A light conversion and diffusion integrated backlight module based on perovskite quantum dot material and a preparation method thereof

Abstract

The application relates to the technical field of display module manufacturing, and discloses a light conversion and diffusion integrated backlight module based on a perovskite quantum dot material and a preparation method thereof, which comprises a light guide plate, a blue light LED light source, a reflecting sheet and a light conversion and diffusion integrated film sheet on the light emitting side. The film sheet is made of maleic anhydride grafted polyolefin elastomer, ethylene-vinyl acetate copolymer, a ternary copolymer containing an epoxy group, polymethylsilsesquioxane and perovskite precursor and the like through extrusion and devolatilization. The epoxy groups and the anhydride groups in the film sheet are crosslinked to form a spatially confined microphase structure anchored through reaction, the perovskite luminophore is wrapped in the inside of the network, and the polymethylsilsesquioxane is distributed at the polymer phase interface. The application can block water and oxygen penetration, improve the stability of the light emitting film sheet in a high temperature and high humidity environment, realize physical isolation and optical decoupling of the light emitting phase and the diffusion phase at the same time, and improve the light emitting uniformity and photoluminescence quantum yield of the backlight module.

Description

Technical Field

[0001] This invention relates to the field of display module manufacturing technology, specifically to an integrated backlight module based on perovskite quantum dot material for light conversion and diffusion, and its preparation method. Background Technology

[0002] Perovskite quantum dot materials have been widely used in wide color gamut liquid crystal display backlighting due to their high luminous efficiency and narrow emission half-width. Typically, perovskite materials are dispersed in a polymer matrix to form a light-converting thin film, which is then combined with components such as light guide plates and reflectors to assemble a backlight module. However, due to the inherent characteristics of the perovskite lattice structure, it is quite sensitive to moisture, oxygen, and thermal stress in the environment. During long-term operation of display devices or in high-temperature and high-humidity service environments, external water molecules and oxygen can easily penetrate into the polymer matrix, causing phase transitions and lattice dissociation in the perovskite material, thereby leading to a decrease in the quantum yield of the thin film.

[0003] To address this environmental stability issue, a conventional solution is to physically blend the perovskite precursor with a hydrophobic polymer. However, in this physically-based blend system, the polymer continuous phase segments are prone to thermal rearrangement and intermolecular slippage under heating. These changes in morphology and size disrupt the original physical barrier structure of the polymer, shortening the diffusion paths of water and oxygen into the interior, making it difficult to maintain the long-term stability of the perovskite luminescent micro-regions.

[0004] On the other hand, to meet the requirements of light emission uniformity in the backlight module, light diffusion functionality needs to be introduced into the thin film. If conventional light diffusing agents are directly added to the existing luminescent polymer system, the luminescent cores and light diffusing particles often exhibit a disordered, random mixing state in spatial distribution. Due to the refractive index mismatch, direct physical contact between the luminescent and diffusing phases easily leads to near-field optical interference and non-radiative recombination losses. This optical coupling phenomenon between the luminescent and diffusing phases directly causes a decrease in the overall quantum yield and luminous efficacy of the backlight module, making it difficult to simultaneously achieve high luminous efficiency and good light emission uniformity. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an integrated light-conversion and diffusion backlight module based on perovskite quantum dot materials and its preparation method. This solves the problems of insufficient structural stability of existing perovskite luminescent films under high temperature and high humidity environments, and the tendency for internal water and oxygen permeation to lead to lattice dissociation. At the same time, in the backlight module, there is an optical coupling loss between the luminescent phase and the light-diffusing phase, which causes a decrease in overall quantum yield and light emission efficiency.

[0006] To address the above problems, the present invention provides the following technical solution: In a first aspect, the present invention provides an integrated light conversion and diffusion backlight module based on perovskite quantum dot material, employing the following technical solution: A backlight module based on perovskite quantum dot material with integrated light conversion and diffusion includes a light guide plate, a blue LED light source disposed on the light-incident side of the light guide plate, a reflective sheet disposed on the backlight side, and an integrated light conversion and diffusion film disposed on the light-outside side. The light-converting and diffusion integrated film is made from the following raw materials in parts by weight: 70-80 parts maleic anhydride-grafted polyolefin elastomer; 20-30 parts ethylene-vinyl acetate copolymer; 2-10 parts ethylene oxide-propylene oxide-ethylene oxide block copolymer; 0.5-2.5 parts styrene-butyl acrylate-glycidyl methacrylate terpolymer; 1.0-8.0 parts polymethylsilsesquioxane; 0.37-1.83 parts cesium bromide; 0.63-3.17 parts lead bromide; and the molar ratio of cesium bromide to lead bromide is 1:0.95-1.25; 0.1-1.5 parts triphenyl phosphite; and 10-20 parts polar solvent. In the integrated light-conversion and diffusion film, the epoxy groups of the styrene-butyl acrylate-glycidyl methacrylate terpolymer undergo a ring-opening crosslinking reaction with the anhydride groups of the maleic anhydride-grafted polyolefin elastomer, which facilitates the formation of a reaction-anchored spatially confined microphase structure. The perovskite luminescent material crystallizes in situ within the spatially confined microphase structure, and the polymethylsilsesquioxane acts as a light-diffusing particle dispersed in the polymer matrix to reduce non-radiative recombination losses caused by direct contact between the luminescent phase and the light-diffusing particles.

[0007] By employing the above technical solution, a multi-component polymer blend system is used to construct a continuous phase and a polar microphase. A terpolymer containing epoxy groups and a polyolefin elastomer containing anhydride groups are used as active components to construct a crosslinking network. This is combined with extrusion devolatilization and spatially confined crystallization using a polar solvent containing a perovskite precursor. Therefore, the system achieves improved reliability of the luminescent film in extreme environments and enhanced light extraction efficiency of the backlight module. In the system, the maleic anhydride-grafted polyolefin elastomer provides a non-polar continuous phase matrix, the ethylene-vinyl acetate copolymer provides a polar micro-region environment to accommodate the precursor, and the ethylene oxide-propylene oxide-ethylene oxide block copolymer acts as a compatibilizer to regulate the microphase separation scale. When the styrene-butyl acrylate-glycidyl methacrylate terpolymer is added to the system as a reactive crosslinking component, under the drive of heating and subsequent solvent devolatilization, the anhydride groups on the polyolefin segments undergo an in-situ ring-opening crosslinking reaction with the epoxy groups in the terpolymer. The specific chemical reaction process is as follows: the maleic anhydride group undergoes ring-opening upon heating to form a carboxyl structure. The carboxyl group further undergoes a nucleophilic substitution reaction with the epoxy ring of the glycidyl ester side chain, causing the epoxy ring to open and generate the corresponding hydroxyl groups and ester bonds. This esterification and crosslinking reaction forms dense covalent crosslinking nodes at the interface between the continuous phase of the polyolefin matrix and the polar microphase, transforming and locking the originally thermodynamically incompatible physically separated microphase structure into a rigid three-dimensional chemical crosslinking network.

[0008] Establishing this chemically cross-linked rigid network helps to fix the phase domain interfaces encapsulated by the block copolymer. Under high-temperature and high-humidity service stress, this cross-linked network restricts large-scale thermal rearrangement and intermolecular slip of the polymer continuous phase segments, and to some extent inhibits phase region coarsening and creep disintegration behavior that occurs in the polymer amorphous region above the relaxation temperature. The stability of the physical barrier morphology and size reduces the free path of diffusion of external water molecules and oxygen into the internal polar luminescent micro-regions, thereby reducing the possibility of phase transition and dissociation of the perovskite lattice encapsulated inside the microphase network due to moisture, enabling it to maintain a high quantum yield retention rate under harsh testing environments such as double 85°C.

[0009] Furthermore, the crystallized perovskite luminescent cores are primarily formed within polar confined microregions constructed using block copolymers, while polymethylsilsesquioxane acts as light-diffusing microparticles dispersed within the polymer matrix, providing light scattering. This structural design helps reduce the direct interfacial contact between the luminescent cores and the light diffusing agent, mitigating near-field optical interference and nonradiative recombination losses caused by refractive index mismatch. This, in turn, improves the film's optical haze while maintaining a high photoluminescence quantum yield.

[0010] Preferably, the light-converting and diffusion integrated film is made from raw materials comprising the following parts by weight: 70-75 parts of maleic anhydride-grafted polyolefin elastomer; 25-30 parts of ethylene-vinyl acetate copolymer; 4-8 parts of ethylene oxide-propylene oxide-ethylene oxide block copolymer; 1.0-2.0 parts of styrene-butyl acrylate-glycidyl methacrylate terpolymer; 3.0-6.0 parts of polymethylsilsesquioxane; 0.8-1.5 parts of cesium bromide; 1.5-2.5 parts of lead bromide; and the molar ratio of cesium bromide to lead bromide is 1:1.00-1.20; 0.5-1.0 parts of triphenyl phosphite; and 12-18 parts of polar solvent.

[0011] By adopting the above technical solution, the ratio range of each component is narrowed, enabling the phase domain distribution scale, chemical crosslinking density, and perovskite luminescent particle precipitation size to approach thermodynamic equilibrium. Controlling the molar ratio of anhydride groups to epoxy groups helps improve the compactness of the reactive crosslinking network. Lead bromide in the precursor is in a slight excess compared to cesium bromide; the excess lead ions help fill surface bromine vacancy defects generated during crystallization, improving the self-passivation effect of the crystal surface and further mitigating the non-radiative recombination decay behavior caused by environmental water and oxygen erosion.

