Process for preparing perovskite quantum dot diffusion plate through in-situ polymerization

Abstract

The invention relates to a technology for preparing a perovskite quantum dot diffusion plate through in-situ polymerization. The technology comprises the following steps that 1, an AB precursor, cesium carbonate, lead bromide and ODE are prepared according to the ratio of 1: 1: 10 and then heated to 285 DEG C to be dissolved; 2) preparing an X precursor: respectively dissolving NaBr or NaI in ODE, wherein the mass ratio of the addition amount of NaBr or NaI is 10%; (3) adding the AB precursor into PS, heating and stirring at 90 DEG C, uniformly mixing, adding the X precursor, and continuously stirring to obtain a mixture; 4, the mixture is subjected to melt extrusion in a single-screw extruder, and the perovskite quantum dot diffusion plate is obtained.The prepared product has the advantages of being high in fluorescence quantum efficiency, narrow in half-peak width (smaller than or equal to 25 nm), wide in color gamut (larger than or equal to 127% of the NTSC standard), high in chromaticity uniformity (delta X and delta Y are both smaller than or equal to 0.01) and the like.

Description

Technical Field

[0001] This invention relates to the field of optical quantum dot diffuser technology, and more particularly to an in-situ polymerization process for preparing perovskite quantum dot diffusers. Background Technology

[0002] Currently, the mainstream display technology in the market is flat panel display technology, with LCD technology being the most important (followed by OLED technology), driving continuous updates and upgrades in flat panel display technology. New displays, as a crucial interface for intelligent interaction, have become a vital support and foundation for emerging industries such as ultra-high-definition video, the Internet of Things, and virtual reality, and are a strategic emerging industry that countries and regions worldwide have been vying to develop in recent years. Currently, LED displays, OLED displays, and QLED displays are becoming the key development directions for next-generation display technologies. Major companies are pursuing excellence in various aspects, resulting in a flourishing market. From the consumer's perspective, the needs of consumers for the display products they purchase have evolved from initial image display to the current pursuit of higher color gamut, longer lifespan, and lower prices. Among them, QLED utilizes the unique luminescent properties of quantum dots, allowing display devices to exhibit pure and rich colors (under the NTSC color gamut standard, ordinary LCD TVs have a color gamut of only 72%, OLED can achieve around 95%, while QLED's color gamut reaches as high as 110%). Brands such as Samsung, TCL, Skyworth, and Hisense have successively launched products equipped with quantum dot technology solutions, gaining increasing recognition from consumers in the global market.

[0003] Existing technological shortcomings: 1. Currently, QLEDs mainly use cadmium-based quantum dots. However, the toxicity of cadmium is strictly limited in consumer products (the standard EU cadmium and its compounds <100ppm=0.01%), requiring low-cadmium or cadmium-free solutions to avoid impacts on people and the environment. 2. The main applications of quantum dots in backlight systems include quantum dot glass tubes, quantum dot films, and quantum dot light-emitting chips. However, quantum dots encapsulated in glass tubes are fragile and difficult to transport. Quantum dot films have high barrier film costs and obvious borders in the adhesive portion. The large amount of quantum dots added to quantum dot glass tubes and films results in extremely high manufacturing costs, hindering widespread adoption. Quantum dot light-emitting chips involve adhering quantum dots to the chip surface. The chip's operating temperature reaches as high as 120℃, and prolonged exposure to high temperatures can cause irreversible damage to the quantum dots, significantly reducing their lifespan. 3. Currently, in-situ growth of perovskite quantum dots (PQDs) in polymers is often difficult to withstand high temperatures, leading to potential failure during polymer molding. Furthermore, the size, morphology, and uniformity of PQD distribution are difficult to control precisely during in-situ synthesis, easily resulting in inconsistent material properties. In addition, the preparation process is highly sensitive to reaction conditions (such as temperature, solvent, and precursor concentration), increasing the complexity and variability of the process. Summary of the Invention

[0004] The purpose of this invention is to provide an in-situ polymerization process for preparing perovskite quantum dot diffusion plates, specifically achieved through the following technical solution:

[0005] The in-situ polymerization process for preparing perovskite quantum dot diffusion plates includes the following steps: Step 1), prepare AB precursor: cesium carbonate: lead bromide: ODE = 1:1:10, and heat to 285℃ to dissolve; Step 2) Preparation of X precursor: NaBr or NaI is dissolved in ODE, with the amount of NaBr or NaI added being 10% by mass; Step 3) Add AB precursor to PS, heat and stir at 90°C, mix evenly, then add X precursor and continue stirring to obtain a mixture; Step 4) The mixture is melt-extruded in a single-screw extruder to obtain a perovskite quantum dot diffusion plate.

[0006] The in-situ polymerization process for preparing perovskite quantum dot diffusion plates is further designed in that, in step 3), AB:Br = 1:5; and the CsPbBr3 generated in PS accounts for 2wt% of the PS content.

[0007] The in-situ polymerization process for preparing perovskite quantum dot diffusion plates is further designed such that, in step 4), the processing temperature is set to 180°C, and the screw speed is set to 50 rpm to ensure uniformity of the mixture.

