from N, O, S, and Se. In this invention, preferred heteroaryl groups are those containing N, S, or O atoms, and more preferably, those containing N or S atoms. Examples of heteroaryl groups include: triazolyl, thiophenyl, furanyl, pyranyl, pyrroleyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indazinyl, isoindolyl, indolyl, benzimidazolyl, dibenzothiophenyl, dibenzopyridyl, and pyrazolopyrimidinyl, etc.

[0039] This invention provides a novel light-converting agent whose molecule incorporates alkyl, alkoxy, halogen, trifluoromethyl, cyano, or nitro groups at the R1 and R2 positions of benzotriazole to regulate spectral absorption. Simultaneously, an unsaturated bond (e.g., a methacrylate or acrylate bond) is introduced on the nitrogen atom (R5 position) of benzotriazole. This allows the light-converting agent to crosslink with the unsaturated bonds in the film after blending, restricting the movement of the light-converting agent after lamination and preventing its migration. This novel light-converting molecule, based on benzotriazole, adjusts spectral absorption and emission while preventing agent migration, thereby avoiding power degradation and reduced reliability in actual components.

[0040] This invention provides a light-converting agent having the structure shown in Formula I.

[0041] In formula I,

[0042] R1 and R2 are each independently selected from C1-C20 alkyl groups optionally substituted with halogens, C1-C20 alkoxy groups optionally substituted with halogens, halogens, hydroxyl groups, cyano groups, and nitro groups.

[0043] Ar1 and Ar2 are each independently selected from C6-C14 arylene and 5-14 heteroarylene, wherein the heteroarylene contains 1, 2, 3 or 4 heteroatoms selected from N, O, S and Se. One bond of the heteroarylene Ar1 is connected to R3 and the other bond is connected to the benzene ring in Formula I. One bond of the heteroarylene Ar2 is connected to R4 and the other bond is connected to the benzene ring in Formula I.

[0044] R3 and R4 are each independently selected from C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C10 cycloalkyl, C1-C20 alkoxy, hydroxyl and -NR′R″, R′ and R″ are each independently selected from H, C1-C10 alkyl and C6-C14 aryl, and R3 and R4 are each independently substituted by 0, 1, 2, 3 or 4 substituents selected from C1-C20 alkyl and C1-C20 alkoxy.

[0045] R5 is selected from C2-C20 alkenyl groups optionally substituted with 1, 2, or 3 -OC(=O)-R6, C2-C20 alkynyl groups optionally substituted with 1, 2, or 3 -OC(=O)-R6, and C1-C20 alkyl groups substituted with 1, 2, or 3 substituents selected from C2-C20 alkenyl groups, C2-C20 alkynyl groups, and -OC(=O)-R6, and R6 is a C1-C20 hydrocarbon group containing at least one -C=C- structure.

[0046] In some embodiments, R3 and R4 are each independently selected from C1-C16 alkyl, C1-C16 alkoxy, hydroxyl, and -NR′R″, R′ and R″ are each independently selected from H, C1-C10 alkyl, and C6-C10 aryl, and R3 and R4 are each independently substituted by 0, 1, or 2 substituents selected from C1-C16 alkyl and C1-C16 alkoxy. Preferably, R3 and R4 are each independently selected from C1-C10 alkyl, C1-C10 alkoxy, and -NR′R″, and R′ and R″ are each independently selected from C1-C10 alkyl and C6-C10 aryl. In some embodiments, -NR′R″ is diphenylamino. In some embodiments, R3 and R4 are each independently selected from the following structures:

[0047] Where * represents the connection site between R3 and Ar1 or the connection site between R4 and Ar2.

[0048] In this document, R3 and R4 may be the same or different. In some implementations, R3 and R4 are the same.

