Narrow-band light-emitting microsphere and preparation method thereof

Abstract

The invention relates to a narrow-band light-emitting microsphere and a preparation method thereof, and relates to the technical field of light-emitting microspheres. In order to solve the technical problems of relatively wide luminescence emission peak, insufficient luminescence purity and relatively low luminescence efficiency of the existing luminescence microsphere, the invention provides the narrow-band luminescence microsphere and the preparation method thereof. The narrow-band light-emitting microsphere disclosed by the invention is a light-emitting microsphere obtained by carrying out precipitation polymerization reaction on an acrylonitrile monomer and a boron or aza multi-resonance fused ring monomer through a free radical polymerization method. According to the present invention, the double-bond-containing boron or aza-multiple resonance fused ring monomer having the narrow band luminescence characteristic is adopted as the luminescence unit, and the resonance effect between the boron atom and the nitrogen (sulfur, selenium and tellurium) atom is utilized to achieve the separation of HOMO and LUMO so as to reduce the excited state structure relaxation degree, such that the narrow half-peak width is achieved; the preparation method of the luminous microspheres is simple, and the luminous purity of the microspheres is greatly improved. The light-emitting microspheres prepared by the method have the characteristics of high color purity, high light-emitting efficiency and narrow light-emitting spectrum.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent microspheres, and particularly to a narrow-band luminescent microsphere synthesized using a boron- or nitrogen-doped multi-resonance fused-ring monomer as a luminescent monomer and a preparation method thereof. Background Art

[0002] Luminescent microspheres emit light under the excitation of ultraviolet light, and this property makes them form an obvious contrast with the background, thereby improving visibility. With this unique advantage, luminescent microspheres have been widely used as tracers in water and air flow tests. In addition, in the biological field, luminescent microspheres also show important application values in medical imaging technology and flow cytometry.

[0003] Methods for preparing luminescent microspheres include copolymerization method, adsorption method, embedding method, self-assembly method, etc. Commercially available luminescent polymer nano- or micro-scale particles usually physically fix dye molecules by adsorption or embedding, which will cause the problem of dye leakage. The leakage of luminescent dyes will reduce the luminescence intensity of the microspheres and affect the sensitivity and accuracy of detection. During the embedding process, the distribution of luminescent dyes in the microspheres is uneven, which is prone to cause the aggregation-caused quenching effect (ACQ), resulting in some luminescent molecules losing their luminescence ability. The unevenly distributed luminescent dyes will affect the luminescence intensity and stability of the microspheres, reducing the sensitivity and specificity of detection. In the embedding method, the embedding amount of luminescent dyes is usually low, and it is difficult to achieve a high concentration of luminescent dye loading. This makes the luminescence emission of the luminescent microspheres unstable, the full width at half maximum is relatively wide, the luminescence purity is insufficient, and the luminescence efficiency is low. The copolymerization method refers to preparing luminescent microspheres by copolymerizing a luminescent substance with polymerizable functional groups and an organic monomer. The luminescent microspheres prepared by this method have stable performance and the luminescent substance is evenly distributed in the microspheres. However, when preparing luminescent microspheres by the copolymerization method, after adding the luminescent dye, the morphology and size of the microspheres will be uneven. Moreover, precise control of reaction conditions such as temperature, time, solvent, etc. is required to ensure the uniform distribution of the luminescent dye and the formation of the microspheres.

[0004] Currently, the luminescent dyes used in the preparation of luminescent microspheres are mainly quantum dot luminescent dyes and organic luminescent dyes. Quantum dots have a relatively broad excitation spectrum and a relatively narrow emission spectrum, but the synthesis of quantum dots is both difficult and expensive. Most of them still use organic luminescent dyes to prepare luminescent microspheres. The concentration of organic luminescent dyes is a key factor affecting the luminescence intensity and full width at half maximum (FWHM). High concentrations of organic luminescent dyes are prone to cause the aggregation-caused quenching (ACQ) effect, resulting in some luminescent molecules losing their luminescence ability, thus affecting the FWHM. At low concentrations, there may be fewer excited photons around the luminescent substance, resulting in a decrease in luminescence intensity. For example, Wang Hui et al. prepared monodisperse polystyrene microspheres using an aggregation-induced emission (AIE) luminogen as the luminescent dye. The particle size of the synthesized microspheres was about 3 μm, and the coefficient of variation (CV) was about 5%, but its FWHM was about 100 nm (Wang Hui, et al. Designed Monomers and Polymers. 25(1), 175–183). Cheng Weiqing et al. obtained a novel luminescent microsphere by self-stabilized precipitation copolymerization of maleic anhydride (MAn), vinyl acetate (VAc), and a luminescent monomer containing rhodamine B family (FM-Rh B). The microsphere exhibited good luminescence properties under both blue and green light, but its FWHM was about 70 nm (Chen, W. (2022). Materials Technology. 37(12), 2148–2157.). The luminescent microspheres prepared from organic luminescent dyes in the above literature still have a relatively broad FWHM (≥70 nm). Thus, it can be seen that the preparation of luminescent microspheres with a narrow spectrum poses certain challenges.

