A composite diffusion plate based on perovskite quantum dots and a preparation method thereof

Abstract

This application discloses a composite diffusion plate based on perovskite quantum dots and its preparation method. The diffusion plate includes a matrix and perovskite quantum dots and diffusion particles distributed in the matrix. The chemical formula of the perovskite quantum dots is ABX3, where A and B represent cations and X represents anions, respectively. The surface of the perovskite quantum dots is modified with ligands and is sequentially coated with a first polymer, a second polymer, and a third polymer from the inside out. The matrix is ​​formed by melting the first polymer, the second polymer, and the third polymer. In the diffusion plate of this application, the quantum dots are coated with three polymer layers. The first layer obtains high-luminescence-performance quantum dots through growth restriction, while the second and third layers block oxygen and water, respectively. The method of this application optimizes luminescence performance and stability by controlling the growth of quantum dots and the thickness of the coating layers. It can be implemented by in-situ extrusion, has a simple process and low requirements, and can provide an effective solution for full-concentration diffusion plates.

Description

Technical Field

[0001] This application relates to a composite diffusion plate based on perovskite quantum dots and its preparation method, belonging to the field of optoelectronic display materials technology. Background Technology

[0002] From a market information perspective, in July 2022, a senior researcher at Najing Technology mentioned that quantum dot films and quantum dot diffusers have become key materials and solutions for upgrading mainstream LCD backlight products. Najing Technology is a leader in quantum dot display technology, exhibiting a clear shift in its technological positioning and product design choices, moving from Cd-containing to low-Cd / Cd-free quantum dots and from diffuser films to diffuser plates. Furthermore, Najing Technology plans to launch a PS-based full-concentration diffuser plate, abandoning the expensive barrier film and significantly reducing costs, providing the necessary conditions for the widespread adoption of quantum dot display terminals. Quantum dot materials have significant application value in various new display technologies. They can not only be used with Mini LED, OLED, and Micro LED technologies to achieve color conversion, but also to manufacture active matrix quantum dot light-emitting diodes (AM-QLED), which is considered the next-generation display technology. With the increasing maturity of quantum dot technology and the continuous improvement of the industry chain, more diverse quantum dot applications will be commercialized.

[0003] It is understood that the quantum dot optical diffuser plate, jointly developed by Chuangyida and Nanosys of the United States, integrates a diffuser plate and a quantum dot emitting layer. It is a key component of high color gamut display devices, boasting advantages such as wide color gamut, high color uniformity, low blue light, long lifespan, automated assembly, and low mass production cost. It represents a significant innovation in LCD backlight technology. The diffuser plate, developed through this collaboration, has been supplied in bulk to leading manufacturers in the industry, including TCL, Hisense, Skyworth, BOE, Huawei, Xiaomi, and Changhong, and won the SID Best Display Component Product Award in 2022.

[0004] Regarding diffusers, it is generally known that when light travels through media with different refractive indices, it undergoes physical processes such as refraction, reflection, and scattering. Optical diffusers are created by adding inorganic or organic light-diffusing agents to a polymer matrix, or by designing an array of microstructures on the surface of the polymer matrix. This adjusts the refraction, reflection, and scattering of light, altering the light propagation path and changing the light angle by approximately 170°. This achieves sufficient scattering of incident light, producing an optical diffusion effect. Optical diffusers can effectively scatter incident light, resulting in a softer and more uniform illumination effect, and are widely used in LCD displays, LED lighting, and imaging systems.

[0005] Perovskite quantum dots are generally known as nanoscale luminescent particles, and the systems are mainly divided into two categories: one is organic / inorganic hybrid lead halide perovskites (MAPbX3, FAPbX3; X = Cl, Br, I, MA = CH3NH3, FA = (NH2)2CH); the other is all-inorganic perovskites (CsPbX3, X = Cl, Br, I). Perovskite quantum dots typically possess advantages such as ultra-high quantum yield, narrow emission half-width, short fluorescence lifetime, high crystallinity, high electron-hole mobility, and low cost, and are widely used in light-emitting diodes and photovoltaic cells. However, perovskite quantum dots also have significant drawbacks. Without proper design control, quantum dot materials exhibit poor stability and are particularly susceptible to environmental conditions such as temperature, humidity, oxygen, and light, leading to rapid degradation of luminescent performance.

[0006] However, the quantum dot diffusion plates currently sold by Chuangyida are based on the CdSe system, which contains Cd and is environmentally unfriendly; at the same time, the quantum dot concentration in the diffusion plates is relatively low, positioning the product as a low-concentration diffusion plate. Nanocrystal Technology is promoting full-concentration diffusion plates, but further solutions are needed to address the aggregation problem of adjacent quantum dots at high concentrations and the growth control issue.

