Abs-based perovskite quantum dot composite material and preparation method thereof

Abstract

The application discloses an ABS-based perovskite quantum dot composite material and a preparation method thereof, relates to the technical field of rare earth quantum dot materials, and belongs to the patent classification C09K11 / 66. The method comprises the following steps: preparing modified cerium oxide by grafting and coating of nano cerium oxide with a KH-570 silane coupling agent and polyvinylpyrrolidone; after preparing CsPbBr3 perovskite quantum dots, the perovskite quantum dots are coated with SiO2 using tetraethyl orthosilicate as a source and are calcined to densify, and then are surface-functionalized with KH-560 to obtain inorganic coated perovskite quantum dots; finally, ABS resin, modified cerium oxide, inorganic coated quantum dots, sodium bicarbonate powder, polyethylene glycol and an additive are melt blended. The application captures free radicals through secondary modified cerium oxide, protects the quantum dots through a dense SiO2 shell, and cooperatively inhibits damage of degradation products by using sodium bicarbonate and polyethylene glycol, so that the heat-resistant stability and fluorescent durability of the composite material are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of rare earth quantum dot materials technology, belonging to patent classification number C09K11 / 66, specifically to an ABS-based perovskite quantum dot composite material and its preparation method. Background Technology

[0002] Perovskite quantum dots (PDOs) have shown great promise in display, lighting, and optoelectronic device applications due to their excellent photoelectric properties, narrow half-peak emission, and tunable emission wavelength. However, their sensitivity to water, oxygen, and heat severely limits their practical application in engineering plastic matrices. Acrylonitrile-butadiene-styrene copolymer (ABS), as a general-purpose engineering plastic with excellent comprehensive performance, possesses good processing flowability and mechanical properties. However, during high-temperature melt processing, it is prone to thermo-oxidative degradation of butadiene segments, generating a large number of free radicals. This not only leads to a decrease in the mechanical properties of the matrix itself but also accelerates lattice destruction and fluorescence quenching of perovskite quantum dots. Existing technologies for combining perovskite quantum dots with polymer matrices mainly include solution blending and melt blending. While solution blending involves low processing temperatures, it suffers from problems such as residual organic solvents and significant environmental impact. Melt blending offers a simple process and allows for continuous production, but the high-temperature processing environment poses a severe challenge to the stability of the quantum dots. Current research has employed inorganic materials to coat perovskite quantum dots to improve their thermal stability. However, single inorganic coatings are prone to cracking under high-temperature shear conditions, resulting in unsatisfactory protective effects. Furthermore, traditional antioxidant addition methods for addressing the thermo-oxidative degradation of ABS matrices during high-temperature processing suffer from drawbacks such as high migration and poor durability. Therefore, how to simultaneously solve the thermal degradation problem of the ABS matrix and the thermal stability problem of perovskite quantum dots while ensuring the feasibility of melt processing is a pressing technical challenge in this field. Summary of the Invention

[0003] The purpose of this invention is to provide an ABS-based perovskite quantum dot composite material and its preparation method, so as to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse nano-cerium oxide powder in anhydrous ethanol by ultrasonic dispersion, add hydrolyzed silane coupling agent KH-570 and carry out condensation grafting reaction under acidic conditions, and obtain silane coupling agent modified cerium oxide powder after washing and drying. 2) The silane coupling agent modified cerium oxide powder is dispersed in N,N-dimethylformamide, and polyvinylpyrrolidone is added for adsorption and coating treatment. After precipitation, washing and drying, the modified cerium oxide is obtained. 3) Cesium carbonate was dissolved in deionized water to prepare a cesium salt solution, and lead bromide was dissolved in dimethyl sulfoxide to prepare a lead salt solution. The solutions were mixed and reacted under nitrogen protection and in the presence of surface ligands to obtain CsPbBr3 perovskite quantum dots. 4) CsPbBr3 perovskite quantum dots were dispersed in cyclohexane, and tetraethyl orthosilicate was added to coat SiO2 by sol-gel method under the catalysis of ammonia. After densification treatment by calcination, the surface was functionalized by silane coupling agent KH-560 to obtain inorganic coated perovskite quantum dots. 5) ABS resin, modified cerium oxide, inorganic coated perovskite quantum dots, sodium bicarbonate powder, polyethylene glycol, compatibilizer, antioxidant, light stabilizer, lubricant and white oil are melt-blended to obtain ABS-based perovskite quantum dot composite material.

[0005] During the high-temperature melt processing of ABS resin, the double bond structure in the butadiene segments is highly susceptible to chain-breaking degradation under the influence of heat and oxygen, generating a large number of active free radicals. These free radicals further trigger chain degradation reactions and cross-linking side reactions, leading to a sharp decline in the mechanical properties and appearance quality of the material. This invention addresses this by performing a two-stage surface modification treatment on nano-cerium oxide: first, an organic-inorganic hybrid interface layer is constructed on its surface using the silane coupling agent KH-570; then, a polymeric protective shell is formed using polyvinylpyrrolidone, achieving nanoscale uniform dispersion of the modified cerium oxide within the ABS matrix. Nano-cerium oxide rare earth materials possess unique Ce... 3+ / Ce 4+ Its reversible variable valence properties and abundant oxygen vacancies on its surface enable it to efficiently capture free radicals generated during the thermal degradation of ABS, interrupting the propagation path of the free radical chain reaction and fundamentally inhibiting the thermo-oxidative degradation process of butadiene segments. Simultaneously, the modified cerium oxide coated with polyvinylpyrrolidone forms a good interfacial bond with the ABS matrix, preventing the aggregation and failure of inorganic nanoparticles and ensuring that its free radical capturing function continues to operate stably throughout the entire processing, thereby significantly improving the heat resistance and processing stability of the ABS composite material.