[0012] Preferably, the grafting rate of the maleic anhydride-grafted polyolefin elastomer is 0.5-1.5 wt%, and it is prepared by reactive extrusion of ethylene-1-octene copolymer and maleic anhydride via free radical initiation.

[0013] By employing the above technical solution, the grafting rate range is limited, which is beneficial for maintaining appropriate flexibility and mechanical calendering processing properties of the main chain backbone, while providing a corresponding density of reactive sites for subsequent interfacial crosslinking. Using reactive extrusion to directly and uniformly graft maleic anhydride onto the polymer long-chain macromolecular backbone can reduce the problem of direct external application of small molecule crosslinking agents easily migrating and escaping to the system surface, leading to a sticky and white film surface.

[0014] Preferably, the styrene-butyl acrylate-glycidyl methacrylate terpolymer has a weight-average molecular weight (Mw) of 6000-12000 and an epoxy equivalent of 250-350 g / eq.

[0015] By employing the above technical solution, the molecular weight within a specific range enables the ternary copolymer to possess matched melt viscosity and chain segment diffusion rate in the melt blend system, allowing it to migrate rapidly to the microphase separation interface. The limited epoxy equivalent ensures that each copolymer molecular chain carries a moderate number of active epoxy sites, reducing the risk of localized melt gelation due to excessive crosslinking sites and the risk of a loose phase network due to insufficient crosslinking. This is beneficial for forming a uniform, stable, and optically free spatially confined morphology.

[0016] Preferably, the polar solvent is dimethyl sulfoxide or N,N-dimethylformamide.

[0017] By adopting the above technical solution, this type of strongly polar aprotic solvent has good solubility and can dissolve cesium bromide and lead bromide precursors to form a uniform and transparent complex liquid. Its boiling point is moderate, which makes it easy to achieve flash vaporization devolatilization in a specific temperature range of the extrusion process by adjusting the temperature and applying vacuum, thereby providing a suitable process operation window for subsequent control of perovskite supersaturation and nucleation rate.

[0018] Secondly, the present invention provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, employing the following technical solution: A method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot material includes the following steps: S1 Solid-phase blending: The maleic anhydride-grafted polyolefin elastomer, ethylene-vinyl acetate copolymer, ethylene oxide-propylene oxide-ethylene oxide block copolymer, styrene-butyl acrylate-glycidyl methacrylate terpolymer and polymethylsilsesquioxane are mixed evenly to obtain a solid-phase premix. S2 liquid phase complexation: Under light-protected conditions, cesium bromide, lead bromide and triphenyl phosphite are added to the polar solvent and stirred until transparent to form a transparent complex solution; S3 In-situ Extrusion and Confined Crystallization: The solid premix is ​​added to a twin-screw extruder for melting, forming a mesoscopic phase separation network consisting of a non-polar continuous phase composed of maleic anhydride-grafted polyolefin elastomer and polar dispersed microdomains enriched from ethylene-vinyl acetate copolymer and ethylene oxide-propylene oxide-ethylene oxide block copolymer; the mesoscopic phase separation network is a phase separation structure formed by the non-polar continuous phase and the polar dispersed microdomains, and the polar dispersed microdomains are used to enrich the perovskite precursor in the transparent complex liquid; the transparent complex liquid is pumped into the twin-screw extruder for shear dispersion; a vacuum operation is performed in the temperature zone of the extruder's rear section to flash evaporate and devolatilize, inducing ring-opening crosslinking of the matrix network and removal of polar solvents, promoting the precipitation and crystallization of the precursor within a confined space; the melt is then cooled and calendered to obtain an integrated light-conversion and diffusion film; S4 Module Assembly: A blue LED light source is placed on the light-incident side of the light guide plate, a reflector is placed on the backlight side of the light guide plate, and the integrated light-converting and diffusing film is placed on the light-emitting side of the light guide plate to obtain the backlight module.

[0019] By employing the above technical solution, a continuous reactive extrusion process integrates the polymer blending microphase separation, chemical crosslinking, and confined crystallization of luminescent crystals into a single processing flow. The solid premix melts to form a mesoscopic phase separation network, and the transparent complex liquid, after shear dispersion, accumulates in the polar microphase region. The principle lies in the two effects of vacuum flash devolatilization in the later stages of the extruder: firstly, the rapid removal of polar solvents under vacuum negative pressure causes the precursor concentration in the polar microregions to sharply exceed the saturation solubility limit, inducing rapid nucleation and crystallization of perovskite within the confined space; secondly, the removal of solvent molecules eliminates the solvation shielding effect on reactive groups and directly triggers the ring-opening esterification crosslinking reaction between anhydride groups and epoxy groups at the barrel heating temperature. The rate of interfacial chemical crosslinking reaction is matched with the crystallization rate induced by solvent evaporation on the spatiotemporal continuum, which allows the newly precipitated tiny perovskite grains to be fixed and encapsulated in the formed rigid three-dimensional microphase network. This reduces the probability of secondary Oswald ripening growth and agglomeration of the grains, thereby simplifying the processing steps of the optical backlight assembly.

[0020] Preferably, in step S3, the temperatures of the first to third temperature zones of the extruder where the solid premix is ​​located are 160-170℃, 170-180℃, and 180-190℃, respectively, and the main screw speed is maintained at 300 rpm; the injection pressure of pumping the transparent complexing liquid into the twin-screw extruder is controlled at 1.5 MPa.

[0021] By adopting the above technical solution, the stepped heating of the barrel temperature and the set main screw speed facilitate molecular-level mixing and rheology of polymer components with different melt indices, forming a mesoscopic phase separation structure with suitable scale. The constant injection pressure allows the transparent complexing liquid to overcome the back pressure generated by the polymer melt at the screw tip, smoothly entering the extruder barrel. The shear field of the screw then breaks it down and disperses it into nanoscale droplets, providing a uniformly dispersed size template for subsequent confined crystallization.

[0022] Preferably, in step S3, the flash devolatilization is carried out in an independent temperature zone of the twin-screw extruder by opening the lateral vacuum exhaust port, controlling the vacuum degree to be -0.08MPa to -0.09MPa, and the temperature of the temperature zone during the flash devolatilization stage is maintained at 195-200℃.

[0023] By employing the above technical solution, the temperature and vacuum level of the independent temperature zone are controlled within a specific range, providing a corresponding thermodynamic driving force for the instantaneous boiling and vaporization of polar solvents. The controlled negative pressure gradient can reduce defects such as melt fracture, material rumination, and bubble residue caused by excessively rapid solvent boiling. At the same time, the higher temperature accelerates the kinetic process of the interfacial esterification and crosslinking reaction, promoting the synchronous coupling of crosslinking network solidification and inorganic light-emitting crystal precipitation, which is beneficial to maintaining the optical haze and internal structural integrity of the final optical film.

[0024] Preferably, before step S1, the maleic anhydride-grafted polyolefin elastomer is pre-prepared as follows: 100 parts by weight of ethylene-1-octene copolymer, 1.0-2.0 parts by weight of maleic anhydride powder, and 0.05-0.1 parts by weight of dicumyl peroxide are added to a mixer for premixing, and then fed into a co-rotating twin-screw extruder with each temperature zone maintained at 160-185°C for reactive extrusion. After cooling in a water bath and pelletizing and drying, the product is obtained.

[0025] By adopting the above technical solution, the free radical grafting reaction of maleic anhydride is completed before the main film processing step, and unreacted small molecules and peroxide decomposition byproducts are removed through a cooling and pelletizing process. This pretreatment step purifies the material system for subsequent continuous extrusion film production, reduces the risk of vacuum pipe and pump blockage caused by the sublimation and volatilization of free maleic anhydride small molecules during the high-temperature devolatilization stage, and ensures that the optical film of the backlight module is free of odor molecules and corrosive residues.

[0026] Preferably, prior to step S1, the styrene-butyl acrylate-glycidyl methacrylate terpolymer is prepared as follows: 23-39 parts by weight of a mixture of styrene, 20 parts by weight of butyl acrylate, and 41-57 parts by weight of glycidyl methacrylate monomers, along with 1.0-2.0 parts by weight of initiator, are added dropwise at a uniform rate to a heated toluene solvent under inert gas protection. After reacting at a constant temperature of 85-95°C, the solvent is removed by vacuum treatment at 120°C and a vacuum degree of -0.08 MPa.

[0027] By employing the above technical solution, utilizing solution polymerization combined with a uniformly dripping monomer feed method, the differences in the reactivity ratios of different monomers in the free radical copolymerization reaction were effectively controlled, resulting in a random yet uniform distribution of styrene, butyl acrylate, and glycidyl methacrylate structural units on the copolymer molecular chain backbone. The high-temperature vacuum operation after the reaction removed residual free monomers and toluene solvent from the system, providing highly reactive and high-purity crosslinking precursor components and reducing the potential quenching interference of impurities on the luminescence properties of perovskite crystals.

[0028] This invention provides an integrated light conversion and diffusion backlight module based on perovskite quantum dot material and its fabrication method. It has the following beneficial effects: 1. This invention involves in-situ ring-opening crosslinking of a polyolefin elastomer containing anhydride groups with a terpolymer containing epoxy groups to form a spatially confined microphase structure with reaction anchoring effect inside the film. This reaction anchoring structure helps maintain the phase domain interface, restricts the thermal rearrangement of polymer chain segments, and reduces the free path of diffusion of external water molecules and oxygen into the internal polar luminescent microregions. This structure inhibits the phase transition and dissociation of the perovskite lattice encapsulated inside the microphase network due to moisture, improving the structural reliability and quantum yield retention of the luminescent film under high temperature and high humidity environments.