[0005] Therefore, how to develop and design luminescent microspheres with a uniform structure and a narrow spectrum through appropriate luminescent dyes and main polymerization monomers, and solve the defects of low luminescence efficiency and relatively broad FWHM faced by the above luminescent microspheres, has become one of the urgent problems to be solved by many forward-looking researchers in the field. Summary of the Invention

[0006] The present invention aims to solve the technical problems of the existing luminescent microspheres having a relatively broad luminescence emission peak, insufficient luminescence purity, and low luminescence efficiency, and provides a narrow-band luminescent microsphere and a preparation method thereof. The present invention uses a boron- or nitrogen-heterocyclic multi-resonance fused-ring monomer with double bonds and narrow-band luminescent characteristics as the luminescent unit, and utilizes the resonance effect between boron atoms and nitrogen (sulfur, selenium, tellurium) atoms to achieve the separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), thereby reducing the degree of excited-state structural relaxation, and thus achieving a narrow FWHM.

[0007] To solve the above technical problems, the technical solutions of the present invention are specifically as follows:

[0008] A narrow-band luminescent microsphere, which is a luminescent microsphere obtained by precipitation polymerization of acrylonitrile monomer with a boron or nitrogen hetero multiple resonance fused-ring monomer through a free radical polymerization method;

[0009] Wherein, the boron or nitrogen hetero multiple resonance fused-ring monomer is selected from one or more of the structures shown in general formulas (I), (II), (III), (IV) and (V):

[0010]

[0011] In formulas (I) to (V), X 1 and X 2 each independently selected from O, S, Se, Te or N;

[0012] Y 1 is selected from a single bond, -CR 1 R 2 -, -C=O-, -SiR 1 R 2 -, -NR 1 -, -POR 1 -, -O-, -S-, -Se-, -S=O- and -SO 2 -; wherein, R 1 and R 2 each independently selected from H, D, a substituted or unsubstituted C1-C30 straight-chain hydrocarbon group, a substituted or unsubstituted C1-C30 branched-chain hydrocarbon group, a substituted or unsubstituted C1-C30 haloalkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C60 aromatic group or a substituted or unsubstituted C5-C60 heteroaromatic group;

[0013] a, b and c are each independently an integer from 0 to 3; q is 0 or 1;

[0014] Z is B or N;

[0015] Ar 1 ~Ar 5 each independently selected from a substituted or unsubstituted C6-C60 aryl ring or a substituted or unsubstituted C3-C60 heteroaryl ring; wherein the heteroatoms of the heteroaryl ring are independently selected from Si, Ge, N, P, O, S or Se;

[0016] R 1 ~R 3 each independently selected from H, D, F, Cl, Br, I, -CN, -NO 2 -, -CF 3 -, -OH, -SH, -NH 2, a straight-chain alkyl group of C1-C30, a branched-chain alkyl group of C3-C30, a cycloalkyl group of C3-C30, an alkoxy group of C1-C30, an alkylthio group of C1-C30, an alkylamino group of C1-C30, an aryl group of C6-C60, an aryl ether group of C6-C60, a heteroaryl group of C3-C60 or a heteroaryl ether group of C3-C60; wherein the heteroatoms of the heteroaromatic group are independently selected from Si, Ge, N, P, O, S or Se.

[0017] In the above technical solution, preferably, a polyfunctional olefin monomer can also be added during the polymerization reaction.