[0006] The lattice structure of perovskite quantum dots faces two threats in high-temperature environments: first, thermal energy directly drives the migration and diffusion of lattice ions, leading to lattice distortion and phase transitions; second, external water and oxygen molecules penetrate and erode the ionic lattice framework, causing irreversible structural collapse and fluorescence quenching. This invention employs a sol-gel method to grow an inorganic SiO2 coating layer in situ on the surface of perovskite quantum dots, followed by high-temperature densification calcination to form a dense, crack-free, continuous glassy protective shell. This dense SiO2 shell forms an effective physical thermal barrier, significantly reducing the rate of external thermal energy transfer to the quantum dot lattice core and slowing down the thermally driven ion migration process. Furthermore, it constructs a highly efficient water and oxygen barrier, cutting off the channels for water and oxygen molecules to penetrate the quantum dot lattice, thus physically blocking the water and oxygen corrosion pathway. In addition, during the densification calcination process, the SiO2 coating layer forms a stable chemical bonding interface with the quantum dot surface, further enhancing the structural integrity and long-term stability of the shell. Subsequent surface grafting treatment with KH-560 silane coupling agent endows the quantum dots with reactive epoxy groups, enabling them to form a chemical bonding interface when melt-blended with the ABS matrix. This prevents the quantum dots from detaching and agglomerating under high temperature and high shear conditions, ensuring the uniformity and durability of the quantum dot fluorescence performance in the composite material.

[0007] Preferably, in step 1), the amount of the silane coupling agent KH-570 is 3 to 8 wt% of the mass of the nano-cerium oxide.

[0008] Preferably, in step 1), the pH value of the condensation grafting reaction is 4.0 to 5.0, the reaction temperature is 60 to 80°C, and the reaction time is 2 to 4 hours.

[0009] Preferably, in step 2), the amount of polyvinylpyrrolidone used is 10 to 20 wt% of the mass of the silane coupling agent modified cerium oxide powder.

[0010] Preferably, in step 2), the adsorption coating temperature is 50–70°C and the time is 3–5 h.

[0011] Preferably, in step 3), the surface ligands are oleic acid and oleylamine.

[0012] Preferably, in step 4), the mass ratio of the CsPbBr3 perovskite quantum to tetraethyl orthosilicate is 1:(2-5).

[0013] Preferably, in step 4), the amount of silane coupling agent KH-560 is 2 to 6 wt% of the quantum mass of CsPbBr3 perovskite.

[0014] Preferably, in step 5), the amounts of each component by weight are as follows: 85-95 parts ABS resin, 2-8 parts modified cerium oxide, 1-5 parts inorganic coated perovskite quantum dots, 0.3-1.0 parts sodium bicarbonate micro powder, 0.2-0.8 parts polyethylene glycol, 0.5-2 parts compatibilizer, 0.1-0.5 parts antioxidant, 0.1-0.5 parts light stabilizer, 0.2-0.5 parts lubricant, and 0.1-0.3 parts white oil.

[0015] This invention discovered in experiments that the polyvinylpyrrolidone polymer protective layer grafted onto the modified cerium oxide surface undergoes partial thermal decomposition under the high-temperature, high-shear environment of twin-screw extrusion, releasing nitrogen-containing small molecule volatiles and trace amounts of acidic degradation products. These degradation products migrate to the surface of the prepared inorganic-coated perovskite quantum dots in the melt system. On one hand, the nitrogen-containing small molecules undergo nucleophilic ring-opening reactions with the KH-560 epoxy groups on the SiO2 coating surface of the quantum dots, consuming the active functional groups on the quantum dot surface used for interfacial bonding and weakening the interfacial bonding strength between the quantum dots and the ABS matrix. On the other hand, the trace acidic products locally corrode the dense structure of the SiO2 coating layer, forming microscopic defects on the shell surface, allowing water and oxygen molecules to gain intrusion channels and reducing the protective effectiveness of the inorganic coating layer for the quantum dots. The combined negative effects of these two aspects lead to problems such as fluorescence intensity decay and fluctuations in heat resistance performance of the composite material after long-term use. This invention introduces sodium bicarbonate micropowder and polyethylene glycol (PEG): Sodium bicarbonate micropowder gradually releases CO2 and water vapor within the melt processing temperature range. On one hand, it forms a weakly alkaline microenvironment in the melt, which can neutralize the acidic degradation products released by the thermal decomposition of PVP in real time, protecting the SiO2 coating layer from acid erosion and maintaining the integrity of its dense structure. On the other hand, the slow release of CO2 can form a microscopic atmospheric barrier inside the melt, blocking the diffusion and migration of nitrogen-containing small molecules to the quantum dot surface, reducing their consumption of KH-560 epoxy groups. PEG, as a low-molecular-weight flexible segment dispersed in the ABS melt, preferentially adsorbs at the interface transition region between modified cerium oxide and quantum dots during processing, forming a flexible buffer layer. On one hand, it physically blocks the direct contact between PVP degradation products and the quantum dot surface; on the other hand, the ether bond structure of PEG itself can form hydrogen bond complexes with nitrogen-containing small molecules, further passivating their chemical activity and causing them to lose their ability to attack epoxy groups. The synergistic effect of sodium bicarbonate and polyethylene glycol simultaneously cuts off the damage pathways of PVP degradation products to the quantum dot coating and surface active groups from both chemical neutralization and physical isolation perspectives, ensuring the stability of the composite material's fluorescence and heat resistance properties during long-term use.

