Quantum dot adhesive film with high refractive index and method of making same

Abstract

The application belongs to the technical field of photovoltaics, and specifically provides a quantum dot adhesive film with high refractive index and a preparation method thereof, aiming to solve the problem in the prior art that the high-refractive-index resin added to improve the refractive index of the adhesive film is sensitive to ultraviolet light, causing the adhesive film to easily yellow under continuous light irradiation, and affecting optical performance and service life. To this end, the quantum dot adhesive film according to the application comprises the following components in parts by weight: 65-85 parts of blank adhesive particles, 2-10 parts of high-refractive-index resin, 1-8 parts of quantum dots, 0.1-2 parts of a coupling agent, 0.5-2 parts of a crosslinking agent, 0.5-2 parts of a co-crosslinking agent, 0.2-2 parts of an anti-aging additive, and 0.3-3 parts of a dispersing agent. The adhesive film according to the application can inhibit the yellowing phenomenon of the adhesive film during light aging, and has both high refractive index and anti-yellowing performance.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic technology, specifically providing a high refractive index quantum dot film and its preparation method. Background Technology

[0002] In fields such as photovoltaics and optoelectronic displays, encapsulation or lamination with encapsulating materials is often required to improve the optical performance of devices. High-refractive-index encapsulating films can effectively reduce light reflection loss at interfaces between different media, improve light transmission efficiency, and thus optimize the overall performance of the device.

[0003] To achieve high refractive index properties in adhesive films, existing technologies commonly employ the method of adding high-refractive-index resins to the film matrix. While these high-refractive-index resins, such as those containing aromatic groups, effectively increase the refractive index of the film, their molecular structure is inherently sensitive to ultraviolet light. Under prolonged exposure to light, these resins are prone to photo-oxidative degradation, producing chromophores and causing severe yellowing of the film. Yellowing not only affects the aesthetics of the product but also reduces its light transmittance, thereby impacting the performance and lifespan of optoelectronic devices.

[0004] While adding antioxidants or UV absorbers can attempt to mitigate yellowing, these traditional additives often have poor compatibility with high-refractive-index resins, easily precipitating in the film and causing optical defects such as increased haze. Furthermore, traditional additives only passively absorb a portion of UV light, offering limited effectiveness in inhibiting yellowing and failing to fundamentally address the problem of high-refractive-index resin degradation due to light exposure.

[0005] Accordingly, a new technical solution is needed in this field to solve the above-mentioned technical problems. Summary of the Invention

[0006] This application aims to solve the above-mentioned technical problems, namely, to solve the problem in the prior art that the high refractive index resin added to improve the refractive index of the film is itself sensitive to ultraviolet light, which causes the film to easily yellow under continuous light irradiation, affecting its optical performance and service life.

[0007] In a first aspect, this application provides a high refractive index quantum dot film, the quantum dot film comprising the following components by weight: 65-85 parts blank particles, 2-10 parts high refractive index resin, 1-8 parts quantum dots, 0.1-2 parts coupling agent, 0.5-2 parts crosslinking agent, 0.5-2 parts co-crosslinking agent, 0.2-2 parts anti-aging agent, and 0.3-3 parts dispersant.

[0008] In the preferred embodiment of the above-mentioned high refractive index quantum dot film, the quantum dot film comprises the following components by weight: 70-80 parts blank particles, 4-8 parts high refractive index resin, 2-6 parts quantum dots, 0.5-1 parts coupling agent, 0.8-1.5 parts crosslinking agent, 0.8-1.2 parts co-crosslinking agent, 0.5-1 parts anti-aging agent, and 0.5-2 parts dispersant.

[0009] In the preferred embodiment of the above-mentioned high refractive index quantum dot film, the quantum dot film comprises the following components by weight: 75 parts blank particles, 6 parts high refractive index resin, 4 parts quantum dots, 0.8 parts coupling agent, 1 part crosslinking agent, 1 part co-crosslinking agent, 0.8 parts anti-aging agent, and 1 part dispersant.

[0010] In the preferred embodiment of the above-mentioned high-refractive-index quantum dot film, the quantum dots include one or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, CdSe / ZnS, CdSe / CdZnS, CdZnSe / ZnS, CdZnSe / CdZnS, CdSe / ZnSe, ZnSe / ZnS, CdSe / CdZnS / ZnS, CdZnS / ZnS, InP / ZnS, InP / ZnSe / ZnS, and perovskite quantum dots; wherein the perovskite quantum dots are CsPb. n Yb 1-n X3 (0≤n<1), where X is one or two of Cl, Br, and I; and / or, the particle size of the quantum dots is 10-55 nm; and / or, the quantum dots are modified quantum dots after surface modification using a modifier, wherein the modifier includes one or more of silane coupling agents, oleic acid, and oleylamine.

[0011] In the preferred embodiment of the above-mentioned high refractive index quantum dot film, the high refractive index resin includes one or more of the following: acrylic resin containing aromatic groups, epoxy resin containing aromatic groups, polyurethane resin containing aromatic groups, polysulfuric acid urethane resin containing aromatic groups, semi-alicyclic polyimide resin, polystyrene resin, polycarbonate resin, and polyarylate resin; and / or, the blank particles are EVA particles or POE particles.