[0018] In the above technical solution, preferably, the narrow-band luminescent microspheres have a particle size distribution of 0.2-8 μm and a dispersion coefficient of 0.1-1.

[0019] In the above technical solution, preferably, the Ar 1 , Ar 2 , Ar 3 , Ar 4 and Ar 5 are each independently selected from one of the structures shown in 1-16:

[0020]

[0021] In the above technical solution, preferably, the boron or nitrogen hetero multiple resonance fused ring monomer is selected from any one or more of the structures shown in A1-1 to E13-3:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] Among them, R 1 to R 15 are each independently selected from H, D, F, Cl, Br, I, -CN, -NO 2 , -CF 3 , -OH, -SH, -NH 2, a straight-chain alkyl group of C1-C30, a branched-chain alkyl group of C3-C30, a cycloalkyl group of C3-C30, an alkoxy group of C1-C30, an alkylthio group of C1-C30, an alkylamino group of C1-C30, an aryl group of C6-C60, an aryl ether group of C6-C60, a heteroaryl group of C3-C60 or a heteroaryl ether group of C3-C60; wherein the heteroatoms of the heteroaromatic groups are independently selected from Si, Ge, N, P, O, S or Se.

[0030] In the above technical solution, it is further preferred that the boron or nitrogen hetero multiple resonance fused-ring monomer is selected from any one or more of the structures shown in a-1 to e-7:

[0031]

[0032]

[0033] A preparation method of narrow-band emission microspheres, and the preparation method includes any one of methods (I) to (VI):

[0034] The method (I) is to polymerize acrylonitrile and any one of the boron or nitrogen hetero multiple resonance fused-ring monomers shown in the structures of formula (I) to formula (V) to obtain copolymerized emission microspheres, including the following steps:

[0035] I-A. Prepare mixture solution I

[0036] Dissolve acrylonitrile and an initiator in an organic solvent, and then add any one of the boron or nitrogen hetero multiple resonance fused-ring monomers shown in the structures of formula (I) to formula (V) to obtain mixture solution I;

[0037] I-B. Prepare emission microspheres

[0038] Transfer the mixture solution I obtained in step I-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product emission microspheres;

[0039] The method (II) is to polymerize acrylonitrile and two different types of monomers among the boron or nitrogen hetero multiple resonance fused-ring monomers shown in the structures of formula (I) to formula (V) to obtain terpolymerized emission microspheres, including the following steps:

[0040] II-A. Prepare mixture solution I

[0041] Dissolve acrylonitrile and an initiator in an organic solvent, and then add two different types of monomers among the boron- or nitrogen-containing multi-resonance fused-ring monomers represented by the formula (I)-(V) to obtain a mixture solution I;

[0042] Ⅱ-B. Preparation of luminescent microspheres

[0043] Transfer the mixture solution I obtained in step Ⅱ-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it repeatedly with ethyl acetate during filtration or centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product luminescent microspheres;

[0044] The method (Ⅲ) is to use acrylonitrile and any one of the boron- or nitrogen-containing multi-resonance fused-ring monomers represented by the formula (I)-(V) to polymerize with a polyfunctional olefin monomer to obtain a ternary copolymer luminescent microsphere, including the following steps:

[0045] Ⅲ-A. Preparation of mixture solution I

[0046] Dissolve acrylonitrile and an initiator in an organic solvent, then add any one of the boron- or nitrogen-containing multi-resonance fused-ring monomers represented by the formula (I)-(V), and then add a polyfunctional olefin monomer to obtain a mixture solution I;

[0047] Ⅲ-B. Preparation of luminescent microspheres

[0048] Transfer the mixture solution I obtained in step Ⅲ-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it repeatedly with ethyl acetate during filtration or centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product luminescent microspheres;

[0049] The method (Ⅳ) is to use acrylonitrile and two different types of monomers among the boron- or nitrogen-containing multi-resonance fused-ring monomers represented by the formula (I)-(V) to polymerize with a polyfunctional olefin monomer to obtain a quaternary copolymer luminescent microsphere, including the following steps:

[0050] ⅣA. Preparation of mixture solution I

[0051] Dissolve acrylonitrile and an initiator in an organic solvent, then add two different types of monomers among the boron- or nitrogen-containing multi-resonance fused-ring monomers represented by the formula (I)-(V), and finally add a polyfunctional olefin monomer to obtain a mixture solution I;