[0007] For Cd-free, high-concentration diffusion plates, poor stability remains a key technical problem that has not yet been well resolved. Therefore, there is an urgent need to develop new perovskite quantum dot-based diffusion plates that can improve stability and optical performance without using costly water-oxygen barrier films, and can be produced using relatively simple and easy methods. Summary of the Invention

[0008] In view of the above, this application provides a perovskite quantum dot optical diffusion plate with multi-layer coating, and an in-situ extrusion preparation method for a full-concentration, Cd-free, and highly stable perovskite quantum dot diffusion plate. First, perovskite precursor cations and anions, in-situ auxiliary ligands, and a first matrix plastic particles are fed into an extruder for melt extrusion granulation. Utilizing the spatial confinement of the first matrix plastic particles and the growth restriction of the auxiliary ligands, perovskite quantum dot seed crystals are obtained in the first matrix layer, with the surface modified by the auxiliary ligands and the outer layer coated by a first matrix polymer. Then, these seed crystals are stirred evenly with a second matrix polymer and then melt-extruded again to obtain particles coated with the second matrix polymer. This process simultaneously helps anneal the internal crystal structure of the quantum dots to eliminate defects, improving optical performance and stability. Finally, these particles are stirred with a third matrix polymer, diffusion particles, and additives and extruded to form an in-situ extruded perovskite quantum dot diffusion plate with excellent optical performance and high stability. The extruded diffusion plate obtained by the method of this application combines the advantages of various polymer matrices, while greatly reducing costs by eliminating the need for expensive water and oxygen barrier films, and significantly improving stability and optical performance.

[0009] According to one aspect of this application, a composite diffusion plate based on perovskite quantum dots is provided, comprising:

[0010] matrix; and

[0011] Perovskite quantum dots and diffused particles distributed in the matrix,

[0012] The chemical formula of the perovskite quantum dots is ABX3, where A and B represent cations and X represents anions, respectively.

[0013] The surface of the perovskite quantum dots is modified with ligands and is coated with a first polymer, a second polymer and a third polymer from the inside out.

[0014] The matrix is ​​formed by melting the first polymer, the second polymer, and the third polymer.

[0015] Optionally, the first polymer is selected from at least one of PMMA, PS, PC, MS, PET, PP, PE, and PAN.

[0016] Optionally, the second polymer is selected from at least one of EVOH, PVA, and PVDC.

[0017] Optionally, the third polymer is selected from at least one of PVDF, PEG, PAM, POM, PVP, PES, SEBS, SMA, and PEEK.

[0018] Optionally, the cation A is selected from Cs. + MA + FA + At least one of the following, wherein the cation B is selected from Pb 2+ Sn 2+ At least one of the following, wherein the anion X is selected from Cl - ,Br - I - At least one of them.

[0019] Preferably, the perovskite quantum dots are selected from at least one of CsPbCl3, MAPbCl3, FAPbCl3, CsPbBr3, MAPbBr3, FAPbBr3, CsPbI3, MAPbI3, FAPbI3, CsSnI3, MASnI3, and FASnI3.

[0020] Optionally, the diffused particles are selected from at least one of nano-SiO2 particles, nano-TiO2 particles, nano-BaSO4 particles, nano-CaCO3 particles, and PMMA microspheres.

[0021] Optionally, the ligand is selected from at least one of DDAB, PEABr, TOPO, DMA, OPA, TBABr, TBACl, IDA, TPP, ODPA, BA, and CA.

[0022] Optionally, the thickness of the coating layer of the first polymer is 2-20 μm.

[0023] Optionally, the thickness of the coating layer of the first polymer is independently selected from any value or a range between 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, and 20μm.

[0024] Preferably, the thickness of the coating layer of the first polymer is 8-12 μm.

[0025] Optionally, the thickness of the coating layer of the second polymer is 5-30 μm.

[0026] Optionally, the thickness of the coating layer of the second polymer is independently selected from any value or a range between any two of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and 30 μm.

[0027] Preferably, the thickness of the coating layer of the second polymer is 12-18 μm.

[0028] Optionally, the thickness of the coating layer of the third polymer is 5-30 μm.

[0029] Optionally, the thickness of the coating layer of the third polymer is independently selected from any value or a range between any two of 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, and 30μm.

[0030] Preferably, the thickness of the coating layer of the third polymer is 12-18 μm.