[0049] In some embodiments, Ar1 and Ar2 are each independently selected from C6-C10 arylene and 5-14 heteroarylene groups, wherein the heteroarylene contains one or two heteroatoms selected from N, O, and S. In some embodiments, Ar1 and Ar2 are each independently selected from the following structures:

[0050] In the above structure, the aromatic ring has two connection sites that connect to other parts of the compound of formula I, and R is a C1-C10 alkyl group. Preferably, Ar1 and Ar2 are each independently selected from the following structures:

[0051] In the above structure, * represents the connection site between Ar1 or Ar2 and the benzene ring in the benzotriazole structure. Ar1 is connected to R3 at other positions indicated by *, and Ar2 is connected to R4 at other positions indicated by *. R is a C1-C10 alkyl group.

[0052] In some implementations, R3-Ar1- or R4-Ar2- may be The aromatic ring has two connection sites that attach to the other parts of the compound of formula I. In some embodiments, R3-Ar1- or R4-Ar2- may be... * represents the connection site between R3-Ar1- or R4-Ar2- and the benzene ring in the benzotriazole structure.

[0053] In this document, Ar1 and Ar2 may be the same or different. In some implementations, Ar1 and Ar2 are the same.

[0054] In some embodiments, R5 is selected from C2-C20 alkenyl, C2-C20 alkynyl, and C1-C20 alkyl groups substituted with 1, 2, or 3 substituents selected from C2-C20 alkenyl, C2-C20 alkynyl, and -OC(=O)-R6, and R6 is C2-C20 alkenyl. Preferably, R5 is selected from C1-C15 alkyl groups substituted with -OC(=O)-R6, and R6 is C2-C10 alkenyl. In some embodiments, R5 is selected from C1-C10 alkyl groups substituted with -OC(=O)-R6, and R6 is C2-C6 alkenyl. Preferably, R5 is selected from the following structures:

[0055] Where n is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; * represents the connection site between R5 and the benzotriazole structure in compound I.

[0056] In some embodiments, the light-converting agent is selected from the following compounds:

[0057] The light-converting agent of this invention, through modification with R1 and R2 groups, can modulate the absorption and emission spectra of the light-converting film. Therefore, this invention also provides a light-converting film containing the light-converting agent of this invention.

[0058] The light-converting film of the present invention includes the light-converting agent and the film of the present invention, and optionally may also include additives.

[0059] In the light-converting film of the present invention, the preferred mass ratio of the light-converting agent to the film is (1-20):1000, for example, 1.5:1000, 2:1000, 3:1000, 5:1000, 10:1000, 15:1000, etc. In this invention, controlling the mass ratio of the light-converting agent to the film to ≥1:1000 allows the light-converting film to exhibit ideal ultraviolet light absorption and light conversion effects. This invention has found that if the mass ratio of the light-converting agent to the matrix exceeds 20:1000, the light-converting agents will aggregate, causing fluorescence quenching and reducing quantum efficiency. Therefore, it is preferable to control the mass ratio of the light-converting agent to the matrix between 1:1000 and 20:1000.

[0060] In the light-converting film of the present invention, the adhesive film may be one or more of POE (an elastomer obtained by random copolymerization of ethylene and α-olefin), EVA (ethylene-vinyl acetate copolymer), EPE (a three-layer structure material of EVA+POE+EVA), PVB (polyvinyl butyral), and silicone.

[0061] In some implementations, the light-converting film consists of a light-converting agent and an adhesive film.

[0062] Available additives include, but are not limited to, crosslinking agents, co-crosslinking agents, plasticizers, antioxidants, and water-absorbing agents. The mass fraction of additives in the light conversion film can be 0.1% to 10%, for example, 0.2%, 0.5%, 1%, 2%, or 5%.