[0052] Ⅳ-B. Preparation of Luminescent Microspheres

[0053] Transfer the mixture solution I obtained in step Ⅳ-A to a three-necked flask, and carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours. Subsequently, cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product luminescent microspheres;

[0054] The method (Ⅴ) is to polymerize acrylonitrile and three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formula (Ⅰ)-(Ⅴ) to obtain a quaternary copolymerized luminescent microsphere, including the following steps:

[0055] ⅤA. Preparation of Mixture Solution I

[0056] Dissolve acrylonitrile and an initiator in an organic solvent, and then add three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formula (Ⅰ)-(Ⅴ) to obtain mixture solution I;

[0057] ⅤB. Preparation of Luminescent Microspheres

[0058] Transfer the mixture solution I obtained in step Ⅴ-A to a three-necked flask, and carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours. Subsequently, cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product luminescent microspheres;

[0059] The method (Ⅵ) is to polymerize acrylonitrile and three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formula (Ⅰ)-(Ⅴ), and a polyfunctional olefin monomer to obtain a quinary copolymerized luminescent microsphere, including the following steps:

[0060] Ⅵ-A. Preparation of Mixture Solution I

[0061] Dissolve acrylonitrile and an initiator in an organic solvent, then add three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formula (Ⅰ)-(Ⅴ), and finally add a polyfunctional olefin monomer to obtain mixture solution I;

[0062] Ⅵ-B. Preparation of Luminescent Microspheres

[0063] Transfer the mixture solution I obtained in Step VI-A to a three-necked flask, and carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours. Subsequently, cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product of luminescent microspheres.

[0064] In the above technical solution, preferably, in Step I-A, the mass ratio of acrylonitrile, the boron or nitrogen hetero multiple resonance fused ring monomer shown in formula (I)-(V), the initiator, and the organic solvent is 1-10: 0.001-0.05: 0.1-2: 80;

[0065] In Step II-A, the mass ratio of acrylonitrile, two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), the initiator, and the organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.1-2: 80;

[0066] In Step III-A, the mass ratio of acrylonitrile, the boron or nitrogen hetero multiple resonance fused ring monomer shown in formula (I)-(V), the polyfunctional olefin monomer, the initiator, and the organic solvent is 1-10: 0.001-0.05: 1-10: 0.1-2: 80;

[0067] In Step IV-A, the mass ratio of acrylonitrile, two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), the polyfunctional olefin monomer, the initiator, and the organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 1-10: 0.1-2: 80;

[0068] In Step V-A, the mass ratio of acrylonitrile, three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), the initiator, and the organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.001-0.05: 0.1-2: 80;

[0069] In Step VI-A, the mass ratio of acrylonitrile, three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), the polyfunctional olefin monomer, the initiator, and the organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.001-0.05: 1-10: 0.1-2: 80.

[0070] In the present invention, preferably, the polyfunctional olefin monomer is selected from divinylbenzene, 4,4'-divinyl-1,1'-biphenyl, 1,4-diamino-2,5-divinylbenzene, 4,4'-divinylthiodiphenyl ether, 3,6-divinyl-9H-carbazole, 4,4'-divinyl-2,2'-bipyridine, 1,4-dialdehyde-2,5-divinylbenzene, 2,5-divinyl-1,4-benzenedicarboxylic acid, 1,4-dibromo-2,5-divinylbenzene, 5,5'-divinyl-2,2'-bipyridine, divinyl terephthalate, diallyl terephthalate, 2,4-divinylpyridine, 3-buten-2-vinylbenzene, 9,10-divinylanthracene, p,p'-divinyl-1,2-diphenylethane, vinyltrimethoxysilane, triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, 3(ethoxy)trimethylolpropane triacrylate, 6(ethoxy)trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate or diethylene glycol dimethacrylate.

[0071] The beneficial effects of the present invention are as follows:

[0072] A narrow-band light-emitting microsphere provided by the present invention is different from the common polystyrene light-emitting microspheres on the market today, which have problems such as narrow light emission, low efficiency, and unstable light emission. The present invention uses a boron or nitrogen hetero multiple resonance fused-ring monomer as the light-emitting monomer and copolymerizes it with acrylonitrile and a cross-linking agent (the cross-linking agent can be selected as none) to prepare the light-emitting microsphere. The preparation method of the light-emitting microsphere is simple, which greatly improves the light emission purity of the microsphere. The light-emitting microsphere prepared by the present invention has the characteristics of high color purity, high light emission efficiency, and narrow light emission spectrum.