[0031] According to another aspect of this application, a method for preparing the composite diffusion plate as described above is provided, comprising:

[0032] a) The salt corresponding to cation A, the salt corresponding to cation B, the salt corresponding to anion X, and the ligand are respectively mixed with the first polymer to obtain A-site cation precursor, B-site cation precursor, anion precursor and ligand precursor;

[0033] b) The A-site cation precursor, the B-site cation precursor, the anion precursor and the ligand precursor are mixed and extruded to obtain seed crystals;

[0034] c) The seed crystals are mixed with the second polymer and extruded to obtain a masterbatch;

[0035] d) The masterbatch is mixed with the third polymer and the diffusion particles, extruded, and then demolded to obtain the composite diffusion plate in situ.

[0036] Optionally, in step a), the salt corresponding to cation A is selected from at least one of stearate, tungstate, molybdate, carbonate, and bicarbonate; the salt corresponding to cation B is selected from at least one of stearate, tungstate, molybdate, carbonate, and bicarbonate; and the salt corresponding to anion X is selected from metal halide.

[0037] Optionally, the mass ratio of the salt corresponding to cation A to the first polymer is 1:2000 to 50:2000.

[0038] Optionally, the mass ratio of the salt corresponding to cation B to the first polymer is 1:2000 to 80:2000.

[0039] Optionally, the mass ratio of the salt corresponding to the anion X to the first polymer is 1:2000 to 40:2000.

[0040] Optionally, the mass ratio of the ligand to the first polymer is 1:2000 to 30:2000.

[0041] Optionally, in step b), the A-site cation precursor, the B-site cation precursor, and the anion precursor are mixed such that the molar ratio of the salt corresponding to cation B to the salt corresponding to cation A is 1:1 to 2:1; and the molar ratio of the salt corresponding to anion X to the salt corresponding to cation A is 1:1 to 5:1.

[0042] Optionally, the A-site cation precursor is mixed with the ligand precursor such that the molar ratio of the salt corresponding to cation A to the ligand is 1:1 to 1:5.

[0043] Optionally, in step b), the extrusion temperature is 150–250°C.

[0044] Optionally, in step b), the extrusion temperature is independently selected from any value or a range between 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C.

[0045] Optionally, in step b), the extrusion rate is 100 r / min to 800 r / min.

[0046] Optionally, in step b), the extrusion rate is independently selected from any value among 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, and 800 r / min, or a range between any two.

[0047] Optionally, in step c), the mass ratio of the seed crystal to the second polymer is 10:2 to 10:5.

[0048] Optionally, in step c), the extrusion temperature is 150–250°C.

[0049] Optionally, in step c), the extrusion temperature is independently selected from any value or a range between 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C.

[0050] Optionally, in step c), the extrusion rate is 100 r / min to 800 r / min.

[0051] Optionally, in step c), the extrusion rate is independently selected from any value among 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, and 800 r / min, or a range between any two.

[0052] Optionally, in step d), the mass ratio of the masterbatch to the third polymer is 10:2 to 10:5.

[0053] The mass ratio of the masterbatch to the diffused particles is 10:0.1 to 10:0.8.

[0054] Optionally, the extrusion temperature in step d) is 150–250°C.

[0055] Optionally, the extrusion temperature in step d) is independently selected from any value or a range between 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, and 250°C.

[0056] Optionally, the extrusion rate in step d) is 100 r / min to 800 r / min.

[0057] Optionally, the extrusion rate in step d) is independently selected from any value among 100 r / min, 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, and 800 r / min, or a range between any two.

[0058] Optionally, the mixing further includes the addition of an additive selected from at least one of nano-SiO2 particles, nano-TiO2 particles, nano-BaSO4 particles, nano-CaCO3 particles, and PMMA microspheres.

[0059] Optionally, the mass ratio of the additive to the masterbatch is 0.01 to 0.08:1. The additives function to alter the light diffusion path, thereby increasing the light output.

[0060] According to this application, when determining the extrusion temperature for each of the above steps, in addition to considering the melt temperature of the polymer used, it is also necessary to consider and optimize the combined effects of various other factors. For example, the extrusion temperature used in step b) is adjusted based on the melt temperature window of the first polymer, taking into account the growth temperature of the quantum dots; the extrusion temperatures used in steps c) and d) are determined based on the melt temperature window of the second or third polymer, taking into account the curing temperature of the quantum dots.

[0061] In the composite diffusion plate according to this application, the surface of perovskite quantum dots is modified with ligands and sequentially coated with a first polymer, a second polymer, and a third polymer from the inside out. Here, by limiting the extrusion temperature of each of the above steps and limiting the coating thickness of the first polymer, the spatial growth of quantum dot seeds can be restricted, thereby obtaining quantum dots with high luminescence performance at the nanoscale. By limiting the coating thickness of the second and third polymers, not only can oxygen and water be blocked, respectively, but defects can also be reduced and controlled. The polymer layers interact and couple with the surface anions and cations of the ionic crystal through the lone pairs of electrons in the characteristic chemical groups of the polymers. In addition, by introducing ligands, the surface defects of the quantum dots can also be effectively modified and controlled. The ligand chemicals also interact with the QDs through the lone pairs of electrons on their special groups.