[0029] 2. This invention reduces the direct interfacial contact between the perovskite luminescent material and the light-diffusing particles by in-situ crystallizing the perovskite luminescent material within a polymer-confined micro-region and dispersing polymethylsilsesquioxane as light-diffusing particles within the polymer matrix. This structural design helps to reduce near-field optical interference and non-radiative recombination losses caused by refractive index mismatch, thereby improving the optical haze of the film and the light emission uniformity of the backlight module while maintaining a high photoluminescence quantum yield.

[0030] 3. The preparation method of this invention employs a continuous in-situ extrusion and devolatilization process, integrating polymer blending, chemical crosslinking, and crystal confinement crystallization into the same processing flow. Polar solvents are rapidly removed via flash devolatilization in the downstream section of the extruder, inducing perovskite nucleation and crystallization within a confined space while simultaneously triggering esterification and crosslinking reactions between the polymer matrix. The simultaneous solidification of the crosslinked network and the precipitation of inorganic luminescent crystals ensure that the precipitated micro-perovskite grains are promptly encapsulated and fixed, reducing the probability of secondary ripening growth and agglomeration of the grains. This method also simplifies the processing steps for optical films. Attached Figure Description

[0031] Figure 1 The graph shows the relationship between optical haze and absolute fluorescence quantum yield for the films in the Example series and Comparative Example 6. Figure 2 The graph shows the quantum yield retention rate changes of the membranes of Example 1, Example 4, Comparative Example 3, and Comparative Example 4 during the double 85 damp heat aging test. Figure 3 Fourier transform infrared spectra of the unreacted premix and the membrane of Example 1; Figure 4 Photoluminescence emission spectra of the films of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 5 under 450 nm blue light excitation conditions; Figure 5The images shown are scanning electron microscope images of the membrane cross-section in Example 1, where (a) is a low-power image and (b) is a high-power image. Figure 6 The following are EDS elemental distribution maps of the membrane cross-section in Example 1, where (a) is an electron image, (b) is a Si elemental distribution map, (c) is a Pb elemental distribution map, (d) is a Br elemental distribution map, and (e) is a Cs elemental distribution map. Figure 7 The images shown are transmission electron microscope images of the membrane in Example 1, where (a) is a low-power image and (b) is a high-power image.

[0032] Figure 8 The images shown are atomic force microscopy (AFM) images of the membrane in Example 1, where (a) is an AFM phase diagram and (b) is an AFM three-dimensional topographic image. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0035] Ethylene-vinyl acetate copolymer, CAS number 24937-78-8, is a high molecular weight random copolymer with a molecular structure composed of C2H4 and C4H6O2 structural units. The mass fraction of vinyl acetate is 18%–28%, the melt index is 2–6 g / 10 min (190℃, 2.16 kg), and the density is 0.94 g / cm³. 3 .

[0036] Ethylene-1-octene copolymer, CAS number 26221-73-8, is a high molecular weight random copolymer elastomer with a molecular structure consisting of C2H4 and C8H4. 16 The structural unit consists of 20%–30% 1-octene monomer by mass, with a melt index of 1–5 g / 10 min (190 °C, 2.16 kg) and a density of 0.86 g / cm³. 3 ~0.88g / cm 3 .

[0037] Ethylene oxide-propylene oxide-ethylene oxide block copolymer, CAS number 9003-11-6, is a nonionic triblock polymer. Its main chain contains C2H4O and C3H6O block units, and its number average molecular weight Mn is 4000-10000 g / mol. The mass fraction of hydrophilic ethylene oxide segments accounts for 20%-40% of the total molecular weight.

[0038] Polymethylsilsesquioxane, CAS No. 68554-70-1, is a solid microsphere made of cross-linked organosilicon resin with an average particle size distribution of 2.0–5.0 μm and a refractive index of 1.42–1.44.

[0039] Maleic anhydride, a common chemical monomer, has the CAS number 108-31-6.

[0040] Dicumyl peroxide, a conventional free radical initiator, CAS number 80-43-3.

[0041] Styrene, a common chemical monomer, has the CAS number 100-42-5.

[0042] Butyl acrylate, a common chemical monomer, CAS number 141-32-2.

[0043] Glycidyl methacrylate, a common chemical monomer, CAS number 106-91-2.

[0044] Azobisisobutyronitrile (AIBN), a conventional free radical initiator, has the CAS number 78-67-1.

[0045] Triphenyl phosphite, a conventional coordination passivating agent, CAS number 101-02-0.

[0046] Cesium bromide is a common inorganic salt with CAS number 7787-69-1.

[0047] Lead bromide, a common inorganic salt, CAS number 10031-22-8.

[0048] Dimethyl sulfoxide, a common polar solvent, CAS number 67-68-5.

[0049] N,N-Dimethylformamide, a common polar solvent, CAS number 68-12-2.

[0050] Toluene, a common organic solvent, has the CAS number 108-88-3.

[0051] Preparation Example 1: This preparation example provides a method for preparing a maleic anhydride-grafted polyolefin elastomer, including the following steps: (1) Premixing: 100g of ethylene-1-octene copolymer, 1.5g of maleic anhydride powder and 0.08g of dicumyl peroxide were put into a high-speed mixer and mixed at 400rpm for 4min to obtain a premix. (2) Reactive extrusion: The premixed material is fed into a co-rotating twin-screw extruder for reactive extrusion. The length-to-diameter ratio of the extruder is 40, and the temperature of each temperature zone is set as follows: Zone 1: 160°C, Zones 2 to 4: 185°C, Zones 5 to 7: 185°C, Die head: 180°C, and the screw speed is set to 220 rpm. (3) Post-processing: The extruded material is cooled in a water tank, granulated and dried to obtain maleic anhydride grafted polyolefin elastomer with a maleic anhydride grafting rate of 1.0 wt%.

[0052] Preparation Example 2: This preparation example provides a method for preparing a maleic anhydride-grafted polyolefin elastomer, including the following steps: (1) Premixing: 100g of ethylene-1-octene copolymer, 1.0g of maleic anhydride powder and 0.05g of dicumyl peroxide were put into a high-speed mixer and mixed at 400rpm for 4min to obtain a premix. (2) Reactive extrusion: The premixed material is fed into a co-rotating twin-screw extruder for reactive extrusion. The length-to-diameter ratio of the extruder is 40, and the temperature of each temperature zone is set as follows: Zone 1: 160°C, Zones 2 to 4: 185°C, Zones 5 to 7: 185°C, Die head: 180°C, and the screw speed is set to 220 rpm. (3) Post-processing: The extruded material is cooled in a water tank, granulated and dried to obtain maleic anhydride grafted polyolefin elastomer with a maleic anhydride grafting rate of 0.5 wt%.

[0053] Preparation Example 3: This preparation example provides a method for preparing a maleic anhydride-grafted polyolefin elastomer, including the following steps: (1) Premixing: 100g of ethylene-1-octene copolymer, 2.0g of maleic anhydride powder and 0.1g of dicumyl peroxide were put into a high-speed mixer and mixed at 400rpm for 4min to obtain a premix. (2) Reactive extrusion: The premixed material is fed into a co-rotating twin-screw extruder for reactive extrusion. The length-to-diameter ratio of the extruder is 40, and the temperature of each temperature zone is set as follows: Zone 1: 160°C, Zones 2 to 4: 185°C, Zones 5 to 7: 185°C, Die head: 180°C, and the screw speed is set to 220 rpm. (3) Post-processing: The extruded material is cooled in a water tank, granulated and dried to obtain maleic anhydride grafted polyolefin elastomer with a maleic anhydride grafting rate of 1.5 wt%.

[0054] Preparation Example 4: This preparation example provides a method for preparing a styrene-butyl acrylate-glycidyl methacrylate terpolymer, comprising the following steps: (1) Solvent preheating: Add 100g of toluene solvent to a reactor equipped with a reflux condenser, a mechanical stirrer and nitrogen protection, and heat to 90℃; (2) Monomer addition: After mixing 33g of styrene, 20g of butyl acrylate and 47g of glycidyl methacrylate with 1.5g of azobisisobutyronitrile initiator evenly, the mixture is added dropwise into the reaction vessel at a uniform rate over 2.5h through a dropping funnel. (3) Polymerization reaction: After the addition is complete, the reaction is kept at 90℃ for 4.5h. (4) Post-devouring treatment: After the reaction is completed, the system temperature is raised to 120°C and the vacuum is slowly drawn to -0.08MPa to remove toluene solvent and unreacted residual monomers; the material is cooled, discharged and crushed to obtain a terpolymer with a weight average molecular weight Mw of 9000 and an epoxy equivalent of about 300g / eq.

[0055] Preparation Example 5: This preparation example provides a method for preparing a styrene-butyl acrylate-glycidyl methacrylate terpolymer, comprising the following steps: (1) Solvent preheating: Add 100g of toluene solvent to a reactor equipped with a reflux condenser, a mechanical stirrer and nitrogen protection, and heat to 95℃; (2) Monomer addition: After mixing 39g of styrene, 20g of butyl acrylate and 41g of glycidyl methacrylate with 2.0g of azobisisobutyronitrile initiator evenly, the mixture is added dropwise into the reaction vessel at a uniform rate over 2.5h through a dropping funnel. (3) Polymerization reaction: After the addition is complete, the reaction is kept at a constant temperature of 95℃ for 4.5h; (4) Post-devouring treatment: After the reaction is completed, the system temperature is raised to 120°C and the vacuum is slowly drawn to -0.08MPa to remove toluene solvent and unreacted residual monomers; the material is cooled, discharged and crushed to obtain a terpolymer with a weight average molecular weight Mw of 6000 and an epoxy equivalent of about 350g / eq.