[0073] The light-emitting microsphere prepared by the present invention has a particle size distribution of 0.2 - 8 μm, a dispersion coefficient of 0.1 - 1, a number average molecular weight of 6000 - 8500, and a molecular weight distribution of 200 - 160000. Its SEM image shows that the surface of the obtained microspheres is rough and smooth, and the particle size is relatively uniform. The light emission is good, the purity is high, and the full width at half maximum is narrow, having great application potential. Description of the Drawings

[0074] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0075] Figure 1 It is the scanning electron microscope image of the light-emitting microsphere obtained in Example 4; Figure 2 It is the particle size distribution diagram of the light-emitting microsphere obtained in Example 4;Figure 3 Scanning electron micrograph of the luminescent microspheres obtained in Example 5; Figure 4 Particle size distribution diagram of the luminescent microspheres obtained in Example 5; Figure 5 Scanning electron micrograph of the luminescent microspheres obtained in Example 6; Figure 6 Particle size distribution diagram of the luminescent microspheres obtained in Example 6; Figure 7 Scanning electron micrograph of the luminescent microspheres obtained in Example 7; Figure 8 Particle size distribution diagram of the luminescent microspheres obtained in Example 7; Figure 9 Scanning electron micrograph of the luminescent microspheres obtained in Example 8; Figure 10 Particle size distribution diagram of the luminescent microspheres obtained in Example 8. Detailed implementation mode

[0076] The present invention provides a narrow-band luminescent microsphere, which is a luminescent microsphere obtained by precipitation polymerization of acrylonitrile monomer with a boron or nitrogen hetero multiple resonance fused ring monomer through a free radical polymerization method; wherein, the boron or nitrogen hetero multiple resonance fused ring monomer is selected from one or more of the structures shown in general formulas (Ⅰ), (Ⅱ), (Ⅲ), (Ⅳ) and (Ⅴ):

[0077]

[0078] In formulas (Ⅰ) to (Ⅴ), X 1 and X 2 each independently selected from O, S, Se, Te or N; Y 1 selected from a single bond, -CR 1 R 2 -, -C=O-, -SiR 1 R 2 -, -NR 1 -, -POR 1 -, -O-, -S-, -Se-, -S=O- and -SO 2 -; wherein, R 1 and R 2 each independently selected from H, D, a substituted or unsubstituted C1-C30 straight-chain hydrocarbon group, a substituted or unsubstituted C1-C30 branched-chain hydrocarbon group, a substituted or unsubstituted C1-C30 haloalkane group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C60 aromatic group or a substituted or unsubstituted C5-C60 heteroaromatic group; a, b and c are each independently an integer from 0 to 3; q is 0 or 1; Z is B or N; Ar 1 ~Ar 5Each independently selected from a substituted or unsubstituted C6-C60 aryl ring or a substituted or unsubstituted C3-C60 heteroaryl ring; wherein the heteroatoms of the heteroaryl ring are independently selected from Si, Ge, N, P, O, S or Se; R 1 ~R 3 Each independently selected from H, D, F, Cl, Br, I, -CN, -NO 2 、-CF 3 、-OH、-SH、-NH 2 、C1-C30 straight-chain alkyl, C3-C30 branched-chain alkyl, C3-C30 cycloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, C1-C30 alkylamino, C6-C60 aryl, C6-C60 aryloxy, C3-C60 heteroaryl or C3-C60 heteroaryloxy; wherein the heteroatoms of the heteroaromatic group are independently selected from Si, Ge, N, P, O, S or Se.

[0079] Preferably, a polyfunctional olefin monomer can also be added during the polymerization reaction.

[0080] Preferably, the narrow-band luminescent microspheres have a particle size distribution of 0.2-8 μm and a dispersion coefficient of 0.1-1.

[0081] Preferably, the Ar 1 、Ar 2 、Ar 3 、Ar 4 and Ar 5 Each independently selected from one of the structures shown in 1-16; the boron or nitrogen hetero multiple resonance fused ring monomer is selected from any one or more of the structures shown in A1-1 to E13-3, and further preferably, the boron or nitrogen hetero multiple resonance fused ring monomer is selected from any one or more of the structures shown in a-1 to e-7, and the structure of the boron or nitrogen hetero multiple resonance fused ring monomer is the same as above.