[0012] In the preferred embodiment of the above-mentioned high-refractive-index quantum dot film, the acrylic resin containing aromatic groups includes one or more of styrene-acrylate copolymer, styrene-methacrylate copolymer, benzyl acrylate polymer, and benzyl methacrylate polymer; and / or, the epoxy resin containing aromatic groups includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, naphthyl ring-containing epoxy resin, and biphenyl ring-containing epoxy resin; and / or, the polyurethane resin containing aromatic groups includes MDI type (diphenyl ether...) The polysulfuric acid polyurethane resin contains one or more of the following: poly(methane diisocyanate) polyurethane, TDI-type (toluene diisocyanate) polyurethane, and benzene ring-containing polyester polyol type polyurethane; and / or, the aromatic polysulfuric acid polyurethane resin contains one or more of the following: polymers of aromatic diisocyanates (such as MDI, TDI) and polythiols, polymers of aromatic diisothiocyanates (such as terephthalic diisothiocyanate) and polythiols or polyols, and polysulfuric acid polyurethanes modified with aromatic epoxy compounds; and / or, the semi-alicyclic polyimide resin contains one or more of the following: alicyclic dianhydrides (such as BHDA, HPMDA, HBPDA) and aromatic poly(methane diisocyanate) and poly(methane diisocyanate); and / or, the semi-alicyclic polyimide resin contains one or more of the following: polymers of aromatic diisocyanates (such as MDI, TDI) and polythiols, polymers of aromatic diisothiocyanates (such as terephthalic diisothiocyanate) and polythiols; and / or, the semi-alicyclic polyimide resin contains one or more of the following: polymers of aromatic diisocyanates (such as MDI, TDI ... Polyimides synthesized from diamines (such as ODA, MDA, BAPP), and polyimides synthesized from aromatic dianhydrides (such as PMDA, ODPA, BPDA) and alicyclic diamines (such as BCH, HMD) are among one or more of the following: polystyrene resins include polystyrene (GPPS), high-impact polystyrene (HIPS), syndiotactic polystyrene (sPS), styrene-acrylonitrile copolymer (AS), styrene-butadiene copolymer (SB), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene (SIS), and styrene- One or more of maleic anhydride copolymers (SMA); and / or, the polycarbonate resin includes one or more of bisphenol A type polycarbonate, bisphenol Z type, bisphenol C type, bisphenol AP type, polycarbonate containing tetramethylbisphenol A, polycarbonate containing biphenyl, and polycarbonate containing naphthol; and / or, the polyaryl ester resin includes one or more of bisphenol A type polyaryl esters (such as U polymer), bisphenol C type polyaryl esters, bisphenol Z type polyaryl esters, copolymers of terephthalic acid / isophthalic acid and bisphenol A, and fully aromatic liquid crystal polyesters (such as Vectra, Xydar, containing naphthalene rings and biphenyl structures).

[0013] In the preferred embodiment of the above-mentioned high refractive index quantum dot film, the coupling agent includes one or more of vinyl silane coupling agents, epoxy silane coupling agents, and amino silane coupling agents; and / or, the crosslinking agent includes one or more of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and benzoyl peroxide; and / or, the co-crosslinking agent includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, and triallyl cyanurate; and / or, the anti-aging agent is a composite system of phenolic antioxidants and hindered amine light stabilizers, wherein the mass ratio of the phenolic antioxidant to the hindered amine light stabilizer is 1:(0.5~2); and / or, the dispersant includes one or more of organosilicon dispersants, polycarboxylate dispersants, and polyurethane dispersants.

[0014] In the preferred embodiment of the above-mentioned high refractive index quantum dot film, the refractive index of the quantum dot film is ≥1.5000, the haze is ≤3.1, the initial yellowing value b is ≤1.2, and the yellowing value b after 1000h photoaging is ≤1.5.

[0015] In a second aspect, this application provides a method for preparing a high-refractive-index quantum dot film, which is used to prepare the above-mentioned high-refractive-index quantum dot film. The preparation method includes the following steps: S1: surface modification of quantum dots using a modifier to obtain modified quantum dots; S2: uniformly mixing blank adhesive particles, high-refractive-index resin, modified quantum dots, coupling agent, crosslinking agent, co-crosslinking agent, anti-aging agent and dispersant to obtain a premix; S3: adding the premix to a screw extruder, extruding and casting to obtain a preliminary film; S4: placing the preliminary film in a laminator and laminating to obtain a high-refractive-index quantum dot film.

[0016] In the preferred embodiment of the above-mentioned method for preparing high refractive index quantum dot films, step S1 specifically includes: mixing quantum dots and modifiers at a mass ratio of 1:(0.03~0.3), adding organic solvent, stirring at 20~60℃ for 0.5~3h, centrifuging, and vacuum drying to obtain modified quantum dots; and / or, in step S2, the mixing is carried out in a high-speed mixer, wherein the mixing temperature is 20~45℃, the rotation speed is 600~1500r / min, and the mixing time is 15~50min; and / or, in step S3, the extrusion temperature is 110~170℃, and the screw rotation speed is 25~60r / min; and / or, in step S4, vacuuming at 145℃ for 5 minutes before lamination, and laminating for 15 minutes after pressurization.

[0017] Compared with the prior art, this application has the following technical effects: 1. This application combines quantum dots, which can efficiently absorb ultraviolet light, with high-refractive-index resins that are prone to yellowing due to ultraviolet degradation. By using quantum dots as an "absorber" and "protective shield" for ultraviolet light, the destruction of the molecular structure of high-refractive-index resin by ultraviolet light is prevented from the root, thereby significantly inhibiting the yellowing phenomenon of the film during photoaging. This helps to ensure the long-term optical stability of the film and can balance high refractive index and anti-yellowing performance.