[0062] According to this application, the thickness of the aforementioned polymer coating can be adjusted, for example, by changing the feed rate and / or limiting the extrusion rate or time.

[0063] Optionally, the raw materials used in steps a) to d) are in powder form, which can be obtained, for example, by crushing masterbatch.

[0064] Optionally, the mixing described in steps a) to d) is carried out independently under stirring.

[0065] Optionally, the stirring speed is 80-150 rpm and the stirring time is 1-5 hours.

[0066] Optionally, the extrusion described in steps b) to d) is carried out independently in an extruder.

[0067] Optionally, in steps b) to d), prior to the extrusion, the screw of the extruder is cleaned using a suitable polymer masterbatch.

[0068] In one specific implementation, the method includes the following steps:

[0069] 1) Preparation of cationic precursors: Weigh cationic A stearate powder and first polymer powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120 rpm for 3 hours using a mixer to obtain A-site cationic precursor powder; weigh cationic B stearate powder and first polymer powder and mix them at room temperature. Stir at 120 rpm for 3 hours using a mixer to obtain B-site cationic precursor powder.

[0070] 2) Preparation of anionic precursor: Weigh anionic X metal halide powder and first polymer powder and mix them at room temperature. Stir at 120 rpm for 3 hours using a stirrer to obtain X-site anionic precursor powder.

[0071] 3) Preparation of ligand precursor: Weigh the ligand powder and the first polymer powder and mix them at room temperature. Stir at 120 rpm for 3 hours using a mixer to obtain ligand precursor powder.

[0072] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure first polymer masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. The A-site cation precursor powder, B-site cation precursor powder, X-site anion precursor powder, and ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at 150℃ at a rate of 250 r / min to obtain ABX3@matrix 1 seed crystals.

[0073] 5) Preparation of masterbatch (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix): Weigh the ABX3@matrix 1 seed crystal and the second polymer powder obtained in 4) and mix them at room temperature. Stir at 120 rpm for 3 hours to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 hour. Then, clean the machine screw with pure second polymer masterbatch for 1 hour. Adjust the pump parameters and set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed the mixture M into the extruder feed port and extrude at 170℃ at a rate of 370 r / min to obtain ABX3@matrix 1@matrix 2 masterbatch.

[0074] 6) Preparation of composite diffusion plates (perovskite quantum dots ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh the ABX3@matrix 1@matrix 2 masterbatch, third polymer powder, diffusion particles and additives obtained in 5) and mix them at room temperature. Stir at 120 rpm for 3 hours to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃, and 90℃ for 1 hour. Then clean the machine screw with pure third polymer powder for 1 hour. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz, and frequency to 18 Hz. Feed mixture P into the extruder feed port, install the die at the extrusion port, and extrude at 150℃ at a rate of 400 r / min to obtain ABX3@matrix 1@matrix 2@matrix 3 diffusion plates.

[0075] The beneficial effects that this application can produce include:

[0076] 1) The composite diffusion plate of this application has a core and shell layer of quantum dots with three polymer matrix layers. The first polymer matrix layer is used to realize the spatial growth restriction of quantum dots to obtain high luminescence performance quantum dot materials at the nanoscale. The second polymer matrix layer can achieve high oxygen barrier effect. The third polymer matrix layer can achieve high water barrier effect, while protecting the high oxygen barrier properties of the second polymer matrix layer under low humidity, thereby achieving high luminescence performance and high stability.

[0077] 2) The preparation method of this application is carried out through multi-step melt coating extrusion. By taking into account the requirements of the primary growth temperature of quantum dots, the secondary curing temperature to eliminate defects, and the different melting temperatures of the three-layer polymer, the growth and coating process of quantum dots are rationally controlled. Furthermore, by controlling the amount of feed and the reaction time, the density and coating thickness of the three-layer coating are controlled, thereby achieving the optimal design of optical performance and stability.

[0078] 3) The preparation method of this application is carried out by in-situ extrusion, which is simple and has low requirements for conditions. Compared with liquid phase high temperature thermal injection synthesis of quantum dot mother liquor, this method has more environmental advantages and lower cost. It can avoid the cumbersome steps of purifying quantum dots, preparing quantum dot films and assembling quantum dot diffusion plates, and in particular, it achieves an effective solution for full concentration diffusion plates. Attached Figure Description

[0079] Figure 1 This is a schematic diagram of the structure and preparation process of the composite diffusion plate according to this application.