[0082] The boron- or nitrogen-containing multi-resonance fused-ring monomers represented by formula (I) of the present invention can be synthesized with reference to the literature: Novel boron- and sulfur-doped polycyclic aromatic hydrocarbon as multiple resonance emitter for ultrapure blue thermally activated delayed fluorescence polymers, Fan Chen, SCIENCE CHINA Chemistry, April 2021 Vol.64 No.4:547–551. The boron- or nitrogen-containing multi-resonance fused-ring monomers represented by formula (II) of the present invention can be synthesized with reference to the literature: Optoelectronic and nonlinear optical properties of triarylamine helicenes: a DFT study, Nasarul Islam & Altaf Hussain Pandith, J Mol Model (2014) 20:2535, DOI 10.1007 / s00894-014-2535-7. The boron- or nitrogen-containing multi-resonance fused-ring monomers represented by formula (III) to formula (V) of the present invention can be synthesized with reference to the literature: Resolving the Photophysics of Nitrogen-Embedded Multiple Resonance Emitters: Origin of Color Purity and Emitting Efficiency, Yaxin Wang, THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, Cite This: J. Phys. Chem. Lett. 2023, 14, 9665-9676.

[0083] A method for preparing narrow-band light-emitting microspheres, the preparation method comprising any one of methods (I) to (VI):

[0084] The method (I) is to polymerize acrylonitrile and any one of the boron- or nitrogen-containing multi-resonance fused-ring monomers having the structures shown in formula (I) to formula (V) to obtain copolymeric light-emitting microspheres, and includes the following steps:

[0085] I-A. Prepare mixture solution I

[0086] Dissolve acrylonitrile and an initiator in an organic solvent, and then add any one of the boron- or nitrogen-containing multi-resonance fused-ring monomers having the structures shown in formula (I) to formula (V) to obtain mixture solution I;

[0087] The mass ratio of acrylonitrile, boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), initiator and organic solvent is 1-10: 0.001-0.05: 0.1-2: 80;

[0088] I-B. Preparation of luminescent microspheres

[0089] Transfer the mixture solution I obtained in step I-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product of luminescent microspheres;

[0090] The method (II) is to use acrylonitrile and two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V) to polymerize to obtain ternary copolymerized luminescent microspheres, including the following steps:

[0091] II-A. Preparation of mixture solution I

[0092] Dissolve acrylonitrile and the initiator in an organic solvent, and then add two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V) to obtain mixture solution I;

[0093] The mass ratio of acrylonitrile, two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), initiator and organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.1-2: 80;

[0094] II-B. Preparation of luminescent microspheres

[0095] Transfer the mixture solution I obtained in step II-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product of luminescent microspheres;

[0096] The method (III) is to use acrylonitrile and any one of the boron or nitrogen hetero multiple resonance fused ring monomers shown in formula (I)-(V), and polymerize with a polyfunctional olefin monomer to obtain ternary copolymerized luminescent microspheres, including the following steps:

[0097] III-A. Preparation of mixture solution I

[0098] Dissolve acrylonitrile and an initiator in an organic solvent, then add any one of the boron or nitrogen hetero multiple resonance fused ring monomers with the structures shown in the formulas (I) - (V), and then add a polyfunctional olefin monomer to obtain a mixture solution I;

[0099] The mass ratio of acrylonitrile, the boron or nitrogen hetero multiple resonance fused ring monomer with the structures shown in the formulas (I) - (V), the polyfunctional olefin monomer, the initiator and the organic solvent is 1 - 10: 0.001 - 0.05: 1 - 10: 0.1 - 2: 80;

[0100] Ⅲ - B. Preparation of luminescent microspheres

[0101] Transfer the mixture solution I obtained in step Ⅲ - A to a three - necked flask, carry out a polymerization reaction at a temperature of 65 - 90 °C without stirring for 2 - 8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until the unreacted monomers and initiator are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40 - 60 °C for 6 - 12 hours to finally obtain the product of luminescent microspheres;