[0018] 2. The adhesive film prepared in this application has high anti-yellowing properties and its refractive index can reach above 1.55, which effectively reduces the reflection loss of light in the device. At the same time, since the quantum dots are surface modified and uniformly dispersed under the action of dispersant, the haze of the adhesive film can be controlled at a low level (≤3.1%), ensuring high light transmittance; thus achieving good optical performance.

[0019] 3. Through the synergistic effect of coupling agents, anti-aging agents, and other additives, the adhesive film prepared in this application also possesses excellent adhesion, mechanical strength, and weather resistance. Its preparation method employs mature extrusion and lamination processes, which are easy to control and suitable for large-scale industrial production. Detailed Implementation

[0020] The preferred embodiments of this application are described below. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0024] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0025] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0026] As mentioned in the background section, the high-refractive-index resin added to increase the refractive index of the film is itself sensitive to ultraviolet light, which causes the film to yellow easily under continuous light irradiation, affecting its optical performance and service life.

[0027] This application provides a high-refractive-index quantum dot film and its preparation method. By compounding quantum dots, which can efficiently absorb ultraviolet light, with a high-refractive-index resin that is prone to yellowing due to ultraviolet degradation, the quantum dots are used as an "absorber" and "protective shield" for ultraviolet light. This fundamentally prevents ultraviolet light from damaging the molecular structure of the high-refractive-index resin, thereby significantly inhibiting the yellowing phenomenon of the film during photoaging. This helps to ensure the long-term optical stability of the film and can balance high refractive index and anti-yellowing performance.

[0028] In a first aspect, this application provides a quantum dot film with a high refractive index.

[0029] Specifically, the quantum dot film of this application comprises the following components by weight: 65-85 parts blank particles, 2-10 parts high refractive index resin, 1-8 parts quantum dots, 0.1-2 parts coupling agent, 0.5-2 parts crosslinking agent, 0.5-2 parts co-crosslinking agent, 0.2-2 parts anti-aging agent, and 0.3-3 parts dispersant.

[0030] The film formulation system of this application constructs a composite material system with complementary functions and synergistic performance through the scientific ratio of eight components. Among them, blank adhesive particles serve as the matrix, providing the mechanical framework and basic adhesion of the film; high refractive index resin is the key functional component to achieve the high refractive index target; quantum dots are the core technical feature for solving the yellowing problem; and coupling agents, crosslinking agents, co-crosslinking agents, anti-aging agents, and dispersants optimize and ensure the comprehensive performance of the film from multiple dimensions such as interface, structure, stability, and uniformity.

[0031] In some preferred embodiments, the quantum dot film comprises the following components by weight: 70-80 parts blank particles, 4-8 parts high refractive index resin, 2-6 parts quantum dots, 0.5-1 part coupling agent, 0.8-1.5 parts crosslinking agent, 0.8-1.2 parts co-crosslinking agent, 0.5-1 part anti-aging agent, and 0.5-2 parts dispersant.

[0032] Compared to the broader range mentioned above, this preferred range aims to achieve a better balance between performance and cost. Specifically, controlling the content of high-refractive-index resin to 4–8 parts can effectively control the potential yellowing risk and material cost introduced by it while ensuring a significant increase in refractive index. At the same time, controlling the content of quantum dots to 2–6 parts ensures sufficient ultraviolet light absorption capacity to match the high-refractive-index resin within this content range, thereby obtaining a more reliable and durable anti-yellowing effect.

[0033] In some preferred embodiments, the quantum dot film comprises the following components by weight: 75 parts blank particles, 6 parts high refractive index resin, 4 parts quantum dots, 0.8 parts coupling agent, 1 part crosslinking agent, 1 part co-crosslinking agent, 0.8 parts anti-aging agent, and 1 part dispersant.

[0034] This specific ratio is the optimal point obtained through extensive experimental optimization. It enables the film to maintain high refractive index, high light transmittance, and low haze while exhibiting strong anti-yellowing ability and good mechanical and adhesive properties, representing a high-performance realization of the technical solution of this application.

[0035] In some preferred embodiments, the quantum dots include one or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, CdSe / ZnS, CdSe / CdZnS, CdZnSe / ZnS, CdZnSe / CdZnS, CdSe / ZnSe, ZnSe / ZnS, CdSe / CdZnS / ZnS, CdZnS / ZnS, InP / ZnS, InP / ZnSe / ZnS, and perovskite quantum dots.

[0036] In some preferred embodiments, the quantum dots are perovskite quantum dots, and the perovskite quantum dots are ytterbium-doped perovskite quantum dots, specifically CsPb. n Yb 1-n X3 (0 ≤ n < 1), where X is one or two of Cl, Br, and I. The optimal quantum dot is CsPb. n Yb 1-nX3 (0 ≦ n < 1), where X is one or two of Cl, Br, and I, has an adjustable bandgap, enabling efficient absorption across the entire ultraviolet band (200–400 nm). It also features a steep absorption band edge and minimal absorption in the visible light region, thus ensuring the film's transmittance. The doping of Yb (ytterbium) introduces downconversion luminescence, converting the low-utilization ultraviolet light of silicon solar cells into high-utilization near-infrared light, thereby breaking theoretical limits and further improving the efficiency of photovoltaic devices.

[0037] In a further preferred embodiment, the ytterbium-doped perovskite quantum dots are CsPb. 0.5 Yb 0.5 X3.

[0038] In some implementations, the quantum dots have a particle size of 10-55 nm.

[0039] In some preferred embodiments, the quantum dots are modified quantum dots after surface modification using a modifier, wherein the modifier includes one or more of silane coupling agents, oleic acid and oleylamine.