[0080] Figure 2 This is a schematic diagram of the structure of the green diffusion plate prepared in Example 1 of this application.

[0081] Figure 3 This is a schematic diagram of the structure of the red diffusion plate prepared in Example 2 of this application.

[0082] Figure 4 This is a schematic diagram of the structure of the green diffusion plate prepared in Example 3 of this application.

[0083] Figure 5 This is a schematic diagram of the structure of the red diffusion plate prepared in Example 4 of this application.

[0084] Figure 6 This is a schematic diagram of the structure of the green diffusion plate prepared in Example 5 of this application.

[0085] Figure 7 This is a schematic diagram of the structure of the red diffusion plate prepared in Example 6 of this application. Detailed Implementation

[0086] As mentioned above, this application provides a multi-coated in-situ extruded diffusion plate, the structure of which and its preparation process are as follows: Figure 1 As shown in the figure. According to this application, the entire diffuser plate extruded in situ is formed by melting and extruding three polymer matrices, with luminescent nanoparticles and diffuser particles (not shown) coated by three polymer layers distributed in its space. The core crystal structure of the nanoparticles can be represented by ABX3, and its surface is modified by ligand molecules to passivate surface defects; the next layer is the first polymer matrix, which is used to spatially confine the growth of quantum dots, and the thickness of this polymer matrix is ​​generally about 10 μm; the next outer ring is the second polymer matrix, which is used to prevent the rapid permeation of oxygen, and the thickness of this polymer matrix is ​​generally about 15 μm; the outermost ring is the third polymer matrix, which is used to prevent the rapid permeation of water vapor, ensuring that the quantum dots are protected from water vapor damage and ensuring the oxygen barrier properties of the second polymer matrix layer, and the thickness of this polymer matrix is ​​generally about 15 μm.

[0087] This application also provides a method for preparing an in-situ extruded perovskite quantum dot diffusion plate with high stability through multiple coatings, comprising: A1) preparing a cationic precursor, an anionic precursor, and a ligand precursor using a first type of matrix plastic particles; A2) adding the cationic precursor, anionic precursor, and ligand precursor to an extruder, mixing them evenly, and extruding them to form a first mixture; A3) adding a second type of matrix plastic particles to the first mixture, stirring them evenly through the extruder, and extruding them to form a second mixture; A4) adding a third type of matrix plastic particles, a diffusing agent, and an additive to the second mixture, stirring them evenly, and extruding them to form a quantum dot light-emitting functional plate. The preparation method provided in this application forms a multi-layered core-shell structure for the quantum dots by repeatedly coating polymer matrices with different functions. This enhances the quantum dots' resistance to external water, oxygen, light, and heat, and improves their stability. On the other hand, through the melting process of cationic and anionic precursors with plastic particles, the plastic particles play an auxiliary role in the growth process, achieving more efficient growth of the quantum dots. At the same time, the repeated coating and heating further promote the regrowth of the quantum dots. This allows for the uniform fusion of quantum dots with various plastic matrices within the plate, thereby improving the color gamut and luminous efficiency.

[0088] According to this application, by combining multiple coatings of polymer matrices with different functionalities with perovskite quantum dots of different systems, the performance of the diffusion plate is improved and its preparation method is refined. Based on this, this application can also be extended to the commercial development of diffusion plates using polymers and quantum dot materials different from those described in this application. Furthermore, this application can be applied to various schemes for preparing products different from diffusion plates using coating layers different from polymers and systems different from perovskite quantum dots.

[0089] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0090] Experimental methods not specified in the following examples are generally performed under standard conditions or as recommended by the manufacturer.

[0091] Unless otherwise specified, the raw materials and reagents used in the embodiments of this application were all purchased commercially.

[0092] The analytical measuring instruments used in the embodiments of this application are as follows:

[0093] Name of measuring instrument: Admesy spectrometer (Netherlands);

[0094] Measuring instrument model: hera01-FO23L20.

[0095] Example 1: CsPbBr3@PMMA@EVOH@PVDF Green Diffuser Plate

[0096] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PMMA powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0097] 2) Preparation of anionic precursor: Weigh 22.5g of zinc bromide (ZnBr2) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-position anionic precursor powder.

[0098] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0099] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PMMA masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbBr3@PMMA seed crystals.

[0100] 5) Preparation of masterbatch (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbBr3@PMMA seed crystals obtained in step 4) above and 2 kg of EVOH powder and mix them at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure EVOH masterbatch for 1 h. Adjust the pump parameters to set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ at a rate of 370 r / min to obtain CsPbBr3@PMMA@EVOH masterbatch.