[0016] An ABS-based perovskite quantum dot composite material was prepared by the method described above.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Improve the heat resistance and processing stability of ABS: Through the nanoscale dispersion of secondary surface-modified cerium oxide and its oxygen vacancies, free radicals are efficiently captured, thereby inhibiting the thermo-oxidative degradation of butadiene segments from the source.

[0018] 2. Ensure uniform and long-lasting fluorescence performance of quantum dots: A dense SiO2 shell is used to construct a thermal barrier and water and oxygen barrier, and KH-560 grafting is combined to achieve chemical bonding between quantum dots and ABS matrix, preventing detachment and aggregation.

[0019] 3. Ensure stable performance over long-term use: Utilize the weak base neutralization and gas barrier effect of sodium bicarbonate, combined with the physical isolation and hydrogen bond passivation of polyethylene glycol, to synergistically eliminate the damage of PVT degradation products to the quantum dot protective layer and interfacial bonding. Attached Figure Description

[0020] Figure 1 This is a SEM image of the microstructure of the ABS-based perovskite quantum dot composite material prepared in Example 4 of the present invention at a magnification of 500×.

[0021] Figure 2 This is a SEM image of the microstructure of the ABS-based perovskite quantum dot composite material prepared in Example 4 of the present invention at a magnification of 5000×.

[0022] Figure 3 This is a SEM image of the microstructure of the ABS-based perovskite quantum dot composite material prepared in Example 4 of the present invention at a magnification of 50000×. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse 10g of nano-cerium oxide powder (particle size 30nm) in 200g of anhydrous ethanol and ultrasonically disperse for 30min; weigh 0.7g of silane coupling agent KH-570 and dissolve it in a mixed solvent of 45mL of anhydrous ethanol and 5mL of deionized water, and stir and hydrolyze at room temperature for 45min; slowly add the hydrolysate to the cerium oxide dispersion, adjust the pH to 4.5 with glacial acetic acid, and reflux at 70℃ with magnetic stirring for 3h; centrifuge (9000r / min, 12min), wash three times each with anhydrous ethanol and deionized water, vacuum dry at 90℃ for 10h, grind through a 200-mesh sieve to obtain silane coupling agent modified cerium oxide powder.

[0025] 2) Disperse 10g of the above-mentioned silane coupling agent modified cerium oxide powder in 250g of N,N-dimethylformamide and ultrasonically disperse for 20min; weigh 1.8g of polyvinylpyrrolidone (PVP, K30) and add it to the dispersion, stir and react at 60℃ for 4h; add anhydrous ethanol to precipitate, centrifuge (9000r / min), wash 3 times with anhydrous ethanol, vacuum dry at 70℃ for 8h, grind and pass through a 300-mesh sieve to obtain modified cerium oxide.

[0026] 3) Weigh 0.326 g of cesium carbonate and dissolve it in 20 mL of deionized water to prepare a cesium salt solution. Weigh 0.367 g of lead bromide and dissolve it in 10 mL of dimethyl sulfoxide to prepare a lead salt solution. Under nitrogen protection, add the lead salt solution dropwise to the cesium salt solution, and simultaneously add 0.037 g of oleic acid and 0.037 g of oleylamine as surface ligands. Stir rapidly at room temperature (1000 r / min) for 10 min. The solution turns bright green, and CsPbBr3 perovskite quantum dots are obtained. Quickly inject the solution into 80 mL of n-hexane to precipitate the precipitate. Centrifuge at high speed (11000 r / min, 8 min) to collect the precipitate. Wash twice with n-hexane to obtain crude CsPbBr3 perovskite quantum dots.

[0027] 4) Prepare a 10 mg / mL dispersion by dispersing crude CsPbBr3 perovskite quantum dots in cyclohexane; weigh tetraethyl orthosilicate (TEOS) at a quantum dot to tetraethyl orthosilicate mass ratio of 1:4, and weigh 25 wt% ammonia water as 2% of the TEOS mass. Slowly add TEOS dropwise to the dispersion and stir at 40°C for 12 h; centrifuge (9000 r / min, 10 min), wash twice each with cyclohexane and anhydrous ethanol, and vacuum at 60°C. Dry for 6 hours; place in a tube furnace, heat to 400℃ at 3℃ / min under nitrogen atmosphere, hold for 2 hours, cool to room temperature, and grind through a 400-mesh sieve; disperse the calcined powder in anhydrous ethanol (mass ratio 1:15), weigh 5wt% of silane coupling agent KH-560 according to the quantum dot mass, stir at 60℃ for 2 hours; centrifuge, wash twice with anhydrous ethanol, vacuum dry at 70℃ for 6 hours, and grind through a 400-mesh sieve to obtain inorganic coated perovskite quantum dots.

[0028] 5) Weigh the raw materials of each component according to the following parts by weight: 93 parts ABS resin, 7 parts modified cerium oxide, 4 parts inorganic coated perovskite quantum dots, 0.8 parts sodium bicarbonate micro powder (particle size 10μm), 0.7 parts polyethylene glycol (PEG-2000), 1.5 parts maleic anhydride grafted ABS compatibilizer (ABS-g-MAH), 0.4 parts antioxidant 1010, 0.4 parts light stabilizer UV-326, 0.4 parts calcium stearate lubricant, and 0.25 parts white oil. After drying ABS resin at 90℃ for 3 hours, all raw materials were added to a high-speed mixer and mixed at 1000 r / min for 15 minutes. The premixed material was then added to a twin-screw extruder with the following temperatures in each zone: zone 1 170℃, zone 2 180℃, zone 3 190℃, zone 4 195℃, zone 5 200℃, and die head 205℃. The screw speed was 300 r / min, and the feeding speed was 20 kg / h. The extrudate was then water-cooled (water temperature 20℃), dried by an air knife, and pelletized (particle size 3 mm) to obtain ABS-based perovskite quantum dot composite material.