[0040] To address the issue of quantum dots easily agglomerating in organic resin matrices, the quantum dots are preferably modified quantum dots that have undergone surface modification using a modifier, wherein the modifier includes one or more of silane coupling agents, oleic acid, and oleylamine. Long-chain organic molecules such as oleic acid and oleylamine can coat the surface of the quantum dots, forming an organic "shell." This shell prevents direct contact and agglomeration between quantum dots through steric hindrance and improves their affinity with the nonpolar EVA matrix, thereby achieving uniform dispersion at the nanoscale.

[0041] In some preferred embodiments, the blank particles are EVA particles.

[0042] The substrate in the encapsulant film is selected by optimization. EVA (ethylene-vinyl acetate copolymer) is a mature material widely used in the photovoltaic encapsulation field. It has the advantages of low cost, good processability, high light transmittance, strong adhesion and excellent flexibility, and is an ideal substrate material for the encapsulant film system of this application.

[0043] In some preferred embodiments, the high refractive index resin includes one or more of the following: acrylic resin containing aromatic groups, epoxy resin containing aromatic groups, polyurethane resin containing aromatic groups, polysulfuric acid urethane resin containing aromatic groups, half-alicyclic polyimide resin, polystyrene resin, polycarbonate resin, and polyarylate resin.

[0044] The core functional resin in the adhesive film is preferentially selected, and the high refractive index resin includes one or more of the following: acrylic resin containing aromatic groups, epoxy resin containing aromatic groups, polyurethane resin containing aromatic groups, polysulfuric acid urethane resin containing aromatic groups, semi-alicyclic polyimide resin, polystyrene resin, polycarbonate resin, and polyarylate resin. These resins share the common characteristic of containing aromatic groups with large π-conjugated systems and high molar refractive index, such as benzene rings, naphthalene rings, and biphenyls, in their molecular structure, thereby effectively improving the refractive index of the material. This application provides a broad candidate list, giving the technical solution the ability to flexibly adjust different performance indicators such as refractive index, cost, and heat resistance according to specific application scenarios.

[0045] Among them, acrylic resins containing aromatic groups include one or more of styrene-acrylate copolymers, styrene-methacrylate copolymers, benzyl acrylate polymers, and benzyl methacrylate polymers.

[0046] Epoxy resins containing aromatic groups include one or more of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, naphthalene ring-containing epoxy resin, and biphenyl-containing epoxy resin.

[0047] Polyurethane resins containing aromatic groups include one or more of MDI-type (diphenylmethane diisocyanate) polyurethane, TDI-type (toluene diisocyanate) polyurethane, and polyester polyol-type polyurethane containing benzene rings.

[0048] Polysulfuric ester resins containing aromatic groups include one or more of the following: polymers of aromatic diisocyanates (such as MDI and TDI) and polythiols, polymers of aromatic diisothiocyanates (such as terephthalic diisothiocyanate) and polythiols or polyols, and polysulfuric esters modified with aromatic epoxy compounds.

[0049] Semi-alicyclic polyimide resins include one or more polyimides synthesized from alicyclic dianhydrides (such as BHDA, HPMDA, HBPDA) and aromatic diamines (such as ODA, MDA, BAPP) and polyimides synthesized from aromatic dianhydrides (such as PMDA, ODPA, BPDA) and alicyclic diamines (such as BCH, HMD).

[0050] Polystyrene resins include one or more of the following: polystyrene (GPPS), high-impact polystyrene (HIPS), syndiotactic polystyrene (sPS), styrene-acrylonitrile copolymer (AS), styrene-butadiene copolymer (SB), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene (SIS), and styrene-maleic anhydride copolymer (SMA).

[0051] Polycarbonate resins include one or more of the following: bisphenol A type polycarbonate, bisphenol Z type, bisphenol C type, bisphenol AP type, polycarbonate containing tetramethylbisphenol A, polycarbonate containing biphenyl, and polycarbonate containing naphthol.

[0052] Polyaryl ester resins include one or more of the following: bisphenol A type polyaryl esters (such as U polymer), bisphenol C type polyaryl esters, bisphenol Z type polyaryl esters, copolymers of terephthalic acid / isophthalic acid and bisphenol A, and fully aromatic liquid crystal polyesters (such as Vectra, Xydar, containing naphthalene rings and biphenyl structures).

[0053] In some preferred embodiments, the coupling agent includes one or more of vinyl silane coupling agents, epoxy silane coupling agents, and amino silane coupling agents. These silane coupling agents can effectively enhance the adhesion strength and resistance to damp heat aging between the encapsulant film and inorganic substrates such as photovoltaic glass and solar cells.

[0054] Among them, vinyl silane coupling agents include one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltri(β-methoxyethoxy)silane.

[0055] Epoxysilane coupling agents include one or more of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0056] Aminosilane coupling agents include one or more of γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane.

[0057] In some preferred embodiments, the crosslinking agent includes one or more of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and benzoyl peroxide.

[0058] In some preferred embodiments, the anti-aging agent is a composite system of phenolic antioxidants and hindered amine light stabilizers, wherein the mass ratio of phenolic antioxidants to hindered amine light stabilizers is 1:(0.5~2). This composite system can produce a synergistic effect. The phenolic antioxidants mainly capture peroxide free radicals, while the hindered amines exert their effects by capturing hydroperoxides and alkyl free radicals. The combination of the two is more effective than using either one alone.

[0059] Among them, phenolic antioxidants include one or more of the following: 2,6-di-tert-butyl-4-methylphenol (BHT), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (1076), N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (1098), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (300), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (3114).

