CN-121975512-A - Method for coating modified fluorescent quantum dots by in-situ polymerization and modified fluorescent quantum dot material

CN121975512ACN 121975512 ACN121975512 ACN 121975512ACN-121975512-A

Abstract

The invention provides a method for coating modified fluorescent quantum dots by in-situ polymerization and a modified fluorescent quantum dot material, the method comprises the following steps of adding the fluorescent quantum dots into a solvent for mechanical/ultrasonic dispersion, then adding a mixed solution of a reactive monomer and a coupling agent, and continuing ultrasonic dispersion uniformly to obtain a solution A; sequentially adding an emulsifying agent, carbonate or phosphate and a water-soluble polymer into deionized water, stirring uniformly to obtain a solution B, adding the solution A into the solution B, stirring at a high speed, adding ultrasonic dispersion for more than 10min, transferring the mixed emulsion into a reaction container, adding an aqueous solution containing a catalyst, heating to 50-90 ℃ under the protection of nitrogen, reacting for 2-10 h, centrifuging, cleaning the separated product, and spray drying. The quantum dot-polymer structure formed by the technical scheme of the invention has the excellent properties of high light transparency, good physical and chemical stability, adjustable mechanical property, easy forming and the like.

Inventors

LIU HONGBO
HUANG HUIXIN
DU ZHONGHUI
CHEN XIAOWEN
Kui Jingjing
DENG WENJUN
YANG YUWAN
CHEN YAQING
CHEN YUXUAN
ZHENG YANXIU

Assignees

深圳职业技术大学

Dates

Publication Date: 20260505
Application Date: 20260320

Claims (9)

1. The method for coating the modified fluorescent quantum dots by in-situ polymerization is characterized by comprising the following steps of: Step S1, adding fluorescent quantum dots into a solvent for mechanical/ultrasonic dispersion, wherein the mass ratio of the quantum dots to the solvent is 1:1-20, then adding a mixed solution of a reactive monomer and a coupling agent, wherein the coupling agent accounts for 0.5-8% of the total mass of the mixed solution, and the mass ratio of the mixed solution of the reactive monomer and the coupling agent to the quantum dots is 1-15:1; Step S2, sequentially adding an emulsifying agent, carbonate or phosphate and a water-soluble polymer into deionized water, and uniformly stirring to obtain a solution B, wherein the content of the emulsifying agent accounts for 0.1-5% of the total mass of the solution B, the content of the carbonate or phosphate accounts for 0.01-1% of the total mass of the solution B, and the content of the water-soluble polymer accounts for 0.5-6% of the total mass of the solution B; And S3, adding the solution A into the solution B, stirring at a high speed, adding ultrasonic for dispersion for more than 10 minutes, wherein the mass ratio of the solution A to the solution B is 1:10-50, transferring the mixed emulsion into a reaction container, adding a catalyst-containing aqueous solution, wherein the catalyst accounts for 3-10% of the mass of the aqueous solution, heating the catalyst-containing aqueous solution to 50-90 ℃ under the protection of nitrogen, reacting for 2-10 hours, centrifugally separating, cleaning the separated product by adopting a cleaning solvent, and then spray-drying to obtain the organic-coated fluorescent quantum dot material.
2. The method for in-situ polymerization coating modification of fluorescent quantum dots according to claim 1, wherein the fluorescent quantum dots are one or a mixture of at least two of CdS、CdSe、CdTe、ZnS、ZnSe、ZnTe、CdSeS、CdSeTe、CdSTe、CdZnS、CdZnSe、CdZnTe、HgS、HgSe、HgTe、CdSe/ZnS、CdS/ZnS、CdSeS/CdS/ZnS、CdSe/CdS/ZnS、CdSe/CdS、InP/ZnS, and the particle size of the fluorescent quantum dots is 1-10 nm.
3. The method for coating and modifying fluorescent quantum dots by in-situ polymerization according to claim 1, wherein in the step S1, the solvent is one or a mixture of at least two of toluene, xylene, n-hexane, pentane, carbon tetrachloride, chloroform, dichloromethane, butyl ether, ethyl acetate, acetone, butanone and tetrahydrofuran.
4. The method for coating and modifying fluorescent quantum dots by in-situ polymerization according to claim 1, wherein the reactive monomer is one or a mixture of at least two of methyl acrylate, methyl methacrylate, ethyl acrylate, hydroxyethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, glycidyl methacrylate, isobornyl methacrylate, hexyl methacrylate, acrylonitrile, acrylamide, butadiene and vinyl acetate; The coupling agent is one or at least two of methacryloxypropyl trimethoxy silane, vinyl triethoxy silane and vinyl tri (beta-methoxyethoxy) silane.
5. The method for in-situ polymerization coating and modification of fluorescent quantum dots according to claim 1, wherein the emulsifier is at least one of anionic emulsifier and nonionic emulsifier, wherein the anionic emulsifier comprises at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium alkylphenol ether sulfosuccinate, sodium fatty acid salt, fatty alcohol polyoxyethylene ether sulfate, sodium secondary alkyl sulfonate and alpha-alkenyl sulfonate, and the nonionic emulsifier comprises at least one of alkylphenol polyoxyethylene ether OP-4, OP-7, OP-9, OP-10, OP-13, OP-15, OP-20, fatty alcohol polyoxyethylene ether and fatty alcohol alkanolamide; the carbonate or phosphate is one of sodium bicarbonate, disodium hydrogen phosphate and sodium dihydrogen phosphate; The water-soluble polymer is at least one of carboxymethyl starch, starch acetate, hydroxymethyl cellulose, carboxymethyl cellulose, sodium hydroxymethyl cellulose, sodium carboxymethyl cellulose, polyacrylamide and polyvinylpyrrolidone; The catalyst is one of ammonium persulfate, potassium persulfate and sodium persulfate.
6. The method for coating the modified fluorescent quantum dots by in-situ polymerization according to claim 1, wherein in the step S3, the step of cleaning the separation product by using a cleaning solvent comprises the step of re-dispersing the separation product in the cleaning solvent for 2-3 times, wherein the cleaning solvent comprises one or at least two of methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, glycerol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether.
7. The method of claim 1, wherein the spray drying comprises one of centrifugal spray drying, high pressure spray drying, and air flow spray drying.
8. The method for in-situ polymerization coating of modified fluorescent quantum dots according to any one of claims 1-7, wherein in step S1, the mass ratio of the quantum dots to the solvent is 1:10-20, the coupling agent accounts for 2-2.5% of the total mass of the mixed solution, and the mass ratio of the mixed solution of the reactive monomer and the coupling agent to the quantum dots is 6-10:1; in the step S2, the content of the emulsifying agent accounts for 0.4-1.5% of the total mass of the solution B, the content of the carbonate or the phosphate accounts for 0.1-0.5% of the total mass of the solution B, and the content of the water-soluble polymer accounts for 1-2% of the total mass of the solution B; in the step S3, the mass ratio of the solution A to the solution B is 1:10-20, the catalyst accounts for 5-10% of the mass of the aqueous solution, and the mass ratio of the aqueous solution containing the catalyst to the solution B is 1:30-45.
9. A modified fluorescent quantum dot material is characterized by being prepared by adopting the method for coating modified fluorescent quantum dots by in-situ polymerization according to any one of claims 1-8.