[0029] Example 2 A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse 10g of nano-cerium oxide powder (particle size 30nm) in 200g of anhydrous ethanol and ultrasonically disperse for 30min; weigh 0.4g of silane coupling agent KH-570 and dissolve it in a mixed solvent of 45mL of anhydrous ethanol and 5mL of deionized water, and stir and hydrolyze at room temperature for 45min; slowly add the hydrolysate to the cerium oxide dispersion, adjust the pH to 4.5 with glacial acetic acid, and reflux at 70℃ with magnetic stirring for 3h; centrifuge (9000r / min, 12min), wash three times each with anhydrous ethanol and deionized water, vacuum dry at 90℃ for 10h, grind through a 200-mesh sieve to obtain silane coupling agent modified cerium oxide powder.

[0030] 2) Disperse 10g of the above-mentioned silane coupling agent modified cerium oxide powder in 250g of N,N-dimethylformamide and ultrasonically disperse for 20min; weigh 1.2g of polyvinylpyrrolidone (PVP, K30) and add it to the dispersion, stir and react at 60℃ for 4h; add anhydrous ethanol to precipitate, centrifuge (9000r / min), wash 3 times with anhydrous ethanol, vacuum dry at 70℃ for 8h, grind and pass through a 300-mesh sieve to obtain modified cerium oxide.

[0031] 3) Weigh 0.326 g of cesium carbonate and dissolve it in 20 mL of deionized water to prepare a cesium salt solution. Weigh 0.367 g of lead bromide and dissolve it in 10 mL of dimethyl sulfoxide to prepare a lead salt solution. Under nitrogen protection, add the lead salt solution dropwise to the cesium salt solution, and simultaneously add 0.037 g of oleic acid and 0.037 g of oleylamine as surface ligands. Stir rapidly at room temperature (1000 r / min) for 10 min. The solution turns bright green, and CsPbBr3 perovskite quantum dots are obtained. Quickly inject the solution into 80 mL of n-hexane to precipitate the precipitate. Centrifuge at high speed (11000 r / min, 8 min) to collect the precipitate. Wash twice with n-hexane to obtain crude CsPbBr3 perovskite quantum dots.

[0032] 4) Prepare a 10 mg / mL dispersion by dispersing crude CsPbBr3 perovskite quantum dots in cyclohexane; weigh tetraethyl orthosilicate (TEOS) at a quantum dot to tetraethyl orthosilicate mass ratio of 1:3, and weigh 25 wt% ammonia water as 2% of the TEOS mass. Slowly add TEOS dropwise to the dispersion and stir at 40°C for 12 h; centrifuge (9000 r / min, 10 min), wash twice each with cyclohexane and anhydrous ethanol, and vacuum at 60°C. Dry for 6 hours; place in a tube furnace, heat to 400℃ at 3℃ / min under nitrogen atmosphere, hold for 2 hours, cool to room temperature, and grind through a 400-mesh sieve; disperse the calcined powder in anhydrous ethanol (mass ratio 1:15), weigh 3wt% of silane coupling agent KH-560 according to the quantum dot mass, stir and react at 60℃ for 2 hours; centrifuge, wash twice with anhydrous ethanol, vacuum dry at 70℃ for 6 hours, and grind through a 400-mesh sieve to obtain inorganic coated perovskite quantum dots.

[0033] 5) Weigh the raw materials of each component according to the following parts by weight: 88 parts ABS resin, 3 parts modified cerium oxide, 2 parts inorganic coated perovskite quantum dots, 0.4 parts sodium bicarbonate micro powder (particle size 10μm), 0.3 parts polyethylene glycol (PEG-2000), 0.8 parts maleic anhydride grafted ABS compatibilizer (ABS-g-MAH), 0.2 parts antioxidant 1010, 0.2 parts light stabilizer UV-326, 0.3 parts calcium stearate lubricant, and 0.15 parts white oil. After drying ABS resin at 90℃ for 3 hours, all raw materials were added to a high-speed mixer and mixed at 1000 r / min for 15 minutes. The premixed material was then added to a twin-screw extruder with the following temperatures in each zone: zone 1 170℃, zone 2 180℃, zone 3 190℃, zone 4 195℃, zone 5 200℃, and die head 205℃. The screw speed was 300 r / min, and the feeding speed was 20 kg / h. The extrudate was then water-cooled (water temperature 20℃), dried by an air knife, and pelletized (particle size 3 mm) to obtain ABS-based perovskite quantum dot composite material.

[0034] Example 3 A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse 10g of nano-cerium oxide powder (particle size 30nm) in 200g of anhydrous ethanol and ultrasonically disperse for 30min; weigh 0.5g of silane coupling agent KH-570 and dissolve it in a mixed solvent of 45mL of anhydrous ethanol and 5mL of deionized water, and stir and hydrolyze at room temperature for 45min; slowly add the hydrolysate to the cerium oxide dispersion, adjust the pH to 4.5 with glacial acetic acid, and reflux at 70℃ with magnetic stirring for 3h; centrifuge (9000r / min, 12min), wash three times each with anhydrous ethanol and deionized water, vacuum dry at 90℃ for 10h, grind through a 200-mesh sieve to obtain silane coupling agent modified cerium oxide powder.