[0060] Hindered amine light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (770), bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate (292 / 765), bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (123), and [[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2, One or more of the following: [4-diyl]-[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] polymer (944), succinic acid and (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol) polymer (622), and 1,6-hexanediamine and N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3,5-triazine-2,4-diamine and morpholine polymer (2020).

[0061] In some preferred embodiments, the dispersant includes one or more of organosilicon dispersants, polycarboxylate dispersants, and polyurethane dispersants.

[0062] Through the synergistic effect of the above components, the high-refractive-index quantum dot film of this application achieves excellent performance indicators: a refractive index ≥1.5000, haze ≤3.1%, initial yellowing value b ≤1.2, and after 1000 hours of photoaging testing, its yellowing value b still remains ≤1.5. These parameters indicate that the film of this application not only successfully raises the refractive index to a level that is difficult to achieve with traditional EVA films (traditional EVA refractive index is about 1.48), effectively reducing light reflection loss in applications such as photovoltaic modules, but also fundamentally solves the yellowing problem caused by high-refractive-index resins by introducing quantum dots, exhibiting good long-term optical stability and weather resistance.

[0063] In a second aspect, this application provides a method for preparing a high-refractive-index quantum dot film, used to prepare the aforementioned high-refractive-index quantum dot film.

[0064] Specifically, the preparation method of this application includes the following steps: S1: Surface modification of quantum dots using a modifier to obtain modified quantum dots.

[0065] S2: Mix blank granules, high refractive index resin, modified quantum dots, coupling agent, crosslinking agent, co-crosslinking agent, anti-aging agent and dispersant evenly to obtain a premix.

[0066] S3: Add the premixed material to the screw extruder, and after extrusion, cast to form a preliminary film.

[0067] S4: Place the preliminary film in a laminator and laminate to obtain a quantum dot film with a high refractive index.

[0068] The preparation method of this application adopts a mature extrusion and lamination process, which is easy to control and suitable for large-scale industrial production.

[0069] In some preferred embodiments, step S1 specifically includes: mixing quantum dots and a modifier at a mass ratio of 1:(0.03~0.3), adding an organic solvent (such as n-hexane), stirring at 20~60°C for 0.5~3 hours, centrifuging, and vacuum drying to obtain modified quantum dots. This temperature and time are sufficient to allow the modifier molecules to form a dense coating layer on the surface of the quantum dots without destroying the crystal structure of the quantum dots themselves.

[0070] In some preferred embodiments, in step S2, mixing is carried out in a high-speed mixer, wherein the mixing temperature is 20~45℃, the rotation speed is 600~1500 r / min, and the mixing time is 15~50 min. This setup ensures that all powdery and granular components achieve macroscopic and microscopic uniformity without melting or degradation.

[0071] In some preferred embodiments, in step S3, the extrusion temperature is 110~170°C and the screw speed is 25~60 r / min. This process window is designed to ensure that the material is fully plasticized and mixed evenly, while avoiding excessively high temperatures that could lead to degradation of quantum dots or resin.

[0072] In some preferred embodiments, in step S4, a vacuum is first applied at 145°C for 5 minutes before lamination to remove air bubbles, and then pressure is applied for lamination for 15 minutes to ensure that the crosslinking reaction proceeds fully.

[0073] The high refractive index quantum dot film and its preparation method of this application are described in detail below through several specific embodiments.

[0074] Example 1 The high refractive index quantum dot film of this embodiment has the following components by weight: 75 parts EVA particles, 6 parts high refractive index resin, 4 parts quantum dots, 0.8 parts coupling agent, 1 part crosslinking agent, 1 part co-crosslinking agent, 0.8 parts anti-aging additive, and 1 part dispersant.

[0075] Among them, the blank particles are EVA particles, the high refractive index resin is bisphenol A type epoxy resin, and the quantum dots are modified CsPb with a particle size of 10 nm. 0.5 Yb 0.5 Cl3, the coupling agent is an aminosilane coupling agent (γ-aminopropyltriethoxysilane), the crosslinking agent is dicumyl peroxide, the co-crosslinking agent is triallyl isocyanurate, the anti-aging additive is a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 in a mass ratio of 1:1, and the dispersant is a polycarboxylate dispersant.

[0076] The preparation process of the high refractive index quantum dot film in this embodiment is as follows: S1: Quantum dots and a modifier (silane coupling agent - KH570) were mixed at a mass ratio of 1:0.3, and n-hexane was added. The mixture was stirred at 30°C for 2 hours. After the reaction was completed, the mixture was centrifuged (10,000 rpm, 10 min) and dried under vacuum at room temperature for 4 hours to obtain modified quantum dots.

[0077] S2: Add the blank granules, high refractive index resin, modified quantum dot powder prepared in step S1, coupling agent, crosslinking agent, co-crosslinking agent, anti-aging agent and dispersant powder to a high-speed mixer according to the components and proportions in the formula. Set the mixing temperature to 30℃ and the rotation speed to 1000 r / min. Mix for 30 minutes until all components are mixed evenly and the color is uniform to obtain the premix.

[0078] S3: Add the above premixed material to a twin-screw extruder, set the temperatures of each zone of the extruder to 65℃, 75℃, 85℃ and 80℃ respectively, and the screw speed to 40 r / min. After extrusion, the material is cooled and shaped by a casting roller to obtain a preliminary film with a thickness of about 0.45mm.