[0063] The light-converting film of the present invention can be produced by adding a mixture of a light-converting agent and film particles to an internal mixer for internal mixing. The mixing temperature can be 100±20℃, and the mixing time can be 10±2 min. The light-converting film obtained by internal mixing can achieve crosslinking between the light-converting agent and the film after high-temperature lamination. The high-temperature lamination is carried out at a temperature above 120℃, preferably at 120-170℃ or 130-160℃, for example, 130℃, 135℃, 140℃, 145℃, and 150℃. The high-temperature lamination time can be 300-2000s, for example, 500s, 600s, 700s, 800s, 1000s, 1200s, 1400s, 1600s, and 1700s, preferably 500-1800s.

[0064] The maximum absorption wavelength of the light-converting film of the present invention is 360-410 nm, for example, 365 nm, 370 nm, 375 nm, 380 nm, 385 nm, 390 nm, 395 nm, 400 nm, 405 nm, or within any range of two values, preferably 375-400 nm. The maximum emission wavelength of the light-converting film of the present invention is 450-520 nm, for example, 455 nm, 460 nm, 465 nm, 470 nm, 475 nm, 480 nm, 485 nm, 490 nm, 495 nm, 500 nm, 505 nm, 510 nm, 515 nm, or within any range of two values, preferably 460-510 nm. The quantum yield of the light-converting film of the present invention is 90-97%, for example, 91%, 92%, 93%, 94%, 95%, 96%, or within any range of two values, preferably 92-95%.

[0065] The present invention also provides a solar cell comprising the light-converting film of the present invention. In some embodiments, the solar cell is an HJT cell.

[0066] In one or more embodiments, the present invention has the following beneficial effects:

[0067] (1) Compared with existing light-converting films, the light-converting film introduced with unsaturated bonds in one or more embodiments of the present invention can prevent the migration of the light-converting agent;

[0068] (2) Compared with existing light-converting films, the absorption and emission spectra of the light-converting film in one or more embodiments of the present invention can be effectively controlled;

[0069] (3) In one or more embodiments of the present invention, the light-converting agent is a novel light-converting molecule designed based on benzotriazole, and its molecular structure is stable.

[0070] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. Percentages and parts are by weight unless otherwise stated.

[0071] In this article, compounds 1-6 were prepared according to the method of preparation examples 1-2.

[0072] Preparation Example 1

[0073] First, functional monomers containing unsaturated acrylates or unsaturated methacrylates are synthesized on benzotriazole.

[0074] Step 1

[0075] Under an inert atmosphere, 20 mmol of 5,6-diR1-2H-benzo[d][1,2,3]triazole (formula a) substituted at the 5,6 position and dissolved in 200 mL of 1,2-dichlorobenzene with 40 mmol of a compound with amino and hydroxyl groups at the terminal groups (formula b, n being 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10). The reaction mixture was heated to 120 °C, and a small amount of solvent and water were removed using a water separator. The temperature was then gradually increased to 150 °C, and the reaction was carried out for 3–4 hours. The reaction mixture was cooled to room temperature, and 200 mL of methanol was added. The mixture was stirred, followed by the addition of 500 mL of water and 25 mL of concentrated hydrochloric acid, and stirring was continued. The mixture was extracted with dichloromethane, repeated three times. The dichloromethane phase was collected, and the solvent was evaporated to obtain the crude product. Further column chromatography yielded an oily product of benzotriazole containing a hydroxyl group at the N-position (formula c).

[0076] Step 2

[0077] Under an inert gas atmosphere, 20 mmol of the final product obtained in step 1 (formula c) and 25 mmol of triethylamine were dissolved in 200 mL of N,N-dimethylformamide, heated to 40 °C, and stirred. Immediately afterwards, 22 mmol of methacryloyl chloride (formula d1) or acryloyl chloride (formula d2) was added dropwise to the reaction system, completing the addition over 30 minutes. After stirring the reaction at 40 °C for 2 h, 10 mmol of triethylamine and 10 mmol of (meth)acryloyl chloride (formula d1 or d2) were added, and stirring continued for 1 h. After cooling to room temperature, the reaction was quenched with 500 mL of water. The mixture was extracted three times with dichloromethane, and the dichloromethane phase was collected. After rotary evaporation to obtain the crude product, column chromatography was performed to obtain the final oily product (formula e1 or e2) containing unsaturated (meth)acrylate groups.