[0056] Preparation Example 6: This preparation example provides a method for preparing a styrene-butyl acrylate-glycidyl methacrylate terpolymer, comprising the following steps: (1) Solvent preheating: Add 100g of toluene solvent to a reactor equipped with a reflux condenser, a mechanical stirrer and nitrogen protection, and heat to 85℃; (2) Monomer addition: After mixing 23g of styrene, 20g of butyl acrylate and 57g of glycidyl methacrylate with 1.0g of azobisisobutyronitrile initiator evenly, the mixture is added dropwise into the reaction vessel at a uniform rate over 2.5h through a dropping funnel. (3) Polymerization reaction: After the addition is complete, the reaction is kept at 85℃ for 4.5h. (4) Post-devouring treatment: After the reaction is completed, the system temperature is raised to 120°C and the vacuum is slowly drawn to -0.08MPa to remove toluene solvent and unreacted residual monomers; the material is cooled, discharged and crushed to obtain a terpolymer with a weight average molecular weight Mw of 12000 and an epoxy equivalent of about 250g / eq.

[0057] Example 1: This embodiment provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, including the following steps: (1) Solid-phase blending: 70g of maleic anhydride-grafted polyolefin elastomer obtained in Preparation Example 1, 30g of ethylene-vinyl acetate copolymer, 6g of ethylene oxide-propylene oxide-ethylene oxide block copolymer, 1.5g of styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 4 and 4.5g of polymethylsilsesquioxane were put into a high-speed mixer and mixed at 500 rpm for 10 min to obtain a solid-phase premix.

[0058] (2) Liquid phase complexation: In a light-proof reaction vessel, 1.1g of cesium bromide, 1.9g of lead bromide and 0.8g of triphenyl phosphite are added to 15g of dimethyl sulfoxide. Magnetic stirring is turned on until the solids are completely dissolved to form a transparent complex liquid. The transparent complex liquid is then connected to a plunger-type liquid injection pump.

[0059] (3) Melting and microphase separation: The solid premix is ​​fed into the co-rotating twin-screw extruder through the main feed port. The temperatures of the first to third temperature zones of the extruder are set to 160°C, 170°C and 180°C respectively. The main screw speed is set to 300 rpm, so that the resin melts and forms a mesophase separation network.

[0060] (4) Liquid injection and enrichment: The temperature of the fourth temperature zone of the extruder is set to 190°C. The transparent complex liquid is continuously pumped into the fourth temperature zone at an injection pressure of 1.5 MPa by a liquid injection pump for shear dispersion.

[0061] (5) In-situ grafting and flash devolatilization: The temperature of the 5th to 6th temperature zones of the extruder is set to 195°C. The side vacuum exhaust port is opened in the 6th temperature zone and the vacuum degree is maintained at -0.09MPa. Covalent network locking and flash removal of dimethyl sulfoxide solvent are achieved simultaneously.

[0062] (6) Confined crystallization and extrusion molding: The temperatures of the 7th and 8th temperature zones of the extruder are set to 165°C and 155°C respectively, so that the system is cooled and confined to crystallize. The melt is then extruded through a coat hanger-type die at 150°C, calendered and cooled by a three-roll calender at 70°C, and then wound up to obtain an integrated light-diffusion film with a thickness of 200μm.

[0063] (7) Backlight module assembly: A blue LED light source is placed on the light-incident side of the light guide plate, a reflector is placed on the backlight side of the light guide plate, and the resulting light-conversion and diffusion integrated film is placed on the light-exit side of the light guide plate. After assembly, a light-conversion and diffusion integrated backlight module based on perovskite quantum dot material is obtained.

[0064] Example 2: This embodiment provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, including the following steps: (1) Solid-phase blending: 70g of maleic anhydride-grafted polyolefin elastomer obtained in Preparation Example 2, 30g of ethylene-vinyl acetate copolymer, 2g of ethylene oxide-propylene oxide-ethylene oxide block copolymer, 0.5g of styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 5 and 1.0g of polymethylsilsesquioxane were put into a high-speed mixer and mixed at 500 rpm for 10 min to obtain a solid-phase premix.

[0065] (2) Liquid phase complexation: In a light-proof reaction vessel, 0.37g of cesium bromide, 0.63g of lead bromide and 0.1g of triphenyl phosphite are added to 10g of dimethyl sulfoxide. Magnetic stirring is turned on until the solid is completely dissolved to form a transparent complex liquid, and the transparent complex liquid is connected to a plunger-type liquid injection pump.

[0066] (3) Melting and microphase separation: The solid premix is ​​fed into the co-rotating twin-screw extruder through the main feed port. The temperatures of the first to third temperature zones of the extruder are set to 160°C, 170°C and 180°C respectively. The main screw speed is set to 300 rpm, so that the resin melts and forms a mesophase separation network.

[0067] (4) Liquid injection and enrichment: The temperature of the fourth temperature zone of the extruder is set to 190°C. The transparent complex liquid is continuously pumped into the fourth temperature zone at an injection pressure of 1.5 MPa by a liquid injection pump for shear dispersion.

[0068] (5) In-situ grafting and flash devolatilization: The temperature of the 5th to 6th temperature zones of the extruder is set to 195°C. The side vacuum exhaust port is opened in the 6th temperature zone and the vacuum degree is maintained at -0.09MPa. Covalent network locking and flash removal of dimethyl sulfoxide solvent are achieved simultaneously.

[0069] (6) Confined crystallization and extrusion molding: The temperatures of the 7th and 8th temperature zones of the extruder are set to 165°C and 155°C respectively, so that the system is cooled and confined to crystallize. The melt is then extruded through a coat hanger-type die at 150°C, calendered and cooled by a three-roll calender at 70°C, and then wound up to obtain an integrated light-diffusion film with a thickness of 200μm.

[0070] (7) Backlight module assembly: Following the same assembly method as in Example 1, the obtained light-converting and diffusion integrated film is assembled with the reflective sheet, light guide plate and blue LED light source to obtain a light-converting and diffusion integrated backlight module based on perovskite quantum dot material.

[0071] Example 3: This embodiment provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, including the following steps: (1) Solid-phase blending: 70g of maleic anhydride-grafted polyolefin elastomer obtained in Preparation Example 3, 30g of ethylene-vinyl acetate copolymer, 10g of ethylene oxide-propylene oxide-ethylene oxide block copolymer, 2.5g of styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 6 and 8.0g of polymethylsilsesquioxane were put into a high-speed mixer and mixed at 500 rpm for 10 min to obtain a solid-phase premix.

[0072] (2) Liquid phase complexation: In a light-proof reaction vessel, 1.83g of cesium bromide, 3.17g of lead bromide and 1.5g of triphenyl phosphite were added to 20g of dimethyl sulfoxide. Magnetic stirring was turned on until the solid was completely dissolved to form a transparent complex liquid, and the transparent complex liquid was connected to a plunger-type liquid injection pump.

[0073] (3) Melting and microphase separation: The solid premix is ​​fed into the co-rotating twin-screw extruder through the main feed port. The temperatures of the first to third temperature zones of the extruder are set to 160°C, 170°C and 180°C respectively. The main screw speed is set to 300 rpm, so that the resin melts and forms a mesophase separation network.

[0074] (4) Liquid injection and enrichment: The temperature of the fourth temperature zone of the extruder is set to 190°C. The transparent complex liquid is continuously pumped into the fourth temperature zone at an injection pressure of 1.5 MPa by a liquid injection pump for shear dispersion.

[0075] (5) In-situ grafting and flash devolatilization: The temperature of the 5th to 6th temperature zones of the extruder is set to 195°C. The side vacuum exhaust port is opened in the 6th temperature zone and the vacuum degree is maintained at -0.09MPa. Covalent network locking and flash removal of dimethyl sulfoxide solvent are achieved simultaneously.

[0076] (6) Confined crystallization and extrusion molding: The temperatures of the 7th and 8th temperature zones of the extruder are set to 165°C and 155°C respectively, so that the system is cooled and confined to crystallize. The melt is then extruded through a coat hanger-type die at 150°C, calendered and cooled by a three-roll calender at 70°C, and then wound up to obtain an integrated light-diffusion film with a thickness of 200μm.

[0077] (7) Backlight module assembly: Following the same assembly method as in Example 1, the obtained light-converting and diffusion integrated film is assembled with the reflective sheet, light guide plate and blue LED light source to obtain a light-converting and diffusion integrated backlight module based on perovskite quantum dot material.

[0078] Example 4: This embodiment provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, including the following steps: (1) Solid-phase blending: 80g of maleic anhydride-grafted polyolefin elastomer obtained in Preparation Example 1, 20g of ethylene-vinyl acetate copolymer, 6g of ethylene oxide-propylene oxide-ethylene oxide block copolymer, 1.5g of styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 4 and 4.5g of polymethylsilsesquioxane were put into a high-speed mixer and mixed at 500 rpm for 10 min to obtain a solid-phase premix.

[0079] (2) Liquid phase complexation: In a light-proof reaction vessel, 0.98g of cesium bromide, 2.02g of lead bromide (i.e., a molar ratio of approximately 1:1.2) and 0.8g of triphenyl phosphite are added to 15g of dimethyl sulfoxide. Magnetic stirring is turned on until the solid is completely dissolved to form a transparent complexing liquid, and the transparent complexing liquid is connected to a plunger-type liquid injection pump.

[0080] (3) Melting and microphase separation: The solid premix is ​​fed into the co-rotating twin-screw extruder through the main feed port. The temperatures of the first to third temperature zones of the extruder are set to 160°C, 170°C and 180°C respectively. The main screw speed is set to 300 rpm, so that the resin melts and forms a mesophase separation network.