[0079] S4: Cut the preliminary adhesive film from step S3 to the required size and place it in a laminator. The lamination program is set as follows: at a temperature of 145°C, first evacuate for 5 minutes to completely remove air and volatiles between the adhesive film and the substrate (such as glass). Then apply a pressure of 1 MPa and maintain this temperature and pressure for lamination for 15 minutes. During this process, the crosslinking agent decomposes to generate free radicals, initiating crosslinking of the EVA molecular chains to form a stable three-dimensional network structure. After lamination, cool to room temperature to obtain the final high-refractive-index quantum dot adhesive film.

[0080] Example 2 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the components are also the same as those in Example 1. The only difference between this embodiment and Example 1 is the mass fraction of each component.

[0081] Specifically, the formulation of the high refractive index quantum dot film in this embodiment is as follows: 65 parts EVA particles, 2 parts high refractive index resin, 1 part quantum dots, 0.1 parts coupling agent, 0.5 parts crosslinking agent, 0.5 parts co-crosslinking agent, 0.2 parts anti-aging additive (a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1), and 0.3 parts dispersant.

[0082] Example 3 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the components are also the same as those in Example 1. The only difference between this embodiment and Example 1 is the mass fraction of each component.

[0083] Specifically, the formulation of the high refractive index quantum dot film in this embodiment is as follows: 70 parts EVA particles, 4 parts high refractive index resin, 2 parts quantum dots, 0.5 parts coupling agent, 0.8 parts crosslinking agent, 0.8 parts co-crosslinking agent, 0.5 parts anti-aging agent (a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1), and 0.5 parts dispersant.

[0084] Example 4 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the components are also the same as those in Example 1. The only difference between this embodiment and Example 1 is the mass fraction of each component.

[0085] Specifically, the formulation of the high refractive index quantum dot film in this embodiment is as follows: 80 parts EVA particles, 8 parts high refractive index resin, 6 parts quantum dots, 1 part coupling agent, 1.5 parts crosslinking agent, 1.2 parts co-crosslinking agent, 1 part anti-aging agent (a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1), and 2 parts dispersant.

[0086] Example 5 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the components are also the same as those in Example 1. The only difference between this embodiment and Example 1 is the mass fraction of each component.

[0087] Specifically, the formulation of the high refractive index quantum dot film in this embodiment is as follows: 85 parts EVA particles, 10 parts high refractive index resin, 8 parts quantum dots, 2 parts coupling agent, 2 parts crosslinking agent, 2 parts co-crosslinking agent, 2 parts anti-aging agent (a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1), and 3 parts dispersant.

[0088] Example 6 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the components are also the same as those in Example 1. The only difference between this embodiment and Example 1 is the mass fraction of each component.

[0089] Specifically, the formulation of the high refractive index quantum dot film in this embodiment is as follows: 75 parts EVA particles, 8 parts high refractive index resin, 6 parts quantum dots, 1 part coupling agent, 1 part crosslinking agent, 0.8 parts co-crosslinking agent, 1 part anti-aging agent (a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1), and 2 parts dispersant.

[0090] Example 7 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the formulation ratio is also the same as that in Example 1. The only difference between this embodiment and Example 1 is the different components in the formulation.

[0091] Specifically, in this embodiment, the blank particles are EVA particles, the high refractive index resin is bisphenol A type polycarbonate, and the quantum dots are modified CsPb with a particle size of 25 nm. 0.8 Yb 0.2 Br3, the coupling agent is an epoxy silane coupling agent (γ-(2,3-epoxypropoxy)propyltrimethoxysilane), the crosslinking agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, the co-crosslinking agent is trimethylolpropane trimethacrylate, the anti-aging additive is a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 in a mass ratio of 1:0.5, and the dispersant is a polycarboxylate dispersant.

[0092] Example 8 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the formulation ratio is also the same as that in Example 1. The only difference between this embodiment and Example 1 is the different components in the formulation.

[0093] Specifically, in this embodiment, the blank particles are EVA particles, the high refractive index resin is styrene-acrylonitrile copolymer, and the quantum dots are modified CsPb with a particle size of 10 nm. 0.3 Yb 0.7 I3, the coupling agent is vinyl silane coupling agent (vinyltrimethoxysilane), the crosslinking agent is benzoyl peroxide, the co-crosslinking agent is triallyl cyanurate, the anti-aging additive is a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 in a mass ratio of 1:2, and the dispersant is polyurethane dispersant.

[0094] Example 9 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the composition ratio of its formulation is also the same as that in Example 1. The only difference between this embodiment and Example 1 is that the anti-aging additive in this embodiment is phenolic antioxidant 1010.

[0095] Example 10 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the composition ratio of its formulation is also the same as that in Example 1. The only difference between this embodiment and Example 1 is that the anti-aging agent in this embodiment is hindered amine light stabilizer 770.

[0096] Example 11 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the composition ratio of its formulation is also the same as that in Example 1. The only difference between this embodiment and Example 1 is that the quantum dots in this embodiment are modified CdZnSe with a particle size of 20nm, and the blank particles are POE particles.

[0097] Example 12 The preparation method of the high refractive index quantum dot film in this embodiment is the same as that in Example 1, and the composition ratio of its formulation is also the same as that in Example 1. The only difference between this embodiment and Example 1 is that the quantum dots in this embodiment are modified CdZnSeS with a particle size of 50nm.

[0098] Comparative Example 1 The difference between the formulation and preparation method of the quantum dot film in Comparative Example 1 and Example 1 is that step S1 does not modify the quantum dots; unmodified CsPb is used directly. 0.5 Yb 0.5 Cl3, i.e., CsPb quantum dots with a particle size of 10 nm. 0.5 Yb 0.5 Cl3.

