Method for preparing quantum dot microspheres by precipitation polymerization, quantum dot microspheres and applications thereof

Abstract

The present invention discloses a method for preparing quantum dot microspheres by precipitation polymerization, the quantum dot microspheres and their applications, which relate to the technical field of quantum dots. First, the concentrations of quantum dots and monomers in the system are controlled so that the ligands on the quantum dots polymerize and the quantum dots agglomerate to form quantum dot clusters, and the quantum dot clusters can continue to be stably dispersed in a good solvent by the quantum dot ligands on the surface of the clusters. After the nucleation period of the quantum dots ends, monomer polymerization is carried out, and its concentration is controlled to always remain below the critical nucleation concentration. The oligomers generated by polymerization gradually adsorb and grow on the quantum dot clusters to form quantum dot microspheres. By separating the nucleation and growth processes, quantum dot microspheres with uniform quantum dot distribution and uniform loading can be directly synthesized when preparing quantum dot microspheres.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum dots, and in particular, to a method for preparing quantum dot microspheres by precipitation polymerization, quantum dot microspheres, and applications thereof. Background Art

[0002] Quantum dots have the advantages of adjustable fluorescence emission wavelength, high photoluminescence quantum yield (PLQY), and good fluorescence stability, and are highly favored in the detection of biomarkers such as proteins, nucleic acids, and cells. However, quantum dots have a small particle size and high surface energy, and are prone to aggregation when used alone, resulting in abnormal test results and limiting their application scenarios.

[0003] Loading multiple quantum dots into a single microsphere to form quantum dot fluorescent microspheres can provide a protective shell for the quantum dots and provide charged coupling groups, and the mutual repulsion of the surface potential can effectively avoid the aggregation of the microspheres. Copolymerization of quantum dots with monomers is a common method for preparing quantum dot fluorescent microspheres with uniform particle size, but often requires complex separation and purification to obtain microspheres with uniform quantum dot distribution, and it is difficult to synthesize quantum dot microspheres with uniform quantum dot distribution and uniform loading in one step.

[0004] During the process of preparing microspheres with uniform particle size by copolymerizing quantum dots with monomers, such as suspension polymerization, emulsion polymerization, etc., the quantum dots are embedded. These methods can ensure that the quantum dots do not leak in the use environment, but the continuous phase of these methods is water, and the high PLQY oil-phase quantum dots cannot be monodispersed in it, making it difficult to ensure the fluorescence uniformity of the quantum dot microspheres and affecting their application in precise quantitative detection.

[0005] Precipitation polymerization is a method for synthesizing monodisperse microspheres by dissolving all materials in a good solvent and precisely controlling the synthesis. However, directly dispersing quantum dots in a good solvent to form a quasi-homogeneous system, the quantum dots will affect the nucleation of monomers and form a large number of aggregates, still making it difficult to ensure the fluorescence uniformity of the quantum dot microspheres.

[0006] Therefore, how to achieve the fluorescence uniformity of quantum dot microspheres during the preparation of quantum dot microspheres is an urgent problem to be solved.

[0007] In view of this, the present invention is specifically proposed. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for preparing quantum dot microspheres by precipitation polymerization, quantum dot microspheres, and applications thereof, aiming to significantly improve the uniformity of quantum dot microspheres, making the quantum dot distribution and loading more uniform.

[0009] The present invention is implemented as follows:

[0010] In a first aspect, the present invention provides a method for preparing quantum dot microspheres by precipitation polymerization, including:

[0011] Mix quantum dots, initiator and monomer in a good solvent to obtain a nucleation reaction solution, and carry out the quantum dot nucleation reaction on the nucleation reaction solution; wherein, the volume fraction of the monomer in the nucleation reaction solution is less than 0.4%.

[0012] After the quantum dot nucleation reaction, add a mixed solution formed by monomer, initiator and crosslinking agent to the system for polymerization reaction, and control the addition rate of the mixed solution to control the monomer concentration below the critical nucleation concentration during the process.

[0013] In an alternative embodiment, first mix the quantum dots and the good solvent, heat up to 80°C - 95°C, and remove oxygen by nitrogen purging to obtain a quantum dot dispersion;

[0014] Mix and dissolve the initiator, monomer and good solvent to obtain a monomer solution, mix the quantum dot dispersion and the monomer solution to obtain a nucleation reaction solution, and react at 80°C - 95°C for 1h - 4h;

[0015] Preferably, inject the monomer solution into the quantum dot dispersion.