[0035] 2) Disperse 10g of the above-mentioned silane coupling agent modified cerium oxide powder in 250g of N,N-dimethylformamide and ultrasonically disperse for 20min; weigh 1.5g of polyvinylpyrrolidone (PVP, K30) and add it to the dispersion, stir and react at 60℃ for 4h; add anhydrous ethanol to precipitate, centrifuge (9000r / min), wash 3 times with anhydrous ethanol, vacuum dry at 70℃ for 8h, grind and pass through a 300-mesh sieve to obtain modified cerium oxide.

[0036] 3) Weigh 0.326 g of cesium carbonate and dissolve it in 20 mL of deionized water to prepare a cesium salt solution. Weigh 0.367 g of lead bromide and dissolve it in 10 mL of dimethyl sulfoxide to prepare a lead salt solution. Under nitrogen protection, add the lead salt solution dropwise to the cesium salt solution, and simultaneously add 0.037 g of oleic acid and 0.037 g of oleylamine as surface ligands. Stir rapidly at room temperature (1000 r / min) for 10 min. The solution turns bright green, and CsPbBr3 perovskite quantum dots are obtained. Quickly inject the solution into 80 mL of n-hexane to precipitate the precipitate. Centrifuge at high speed (11000 r / min, 8 min) to collect the precipitate. Wash twice with n-hexane to obtain crude CsPbBr3 perovskite quantum dots.

[0037] 4) Prepare a 10 mg / mL dispersion by dispersing crude CsPbBr3 perovskite quantum dots in cyclohexane; weigh tetraethyl orthosilicate (TEOS) at a quantum dot to tetraethyl orthosilicate mass ratio of 1:3.5, and weigh 25 wt% ammonia water as 2% of the TEOS mass. Slowly add TEOS dropwise to the dispersion and stir at 40°C for 12 h; centrifuge (9000 r / min, 10 min), wash twice each with cyclohexane and anhydrous ethanol, and sterilize at 60°C. Dry in air for 6 hours; place in a tube furnace, heat to 400℃ at 3℃ / min under nitrogen atmosphere, hold for 2 hours, cool to room temperature, and grind through a 400-mesh sieve; disperse the calcined powder in anhydrous ethanol (mass ratio 1:15), weigh 4wt% of silane coupling agent KH-560 according to the quantum dot mass, stir at 60℃ for 2 hours; centrifuge, wash twice with anhydrous ethanol, vacuum dry at 70℃ for 6 hours, and grind through a 400-mesh sieve to obtain inorganic coated perovskite quantum dots.

[0038] 5) Weigh the raw materials of each component according to the following parts by weight: 90 parts ABS resin, 5 parts modified cerium oxide, 3 parts inorganic coated perovskite quantum dots, 0.6 parts sodium bicarbonate micro powder (particle size 10μm), 0.5 parts polyethylene glycol (PEG-2000), 1 part maleic anhydride grafted ABS compatibilizer (ABS-g-MAH), 0.3 parts antioxidant 1010, 0.3 parts light stabilizer UV-326, 0.35 parts calcium stearate lubricant, and 0.2 parts white oil. After drying ABS resin at 90℃ for 3 hours, all raw materials were added to a high-speed mixer and mixed at 1000 r / min for 15 minutes. The premixed material was then added to a twin-screw extruder with the following temperatures in each zone: zone 1 170℃, zone 2 180℃, zone 3 190℃, zone 4 195℃, zone 5 200℃, and die head 205℃. The screw speed was 300 r / min, and the feeding speed was 20 kg / h. The extrudate was then water-cooled (water temperature 20℃), dried by an air knife, and pelletized (particle size 3 mm) to obtain ABS-based perovskite quantum dot composite material.

[0039] Example 4 A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse 10g of nano-cerium oxide powder (particle size 30nm) in 200g of anhydrous ethanol and ultrasonically disperse for 30min; weigh 0.8g of silane coupling agent KH-570 and dissolve it in a mixed solvent of 45mL of anhydrous ethanol and 5mL of deionized water, and stir and hydrolyze at room temperature for 45min; slowly add the hydrolysate to the cerium oxide dispersion, adjust the pH to 5 with glacial acetic acid, and reflux at 80℃ with magnetic stirring for 4h; centrifuge (9000r / min, 12min), wash three times each with anhydrous ethanol and deionized water, vacuum dry at 90℃ for 10h, grind and pass through a 200-mesh sieve to obtain silane coupling agent modified cerium oxide powder.

[0040] 2) Disperse 10g of the above-mentioned silane coupling agent modified cerium oxide powder in 250g of N,N-dimethylformamide and ultrasonically disperse for 20min; weigh 2g of polyvinylpyrrolidone (PVP, K30) and add it to the dispersion, stir and react at 70℃ for 5h; add anhydrous ethanol to precipitate, centrifuge (9000r / min), wash 3 times with anhydrous ethanol, vacuum dry at 70℃ for 8h, grind and pass through a 300-mesh sieve to obtain modified cerium oxide.

[0041] 3) Weigh 0.326 g of cesium carbonate and dissolve it in 20 mL of deionized water to prepare a cesium salt solution. Weigh 0.367 g of lead bromide and dissolve it in 10 mL of dimethyl sulfoxide to prepare a lead salt solution. Under nitrogen protection, add the lead salt solution dropwise to the cesium salt solution, and simultaneously add 0.037 g of oleic acid and 0.037 g of oleylamine as surface ligands. Stir rapidly at room temperature (1000 r / min) for 10 min. The solution turns bright green, and CsPbBr3 perovskite quantum dots are obtained. Quickly inject the solution into 80 mL of n-hexane to precipitate the precipitate. Centrifuge at high speed (11000 r / min, 8 min) to collect the precipitate. Wash twice with n-hexane to obtain crude CsPbBr3 perovskite quantum dots.