[0081] (4) Liquid injection and enrichment: The temperature of the fourth temperature zone of the extruder is set to 190°C. The transparent complex liquid is continuously pumped into the fourth temperature zone at an injection pressure of 1.5 MPa by a liquid injection pump for shear dispersion.

[0082] (5) In-situ grafting and flash devolatilization: The temperature of the 5th to 6th temperature zones of the extruder is set to 195°C. The side vacuum exhaust port is opened in the 6th temperature zone and the vacuum degree is maintained at -0.09MPa. Covalent network locking and flash removal of dimethyl sulfoxide solvent are achieved simultaneously.

[0083] (6) Confined crystallization and extrusion molding: The temperatures of the 7th and 8th temperature zones of the extruder are set to 165°C and 155°C respectively, so that the system is cooled and confined to crystallize. The melt is then extruded through a coat hanger-type die at 150°C, calendered and cooled by a three-roll calender at 70°C, and then wound up to obtain an integrated light-diffusion film with a thickness of 200μm.

[0084] (7) Backlight module assembly: Following the same assembly method as in Example 1, the obtained light-converting and diffusion integrated film is assembled with the reflective sheet, light guide plate and blue LED light source to obtain a light-converting and diffusion integrated backlight module based on perovskite quantum dot material.

[0085] Example 5: This embodiment provides a method for fabricating an integrated light conversion and diffusion backlight module based on perovskite quantum dot materials, including the following steps: (1) Solid-phase blending: 70g of maleic anhydride-grafted polyolefin elastomer obtained in Preparation Example 1, 30g of ethylene-vinyl acetate copolymer, 6g of ethylene oxide-propylene oxide-ethylene oxide block copolymer, 1.5g of styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 4 and 4.5g of polymethylsilsesquioxane were put into a high-speed mixer and mixed at 500 rpm for 10 min to obtain a solid-phase premix.

[0086] (2) Liquid phase complexation: In a light-proof reaction vessel, 1.1g of cesium bromide, 1.9g of lead bromide and 0.8g of triphenyl phosphite are added to 15g of N,N-dimethylformamide. Magnetic stirring is turned on until the solid is completely dissolved to form a transparent complex liquid, and the transparent complex liquid is connected to a plunger-type liquid injection pump.

[0087] (3) Melting and microphase separation: The solid premix is ​​fed into the co-rotating twin-screw extruder through the main feed port. The temperatures of the first to third temperature zones of the extruder are set to 170°C, 180°C and 190°C respectively. The main screw speed is set to 300 rpm, so that the resin melts and forms a mesophase separation network.

[0088] (4) Liquid injection and enrichment: The temperature of the fourth temperature zone of the extruder is set to 200°C. The transparent complex liquid is continuously pumped into the fourth temperature zone at an injection pressure of 1.5 MPa by a liquid injection pump for shear dispersion.

[0089] (5) In-situ grafting and flash volatilization: Set the temperature of the 5th to 6th temperature zones of the extruder to 200°C, open the side vacuum exhaust port in the 6th temperature zone and maintain the vacuum degree at -0.08MPa, so as to simultaneously achieve covalent network locking and flash removal of N,N-dimethylformamide solvent.

[0090] (6) Confined crystallization and extrusion molding: The temperatures of the 7th and 8th temperature zones of the extruder are set to 170°C and 160°C respectively, so that the system is cooled and confined crystallized; the melt is then extruded through a coat hanger type die at a temperature of 155°C, calendered and cooled by a three-roll calender at 70°C, and then wound up to obtain an integrated light-diffusion film with a thickness of 200μm.

[0091] (7) Backlight module assembly: Following the same assembly method as in Example 1, the obtained light-converting and diffusion integrated film is assembled with the reflective sheet, light guide plate and blue LED light source to obtain a light-converting and diffusion integrated backlight module based on perovskite quantum dot material.

[0092] Comparative Example 1: Compared with Example 1, the difference is that the liquid phase complexation and liquid injection steps are not performed. Instead, 1.1g of cesium bromide, 1.9g of lead bromide and 0.8g of triphenyl phosphite solid powder are directly added to the solid phase premix. 1.5g of the styrene-butyl acrylate-glycidyl methacrylate terpolymer obtained in Preparation Example 4 is still added to the solid phase premix, and the rest are the same.

[0093] Comparative Example 2: Compared with Example 1, the difference is that the solid premix does not contain ethylene oxide-propylene oxide-ethylene oxide block copolymer, while the rest are the same.

[0094] Comparative Example 3: Compared with Example 1, the difference is that the solid premix does not contain the styrene-butyl acrylate-glycidyl methacrylate terpolymer, while all other aspects are the same.

[0095] Comparative Example 4: Compared with Example 1, the difference is that an equal weight of ethylene-1-octene copolymer is used to replace the maleic anhydride-grafted polyolefin elastomer, otherwise the same.

[0096] Comparative Example 5: Compared with Example 1, the difference is that the lateral high vacuum exhaust port is closed in the sixth temperature zone of the extruder, and vacuum flash evaporation is not performed; otherwise, they are the same.

[0097] Comparative Example 6: Compared with Example 1, the difference is that instead of in-situ injection reaction crystallization, perovskite luminescent nanocrystal powder is synthesized in advance and then physically blended and extruded with polymethylsilsesquioxane and other resin matrices. All other aspects are the same.

[0098] Test Example 1: This test example is used to characterize the changes in the characteristic absorption peaks of anhydride groups, epoxy groups, and ester groups in the membrane sample of Example 1. The specific test method includes the following steps: (1) Sample preparation: The film sample prepared by extrusion molding in Example 1 and the powder premix that was physically mixed according to the proportion of each group in the solid phase blending step in Example 1 but did not undergo the high temperature reaction extrusion process were obtained as control samples.

[0099] (2) Sample pretreatment: Cut the membrane sample of Example 1 into 1cm×1cm test blocks, wipe the surface with anhydrous ethanol, and dry in a vacuum drying oven at 45°C for 2h; at the same time, take the control group powder sample and vacuum dry at 45°C for 2h.

[0100] (3) Infrared spectroscopy test: The attenuated total reflectance mode of a Fourier transform infrared spectrometer was used for the test. During the test, the film sample from Example 1 and the powder sample from the control group were placed on the sample stage of the attenuated total reflectance test accessory, and the same contact pressure was applied for scanning. The scanning wavenumber range was set to 4000 cm⁻¹. -1 Up to 500cm -1 The spectral resolution was set to 4cm. -1 The cumulative number of scans for a single test is set to 32.

[0101] (4) Data processing: Export the infrared spectral data of each sample, smooth and correct the scanning baseline using spectral analysis software, and set the baseline to 2920 cm⁻¹. -1 The nearby polyolefin CH stretching vibration peak was used as an internal standard peak for normalization, and the peaks at 1783 cm⁻¹ were extracted. -1 Nearby, 912cm -1 Nearby and 1736cm -1 Normalized relative absorbance values ​​at the peak heights of nearby characteristic absorption peaks. Among them, 1783 cm⁻¹ -1 Characteristic absorption of the corresponding acid anhydride group nearby, 912 cm⁻¹ -1 The characteristic absorption of the nearby corresponding epoxy group is 1736 cm⁻¹. -1 The characteristic absorption of the corresponding ester group is observed nearby. The test results are shown in Table 1.

[0102] Table 1. Normalized relative absorbance data of characteristic functional groups in different samples:

[0103] According to Table 1 and Figure 3 The data, compared with the unreacted premix, showed that the membrane sample of Example 1 measured 1783 cm⁻¹. -1 The normalized relative absorbance of the characteristic peaks of the nearby anhydride groups decreased from 0.652 to 0.084 at 912 cm⁻¹. -1 The normalized relative absorbance of the characteristic peak of the nearby epoxy groups decreased from 0.421 to 0.036; meanwhile, at 1736 cm⁻¹... -1The normalized relative absorbance of the nearby ester characteristic peaks increased from 0.835 to 1.427. Figure 3 The complete infrared spectrum further shows that, compared with the unreacted premix, the peak intensity of the film in Example 1 is reduced at the absorption peak positions corresponding to the anhydride group and epoxy group, and shows an enhanced trend in the ester group absorption region.

[0104] The results show that after extrusion molding, the characteristic absorption signals corresponding to the anhydride and epoxy groups in the system decrease, while the characteristic absorption signal corresponding to the ester group increases. This trend is consistent with the characteristic changes of the epoxy and anhydride groups undergoing ring-opening esterification under hot working conditions. Considering 1736 cm⁻¹ -1 The nearby absorption peaks may also contain contributions from the acetate and acrylate structures in the ethylene-vinyl acetate copolymer. Therefore, the test results can serve as an auxiliary basis for judging the existence of ring-opening esterification bond structures in the system and can be used to illustrate the possibility of chemical interaction between the reactive anchoring agent and the maleic anhydride-grafted polyolefin elastomer.

[0105] Test Example 2: This test example is used to characterize the crystal phase structure of the film in Example 1, the film in Comparative Example 5, and the blank resin film. The specific test method includes the following steps: (1) Sample preparation: The light-conversion and diffusion integrated backlight module prepared in Example 1, the film prepared in Comparative Example 5, and the blank resin film extruded without the addition of perovskite precursor components and using the same resin formulation were taken as X-ray diffraction test samples.

[0106] (2) Sample fixation: Cut each membrane sample into a 20mm×20mm square flat sample, use double-sided tape to attach it flat to the glass sample base for X-ray diffractometer, and press it to reduce the influence of test surface undulation on diffraction signal.