Description

Method for coating modified fluorescent quantum dots by in-situ polymerization and modified fluorescent quantum dot material Technical Field The invention relates to the technical field of nano fluorescent quantum dots, in particular to a method for coating modified fluorescent quantum dots by in-situ polymerization and a modified fluorescent quantum dot material. Background White light LEDs are widely used in the field of lighting because of their high luminous efficiency as fourth generation lighting sources. Currently, the main technical approaches for realizing the white light LED include modes of multi-chip combination, multi-color composite light conversion, single fluorescent material excitation by the LED chip, and the like. Wherein, the fluorescent powder is widely used as a light conversion material because of the advantages of mature preparation process, controllable cost, adjustable performance and the like. However, the conventional fluorescent powder has the problems of limited light conversion efficiency, insufficient color gamut coverage, high blue light component and the like, and further development of the fluorescent powder is limited to a certain extent. In recent years, quantum Dots (QDs) have received attention as a new semiconductor nanomaterial due to their unique optical properties. When the size of the material is smaller than the Bohr radius of excitons, the quantum dot shows remarkable quantum confinement effect and size-dependent luminescence property, the emission wavelength can be precisely regulated by regulating the particle size of the quantum dot, and the quantum dot has the advantages of high luminous color purity, excellent quantum efficiency, strong light attenuation resistance and the like, and is considered to be an ideal light conversion material which has potential to replace the traditional fluorescent powder. At present, the research of quantum dots applied to white light LEDs is mainly divided into three types, namely quantum dot and fluorescent powder compound type, single-phase quantum dot white type and multicolor quantum dot compound type. Among them, the multicolor quantum dot composite technology is regarded as the most promising technology route because of the outstanding performance in terms of color gamut and color expressive force. However, the quantum dots still face key technical challenges in practical application processes, especially how to stably and uniformly disperse the quantum dots in the LED packaging material or the backlight module. The core of the problem lies in the regulation and control of the surface property of the quantum dot, and the compatibility of the quantum dot with a polymer matrix (such as an adhesive, plastic and the like) is improved through effective organic modification, so that the quantum dot packaging material or the quantum dot functional film with stable performance is prepared. At present, research on quantum dots at home and abroad is mainly focused on synthesis and performance optimization of materials, and obvious defects still exist in the aspects of combination of the quantum dots, the existing LED packaging technology and backlight technology. In particular, the research on the organic modification of the surface of the quantum dot is insufficient, which has become one of the key bottlenecks for restricting the further development of the quantum dot display technology. Therefore, the development of the surface modification technology and the composite technology suitable for the high-efficiency application of the quantum dots has important research value and application prospect. Disclosure of Invention Aiming at the technical problems, the invention discloses a method for coating and modifying fluorescent quantum dots by in-situ polymerization, and the formed quantum dot-polymer structure has the excellent properties of high light transparency, good physical and chemical stability, adjustable mechanical properties, easy forming and the like. The surface organic coating modification of the quantum dot greatly improves the compatibility of the quantum dot and other high polymer resin materials, and can be compounded with the quantum dot to prepare quantum dot optical materials, such as quantum dot adhesives or quantum dot films. In this regard, the invention adopts the following technical scheme: The in-situ polymerization coating modified fluorescent quantum dot method includes the following steps: Step S1, adding fluorescent quantum dots with the particle size of 1-10 nm into a solvent for mechanical/ultrasonic dispersion, wherein the mass ratio of the quantum dots to the solvent is 1:1-20, then adding a mixed solution of a reactive monomer and a coupling agent, wherein the coupling agent accounts for 0.5-8% of the total mass of the mixed solution, and the mass ratio of the mixed solution of the reactive monomer and the coupling agent to the quantum dots is 1-15:1; Step S2, sequentially adding an emulsifying