[0008] The beneficial effects of this invention are as follows: This invention utilizes an in-situ growth process of perovskite quantum dots in polymers, followed by multilayer co-extrusion and integration with a high-performance 1+N composite optical functional board. It produces a novel integrated backlight module that combines light conversion, photosynthesis, light homogenization, and brightness enhancement functions. Primarily used in televisions, commercial displays, and laptops, it is a key component in high color gamut QLED display devices. The product obtained by this invention exhibits high fluorescence quantum efficiency, narrow half-width at half-maximum (≤25 nm), wide color gamut (≥127% of NTSC standard), and high color uniformity (ΔX, ΔY both ≤0.01), realizing the application of perovskite quantum dots in display devices and representing a significant innovation in high color gamut QLED. Attached Figure Description

[0009] Figure 1 This is a process flow diagram of the perovskite quantum dot diffusion plate of this patent.

[0010] Figure 2 This is the fluorescence spectrum of the comparative product.

[0011] Figure 3 This is a stability test chart for the product in the example. Detailed Implementation

[0012] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0013] Example: Preparation of AB precursor: Cesium carbonate: Lead bromide: ODE = 1:1:10, the mixture was heated to 285℃ to dissolve. Preparation of X precursor: NaBr dissolved in ODE, with NaBr added at a concentration of 10%. The AB precursor was added to PS, heated and stirred at 90℃ until homogeneous. Then, the Br precursor was added and stirring continued, with an AB:Br ratio of 1:5. The CsPbBr3 content in PS was 2 wt%. The mixture was melt-extruded in a single-screw extruder to obtain perovskite quantum dot diffusion plates. The processing temperature was set to 180℃, and the screw speed was set to 50 rpm to ensure uniform mixing of the composite material.

[0014] Comparative example: Preparation of AB precursor: Cesium carbonate: Lead bromide: ODE = 1:1:10, the mixture was heated to 285℃ to dissolve. Preparation of X precursor: NaBr and NaI were dissolved in ODE, with each NaBr and NaI added at a mass percentage of 10%. AB precursor was added to PS, heated and stirred at 90℃ until homogeneous. Then, two X precursors were added and stirring continued, with an AB:Br:I ratio of 1:3:2. The resulting CsPbBr / I3 accounted for 2 wt% of the PS content. The mixture was melt-extruded in a single-screw extruder to obtain perovskite quantum dot diffusion plates. The processing temperature was set to 180℃, and the screw speed was set to 50 rpm to ensure homogeneous mixing of the composite material.

[0015] When the extrusion temperature was lowered to near the PS melting temperature, the luminescence performance of the quantum dots was significantly improved. Optimizing the precursor ratio, specifically increasing the X content to AB:X = 1:5 and 1:10, effectively increased the fluorescence intensity. Using Br and I precursors respectively, the prepared quantum dot plates exhibited fluorescence wavelengths of 526.4 nm and 619.2 nm. However, the two pre-prepared X precursors could not be extruded simultaneously, as... Figure 2As shown, because Br and I occupy each other's positions, a double peak (546.2 nm and 587.8 nm) appears in the mixed plate. That is, in the PeQDs structure, I occupies the position of Br, causing a redshift of CsPbBr3, and vice versa. Granulation of the precursor and PS particles followed by injection molding significantly improved the dispersion problem of quantum dots in the light conversion functional plate. This is because the quantum dot precursor is dispersed in the molten state during granulation, uniformly distributed in the PS particles. After thorough stirring in the molten state, the quantum dot / PS particles are uniformly dispersed during injection molding. The fluorescence intensity of the CsPbBr3 / PS light conversion functional plate gradually increases when immersed in water, and the PL intensity begins to slowly decrease after 10 days of immersion. When stored for 200 days, the PL intensity does not decrease significantly. This indicates that the PS matrix has an effective waterproof protection effect on CsPbBr3.

Claims

1. A process for preparing perovskite quantum dot diffusion plates by in-situ polymerization, characterized in that... Includes the following steps: Step 1), prepare AB precursor: cesium carbonate: lead bromide: ODE = 1:1:10, and heat to 285℃ to dissolve; Step 2) Preparation of X precursor: NaBr or NaI is dissolved in ODE, with the amount of NaBr or NaI added being 10% by mass; Step 3) Add AB precursor to PS, heat and stir at 90°C, mix evenly, then add X precursor and continue stirring to obtain a mixture; Step 4) The mixture is melt-extruded in a single-screw extruder to obtain a perovskite quantum dot diffusion plate.

2. The in-situ polymerization process for preparing perovskite quantum dot diffusion plates according to claim 1, characterized in that, In step 3), AB:Br = 1:5; the CsPbBr3 generated in PS accounts for 2wt% of the PS content.

3. The in-situ polymerization process for preparing perovskite quantum dot diffusion plates according to claim 1, characterized in that, Step 4) Set the processing temperature to 180℃ and the screw speed to 50 rpm to ensure uniform mixing.

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