[0107] (3) Test conditions: X-ray diffractometer was used for testing. The X-ray source was Cu target Kα rays with a wavelength of 0.15406nm. The working tube voltage was 40kV and the tube current was 40mA.

[0108] (4) Scanning conditions: Place the base with the sample fixed in the instrument test chamber and use continuous scanning mode for testing. The 2θ scanning angle range is 10° to 40°, the scanning rate is 4° / min, and the step size is 0.02°.

[0109] (5) Data processing: Collect diffraction signal data of each sample, perform background subtraction and smoothing processing through analysis software, extract the 2θ angle, corresponding crystal plane, diffraction peak intensity and half peak width of characteristic diffraction peaks, and summarize them into Table 2.

[0110] Table 2. X-ray diffraction characteristic peak parameters of different samples:

[0111] According to the data in Table 2, the film of Example 1 exhibits diffraction peaks near 15.18°, 21.54°, and 30.62°, which can be attributed to the (100), (110), and (200) crystal planes of the CsPbBr3 crystal, respectively. Combining the corresponding diffraction peak intensities and full width at half maximum (FWHM) data, it can be seen that a CsPbBr3 perovskite crystal phase with a certain degree of crystallinity has been formed in the film of Example 1.

[0112] No characteristic diffraction peaks of the CsPbBr3 related crystal planes were observed in the blank resin film, indicating that the corresponding diffraction signals mainly originated from the crystal phase formed after processing of the perovskite precursor components. Compared with the film of Example 1, the film of Comparative Example 5 also showed corresponding diffraction peaks at positions close to 2θ, but its diffraction peak intensity was lower and its full width at half maximum (FWHM) was larger, indicating that the crystal integrity of the obtained perovskite crystal phase was relatively low under conditions without vacuum flash devolatilization.

[0113] The above results indicate that the lateral vacuum exhaust-assisted flash devolatilization process helps to promote the formation of CsPbBr3 perovskite crystal phase in the polymer confined phase region of the liquid-injected precursor, and is beneficial to improving the crystal quality of the obtained crystal phase.

[0114] Test Example 3: This test example is used to characterize the thermogravimetric loss of the membrane sample from Example 1 and the membrane sample from Comparative Example 5 in the temperature range of 150°C to 200°C. The specific test method includes the following steps: (1) Sample preparation: A portion of the membrane sample prepared in Example 1 and the membrane sample prepared in Comparative Example 5 were cut out as test objects and stored in a sealed, light-proof container at room temperature before testing.

[0115] (2) Sample weighing: Using a 1 / 100,000 analytical balance, weigh 11.3 mg of the membrane sample of Example 1 and 12.6 mg of the membrane sample of Comparative Example 5 respectively, and place the weighed samples in a standard alumina crucible.

[0116] (3) Test atmosphere setting: Turn on the thermogravimetric analyzer host and control software, set the test atmosphere to high-purity nitrogen, and adjust the nitrogen flow rate to 50 mL / min.

[0117] (4) Heating test: Place the crucible containing the sample to be tested in the heating furnace and set the temperature control program to heat from 30°C to 300°C at a heating rate of 10°C / min.

[0118] (5) Data processing: Collect temperature and mass change data recorded during the test, perform first-order derivative processing on the mass change curve using software to obtain differential thermogravimetric signal, and extract the mass retention rate, mass loss rate and the temperature corresponding to the maximum weight loss rate in the temperature range of 150℃ to 200℃. The results are shown in Table 3.

[0119] Table 3. Thermogravimetric and differential thermogravimetric analysis data of different membrane samples:

[0120] According to the data in Table 3, the mass loss rate of the membrane sample in Comparative Example 5 was 7.85% in the temperature range of 150℃ to 200℃, and the temperature corresponding to the maximum weight loss rate was around 182.4℃. This temperature range is close to the volatilization temperature range of dimethyl sulfoxide, suggesting that there may be a certain amount of residual polar solvent in the membrane of Comparative Example 5.

[0121] In Example 1, the membrane sample exhibited a mass loss rate of 0.16% within the same temperature range, and no distinguishable independent weight loss peaks were observed. This result indicates that, under the lateral vacuum degassing and flash evaporation conditions employed in Example 1, the residual amount of volatile solvents in the membrane sample was relatively low.

[0122] Combining the process differences between Example 1 and Comparative Example 5, the above test results indicate that the lateral vacuum degassing-assisted flash devolatilization process helps reduce the residue of high-boiling-point polar solvents in the membrane. The reduction in solvent residue helps decrease the plasticizing effect of the solvent on the polymer phase region and facilitates the formation of a more stable crystallization environment for the precursor components within the confined phase region. These test results can serve as evidence that the vacuum flash devolatilization step has a positive effect on reducing solvent residue and improving subsequent in-situ crystallization conditions.

[0123] Test Example 4: This test example is used to characterize the emission peak position, full width at half maximum (FWHM), and absolute fluorescence quantum yield of different film samples under 450 nm blue light excitation. The specific test method includes the following steps: (1) Sample preparation: The light-conversion and diffusion integrated backlight module prepared in Example 1, Example 2 and Example 3, as well as the film samples prepared in Comparative Example 1, Comparative Example 2 and Comparative Example 5, were selected as test objects.

[0124] (2) Sample cutting and fixing: Cut each membrane sample into a square specimen of 25mm×25mm, use a rubber bulb to blow away the electrostatic adsorption dust on the surface of the specimen, and attach the specimen to a non-fluorescent absorbing aluminum fixture with a light-transmitting hole.

[0125] (3) Emission spectroscopy test: Turn on the steady-state fluorescence spectrometer with integrating sphere attachment and preheat the xenon lamp source. Set the excitation wavelength to 450nm, the emission spectrum scanning range to 480nm to 600nm, the excitation side slit width to 2.5nm, the emission side slit width to 2.5nm, and the data sampling interval to 0.5nm.

[0126] (4) Extraction of emission peak parameters: Place the fixture with the sample fixed in the center of the integrating sphere, run the spectral scanning program, record the photoluminescence emission spectrum of each film sample, and extract the emission peak position and half peak width from the spectral curve.

[0127] (5) Absolute fluorescence quantum yield test: Under the same excitation conditions, the reference spectrum without the sample and the scattering and emission spectra after the sample is placed were tested respectively. The absolute fluorescence quantum yield of each film sample was calculated based on the spectral integral area using the quantum yield calculation module built into the instrument. The results are shown in Table 4.

[0128] Table 4. Emission peak parameters and absolute fluorescence quantum yield data for different membrane samples:

[0129] According to Table 4 and Figure 4 According to the data, the emission peaks of the film samples in Examples 1, 2 and 3 under 450nm blue light excitation were distributed between 519.8nm and 522.1nm, with a full width at half maximum (FWHM) of 20.3nm to 21.1nm and an absolute fluorescence quantum yield of 84.7% to 86.4%. Figure 4 The photoluminescence emission spectra shown indicate that the films of Examples 1, 2, and 3 all exhibit narrow green emission peaks with relatively concentrated peak shapes. In contrast, the emission peaks of the films of Comparative Examples 1, 2, and 5 show varying degrees of redshift and broadening. These results demonstrate that the emission peaks of the film samples from these examples are more concentrated, narrower, and possess higher absolute fluorescence quantum yields.

[0130] Compared to Example 1, Comparative Example 1 eliminated the liquid-phase complexation and liquid injection steps while retaining the reactive anchoring agent, replacing them with a direct blending process using inorganic salt powders. The emission peak of the Comparative Example 1 film was 535.6 nm, with a full width at half maximum (FWHM) of 35.4 nm and an absolute fluorescence quantum yield of 12.3%. These results indicate that when using the direct blending method with inorganic salt powders, the emission peak of the resulting film exhibits a redshift and broadening, leading to a decrease in luminescence efficiency. These changes may be related to insufficient uniformity of dispersion of the inorganic salt powder in the polymer melt, local agglomeration, and the resulting broadening of the grain size distribution and increase in defect states.

[0131] Compared to Example 1, Comparative Example 2 did not contain the ethylene oxide-propylene oxide-ethylene oxide block copolymer. The emission peak of the film in Comparative Example 2 was 528.9 nm, with a full width at half maximum (FWHM) of 29.8 nm and an absolute fluorescence quantum yield of 31.5%. These results indicate that the absence of the hydrophilic block copolymer weakens the confinement and enrichment effect of the precursor component in the polymer system, potentially affecting the size distribution and defect state of the resulting luminescent phase, thus causing a redshift in the emission peak and a decrease in the absolute fluorescence quantum yield.

[0132] Compared to Example 1, Comparative Example 5 did not undergo lateral vacuum flash devolatilization. The emission peak of the film in Comparative Example 5 was 525.2 nm, with a full width at half maximum (FWHM) of 26.5 nm and an absolute fluorescence quantum yield of 42.1%. These results indicate that, without vacuum flash devolatilization, residual polar solvents may affect precursor precipitation, crystal growth, and surface defect states, thereby affecting the luminescence performance of the film sample.

[0133] The results above show that liquid-phase complexation and liquid injection, hydrophilic microphase confinement, and lateral vacuum flash devolatilization all affect the emission peak position, full width at half maximum (FWHM), and absolute fluorescence quantum yield of the membrane samples. The membrane samples in the examples exhibited a narrower emission peak width and a higher absolute fluorescence quantum yield under the synergistic effect of the above process conditions. Figure 4 The complete emission spectrum corresponds to the peak position, half-maximum width, and absolute fluorescence quantum yield data in Table 4, further illustrating that the film of the embodiment has a more concentrated emission peak shape and lower emission defect-related loss.