[0101] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbBr3@PMMA@EVOH masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix them at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h to preheat. Then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port and install the die at the extrusion port. Extrude at 150℃ and a rate of 400 r / min to obtain CsPbBr3@PMMA@EVOH@PVDF green diffusion plate. The coating structure of the green diffusion plate prepared in Example 1 is as follows: Figure 2 As shown.

[0102] Example 2: CsPbI3@PMMA@EVOH@PVDF red diffusion plate

[0103] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PMMA powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0104] 2) Preparation of anionic precursor: Weigh 31.9g of zinc iodide (ZnI2) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-site anionic precursor powder.

[0105] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0106] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PMMA masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbI3@PMMA seed crystals.

[0107] 5) Preparation of masterbatch (perovskite quantum dots ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbI3@PMMA seed crystals obtained in step 4) above and 2 kg of EVOH powder and mix them at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-section temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure EVOH masterbatch for 1 h. Adjust the pump parameters to set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ and a rate of 370 r / min to obtain CsPbI3@PMMA@EVOH masterbatch.

[0108] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbI3@PMMA@EVOH masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix them at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h to preheat. Then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port and install the die at the extrusion port. Extrude at 150℃ and a rate of 400 r / min to obtain CsPbI3@PMMA@EVOH@PVDF red diffusion plate. The coating structure of the red diffuser plate prepared in Example 2 is as follows: Figure 3 As shown.

[0109] Example 3: CsPbBr3@PMMA@PVA@PVDF Green Diffuser Plate

[0110] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PMMA powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0111] 2) Preparation of anionic precursor: Weigh 22.5g of zinc bromide (ZnBr2) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-position anionic precursor powder.

[0112] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0113] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PMMA masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbBr3@PMMA seed crystals.

[0114] 5) Preparation of masterbatch (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbBr3@PMMA seed crystals obtained in step 4) above and 2 kg of PVA powder and mix them at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure PVA masterbatch for 1 h. Adjust the pump parameters and set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ and a rate of 370 r / min to obtain CsPbBr3@PMMA@PVA masterbatch.

[0115] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbBr3@PMMA@PVA masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix them at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h to preheat. Then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port and install the die at the extrusion port. Extrude at 150℃ and a rate of 400 r / min to obtain CsPbBr3@PMMA@PVA@PVDF green diffusion plate. The coating structure of the green diffusion plate prepared in Example 3 is as follows: Figure 4 As shown.

[0116] Example 4: CsPbI3@PMMA@PVA@PVDF red diffusion plate

[0117] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PMMA powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0118] 2) Preparation of anionic precursor: Weigh 31.9g of zinc iodide (ZnI2) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-site anionic precursor powder.

[0119] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PMMA powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0120] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PMMA masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbI3@PMMA seed crystals.

[0121] 5) Preparation of masterbatch (perovskite quantum dots ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbI3@PMMA seed crystals obtained in step 4) above and 2 kg of PVA powder and mix them at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure PVA masterbatch for 1 h. Adjust the pump parameters and set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ and a rate of 370 r / min to obtain CsPbI3@PMMA@PVA masterbatch.

[0122] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbI3@PMMA@PVA masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix them at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h to preheat. Then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port and install the die at the extrusion port. Extrude at 150℃ and a rate of 400 r / min to obtain CsPbI3@PMMA@PVA@PVDF red diffusion plate. The coating structure of the red diffuser plate prepared in Example 4 is as follows: Figure 5 As shown.

[0123] Example 5: CsPbBr3@PS@EVOH@PVDF Green Diffuser Plate

[0124] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PS powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0125] 2) Preparation of anionic precursor: Weigh 22.5g of zinc bromide (ZnBr2) powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-site anionic precursor powder.

[0126] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0127] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PS masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbBr3@PS seed crystals.

[0128] 5) Preparation of masterbatch (perovskite quantum dots ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbBr3@PS seed crystals obtained in step 4) above and mix with 2 kg of EVOH powder at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure EVOH masterbatch for 1 h. Adjust the pump parameters to set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ at a rate of 370 r / min to obtain CsPbBr3@PS@EVOH masterbatch.

[0129] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbBr3@PS@EVOH masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix them at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h to preheat. Then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters and set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port and install the die at the extrusion port. Extrude at 150℃ and a rate of 400 r / min to obtain CsPbBr3@PS@EVOH@PVDF green diffusion plate. The coating structure of the green diffusion plate prepared in Example 5 is as follows: Figure 6 As shown.

[0130] Example 6: CsPbI3@PS@EVOH@PVDF red diffusion plate

[0131] 1) Preparation of cationic precursors: Weigh 41.6g of cesium stearate powder and 20kg of PS powder (obtained by pulverizing masterbatch) and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain A-site cationic precursor powder; weigh 77.4g of lead stearate powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain B-site cationic precursor powder.