[0078] Preparation Example 2

[0079] Taking methacrylate functional monomers as an example, the final optically convertible molecule was synthesized.

[0080] Step 3

[0081] In a reflux condenser connected to HBr, a mixture of 50 mmol of 5,6-diR1-2H-benzo[d][1,2,3]triazole (formula e1) with an N-position substituted unsaturated methacrylate group, 150 mmol of liquid bromine, and 50 mL of 48 wt% HBr aqueous solution was heated to 130 °C and reacted for 24 h. The reaction mixture was then poured into 200 mL of ice water, and 100 mL of 1 mol / L NaOH solution was added simultaneously. After thorough stirring, the mixture was extracted three times with dichloromethane, and the dichloromethane phase was collected. After the solvent was evaporated, the final oily product (formula f) was obtained by column chromatography.

[0082] Step 4

[0083] Under an inert atmosphere, 1 mol of 4,7-dibromo-5,6-diR1-2H-benzo[d][1,2,3]triazole (formula f) with N-position substituted unsaturated methacrylate groups and 2.5 mol of 4-alkyl(oxy)phenylboronic acid (formula g) were dissolved in 200 mL of toluene. 200 mmol of tetra(triphenylphosphine)palladium (0), 2 mol of sodium carbonate and 20 mL of deionized water were added. The mixture was heated to 120 °C and refluxed for 24 hours. After cooling to room temperature, 200 mL of water was added to the reaction flask to quench the reaction. The mixture was extracted three times with dichloromethane, the solvent was evaporated, and the target product was purified by column chromatography to finally obtain a white powder (formula h).

[0084] Preparation Example 3: Preparation of a light-converting film

[0085] The preparation process of the light-converting film involved in all embodiments is as follows. The film particles and the light-converting agent are added simultaneously to the internal mixer (100°C, 10 min) in the ratio mentioned in the embodiments (light-converting agent: film particles ≥ 1: 1000) to obtain the final light-converting film.

[0086] Preparation Example 4: Preparation of Small Laminated Components

[0087] The preparation process of the small laminates in all embodiments is as follows. As shown in Figure 1, the structure of the small laminate from front to back is as follows: patterned glass / light conversion film / battery cell / film without light conversion agent / patterned glass. The preparation method is as follows: the small laminates are arranged in the order of patterned glass / light conversion film / battery cell / film without light conversion agent / patterned glass, with the front of the battery cell facing the side of the light conversion film. The small laminates are placed in a laminator for lamination (first vacuuming at 145°C for 6 min, then maintaining 145°C and holding at -80 kPa for 60 s, -60 kPa for 60 s, and -20 kPa for 1200 s respectively). After cooling to room temperature (25°C), the small laminate sample is obtained.

[0088] Methods for testing absorption wavelength

[0089] After lamination using a laminator (150℃, 600s), the sample was tested using a UV spectrophotometer.

[0090] Methods for testing quantum yield and emission wavelength

[0091] After lamination using a laminator (150℃, 600s), the results were measured using an Edinburgh FLS1000 fluorescence spectrometer.

[0092] Migration Resistance Test

[0093] The small laminates were baked in an oven at 105°C for 200 hours. Some of the light-converting agent migrated from the light-converting film containing the agent to the unconverting film, and gradually migrated towards the center of the unconverting film. After being removed and cooled to room temperature (25°C), the back of the small laminates was irradiated with 365nm ultraviolet light, and the light-converting agent emitted fluorescence. The farthest distance the light-converting agent migrated towards the center was measured, starting from the edge of the solar cell.