[0099] Comparative Example 2 The formulation of the film in Comparative Example 2 is as follows: 75 parts EVA granules, 4 parts high refractive index resin, 0.8 parts coupling agent, 1 part crosslinking agent, 1 part co-crosslinking agent, 0.8 parts anti-aging agent, and 1 part dispersant.

[0100] Among them, the blank colloid particles are EVA colloid particles, the high refractive index resin is bisphenol A type epoxy resin, the coupling agent is aminosilane coupling agent (γ-aminopropyltriethoxysilane), the crosslinking agent is dicumyl peroxide, the co-crosslinking agent is triallyl isocyanurate, the anti-aging additive is a system of phenolic antioxidant 1010 and hindered amine light stabilizer 770 compounded in a mass ratio of 1:1, and the dispersant is a polycarboxylate dispersant.

[0101] The preparation process of the adhesive film in Comparative Example 2 is as follows: S1: Add the blank granules, high refractive index resin, coupling agent, crosslinking agent, co-crosslinking agent, anti-aging agent and dispersant powder to a high-speed mixer according to the components and proportions in the formula. Set the mixing temperature to 30℃ and the rotation speed to 1000 r / min. Mix for 30 minutes until all components are mixed evenly and the color is uniform to obtain the premix.

[0102] S2: Add the above premixed material into a twin-screw extruder, set the temperatures of each zone of the extruder to 65℃, 75℃, 85℃ and 80℃ respectively, and the screw speed to 40 r / min. After extrusion, the material is cooled and shaped by a casting roller to obtain a preliminary film with a thickness of about 0.45mm.

[0103] S3: Cut the preliminary adhesive film from step S2 to the required size and place it in a laminator. The lamination program is set as follows: at a temperature of 145°C, first evacuate for 5 minutes to completely remove air and volatiles between the adhesive film and the substrate (such as glass). Then apply a pressure of 1 MPa and maintain this temperature and pressure for lamination for 15 minutes. During this process, the crosslinking agent decomposes to generate free radicals, which initiate crosslinking of the EVA molecular chains, forming a stable three-dimensional network structure. After lamination, cool to room temperature to obtain the final adhesive film.

[0104] Test case The performance of the films prepared in the examples and comparative examples was tested. Specifically, the refractive index, haze, initial yellowing value b, and yellowing value b after 1000h of photoaging were tested. The test results are shown in Table 1.

[0105] Specifically, the refractive index is measured using an Abbe refractometer at a wavelength of 589 nm.

[0106] The method for testing haze is as follows: use a haze meter to measure the haze.

[0107] Test method for yellowing value: Use a colorimeter to measure, set the light source to D65 (simulated sunlight), the observation angle to 10°, measure 3 times at different positions on the film, and then take the arithmetic mean as the final result (the results in the table are the arithmetic mean).

[0108] The light aging test is as follows: the film sample is placed in an aging chamber with standard sunlight intensity (AM1.5) for 1000 hours of accelerated light aging test.

[0109] Table 1 Test data for the examples and comparative examples The test data in Table 1 show that: Comparing Example 1 with Comparative Example 1, the haze of Example 1 is much smaller than that of Comparative Example 1. The initial yellowing value and the yellowing value after photoaging of Example 1 are both smaller than those of Comparative Example 1. Therefore, it can be seen that the quantum dots used in the preparation of the film are modified quantum dots, which can effectively reduce the haze of the film and improve the light transmittance, and can maintain good optical performance when applied to batteries.

[0110] Comparing Examples 1 to 12 with Comparative Example 2, the refractive index of Examples 1 to 12 was improved compared to Comparative Example 2, the haze of Examples 1 to 12 was lower than that of Comparative Example 2, and the initial yellowing value and the yellowing value after photoaging of Examples 1 to 12 were significantly reduced compared to Comparative Example 2. It can be seen that the present application, by adding quantum dots that can efficiently absorb ultraviolet light to the film containing high refractive index resin, significantly suppresses the yellowing phenomenon of the film during photoaging, which helps to ensure the long-term optical stability of the film and can take into account both high refractive index and anti-yellowing performance.

[0111] Furthermore, comparing Example 1 with Examples 9 and 10, it can be seen that the haze, initial yellowing value, and yellowing value after photoaging of Example 1 are all better than those of Examples 9 and 10. Therefore, it can be concluded that the preferred anti-aging agent is a composite system of phenolic antioxidant and hindered amine light stabilizer.

[0112] The technical solutions of this application have been described in conjunction with preferred embodiments. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A high-refractive-index quantum dot film, characterized in that, The quantum dot film comprises the following components in parts by weight: 65-85 parts blank colloid particles, 2-10 parts high refractive index resin, 1-8 parts quantum dots, 0.1-2 parts coupling agent, 0.5-2 parts crosslinking agent, 0.5-2 parts co-crosslinking agent, 0.2-2 parts anti-aging additive, and 0.3-3 parts dispersant.

2. The high refractive index quantum dot film according to claim 1, characterized in that, The quantum dot film comprises the following components in parts by weight: 70-80 parts blank colloid particles, 4-8 parts high refractive index resin, 2-6 parts quantum dots, 0.5-1 part coupling agent, 0.8-1.5 parts crosslinking agent, 0.8-1.2 parts co-crosslinking agent, 0.5-1 part anti-aging additive, and 0.5-2 parts dispersant.

3. The high refractive index quantum dot film according to claim 2, characterized in that, The quantum dot film comprises the following components in parts by weight: 75 parts blank colloid particles, 6 parts high refractive index resin, 4 parts quantum dots, 0.8 parts coupling agent, 1 part crosslinking agent, 1 part co-crosslinking agent, 0.8 parts anti-aging additive, and 1 part dispersant.