[0016] In an alternative embodiment, the quantum dots are quantum dots with vinyl ligands on the surface. The mass of quantum dots corresponding to every 100 ml of the quantum dot dispersion is 0.3g - 1g, and the volume ratio of the quantum dot dispersion to the monomer solution is 200:1.0 - 2.0;

[0017] Preferably, the vinyl ligands on the surface of the quantum dots are selected from at least one of acrylic acid and its derivatives, acrylate and its derivatives, and methacrylate and its derivatives;

[0018] More preferably, the vinyl ligands on the surface of the quantum dots are selected from at least one of n-octenoic acid, n-nonenoic acid, n-decenoic acid, acrylic acid phosphate, ethylene glycol acrylate, propanediol methacrylate, and butanediol methacrylate.

[0019] In an alternative embodiment, the good solvent is selected from non-coordinating inert solvents with solubility parameters of 21 - 25;

[0020] Preferably, the good solvent is selected from at least one of tetrachloroethane, pyridine, cyclohexanol, n-butanol, isobutanol, n-propanol, acetonitrile, and dimethylformamide.

[0021] In an alternative embodiment, the monomer in the monomer solution is a compound or its derivative having only one vinyl group;

[0022] Preferably, the monomer is selected from at least one of styrene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate, butyl acrylate, and acrylic acid;

[0023] Preferably, when preparing the monomer solution, the volume ratio of the monomer to the good solvent is controlled to be 1:1 - 10;

[0024] Preferably, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptonitrile, and azoisobutyronitrile carboxamide; the content of the initiator corresponding to every 100 mL of the nucleation reaction solution is 0.001 g - 0.01 g.

[0025] In an alternative embodiment, the volume ratio of the reaction solution in the reaction kettle after the quantum dot nucleation reaction to the volume of the mixed solution is 30 - 50:1. After the mixed solution is added dropwise to the reaction solution, the reaction continues at 60°C - 80°C for 2 h - 5 h;

[0026] Preferably, the dropping time of the mixed solution is controlled to be 40 min - 70 min;

[0027] More preferably, the dropping rate of the mixed solution is 0.05 mL / min - 0.15 mL / min.

[0028] In an alternative embodiment, during the preparation of the mixed solution, the volume ratio of the monomer to the crosslinking agent is 2.3 - 19:1. Let the total volume of the monomer and the crosslinking agent be V, and the content of the initiator corresponding to 100 mL of V is 0.1 g - 1 g.

[0029] In an alternative embodiment, the crosslinking agent is selected from compounds containing at least two vinyl groups;

[0030] Preferably, the crosslinking agent is selected from at least one of divinylbenzene, allyl ether, diethyl diallylmalonate, diallyl disulfide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3 - propanediol diacrylate, 1,3 - propanediol dimethacrylate, 1,3 - butanediol diacrylate, 1,3 - butanediol dimethacrylate, 1,4 - butanediol diacrylate, and 1,4 - butanediol dimethacrylate.

[0031] In a second aspect, the present invention provides a quantum dot microsphere prepared by the preparation method according to any one of the foregoing embodiments.

[0032] In a third aspect, the present invention provides an application of the quantum dot microsphere according to the foregoing embodiment in quantitative detection.

[0033] The present invention has the following beneficial effects: First, control the concentrations of quantum dots and monomers in the system, polymerize the ligands on the quantum dots, and cause the quantum dots to aggregate to form quantum dot clusters. The quantum dot clusters can continue to be stably dispersed in a good solvent by the quantum dot ligands on the cluster surface. After the end of the quantum dot nucleation period, monomer polymerization is carried out, and its concentration is always controlled below the critical nucleation concentration. The oligomers generated by polymerization gradually adsorb and grow on the quantum dot clusters to form quantum dot microspheres. By separating the nucleation and growth processes, quantum dot microspheres with uniform quantum dot distribution and uniform loading can be directly synthesized when preparing quantum dot microspheres. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0035] Figure 1 Electron microscopy image of the quantum fluorescence microspheres prepared in Example 1;

[0036] Figure 2 Electron microscopy image of the quantum fluorescence microspheres prepared in Example 2;

[0037] Figure 3 Fluorescence emission spectra of Example 1 and Comparative Example 2;

[0038] Figure 4 Fluorescence emission spectra of Example 1 and Comparative Example 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0040] The embodiments of the present invention provide a method for preparing quantum dot microspheres by precipitation polymerization, including the following steps:

[0041] S1. Quantum dot nucleation

[0042] Mix quantum dots, initiator, and monomer in a good solvent to obtain a nucleation reaction solution, and carry out a quantum dot nucleation reaction on the nucleation reaction solution; wherein, the volume fraction of the monomer in the nucleation reaction solution is less than 0.4%, and by strictly controlling the dosage of the monomer, spontaneous nucleation of the monomer can be effectively avoided.