[0094] Example 1

[0095] Synthesize the following molecular compound 1:

[0096] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1 ¹H NMR (400 MHz, deuterated chloroform) δ = 7.40–7.30 (m, 8H), 6.50 (s, 1H), 6.40 (s, 1H), 4.63 (t, J = 7.5 Hz, 2H), 4.01 (t, J = 7.4 Hz, 2H), 2.00 (s, 3H), 1.33 (s, 18H). MALDI-TOF result was 545.7.

[0097] Following the method of Preparation Example 3, the prepared light-converting agent and EVA film particles were mixed in a mixer at a mass ratio of 1:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 375 nm, and the maximum emission wavelength was 460 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 95%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0098] Example 2

[0099] Synthesize the following molecular compound 2:

[0100] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1 ¹H NMR (400MHz, deuterated chloroform) δ = 7.40–7.30 (m, 8H), 6.41–6.10 (m, 2H), 6.01–5.82 (m, 1H), 4.65 (t, J = 7.2Hz, 2H), 4.05 (t, J = 7.5Hz, 2H), 1.33 (s, 18H). MALDI-TOF result was 531.7.

[0101] Following the method of Preparation Example 3, the prepared light-converting agent and POE film particles were mixed in a mixer at a mass ratio of 1.5:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 375 nm, and the maximum emission wavelength was 460 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 95%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0102] Example 3

[0103] Synthesize the following molecular compound 3:

[0104] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1 ¹H NMR (400MHz, deuterated chloroform) δ = 6.87 (d, J = 7.0Hz, 2H), 6.48 (s, 1H), 6.40 (s, 1H), 6.16 (d, J = 7.4Hz, 2H), 4.70 (m, 2H), 3.97 (t, J = 7.1Hz, 2H), 3.71 (t, J = 7.5Hz, 2H), 2.05–1.90 (m, 5H), 1.60 (m, 2H), 1.43 (m, 2H), 1.35–1.25 (m, 20H). MALDI-TOF result: 603.7.

[0105] Following the method of Preparation Example 3, the prepared light-converting agent and PVB film particles were mixed in a mixer at a mass ratio of 1.5:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 380 nm, and the maximum emission wavelength was 470 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 93%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0106] Example 4

[0107] Synthesize the following molecular compound 4:

[0108] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1¹H NMR (400MHz, deuterated chloroform) δ = 8.12–7.90 (m, 8H), 7.78 (s, 2H), 7.32 (m, 2H), 6.50 (s, 1H), 6.40 (s, 1H), 4.00 (t, J = 7.3Hz, 2H), 3.75 (t, J = 7.5Hz, 2H), 2.65 (m, 4H), 2.02–1.90 (m, 5H), 1.70–1.50 (m, 8H), 1.30–1.20 (m, 16H), 1.00 (t, J = 7.4Hz, 6H), 0.88 (t, J = 7.5Hz, 6H). MALDI-TOF result: 10¹².³.

[0109] Following the method of Preparation Example 3, the prepared light-converting agent and EPE film particles were mixed in a mixer at a mass ratio of 2:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 395 nm, and the maximum emission wavelength was 500 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 92%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0110] Example 5

[0111] Synthesize the following molecular compound 5:

[0112] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1 ¹H NMR (400MHz, deuterated chloroform) δ = 7.55 (d, J = 7.3Hz, 4H), 7.37 (d, J = 7.3Hz, 4H), 7.24 (t, J = 7.5Hz, 8H), 7.10–7.02 (m, 12H), 6.41 (m, 1H), 6.12 (m, 1H), 5.83 (m, 1H), 3.98 (t, J = 7.0Hz, 2H), 3.72 (t, J = 6.9Hz, 2H), 2.00 (m, 2H), 1.61 (m, 2H). MALDI-TOF result: 821.9.