[0134] Test Example 5: This test example is used to evaluate the effect of the amount of polymethylsilsesquioxane light diffusing agent added on the total transmittance, optical haze, and absolute fluorescence quantum yield of the film, and to compare the difference in the effect of light diffusing agent on luminescence performance between in-situ reaction confinement systems and physically blended systems. The specific test method includes the following steps: (1) Sample preparation: 0 parts of the diffusing agent film sample prepared by the basic formulation variant of Example 1 without the addition of polymethylsilsesquioxane light diffusing agent were selected, as well as three light-conversion and diffusing integrated film samples with the same amount of other components and process conditions as in Example 1, except that the amount of polymethylsilsesquioxane added was adjusted to 1.0g, 4.5g and 8.0g respectively. At the same time, the film sample prepared by Comparative Example 6 was selected as the test object.

[0135] (2) Sample cutting and pretreatment: Cut each of the above membrane samples into 50mm×50mm square test pieces. Use a lint-free cloth to wipe the front and back of the test pieces with a small amount of isopropanol, and place them in a fume hood to evaporate and dry naturally, so as to reduce the influence of surface stains on the light scattering test results.

[0136] (3) Instrument calibration: Turn on the haze meter and transmittance tester, use the instrument’s built-in air baseline for calibration, and use a standard white board and black board for correction.

[0137] (4) Transmittance and haze test: Place the film sample tightly against the integrating sphere test window of the haze meter and fix it with a clamp. During the test, the instrument light source emits a standard C light source and illuminates the sample perpendicularly. Collect the total transmitted light flux and the scattered light flux that deviates from the incident light direction by more than 2.5°. Calculate and record the total transmittance and optical haze of each sample. Test each sample three times at different positions and take the arithmetic mean.

[0138] (5) Absolute fluorescence quantum yield test: The same film sample that had undergone haze testing was transferred to a steady-state fluorescence spectrometer with an integrating sphere attachment, and its absolute fluorescence quantum yield was measured at an excitation wavelength of 450 nm. The photometric and spectroscopic test data were summarized, and the results are shown in Table 5.

[0139] Table 5. Optical haze and absolute fluorescence quantum yield data for different film samples:

[0140] According to Table 5 and Appendix Figure 1 The data showed that, with the dosage of other components and process conditions remaining constant, and only the amount of polymethylsilsesquioxane added changing, as the mass fraction of polymethylsilsesquioxane increased from 0 to 8.0, the optical haze of the membrane increased from 16.37% to 98.16%, while the total transmittance decreased from 91.24% to 76.12%. This result indicates that the addition of polymethylsilsesquioxane can improve the light scattering of the membrane and correspondingly reduce the total transmittance.

[0141] Within the range of diffusing agent addition, the absolute fluorescence quantum yield of each membrane sample ranged from 85.94% to 87.15%. This result indicates that, in the basic formulation system of Example 1, the variation in the amount of polymethylsilsesquioxane added mainly affects the light scattering properties of the membrane, with a relatively small impact on the absolute fluorescence quantum yield.

[0142] Compared to the film containing 4.5 parts of diffusing agent, the film in Comparative Example 6 used the same mass fraction of polymethylsilsesquioxane, but its preparation method involved pre-synthesizing perovskite luminescent nanocrystal powder and then physically blending it with the resin matrix and light diffusing agent. The total transmittance of the film in Comparative Example 6 was 80.58%, and its optical haze was 88.52%, which were close to those of the film containing 4.5 parts of diffusing agent; however, its absolute fluorescence quantum yield was 41.27%, lower than the 86.43% of the film containing 4.5 parts of diffusing agent.

[0143] The above results indicate that, under similar light diffusing agent content and macroscopic light scattering parameters, different methods of introducing the luminescent phase have a significant impact on the absolute fluorescence quantum yield of the film. In Comparative Example 6, the pre-synthesized perovskite luminescent nanocrystal powder was directly blended with polymethylsilsesquioxane microspheres and a resin matrix. This may increase the contact opportunities between the luminescent nanocrystals and the inorganic silicon microspheres or resin phase interface, affecting the surface ligands or interface passivation structure of the luminescent nanocrystals, thereby increasing non-radiative recombination-related defects.

[0144] In contrast, in the example system, the nucleation and growth of the perovskite precursor mainly occur within the confined phase region formed by the block copolymer and are constrained by the reactive anchoring structure. This structure helps reduce the degree of direct interfacial contact between the luminescent phase and the polymethylsilsesquioxane microspheres, thereby reducing the adverse effects of the light diffusing agent on the luminescence performance. Combined with the results in Table 5 showing that the film of Example 1 maintained an absolute fluorescence quantum yield of 86.43% even with an optical haze of 89.71%, while Comparative Example 6 only achieved an absolute fluorescence quantum yield of 41.27% at a similar haze, this demonstrates from a performance perspective that the in-situ confined crystallization system of the present invention is more advantageous than the physically blended system in reducing the quenching effect of diffusing particles on the luminescent phase. These test results indicate that the reactive confined system of the present invention is beneficial in maintaining a high absolute fluorescence quantum yield while improving optical haze.

[0145] Test Example 6: This test example is used to evaluate the luminescence stability of different film samples under conditions of 85℃ and 85% relative humidity. The specific test method includes the following steps: (1) Sample preparation: The light-conversion and diffusion integrated backlight module samples prepared in Examples 1 and 4, as well as the film samples prepared in Comparative Examples 3 and 4, were selected as the test objects for damp heat aging.

[0146] (2) Initial quantum yield test: Each membrane sample was cut into a 30mm×30mm test block. The absolute fluorescence quantum yield of each sample was measured at an excitation wavelength of 450nm using a steady-state fluorescence spectrometer with an integrating sphere module. This value was taken as the initial quantum yield of each sample at 0 hours.

[0147] (3) Humid heat aging treatment: Turn on the constant temperature and humidity test chamber and set the ambient temperature to 85℃ and the relative humidity to 85%. After the temperature and humidity inside the chamber reach the set values ​​and remain stable, place each membrane test block attached to the clean glass substrate on the sample rack inside the test chamber, leaving a gap between the samples so that their surfaces are exposed to the humid heat environment.

[0148] (4) Sampling in stages: The total test duration is set at 500 hours. At the time points of 100 hours, 200 hours, 300 hours, 400 hours and 500 hours of the test, each sample is taken out of the test chamber.

[0149] (5) Quantum yield retention rate calculation: The test blocks were taken out and allowed to stand in the dark for 2 hours at room temperature (25°C) and relative humidity (50%). The absolute fluorescence quantum yield of each sample was then measured again, and the absolute fluorescence quantum yield measured at each time point was divided by the initial quantum yield of the corresponding sample to calculate the quantum yield retention rate. The results are shown in Table 6.

[0150] Table 6. Quantum yield retention data of different membrane samples in the double 85 damp heat aging test:

[0151] According to Table 6 and Appendix Figure 2 The data shows that after aging for 500 hours at 85°C and 85% relative humidity, the quantum yield retention rates of the membranes in Example 1 and Example 4 were 80.4% and 82.1%, respectively. As the aging time increased, the quantum yield retention rates of the membranes in Example 1 and Example 4 gradually decreased, but the overall decrease was relatively small.

[0152] Example 4 used a higher proportion of maleic anhydride-grafted polyolefin elastomer compared to Example 1, and employed a slightly lead-rich precursor formulation. The quantum yield retention of the film in Example 4 after 500 hours was 82.1%, slightly higher than the 80.4% of the film in Example 1. This result indicates that appropriately increasing the proportion of reactive polyolefin elastomer and using a slightly lead-rich precursor formulation in this system may help improve the luminescence retention performance of the film samples under humid and hot conditions.

[0153] Compared to Example 1, Comparative Example 3 did not contain the styrene-butyl acrylate-glycidyl methacrylate terpolymer; compared to Example 1, Comparative Example 4 used an equal weight of ethylene-1-octene copolymer to replace the maleic anhydride-grafted polyolefin elastomer. The quantum yield retention rates of the membranes in Comparative Example 3 and Comparative Example 4 decreased more rapidly during aging, with quantum yield retention rates of 12.3% and 9.7% respectively after 500 hours of aging.

[0154] The above results indicate that the presence of reactive anchoring agents and maleic anhydride-grafted polyolefin elastomers has a positive impact on the luminescence retention performance of the film samples in a humid and hot environment. This may be because the anhydride groups on the polyolefin matrix and the epoxy groups on the anchoring agent undergo a ring-opening reaction during thermal processing, forming a certain number of covalent bonding sites, which helps maintain the stability of the phase domain interface formed by the block copolymer.

[0155] In Comparative Examples 3 and 4, due to the lack of corresponding reactive anchoring structures or anhydride grafting structures, the polymer phase region mainly relies on physical interactions for maintenance. Under high temperature and high humidity conditions, the plasticizing effect of water molecules and the movement of polymer chain segments may reduce the structural stability of the phase region, thereby increasing the possibility of water and oxygen penetrating into the perovskite luminescent phase region and adversely affecting the stability of the perovskite luminescent phase.

[0156] Therefore, the test results indicate that the reaction-confined structure constructed by grafting maleic anhydride onto polyolefin elastomer with a reactive anchoring agent helps improve the luminescence retention performance of perovskite luminescent nanocrystals under humid heat aging conditions. Combined with the infrared results in Test Example 1, which showed a decrease in characteristic peaks of anhydride and epoxy groups and an increase in characteristic peaks of ester groups, it can be concluded that the improvement in luminescence retention performance is related to the formation of open-ring esterification bonding structures and the reaction anchoring effect in the system.