[0132] 2) Preparation of anionic precursor: Weigh 31.9g of zinc iodide (ZnI2) powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain X-site anionic precursor powder.

[0133] 3) Preparation of ligand precursor: Weigh 40.6g of bis(decyl)dimethylammonium bromide (DDAB) powder and 20kg of PS powder and mix them at room temperature. Stir at 120rpm for 3h using a mixer to obtain ligand precursor powder.

[0134] 4) Preparation of seed crystals (perovskite quantum dots ABX3@first polymer matrix): The extruder temperature was set to a six-stage temperature control program of 80℃, 100℃, 120℃, 150℃, 150℃, and 110℃ for 1 hour of preheating. Then, the machine screw was cleaned with pure PS masterbatch for 1 hour. The pump parameters were adjusted to a pump displacement of 10 ml / rev, 1.51 rpm / Hz, and a frequency of 16 Hz. 5 kg of A-site cation precursor powder, 5 kg of B-site cation precursor powder, 10 kg of X-site anion precursor powder, and 20 kg of ligand precursor powder were weighed and mixed at room temperature. The mixture was stirred at 120 rpm for 3 hours to obtain mixture K. Mixture K was fed into the extruder feed port and extruded at a temperature of 150℃ and a rate of 250 r / min to obtain CsPbI3@PS seed crystals.

[0135] 5) Preparation of masterbatch (perovskite quantum dots ABX3@first polymer matrix@second polymer matrix): Weigh 10 kg of CsPbI3@PS seed crystals obtained in step 4) above and mix with 2 kg of EVOH powder at room temperature. Stir at 120 rpm for 3 h using a mixer to obtain mixture M. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 130℃, 170℃, 170℃, and 120℃ for 1 h of preheating. Then, clean the machine screw with pure EVOH masterbatch for 1 h. Adjust the pump parameters to set the pump displacement to 15 ml / rev, 1.37 rpm / Hz, and frequency to 20 Hz. Feed mixture M into the extruder feed port and extrude at 170℃ at a rate of 370 r / min to obtain CsPbI3@PS@EVOH masterbatch.

[0136] 6) Preparation of composite diffusion plate (perovskite quantum dot ABX3@first polymer matrix@second polymer matrix@third polymer matrix): Weigh 10 kg of CsPbI3@PS@EVOH masterbatch prepared in step 5) above, 4 kg of PVDF and 0.5 kg of diffusion particles SiO2 and mix at room temperature. Stir at 120 rpm for 3 h to obtain mixture P. Set the extruder temperature to a six-stage temperature control program of 80℃, 100℃, 150℃, 150℃, 150℃ and 90℃ for 1 h, and then clean the machine screw with pure PVDF powder for 1 h. Adjust the pump parameters to set the pump displacement to 13 ml / rev, 1.51 rpm / Hz and frequency to 18 Hz. Feed mixture P into the extruder feed port, install the die at the extrusion port, and extrude at 150℃ and a rate of 400 r / min to obtain CsPbI3@PS@EVOH@PVDF red diffusion plate. The coating structure of the red diffusion plate prepared in Example 6 is as follows. Figure 7 As shown.

[0137] The luminescence performance of the diffuser plates prepared in the above embodiments was tested, as shown in the table below.

[0138]

[0139]

[0140] a The test conditions were: temperature 65 degrees Celsius, humidity 95%, for 1000 hours.

[0141] b The test conditions were: temperature 45 degrees Celsius, humidity 95%, and light intensity 38 W / m². 2 (450nm), 1000h.

[0142] The above descriptions are merely several embodiments of this application and are not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, these embodiments are not intended to limit this application. Any modifications or alterations made by those skilled in the art using the disclosed technical content without departing from the scope of the technical solution of this application are equivalent to equivalent implementations and fall within the scope of the technical solution of this application.

Claims

1. A composite diffusion plate based on perovskite quantum dots, characterized in that, include: matrix and Perovskite quantum dots and diffused particles distributed in the matrix, The chemical formula of the perovskite quantum dots is ABX3, where A and B represent cations and X represents anions, respectively. The surface of the perovskite quantum dots is modified with ligands and is coated with a first polymer, a second polymer and a third polymer from the inside out. The matrix is ​​formed by melting the first polymer, the second polymer, and the third polymer. The first polymer is selected from at least one of PMMA, PS, PC, MS, PET, PP, PE, and PAN; The second polymer is selected from at least one of EVOH, PVA, and PVDC; The third polymer is selected from at least one of PVDF, PEG, PAM, POM, PVP, PES, SEBS, SMA, and PEEK; The cation A is selected from Cs. + MA + FA + At least one of the following, wherein the cation B is selected from Pb 2+ Sn 2+ At least one of the following, wherein the anion X is selected from Cl - ,Br - I - At least one of them; The perovskite quantum dots are selected from at least one of CsPbCl3, MAPbCl3, FAPbCl3, CsPbBr3, MAPbBr3, FAPbBr3, CsPbI3, MAPbI3, FAPbI3, CsSnI3, MASnI3, and FASnI3.