[0043] In the actual operation process, first mix the quantum dots with a good solvent, heat up to 80°C - 95°C, remove oxygen by passing nitrogen to obtain a quantum dot dispersion liquid for standby; mix and dissolve the initiator, monomer and good solvent to obtain a monomer solution, mix the quantum dot dispersion liquid and the monomer solution to obtain a nucleation reaction liquid, and react for 1h - 4h under the condition of 80°C - 95°C to enable the ligand groups on the quantum dots to fully react.

[0044] Specifically, the reaction temperature can be 80°C, 83°C, 85°C, 87°C, 90°C, 92°C, 95°C, etc., and the reaction time can be 1h, 2h, 3h, 4h, etc., or any value between the adjacent values above.

[0045] In some embodiments, the monomer solution can be injected into the quantum dot dispersion liquid. With the help of a syringe, the monomer solution can be injected into the quantum dot dispersion liquid at one time.

[0046] In some embodiments, the vinyl ligand on the surface of the quantum dots is selected from at least one of acrylic acids and their derivatives, acrylate esters and their derivatives, and methacrylate esters and their derivatives; preferably, the vinyl ligand on the surface of the quantum dots is selected from at least one of n-octenoic acid, n-nonenoic acid, n-decenoic acid, acrylic acid phosphate ester, ethylene glycol acrylate, propanediol methacrylate, and butanediol methacrylate, and can be any one or several of the above.

[0047] In some embodiments, the good solvent is selected from non-coordinating inert solvents with solubility parameters (which can be calculated by the molar attraction constant and molecular weight of the structural group) in the range of 21 - 25, such as tetrachloroethane, pyridine, cyclohexanol, n-butanol, isobutanol, n-propanol, acetonitrile, and dimethylformamide, etc., and can be any one or several of the above. The above calculation of the solubility parameter is a conventional calculation method and can be calculated according to the molar attraction constant of the structural group. The formula is as follows:

[0048]

[0049] In the formula, ρ is the relative density, Fi is the molar attraction constant, and M0 is the molecular weight of the molecule. For details, see pages 82 - 86 of "Polymer Physics", Chemical Industry Press, Fourth Edition.

[0050] In some embodiments, the monomer in the monomer solution is a compound or its derivative that has and only has one vinyl group; preferably, the monomer is selected from at least one of styrene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate, butyl acrylate, and acrylic acid, and can be any one or several of the above.

[0051] The type of the initiator is not limited. In some embodiments, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptonitrile, and azoisobutyronitrile formamide, and can be any one or several of the above.

[0052] To better control the quantum dot nucleation and make the obtained quantum dot clusters more uniform, the inventors precisely controlled the dosages of each raw material: for every 100 milliliters of the quantum dot dispersion, the mass of the quantum dots was 0.3 g - 1 g, and the volume ratio of the quantum dot dispersion to the monomer solution was 200:1.0 - 2.0; the volume ratio of the monomer to the good solvent was controlled to be 1:1 - 10, and for every 100 mL of the nucleation reaction solution, the content of the initiator was 0.01 g - 0.1 g.

[0053] Specifically, for every 100 milliliters of the quantum dot dispersion, the mass of the quantum dots could be 0.3 g, 0.5 g, 0.7 g, 1.0 g, etc. The concentration of the quantum dots should not be too high, otherwise it would be difficult to control the nucleation period and visible agglomeration would form.

[0054] Specifically, the volume ratio of the quantum dot dispersion to the monomer solution could be 200:1.0, 200:1.5, 200:2.0, etc., or any value between the adjacent values above.

[0055] Specifically, when preparing the monomer solution, the volume ratio of the monomer to the good solvent could be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc. The concentration of the monomer should not be too high, and the concentration after injection should be less than 0.4% (v / v) to avoid spontaneous nucleation.