[0042] 4) Prepare a 10 mg / mL dispersion by dispersing crude CsPbBr3 perovskite quantum dots in cyclohexane; weigh tetraethyl orthosilicate (TEOS) at a quantum dot to tetraethyl orthosilicate mass ratio of 1:5, and weigh 25 wt% ammonia water as 2% of the TEOS mass. Slowly add TEOS dropwise to the dispersion and stir at 40 °C for 12 h; centrifuge (9000 r / min, 10 min), wash twice each with cyclohexane and anhydrous ethanol, and vacuum at 60 °C. Dry for 6 hours; place in a tube furnace, heat to 400℃ at 3℃ / min under nitrogen atmosphere, hold for 2 hours, cool to room temperature, and grind through a 400-mesh sieve; disperse the calcined powder in anhydrous ethanol (mass ratio 1:15), weigh 6wt% of silane coupling agent KH-560 according to the quantum dot mass, stir and react at 60℃ for 2 hours; centrifuge, wash twice with anhydrous ethanol, vacuum dry at 70℃ for 6 hours, and grind through a 400-mesh sieve to obtain inorganic coated perovskite quantum dots.

[0043] 5) Weigh the raw materials of each component according to the following weight parts: 95 parts ABS resin, 8 parts modified cerium oxide, 5 parts inorganic coated perovskite quantum dots, 1 part sodium bicarbonate micro powder (particle size 10μm), 0.8 parts polyethylene glycol (PEG-2000), 2 parts maleic anhydride grafted ABS compatibilizer (ABS-g-MAH), 0.5 parts antioxidant 1010, 0.5 parts light stabilizer UV-326, 0.5 parts calcium stearate lubricant, and 0.3 parts white oil. After drying ABS resin at 90℃ for 3 hours, all raw materials were added to a high-speed mixer and mixed at 1000 r / min for 15 minutes. The premixed material was then added to a twin-screw extruder with the following temperatures in each zone: zone 1 170℃, zone 2 180℃, zone 3 190℃, zone 4 195℃, zone 5 200℃, and die head 205℃. The screw speed was 300 r / min, and the feeding speed was 20 kg / h. The extrudate was then water-cooled (water temperature 20℃), dried by an air knife, and pelletized (particle size 3 mm) to obtain ABS-based perovskite quantum dot composite material.

[0044] Example 5 A method for preparing an ABS-based perovskite quantum dot composite material includes the following steps: 1) Disperse 10g of nano-cerium oxide powder (particle size 30nm) in 200g of anhydrous ethanol and ultrasonically disperse for 30min; weigh 0.3g of silane coupling agent KH-570 and dissolve it in a mixed solvent of 45mL of anhydrous ethanol and 5mL of deionized water, and stir and hydrolyze at room temperature for 45min; slowly add the hydrolysate to the cerium oxide dispersion, adjust the pH to 4 with glacial acetic acid, and reflux the reaction at 60℃ with magnetic stirring for 2h; centrifuge (9000r / min, 12min), wash three times each with anhydrous ethanol and deionized water, vacuum dry at 90℃ for 10h, grind and pass through a 200-mesh sieve to obtain silane coupling agent modified cerium oxide powder.

[0045] 2) Disperse 10g of the above-mentioned silane coupling agent modified cerium oxide powder in 250g of N,N-dimethylformamide and ultrasonically disperse for 20min; weigh 1g of polyvinylpyrrolidone (PVP, K30) and add it to the dispersion, stir and react at 50℃ for 3h; add anhydrous ethanol to precipitate, centrifuge (9000r / min), wash 3 times with anhydrous ethanol, vacuum dry at 70℃ for 8h, grind and pass through a 300-mesh sieve to obtain modified cerium oxide.

[0046] 3) Weigh 0.326 g of cesium carbonate and dissolve it in 20 mL of deionized water to prepare a cesium salt solution. Weigh 0.367 g of lead bromide and dissolve it in 10 mL of dimethyl sulfoxide to prepare a lead salt solution. Under nitrogen protection, add the lead salt solution dropwise to the cesium salt solution, and simultaneously add 0.037 g of oleic acid and 0.037 g of oleylamine as surface ligands. Stir rapidly at room temperature (1000 r / min) for 10 min. The solution turns bright green, and CsPbBr3 perovskite quantum dots are obtained. Quickly inject the solution into 80 mL of n-hexane to precipitate the precipitate. Centrifuge at high speed (11000 r / min, 8 min) to collect the precipitate. Wash twice with n-hexane to obtain crude CsPbBr3 perovskite quantum dots.

[0047] 4) Prepare a 10 mg / mL dispersion by dispersing crude CsPbBr3 perovskite quantum dots in cyclohexane; weigh tetraethyl orthosilicate (TEOS) at a quantum dot to tetraethyl orthosilicate mass ratio of 1:2, and weigh 2% (25 wt%) of ammonia water as TEOS. Slowly add TEOS dropwise to the dispersion and stir at 40°C for 12 h; centrifuge (9000 r / min, 10 min), wash twice each with cyclohexane and anhydrous ethanol, and vacuum at 60°C. Dry for 6 hours; place in a tube furnace, heat to 400℃ at 3℃ / min under nitrogen atmosphere, hold for 2 hours, cool to room temperature, and grind through a 400-mesh sieve; disperse the calcined powder in anhydrous ethanol (mass ratio 1:15), weigh 2wt% of silane coupling agent KH-560 according to the quantum dot mass, stir and react at 60℃ for 2 hours; centrifuge, wash twice with anhydrous ethanol, vacuum dry at 70℃ for 6 hours, and grind through a 400-mesh sieve to obtain inorganic coated perovskite quantum dots.