[0113] Following the method of Preparation Example 3, the prepared light-converting agent and EPE film particles were mixed in a mixer at a mass ratio of 2:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 400 nm, and the maximum emission wavelength was 510 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 92%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0114] Example 6

[0115] Synthesize the following molecular compound 6:

[0116] Based on R1-R5, Ar1, and Ar2 in compound 1, select the corresponding compounds of formula a, b, and g, and synthesize this molecule according to the general synthetic steps in Preparation Examples 1-2. 1 ¹H NMR (400MHz, deuterated chloroform) δ = 8.33 (d, J = 7.2Hz, 8H), 8.07 (m, 2H), 7.98 (m, 2H), 7.90–7.80 (m, 6H), 7.70 (m, 2H), 6.48 (s, 1H), 6.40 (s, 1H), 4.10–3.95 (m, 6H), 3.72 (t, J = 7.2Hz, 2H), 3.75 (t, J = 7.5Hz, 2H), 2.01–1.90 (m, 5H), 1.62 (m, 2H), 1.43 (m, 18H), 1.34 (t, J = 7.4Hz, 6H). MALDI-TOF result: 814.0.

[0117] Following the method of Preparation Example 3, the prepared light-converting agent and EPE film particles were mixed in a mixer at a mass ratio of 2:1000 to obtain a light-converting film. After lamination, the maximum absorption wavelength of the light-converting film was tested to be 388 nm, and the maximum emission wavelength was 502 nm. Simultaneously, the quantum yield of the light-converting film was tested to be 93%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / battery / film without light-converting agent / glass was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 0.

[0118] Comparative Example 1

[0119] The compound with this structure was purchased from Shenzhen Ruixun Optoelectronic Materials Technology Co., Ltd. Following the method of Preparation Example 3, this compound was mixed with EVA film particles at a mass ratio of 1.5:1000 in a mixer to prepare a light-converting film. After lamination, the maximum absorption wavelength of the film was tested to be 345 nm, and the maximum emission wavelength was 420 nm. The quantum yield of the light-converting film was also tested to be 93%. Following the method of Preparation Example 4, a small laminate of glass / light-converting film / cell / film / glass without light-converting agent was further prepared, and a migration resistance test was performed. The actual migration distance of the light-converting agent was 2.5 cm.

[0120] Comparative Example 2

[0121] The steps of Example 1 were repeated, except that in the step of preparing the light-converting film, the mass ratio of the light-converting agent to the EVA film particles was 0.5:1000. The maximum absorption wavelength of the film was tested to be 375 nm, the maximum emission wavelength to be 460 nm, and the quantum yield of the light-converting film was tested to be 80%. After further preparing small laminates of glass / light-converting film / battery / film / glass without light-converting agent, migration resistance tests were performed, and the actual migration distance of the light-converting agent was 0.

[0122] Table 1

[0123] It is worth noting that if the unsaturated (meth)acrylate groups are not attached, and only conventional alkyl side chains are present in the film, the light-converting agent exists in a physically blended form. When heated, it is prone to thermal motion, leading to migration. As shown in Figure 2, before lamination, the light-converting agent molecules with unsaturated (meth)acrylate groups also exist in the film system in a physically blended form, exhibiting significant thermal motion upon heating. However, as shown in Figure 3, after lamination, during the cross-linking process of the film, the light-converting agent molecules also participate in the cross-linking reaction. The light-converting agent molecules connect to the film molecular chains, forming chemical bonds. These bonds prevent the light-converting agent molecules from moving freely when heated, thus producing migration resistance and improving the reliability of the light-converting film.