[0056] Specifically, for every 100 mL of the nucleation reaction solution, the content of the initiator could be 0.01 g, 0.03 g, 0.05 g, 0.07 g, 0.10 g, etc. The free radicals decomposed by the initiator have strong oxidizing properties. Too much initiator would cause oxidation defects to form on the surface of the quantum dots, affecting the fluorescence performance. Therefore, the initiator concentration needs to be controlled within 0.01% - 0.1% (m / V).

[0057] S2. Monomer polymerization

[0058] After the quantum dot nucleation reaction, a mixed solution formed by the monomer, initiator, and crosslinker was added to the system for polymerization reaction. By controlling the addition rate of the mixed solution, the total concentration of the monomer and crosslinker during the process was always kept below the critical nucleation concentration. The critical nucleation concentration can be controlled according to experience. If there is no relevant experience during actual operation, the dropping rate can be controlled to be slow enough and slowly dropped.

[0059] In the actual operation process, the volume ratio of the reaction solution in the reaction kettle to the mixed solution after the quantum dot nucleation reaction is 30 - 50:1. After the mixed solution is added dropwise to the reaction solution, the reaction continues for 2h - 5h under the condition of 60°C - 80°C. Since the amount of the mixed solution is small, its slow addition is controlled to ensure that the total concentration of the monomer and the crosslinking agent is always below the critical nucleation concentration, preventing secondary nucleation of the monomer. The oligomers generated by polymerization gradually adsorb and grow on the quantum dot clusters to form quantum dot microspheres. After the reaction is completed, the quantum dot fluorescent microspheres are obtained by centrifugation and solvent replacement.

[0060] Specifically, the volume ratio of the reaction solution in the reaction kettle to the mixed solution after the quantum dot nucleation reaction can be 30:1, 35:1, 40:1, 45:1, 50:1, etc.; the dropping time of the mixed solution is controlled to be 40min - 70min to ensure that the total concentration of the monomer and the crosslinking agent is always below the critical nucleation concentration, which can be specifically 40min, 50min, 60min, 70min, etc. Specifically, the dropping rate of the mixed solution can be 0.05mL / min - 0.15mL / min, such as 0.05mL / min, 0.10mL / min, 0.15mL / min, etc.

[0061] To further control the polymerization reaction of the monomer and obtain uniform quantum dot microspheres, the inventor optimized the dosages of each raw material: in the preparation process of the mixed solution, the volume ratio of the monomer to the crosslinking agent is 2.3 - 19:1. Let the total volume of the monomer and the crosslinking agent be V, and the content of the initiator corresponding to 100mL of V is 0.1g - 1g.

[0062] Specifically, the volume ratio of the monomer to the crosslinking agent can be 2.3:1, 2.5:1, 3.0:1, 5.0:1, 7.0:1, 9.0:1, 13.0:1, 15.0:1, 17.0:1, 19.0:1, etc. The content of the initiator corresponding to 100mL of V can be 0.1g, 0.3g, 0.5g, 0.7g, 1.0g, etc. If the proportion of the crosslinking agent is too high, the critical nucleation concentration decreases, and the monomer / crosslinking agent is prone to self - nucleation; if the proportion of the crosslinking agent is too low, the molecular weight of the generated oligomers is small and it is difficult to adsorb on the quantum dot clusters, and the obtained product lacks a functional polymer shell layer and cannot be dispersed in an aqueous solution.

[0063] In some embodiments, the crosslinking agent is selected from compounds containing at least two vinyl groups; preferably, the crosslinking agent is selected from at least one of divinylbenzene, allyl ether, diethyl diallylmalonate, diallyl disulfide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3 - propanediol diacrylate, 1,3 - propanediol dimethacrylate, 1,3 - butanediol diacrylate, 1,3 - butanediol dimethacrylate, 1,4 - butanediol diacrylate, and 1,4 - butanediol dimethacrylate, and can be any one or several of the above.

[0064] It should be noted that in the preparation method provided by the embodiments of the present invention, in the nucleation stage, the quantum dots containing vinyl ligands are dispersed in a good solvent and nucleated under the action of an initiator, and then a monomer / crosslinking agent - initiator mixed solution is added dropwise. This mixed solution can be dissolved in the good solvent, and under quasi - homogeneous conditions, quantum dot fluorescent microspheres are prepared by precipitation polymerization.

[0065] The embodiments of the present invention provide a quantum dot microsphere, which is prepared by the above - mentioned preparation method. By separating the nucleation and growth steps in a quasi - homogeneous system, quantum dot fluorescent microspheres with uniform particle size and uniform quantum dot loading can be obtained, which can be applied in quantitative detection and is beneficial to further improving the detection accuracy.