2. The composite diffusion plate according to claim 1, characterized in that, The diffused particles are selected from at least one of nano-SiO2 particles, nano-TiO2 particles, nano-BaSO4 particles, nano-CaCO3 particles, and PMMA microspheres.

3. The composite diffusion plate according to claim 1, characterized in that, The ligand is selected from at least one of DDAB, PEABr, TOPO, DMA, OPA, TBABr, TBACl, IDA, TPP, ODPA, BA, and CA.

4. The composite diffusion plate according to claim 1, characterized in that, The thickness of the coating layer of the first polymer is 2-20 μm.

5. The composite diffusion plate according to claim 1, characterized in that, The thickness of the coating layer of the second polymer is 5-30 μm.

6. The composite diffusion plate according to claim 1, characterized in that, The thickness of the coating layer of the third polymer is 5-30 μm.

7. A method for preparing a composite diffusion plate according to any one of claims 1-6, characterized in that, include: a) The salt corresponding to cation A, the salt corresponding to cation B, the salt corresponding to anion X, and the ligand are respectively mixed with the first polymer to obtain A-site cation precursor, B-site cation precursor, anion precursor and ligand precursor; b) The A-site cation precursor, the B-site cation precursor, the anion precursor and the ligand precursor are mixed and extruded to obtain seed crystals; c) The seed crystals are mixed with the second polymer and extruded to obtain a masterbatch; d) The masterbatch is mixed with the third polymer and the diffusion particles, extruded, and then demolded to obtain the composite diffusion plate in situ.

8. The method according to claim 7, characterized in that, In step a), the salt corresponding to cation A is selected from at least one of stearate, tungstate, molybdate, carbonate, and bicarbonate; the salt corresponding to cation B is selected from at least one of stearate, tungstate, molybdate, carbonate, and bicarbonate; and the salt corresponding to anion X is selected from metal halide.

9. The method according to claim 7, characterized in that, In step a), the mass ratio of the salt corresponding to cation A to the first polymer is 1:2000 to 50:2000.

10. The method according to claim 7, characterized in that, In step a), the mass ratio of the salt corresponding to cation B to the first polymer is 1:2000 to 80:2000.

11. The method according to claim 7, characterized in that, In step a), the mass ratio of the salt corresponding to the anion X to the first polymer is 1:2000 to 40:2000.

12. The method according to claim 7, characterized in that, In step a), the mass ratio of the ligand to the first polymer is 1:2000 to 30:2000.

13. The method according to claim 7, characterized in that, In step b), the A-site cation precursor, the B-site cation precursor, and the anion precursor are mixed such that the molar ratio of the salt corresponding to cation B to the salt corresponding to cation A is 1:1 to 2:1; and the molar ratio of the salt corresponding to anion X to the salt corresponding to cation A is 1:1 to 5:

1.

14. The method according to claim 7, characterized in that, In step b), the A-site cation precursor is mixed with the ligand precursor such that the molar ratio of the salt corresponding to cation A to the ligand is 1:1 to 1:

5.

15. The method according to claim 7, characterized in that, In step b), the extrusion temperature is 150–250°C.

16. The method according to claim 7, characterized in that, In step b), the extrusion rate is 100 r / min to 800 r / min.

17. The method according to claim 7, characterized in that, In step c), the mass ratio of the seed crystal to the second polymer is 10:2 to 10:

5.

18. The method according to claim 7, characterized in that, In step c), the extrusion temperature is 150–250°C.

19. The method according to claim 7, characterized in that, In step c), the extrusion rate is 100 r / min to 800 r / min.

20. The method according to claim 7, characterized in that, In step d), the mass ratio of the masterbatch to the third polymer is 10:2 to 10:5; The mass ratio of the masterbatch to the diffused particles is 10:0.1 to 10:0.

8.

21. The method according to claim 7, characterized in that, In step d), the extrusion temperature is 150–250°C.

22. The method according to claim 7, characterized in that, In step d), the extrusion rate is 100 r / min to 800 r / min.

23. The method according to claim 7, characterized in that, In step d), the mixing further includes adding an additive, which is selected from at least one of nano-SiO2 particles, nano-TiO2 particles, nano-BaSO4 particles, nano-CaCO3 particles, and PMMA microspheres.

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