[0048] 5) Weigh the raw materials of each component according to the following parts by weight: 85 parts ABS resin, 2 parts modified cerium oxide, 1 part inorganic coated perovskite quantum dots, 0.3 parts sodium bicarbonate micro powder (particle size 10μm), 0.2 parts polyethylene glycol (PEG-2000), 0.5 parts maleic anhydride grafted ABS compatibilizer (ABS-g-MAH), 0.1 parts antioxidant 1010, 0.1 parts light stabilizer UV-326, 0.2 parts calcium stearate lubricant, and 0.1 parts white oil. After drying ABS resin at 90℃ for 3 hours, all raw materials were added to a high-speed mixer and mixed at 1000 r / min for 15 minutes. The premixed material was then added to a twin-screw extruder with the following temperatures in each zone: zone 1 170℃, zone 2 180℃, zone 3 190℃, zone 4 195℃, zone 5 200℃, and die head 205℃. The screw speed was 300 r / min, and the feeding speed was 20 kg / h. The extrudate was then water-cooled (water temperature 20℃), dried by an air knife, and pelletized (particle size 3 mm) to obtain ABS-based perovskite quantum dot composite material.

[0049] Comparative Example 1: The difference between Comparative Example 1 and Example 4 is that modified cerium oxide is not added in step 5).

[0050] Comparative Example 2: The difference between Comparative Example 2 and Example 4 is that in step 5), the modified cerium oxide is replaced with ordinary cerium oxide.

[0051] Comparative Example 3: The difference between Comparative Example 3 and Example 4 is that inorganic coated perovskite quantum dots are not added in step 5).

[0052] Comparative Example 4: The difference between Comparative Example 4 and Example 4 is that in step 5), the inorganic coated perovskite quantum dots are replaced with the CsPbBr3 perovskite quantum dots obtained in step 3).

[0053] Comparative Example 5: The difference between Comparative Example 5 and Example 4 is that sodium bicarbonate powder and polyethylene glycol are not added in step 5).

[0054] Comparative Example 6: The difference between Comparative Example 6 and Example 4 is that sodium bicarbonate powder is not added in step 5).

[0055] Comparative Example 7: The difference between Comparative Example 7 and Example 4 is that polyethylene glycol is not added in step 5).

[0056] Performance testing: 1. Tensile strength test: The composite material granules obtained in each example and comparative example were injection molded to prepare standard tensile test specimens (Type 1A). The test was conducted in accordance with GB / T 1040.2-2006 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics". The tensile speed was 50 mm / min, the test temperature was 23±2℃, and the relative humidity was 50±10%. Five specimens were tested in each group, and the arithmetic mean was taken.

[0057] 2. Notched impact strength test: The composite material granules obtained in each example and comparative example were injection molded to prepare standard impact specimens (80mm×10mm×4mm). The test was conducted in accordance with GB / T 1843-2008 "Determination of impact strength of plastic cantilever beam". The notch type was type A (notch radius 0.25mm), the test temperature was 23±2℃, the pendulum energy was 5.5J, and 10 specimens were tested in each group. The arithmetic mean was taken.

[0058] 3. Vicat softening temperature test: The composite material granules obtained from each example and comparative example were injection molded to prepare standard specimens (10mm×10mm×4mm). The Vicat softening temperature (VST) of thermoplastic plastics was tested according to GB / T 1633-2000 "Determination of Vicat softening temperature (VST) of thermoplastic plastics". The A50 method (load 10N, heating rate 50℃ / h) was used. The specimens were conditioned in a standard laboratory environment for no less than 24h before testing. Three specimens were tested in each group, and the arithmetic mean was taken.

[0059] 4. Fluorescence quantum yield test: The composite material granules obtained in each example and comparative example were hot-pressed to prepare thin sheet samples (thickness 0.5 mm). A fluorescence spectrometer equipped with an integrating sphere accessory was used to irradiate the samples with excitation light at a wavelength of 365 nm. The photoluminescence quantum yield (PLQY) of the samples was determined by the absolute method of integrating sphere. The test was carried out at room temperature. Three samples were tested in each group, and the arithmetic mean was taken.

[0060] 5. Test of fluorescence retention rate after thermal aging: The thin film samples prepared in each example and comparative example (same as test 4) were placed in a forced-air drying oven and subjected to continuous thermal aging treatment at 150℃ for 240h in accordance with GB / T 7141-2008 "Test Method for Thermal Aging of Plastics". After removal, they were cooled at room temperature and conditioned for 24h. Then, the fluorescence quantum yield after thermal aging was determined according to the method of test 4. The fluorescence retention rate was calculated according to the formula: fluorescence retention rate (%) = (PLQY after aging / PLQY before aging) × 100%.

[0061] 6. Fluorescence retention rate test under damp heat aging: The thin film samples prepared in each example and comparative example (same as test 4) were placed in a constant temperature and humidity test chamber and continuously treated for 500 h at a temperature of 85℃ and a relative humidity of 85% in accordance with GB / T 2423.3-2016 "Environmental testing - Part 2: Test methods - Cab: Constant damp heat test". After removal, the samples were cooled at room temperature and conditioned for 24 h. The fluorescence quantum yield after damp heat aging was then determined according to the method in test 4. The fluorescence retention rate was calculated according to the formula: Fluorescence retention rate (%) = (PLQY after aging / PLQY before aging) × 100%.