[0066] The features and properties of the present invention will be further described in detail below in conjunction with embodiments.

[0067] Example 1

[0068] This example provides a method for preparing quantum dot microspheres by precipitation polymerization, which includes the following steps:

[0069] (1) Disperse 2.0 g of quantum dots (ZnCdSe quantum dots, the same below) in 200 mL of tetrachloroethane, heat up to 90 °C in a reactor, continuously stir, and purge with nitrogen to remove oxygen for standby.

[0070] (2) Dissolve 0.02 g of azobisisobutyronitrile in 0.8 mL of styrene and 0.8 mL of tetrachloroethane, inject it into the reactor, and react at 90 °C for 3 h.

[0071] (3) Dissolve 0.05 g of azobisisobutyronitrile in 3 mL of styrene, 0.5 mL of acrylic acid, and 1.5 mL of divinylbenzene, and add it dropwise to the system obtained in step (2) at a rate of 0.1 mL / min. After the dropwise addition, continue to react at 70 °C for 3 h, collect by centrifugation, and then disperse with pure water, repeating twice.

[0072] Test the electron micrograph of the quantum dot fluorescent microspheres prepared in Example 1, as Figure 1As shown, it can be seen that the prepared quantum dot fluorescent microspheres are evenly distributed, with uniform particle size and uniform quantum dot loading.

[0073] Example 2

[0074] This example provides a method for preparing quantum dot microspheres by precipitation polymerization, which includes the following steps:

[0075] (1) Disperse 2.0 g of quantum dots in 200 mL of pyridine, heat up to 90 °C in a reactor, continuously stir and purge with nitrogen to remove oxygen for standby.

[0076] (2) Dissolve 0.002 g of azobisisobutyronitrile in 0.1 mL of styrene and 1.0 mL of tetrachloroethane, inject it into the reactor, and react for 3 h under the condition of 90 °C.

[0077] (3) Dissolve 0.005 g of azobisisobutyronitrile in 4.25 mL of styrene, 0.5 mL of acrylic acid, and 0.25 mL of divinylbenzene, and dropwise add it to the system obtained in step (2) at a rate of 0.1 mL / min. After the addition is complete, continue to react for 3 h under the condition of 70 °C, collect by centrifugation, and then disperse with pure water, repeating twice.

[0078] Test the electron microscopy image of the quantum dot fluorescent microspheres prepared in Example 1, as Figure 2 shown. It can be seen that the prepared quantum dot fluorescent microspheres are evenly distributed, with uniform particle size and uniform quantum dot loading.

[0079] Comparative Example 1

[0080] This comparative example provides a method for preparing quantum dot microspheres by precipitation polymerization. The difference from Example 1 is only that: after injecting into the reactor in step (2), no reaction is carried out, and the solution in step (3) is directly dropped. Specifically as follows:

[0081] (1) Disperse 2.0 g of quantum dots in 200 mL of tetrachloroethane, heat up to 90 °C in a reactor, continuously stir and purge with nitrogen to remove oxygen for standby.

[0082] (2) Dissolve 0.02 g of azobisisobutyronitrile in 0.8 mL of styrene and 0.8 mL of tetrachloroethane, and inject it into the reactor.

[0083] (3) Dissolve 0.05 g of azobisisobutyronitrile in 3 mL of styrene, 0.5 mL of acrylic acid, and 1.5 mL of divinylbenzene, and dropwise add it to the mixed system in step (2) at a rate of 0.1 mL / min. After the addition is complete, continue to react for 3 h under the condition of 70 °C, collect by centrifugation, and then disperse with pure water, repeating twice.

[0084] Comparative Example 2

[0085] This comparative example provides a method for preparing quantum dot microspheres by precipitation polymerization. The difference from Example 1 is only that: in step (1), the dosage of quantum dots is increased to 5 g.

[0086] Comparative Example 3

[0087] This comparative example provides a method for preparing quantum dot microspheres by precipitation polymerization. The difference from Example 1 is only that: in step (2), the dosage of the initiator is increased to 0.2 g.

[0088] Test Example

[0089] The fluorescence emission diagrams of Example 1 and Comparative Example 2 are as Figure 3 shown. The solid line is for Example 1, where the quantum dot clusters have a uniform particle size and there is only one particle size peak; the dashed line is for Comparative Example 2, where there is an excessive amount of quantum dots, resulting in uncontrollable aggregation of quantum dots, non-uniform particle size, and two broad particle size peaks.