[0157] Test Example 7: This test example is used to characterize the cross-sectional microstructure, elemental spatial distribution, and nanoscale microphase structure of the membrane in Example 1. The specific test method includes the following steps: (1) Sample preparation: The light-conversion-diffusion integrated film prepared in Example 1 was placed in liquid nitrogen for freezing treatment and then subjected to brittle fracture to obtain cross-sectional samples. The cross-sectional samples were fixed on a conductive sample stage and then subjected to surface sputtering with gold or platinum for observation under a scanning electron microscope and energy dispersive spectroscopy (EDS). Another film from Example 1 was subjected to ultrathin sectioning or ion thinning treatment for observation under a transmission electron microscope; a flat area of ​​the film was used for phase imaging testing under an atomic force microscope.

[0158] (2) Scanning electron microscopy observation: The brittle fracture cross section of the membrane in Example 1 was observed at low and high magnification using a scanning electron microscope. The morphology of the continuous polymer matrix, dispersed particles, and internal phase regions in the membrane cross section was recorded. The test results are shown in […]. Figure 5 .

[0159] (3) EDS elemental distribution test: Energy dispersive spectroscopy (EDS) was performed within the observation area of ​​a scanning electron microscope to collect the distribution maps of Si, Pb, Br, and Cs elements. Si was used to characterize the spatial distribution of the light-diffusing particles in polymethylsilsesquioxane, while Pb, Br, and Cs were used to characterize the spatial distribution of the CsPbBr3 perovskite luminescent phase. The test results are shown in […]. Figure 6 .

[0160] (4) Transmission electron microscopy and atomic force microscopy tests: The nanoscale dispersed phase and microphase structure in the film of Example 1 were observed using transmission electron microscopy; the phase difference and phase region connectivity morphology on the film surface or slice area were observed using atomic force microscopy in phase mode. The test results are shown in […]. Figure 7 .

[0161] (5) Results Analysis: From Figure 5 As can be seen, the cross-section of the membrane in Example 1 shows a continuous polymer matrix and dispersed spherical microparticle structures, indicating that the polymethylsilsesquioxane light-diffusing microparticles can form a dispersed phase within the membrane. Figure 6 It is evident that Si exhibits a discrete enrichment distribution, while Pb, Br, and Cs elements show a relatively uniform distribution across the film cross-section. Furthermore, the distribution areas of Pb, Br, and Cs elements do not completely overlap with the Si enrichment areas, indicating a certain spatial separation between the polymethylsilsesquioxane diffuse phase and the perovskite luminescent phase within the film. Figure 7 and Figure 8 It is evident that nanoscale phase regions exist within the membrane, and the phase difference between the continuous phase and the dispersed phase can be observed in the AFM phase diagram, indicating that a microphase separation structure is formed inside the membrane of Example 1.

[0162] Combined with test case 1 Figure 3 As shown in Table 1, the characteristic peaks of anhydride and epoxy groups decreased while the ester group peak increased, indicating a tendency for anhydride and epoxy groups to undergo ring-opening esterification and form chemically bonded structures. The above morphological characterization and infrared spectral results together demonstrate that a reaction-anchored, spatially confined microphase structure was formed in the film of Example 1. This structure facilitates in-situ crystallization of the perovskite luminescent phase within the confined phase region and reduces the probability of direct contact between the perovskite luminescent phase and the polymethylsilsesquioxane light-diffusing particles.

[0163] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A backlight module integrating light conversion and diffusion based on perovskite quantum dot material, characterized in that, It includes a light guide plate, a blue LED light source disposed on the light-incident side of the light guide plate, a reflective sheet disposed on the backlight side, and an integrated light-converting and diffusing film disposed on the light-emitting side; The light-conversion and diffusion integrated film is made from raw materials comprising the following parts by weight: 70-80 parts of maleic anhydride-grafted polyolefin elastomer; 20-30 parts of ethylene-vinyl acetate copolymer; 2-10 parts of ethylene oxide-propylene oxide-ethylene oxide block copolymer; 0.5-2.5 parts of styrene-butyl acrylate-glycidyl methacrylate terpolymer; 1.0-8.0 parts of polymethylsilsesquioxane; 0.37-1.83 parts of cesium bromide; 0.63-3.17 parts of lead bromide, and the molar ratio of cesium bromide to lead bromide is 1:0.95-1.25; Triphenyl phosphite, 0.1-1.5 parts; 10-20 parts of polar solvent.

2. The integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 1, characterized in that, The light-conversion and diffusion integrated film is made from raw materials comprising the following parts by weight: 70-75 parts of maleic anhydride-grafted polyolefin elastomer; 25-30 parts of ethylene-vinyl acetate copolymer; 4-8 parts of ethylene oxide-propylene oxide-ethylene oxide block copolymer; 1.0-2.0 parts of styrene-butyl acrylate-glycidyl methacrylate terpolymer; 3.0-6.0 parts of polymethylsilsesquioxane; 0.8-1.5 parts of cesium bromide; 1.5-2.5 parts of lead bromide, and the molar ratio of cesium bromide to lead bromide is 1:1.00-1.20; Triphenyl phosphite 0.5-1.0 parts; 12-18 parts of polar solvent.

3. The integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 1, characterized in that, The maleic anhydride-grafted polyolefin elastomer has a grafting rate of 0.5-1.5 wt%, and is prepared by reactive extrusion of ethylene-1-octene copolymer and maleic anhydride under the action of a free radical initiator.

4. The integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 1, characterized in that, The weight-average molecular weight (Mw) of the styrene-butyl acrylate-glycidyl methacrylate terpolymer is 6000-12000 g / mol, and the epoxy equivalent is 250-350 g / eq.

5. The integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 1, characterized in that, The polar solvent is dimethyl sulfoxide or N,N-dimethylformamide.

6. A method for preparing an integrated light-conversion and diffusion backlight module based on perovskite quantum dot material according to any one of claims 1-5, characterized in that, Includes the following steps: S1 Solid-phase blending: The maleic anhydride-grafted polyolefin elastomer, ethylene-vinyl acetate copolymer, ethylene oxide-propylene oxide-ethylene oxide block copolymer, styrene-butyl acrylate-glycidyl methacrylate terpolymer and polymethylsilsesquioxane are mixed evenly to obtain a solid-phase premix. S2 liquid phase complexation: Under light-protected conditions, cesium bromide, lead bromide and triphenyl phosphite are added to the polar solvent and stirred until transparent to form a transparent complex liquid; S3 In-situ Extrusion and Confined Crystallization: The solid premix is ​​added to a twin-screw extruder for melting, forming a non-polar continuous phase composed of maleic anhydride-grafted polyolefin elastomer and a mesoscopic phase separation network composed of polar dispersed microregions enriched from ethylene-vinyl acetate copolymer and ethylene oxide-propylene oxide-ethylene oxide block copolymer; the mesoscopic phase separation network is a phase separation structure jointly formed by the non-polar continuous phase and the polar dispersed microregions, and the polar dispersed microregions are used to enrich the perovskite precursor in the transparent complex liquid. The transparent complex liquid is pumped into the twin-screw extruder for shear dispersion; a vacuum operation is started in the temperature zone of the extruder to perform flash evaporation and devolatilization, inducing ring-opening crosslinking of the matrix network and removal of polar solvents, promoting the precipitation and crystallization of the precursor in a confined space; the melt is then cooled and calendered to obtain an integrated light-conversion and diffusion film; S4 Module Assembly: A blue LED light source is placed on the light-incident side of the light guide plate, a reflector is placed on the backlight side of the light guide plate, and the integrated light-converting and diffusing film is placed on the light-emitting side of the light guide plate to obtain the backlight module.

7. The method for preparing an integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 6, characterized in that, In step S3, the temperatures of the first to third temperature zones of the extruder containing the solid premix are 160-170℃, 170-180℃, and 180-190℃, respectively, and the main screw speed is maintained at 300 rpm; the injection pressure of pumping the transparent complexing liquid into the twin-screw extruder is controlled at 1.5 MPa.

8. The method for preparing an integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 6, characterized in that, In step S3, the flash devolatilization is carried out in an independent temperature zone of the twin-screw extruder by opening the side vacuum exhaust port, controlling the vacuum degree to be -0.08MPa to -0.09MPa, and the temperature of the temperature zone during the flash devolatilization stage is maintained at 195-200℃.

9. The method for preparing an integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 6, characterized in that, Before step S1, the maleic anhydride-grafted polyolefin elastomer is prepared as follows: 100 parts by weight of ethylene-1-octene copolymer, 1.0-2.0 parts by weight of maleic anhydride powder and 0.05-0.1 parts by weight of dicumyl peroxide are added to a mixer for premixing, and then fed into a co-rotating twin-screw extruder with each temperature zone maintained at 160-185°C for reactive extrusion. After cooling in a water bath and pelletizing and drying, the product is obtained.

10. The method for preparing an integrated light conversion and diffusion backlight module based on perovskite quantum dot material according to claim 6, characterized in that, Prior to step S1, the styrene-butyl acrylate-glycidyl methacrylate terpolymer is prepared as follows: 23-39 parts by weight of a mixture of styrene, 20 parts by weight of butyl acrylate, and 41-57 parts by weight of glycidyl methacrylate monomers, along with 1.0-2.0 parts by weight of initiator, are added dropwise at a uniform rate to a heated toluene solvent under inert gas protection. After reacting at a constant temperature of 85-95°C, the solvent is removed by vacuum treatment at 120°C and a vacuum degree of -0.08 MPa.

Images