Claims

1. A light conversion agent having the structure shown in formula I below, characterized in that, In formula I, R1and R2are each independently selected from the group consisting of C1-C20alkyl optionally substituted with halogen, C1-C20alkoxy optionally substituted with halogen, halogen, hydroxyl, cyano and nitro; Ar1and Ar2are each independently selected from the group consisting of C6-C14arylene and 5-14 membered heteroarylene, the heteroarylene containing 1, 2, 3 or 4 heteroatoms selected from N, O, S and Se; R3and R4are each independently selected from the group consisting of C1-C20alkyl, C2-C20alkenyl, C2-C20alkynyl, C3-C10cycloalkyl, C1-C20alkoxy, hydroxyl and -NR'R", R' and R" are each independently selected from the group consisting of H, C1-C10alkyl and C6-C14aryl, R3and R4are each independently substituted with 0, 1, 2, 3 or 4 substituents selected from the group consisting of C1-C20alkyl and C1-C20alkoxy; R5is selected from the group consisting of C2-C20alkenyl optionally substituted with 1, 2 or 3 -OC(=O)-R6, C2-C20alkynyl optionally substituted with 1, 2 or 3 -OC(=O)-R6, and C1-C20alkyl substituted with 1, 2 or 3 substituents selected from the group consisting of C2-C20alkenyl, C2-C20alkynyl and -OC(=O)-R6, R6is C1-C20alkyl containing at least one -C=C- structure.

2. The light conversion agent of claim 1, wherein R3and R4are each independently selected from the group consisting of C1-C16alkyl, C1-C16alkoxy, hydroxyl and -NR'R", R' and R" are each independently selected from the group consisting of H, C1-C10alkyl and C6-C10aryl, R3and R4are each independently substituted with 0, 1 or 2 substituents selected from the group consisting of C1-C16alkyl and C1-C16alkoxy; Preferably, R3and R4are each independently selected from the group consisting of C1-C10alkyl, C1-C10alkoxy and -NR'R", R' and R" are each independently selected from the group consisting of C1-C10alkyl and C6-C10aryl; Preferably, R3and R4are each independently selected from the following structures: wherein * represents the connecting site of R3and Ar1or the connecting site of R4and Ar2.

3. The light conversion agent of claim 1, wherein Ar1and Ar2are each independently selected from the group consisting of C6-C10arylene and 5-14 membered heteroarylene, the heteroarylene containing 1 or 2 heteroatoms selected from N, O and S; Preferably, Ar1and Ar2are each independently selected from the following structures: In the above structure, there are two connecting sites on the aromatic ring connecting with other parts of the compound of formula I, and R is C1-C10alkyl.

4. The light conversion agent of claim 1, wherein R5is selected from the group consisting of C2-C20alkenyl, C2-C20alkynyl, and C1-C20alkyl substituted with 1, 2 or 3 substituents selected from the group consisting of C2-C20alkenyl, C2-C20alkynyl and -OC(=O)-R6, R6is C2-C20alkenyl; Preferably, R5is selected from C1-C15alkyl substituted with -OC(=O)-R6, R6is C2-C10alkenyl; Preferably, R5is selected from the following structures: wherein n is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; and * represents the connecting site of R5and the benzotriazole structure in the compound of formula I.

5. The light conversion agent of claim 1, wherein The light conversion agent is selected from the following compounds:

6. A light conversion film, characterized in that The light conversion film comprises a film and the light conversion agent according to any one of claims 1-5; the mass ratio of the light conversion agent to the film in the light conversion film is (1-20):1000.

7. The light conversion film of claim 6, wherein, The light conversion film has one or more of the following characteristics: The light conversion film has one or more of the following characteristics: The adhesive film is selected from one or more of POE, EVA, EPE, PVB and silicone glue; The maximum absorption wavelength of the light conversion film is 360-410 nm; preferably 375-400 nm; The maximum emission wavelength of the light conversion film is 450-520 nm; preferably 460-510 nm; The quantum yield of the light conversion film is 90-97%; preferably 92-95%.

8. A method of producing the light conversion film according to claim 6 or 7, characterized in that, The method comprises mixing the adhesive film particles and the light conversion agent.

9. The method of claim 8, wherein, The temperature of the mixing is 100±20℃, and the mixing time is 10±2 min.

10. A solar cell, characterized by, The solar cell comprises the light conversion film of claim 6 or 7; preferably, the solar cell is an HJT cell.

Images