[0090] The fluorescence emission diagrams of Example 1 and Comparative Example 3 are as Figure 4 shown. The solid line is for Example 1 and the dashed line is for Comparative Example 3. An excessive initiator in the nucleation stage directly causes the formation of oxidation defects on the surface of the quantum dots, resulting in a significant decrease in fluorescence intensity.

[0091] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing quantum dot microspheres by precipitation polymerization, characterized in that, Including: Mixing quantum dots, an initiator, and a monomer in a good solvent to obtain a nucleation reaction solution, and performing a quantum dot nucleation reaction on the nucleation reaction solution; wherein, the volume fraction of the monomer in the nucleation reaction solution is less than 0.4%; After the quantum dot nucleation reaction, adding a mixed solution formed by the monomer, the initiator, and a crosslinking agent to the system for a polymerization reaction, and controlling the addition rate of the mixed solution to control the monomer concentration below the critical nucleation concentration during the process; First, mixing the quantum dots and the good solvent, heating to 80°C - 95°C, and removing oxygen by nitrogen purging to obtain a quantum dot dispersion; Mixing and dissolving the initiator, the monomer, and the good solvent to obtain a monomer solution, mixing the quantum dot dispersion and the monomer solution to obtain the nucleation reaction solution, and reacting at 80°C - 95°C for 1 h - 4 h; The quantum dots are quantum dots with vinyl ligands on the surface. The mass of quantum dots corresponding to every 100 milliliters of the quantum dot dispersion is 0.3 g - 1 g, and the volume ratio of the quantum dot dispersion to the monomer solution is 200:1.0 - 2.0; The initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptonitrile, and azoisobutyronitrile carboxamide; the content of the initiator corresponding to every 100 mL of the nucleation reaction solution is 0.001 g - 0.01 g; The vinyl ligands on the surface of the quantum dots are selected from at least one of acrylic acids, acrylate esters and their derivatives, and methacrylate esters and their derivatives.

2. The method according to claim 1, characterized in that Injecting the monomer solution into the quantum dot dispersion.

3. The method according to claim 1, wherein The vinyl ligands on the surface of the quantum dots are selected from at least one of n-octenoic acid, n-nonenoic acid, n-decenoic acid, acrylic acid phosphate, ethylene glycol acrylate, propylene glycol methacrylate, and butanediol methacrylate.

4. The method according to claim 1, wherein The good solvent is selected from non-coordinating inert solvents with solubility parameters of 21 - 25.

5. The method according to claim 4, characterized in that The good solvent is selected from at least one of tetrachloroethane, pyridine, cyclohexanol, n-butanol, isobutanol, n-propanol, acetonitrile, and dimethylformamide.

6. The method according to claim 1, wherein The monomer in the monomer solution is a compound having and only having one vinyl group.

7. The method according to claim 6, wherein The monomer is selected from at least one of styrene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate, butyl acrylate, and acrylic acid.

8. The method according to claim 6, wherein When preparing the monomer solution, controlling the volume ratio of the monomer to the good solvent to be 1:1 - 10.

9. The method according to claim 1, wherein After the quantum dot nucleation reaction, the volume ratio of the reaction solution in the reaction kettle to the mixed solution is 30 - 50:

1. After dropping the mixed solution into the reaction solution, continue to react at 60°C - 80°C for 2 h - 5 h.

10. The method according to claim 9, wherein Controlling the dropping time of the mixed solution to be 40 min - 70 min.

11. The method according to claim 10, characterized in that, The dropping rate of the mixed solution is 0.05 mL / min - 0.15 mL / min.

12. The method according to claim 9, wherein During the preparation of the mixed solution, the volume ratio of the monomer to the crosslinking agent is 2.3 - 19:

1. Let the total volume of the monomer and the crosslinking agent be V, and the content of the initiator corresponding to 100 mL of V is 0.1 g - 1 g.

13. The method according to claim 12, wherein The crosslinking agent is selected from compounds containing at least two vinyl groups.

14. The method according to claim 13, characterized in that, The crosslinking agent is selected from at least one of divinylbenzene, allyl ether, diethyl diallylmalonate, diallyl disulfide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, and 1,4-butanediol dimethacrylate.

15. A quantum dot microsphere, characterized in that, It is prepared by the preparation method described in any one of claims 1-14.

Images