[0062] Table 1: Performance Test Results of Examples and Comparative Samples Note: Comparative Example 3 does not contain perovskite quantum dots, so its fluorescence correlation performance could not be measured and is indicated by "—".

[0063] As can be seen from Table 1: The Vicat softening temperature of Comparative Example 1 (without modified cerium oxide) was only 97.8°C, which was 12.7°C lower than that of Example 4, and the thermal aging fluorescence retention rate dropped to 68.3%. This indicates that modified cerium oxide effectively inhibited the thermo-oxidative degradation of ABS by capturing free radicals, while indirectly protecting the fluorescence stability of quantum dots.

[0064] The notched impact strength of Comparative Example 2 (using unmodified cerium oxide) was only 14.6 kJ / m. 2 Compared to Example 4, the cerium oxide content decreased by 15.1%, and the Vicat softening temperature was also significantly lower than that of Example 4. This indicates that the unmodified cerium oxide undergoes severe agglomeration in the ABS matrix, which not only fails to effectively perform the free radical capture function, but also significantly reduces the toughness of the material as a stress concentration point.

[0065] The fluorescence quantum yield of Comparative Example 4 (using uncoated quantum dots) was only 32.6%, and the fluorescence retention rates after thermal aging and humid heat aging dropped sharply to 26.8% and 14.5%, respectively. This demonstrates that the SiO2 inorganic coating layer and KH-560 surface functionalization treatment play an irreplaceable key role in protecting quantum dots from high-temperature processing damage and long-term water and oxygen erosion.

[0066] The thermal aging fluorescence retention rates of Comparative Example 5 (without sodium bicarbonate micropowder and polyethylene glycol), Comparative Example 6 (without sodium bicarbonate micropowder), and Comparative Example 7 (without polyethylene glycol) were 71.5%, 76.8%, and 75.2%, respectively, all significantly lower than the 91.5% of Example 4. This indicates that the synergistic effect of sodium bicarbonate and polyethylene glycol is indispensable for eliminating the interfacial interference of PVP degradation products on the quantum dot coating layer. Comparative Example 5 showed the most severe performance degradation when both additives were absent, while Comparative Examples 6 and 7 showed comparable performance degradation when each additive was absent. This suggests that the chemical neutralization effect of sodium bicarbonate and the physical isolation effect of polyethylene glycol have a synergistic and complementary effect in protecting the quantum dots, and both are indispensable.

[0067] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the essence and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an ABS-based perovskite quantum dot composite material, characterized in that, Includes the following steps: 1) Disperse nano-cerium oxide powder in anhydrous ethanol by ultrasonic dispersion, add hydrolyzed silane coupling agent KH-570 and carry out condensation grafting reaction under acidic conditions, and obtain silane coupling agent modified cerium oxide powder after washing and drying. 2) The silane coupling agent modified cerium oxide powder is dispersed in N,N-dimethylformamide, and polyvinylpyrrolidone is added for adsorption and coating treatment. After precipitation, washing and drying, the modified cerium oxide is obtained. 3) Cesium carbonate was dissolved in deionized water to prepare a cesium salt solution, and lead bromide was dissolved in dimethyl sulfoxide to prepare a lead salt solution. The solutions were mixed and reacted under nitrogen protection and in the presence of surface ligands to obtain CsPbBr3 perovskite quantum dots. 4) CsPbBr3 perovskite quantum dots were dispersed in cyclohexane, and tetraethyl orthosilicate was added to coat SiO2 by sol-gel method under the catalysis of ammonia. After densification treatment by calcination, the surface was functionalized by silane coupling agent KH-560 to obtain inorganic coated perovskite quantum dots. 5) ABS resin, modified cerium oxide, inorganic coated perovskite quantum dots, sodium bicarbonate powder, polyethylene glycol, compatibilizer, antioxidant, light stabilizer, lubricant and white oil are melt-blended to obtain ABS-based perovskite quantum dot composite material.

2. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 1), the amount of the silane coupling agent KH-570 is 3 to 8 wt% of the mass of nano-cerium oxide.

3. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 1), the pH value of the condensation grafting reaction is 4.0 to 5.0, the reaction temperature is 60 to 80°C, and the reaction time is 2 to 4 hours.

4. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 2), the amount of polyvinylpyrrolidone used is 10 to 20 wt% of the mass of the silane coupling agent modified cerium oxide powder.

5. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 2), the adsorption coating temperature is 50–70°C and the time is 3–5 hours.

6. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 3), the surface ligands are oleic acid and oleylamine.

7. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 4), the mass ratio of the CsPbBr3 perovskite quantum to tetraethyl orthosilicate is 1:(2-5).

8. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 4), the amount of silane coupling agent KH-560 used is 2 to 6 wt% of the quantum mass of CsPbBr3 perovskite.

9. The method for preparing an ABS-based perovskite quantum dot composite material according to claim 1, characterized in that, In step 5), the amounts of each component by weight are as follows: 85-95 parts of ABS resin, 2-8 parts of modified cerium oxide, 1-5 parts of inorganic coated perovskite quantum dots, 0.3-1.0 parts of sodium bicarbonate micro powder, 0.2-0.8 parts of polyethylene glycol, 0.5-2 parts of compatibilizer, 0.1-0.5 parts of antioxidant, 0.1-0.5 parts of light stabilizer, 0.2-0.5 parts of lubricant, and 0.1-0.3 parts of white oil.

10. An ABS-based perovskite quantum dot composite material, characterized in that, It is prepared by the method described in any one of claims 1 to 9 above.

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