4. The high refractive index quantum dot film according to claim 1, characterized in that, The quantum dots include one or more of CdSe, CdS, CdZnSe, CdZnS, CdZnSeS, CdSe / ZnS, CdSe / CdZnS, CdZnSe / ZnS, CdZnSe / ZnS, CdZnSe / CdZnS, CdSe / ZnSe, ZnSe / ZnS, CdSe / CdZnS / ZnS, CdZnS / ZnS, InP / ZnS, InP / ZnSe / ZnS, and perovskite quantum dots, wherein the perovskite quantum dots are CsPb. n Yb 1-n X3 (0≤n<1), where X is one or two of Cl, Br, and I; And / or, the particle size of the quantum dots is 10-55 nm; And / or, the quantum dots are modified quantum dots after surface modification using a modifier, wherein the modifier includes one or more of silane coupling agents, oleic acid and oleylamine.

5. The high refractive index quantum dot film according to claim 1, characterized in that, The high refractive index resin includes one or more of the following: acrylic resin containing aromatic groups, epoxy resin containing aromatic groups, polyurethane resin containing aromatic groups, polysulfuric acid ester resin containing aromatic groups, semi-alicyclic polyimide resin, polystyrene resin, polycarbonate resin, and polyarylate resin. And / or, the blank particles are EVA particles or POE particles.

6. The high refractive index quantum dot film according to claim 1, characterized in that, The acrylic resin containing aromatic groups includes one or more of styrene-acrylate copolymers, styrene-methacrylate copolymers, benzyl acrylate polymers, and benzyl methacrylate polymers. And / or, the epoxy resin containing aromatic groups includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenolic epoxy resin, o-cresol phenolic epoxy resin, naphthalene ring-containing epoxy resin, and biphenyl-containing epoxy resin. And / or, the polyurethane resin containing aromatic groups includes one or more of MDI-type (diphenylmethane diisocyanate) polyurethane, TDI-type (toluene diisocyanate) polyurethane, and polyester polyol-type polyurethane containing benzene rings. And / or, the polysulfuric ester resin containing aromatic groups includes one or more of the following: a polymer of aromatic diisocyanate and polythiol, a polymer of aromatic diisothiocyanate and polythiol or polyol, and polysulfuric ester modified with aromatic epoxy compounds. And / or, the hemicyclic polyimide resin includes one or more of the following: polyimides synthesized from alicyclic dianhydrides and aromatic diamines, and polyimides synthesized from aromatic dianhydrides and alicyclic diamines; And / or, the polystyrene resin includes one or more of polystyrene, high-impact polystyrene, syndiotactic polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene, and styrene-maleic anhydride copolymer; And / or, the polycarbonate resin includes one or more of bisphenol A type polycarbonate, bisphenol Z type, bisphenol C type, bisphenol AP type, polycarbonate containing tetramethylbisphenol A, polycarbonate containing biphenyl, and polycarbonate containing naphthol. And / or, the polyarylate resin includes one or more of bisphenol A type polyarylate, bisphenol C type polyarylate, bisphenol Z type polyarylate, copolymers of terephthalic acid / isophthalic acid and bisphenol A, and fully aromatic liquid crystal polyester.

7. The high refractive index quantum dot film according to claim 1, characterized in that, The coupling agent includes one or more of vinyl silane coupling agents, epoxy silane coupling agents, and amino silane coupling agents; And / or, the crosslinking agent includes one or more of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and benzoyl peroxide; And / or, the co-crosslinking agent includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate, and triallyl cyanurate; And / or, the anti-aging agent is a composite system of phenolic antioxidants and hindered amine light stabilizers, wherein the mass ratio of the phenolic antioxidants to the hindered amine light stabilizers is 1:(0.5~2). And / or, the dispersant includes one or more of organosilicon dispersants, polycarboxylate dispersants, and polyurethane dispersants.

8. The high refractive index quantum dot film according to any one of claims 1 to 7, characterized in that, The quantum dot film has a refractive index ≥1.5000, haze ≤3.1, initial yellowing value b≤1.2, and yellowing value b≤1.5 after 1000h photoaging.

9. A method for preparing a high-refractive-index quantum dot film, used to prepare the high-refractive-index quantum dot film according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: S1: Surface modification of quantum dots using a modifier to obtain modified quantum dots; S2: Mix blank granules, high refractive index resin, modified quantum dots, coupling agent, crosslinking agent, co-crosslinking agent, anti-aging additive and dispersant evenly to obtain a premix; S3: Add the premixed material to the screw extruder, extrude it and then cast it to obtain a preliminary film; S4: Place the preliminary adhesive film in a laminator and laminate it to obtain a quantum dot adhesive film with a high refractive index.

10. The method for preparing a high-refractive-index quantum dot film according to claim 9, characterized in that, Step S1 specifically includes: mixing quantum dots and modifiers at a mass ratio of 1:(0.03~0.3), adding organic solvent, stirring at 20~60℃ for 0.5~3h, centrifuging, and vacuum drying to obtain modified quantum dots; And / or, in step S2, the mixing is carried out in a high-speed mixer, wherein the mixing temperature is 20~45℃, the rotation speed is 600~1500r / min, and the mixing time is 15~50min; And / or, in step S3, the extrusion temperature is 110~170℃ and the screw speed is 25~60r / min; And / or, in step S4, vacuuming is performed at 145°C for 5 minutes before lamination, and lamination is performed for 15 minutes after pressurization.

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