[0102] The method (Ⅳ) is to use acrylonitrile and two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers with the structures shown in the formulas (I) - (V) to polymerize with a polyfunctional olefin monomer to obtain a quaternary copolymerized luminescent microsphere, including the following steps:

[0103] Ⅳ - A. Preparation of mixture solution I

[0104] Dissolve acrylonitrile and an initiator in an organic solvent, then add two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers with the structures shown in the formulas (I) - (V), and finally add a polyfunctional olefin monomer to obtain a mixture solution I;

[0105] The mass ratio of acrylonitrile, two different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers with the structures shown in the formulas (I) - (V), the initiator and the organic solvent is 1 - 10: 0.001 - 0.05: 0.001 - 0.05: 1 - 10: 0.1 - 2: 80;

[0106] Ⅳ - B. Preparation of luminescent microspheres

[0107] Transfer the mixture solution I obtained in Step IV-A to a three-necked flask, and carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours. Subsequently, cool the product to room temperature, filter or centrifuge out the product, and wash it repeatedly with ethyl acetate during filtration or centrifugation until the unreacted monomers and initiator are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product, the luminescent microspheres;

[0108] The method (V) is to polymerize acrylonitrile and three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formulas (I)-(V) to obtain quaternary copolymer luminescent microspheres, including the following steps:

[0109] V-A. Prepare the mixture solution I

[0110] Dissolve acrylonitrile and an initiator in an organic solvent, and then add three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formulas (I)-(V) to obtain the mixture solution I;

[0111] The mass ratio of acrylonitrile, three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formulas (I)-(V), the initiator, the organic solvent is 1-10:0.001-0.05:0.001-0.05:0.001-0.05:0.1-2:80;

[0112] V-B. Prepare the luminescent microspheres

[0113] Transfer the mixture solution I obtained in Step V-A to a three-necked flask, and carry out a polymerization reaction at a temperature of 65-90 °C without stirring for 2-8 hours. Subsequently, cool the product to room temperature, filter or centrifuge out the product, and wash it repeatedly with ethyl acetate during filtration or centrifugation until the unreacted monomers and initiator are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40-60 °C for 6-12 hours to finally obtain the product, the luminescent microspheres;

[0114] The method (VI) is to polymerize acrylonitrile and three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formulas (I)-(V) with a polyfunctional olefin monomer to obtain quinary copolymer luminescent microspheres, including the following steps:

[0115] VI-A. Prepare the mixture solution I

[0116] Dissolve acrylonitrile and an initiator in an organic solvent, then add three different types of monomers among the boron or nitrogen hetero multiple resonance fused ring monomers shown in the formulas (I)-(V), and finally add a polyfunctional olefin monomer to obtain the mixture solution I;

[0117] Acrylonitrile, three monomers of different types among the boron- or nitrogen-containing multi-resonance fused ring monomers of the structures of formula (I) to formula (V), polyfunctional olefin monomers, initiator and organic solvent, with a mass ratio of 1 to 10: 0.001 to 0.05: 0.001 to 0.05: 0.001 to 0.05: 1 to 10: 0.1 to 2: 80;

[0118] Ⅵ-B. Preparation of luminescent microspheres

[0119] Transfer the mixture solution I obtained in step Ⅵ-A to a three-necked flask, carry out a polymerization reaction at a temperature of 65 to 90 °C without stirring for 2 to 8 hours, then cool the product to room temperature, filter or centrifuge out the product, and wash it with ethyl acetate multiple times during filtration or centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by filtration in a vacuum drying oven at 40 - 60 °C for 6 to 12 hours to finally obtain the product of luminescent microspheres.

[0120] In the present invention, the initiator plays a role in providing free radicals to initiate the free radical polymerization reaction of monomers. The initiator is independently selected from azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate or azobis(isobutyramidine) hydrochloride. The initiators used in the present invention are all products sold on the current market, such as azobisisobutyronitrile sold by Shanghai Merck Chemical Technology Co., Ltd. under the trade name of azobisisobutyronitrile.

[0121] In the present invention, the organic solvent plays a role in dissolving monomers, initiators, and luminescent monomers in the preparation of luminescent microspheres and facilitating the polymerization reaction, ensuring the solvent medium for the precipitation of the polymerization product, and thus affecting the morphology, structure, and properties of the microspheres. The organic solvent is preferably selected from methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, isoamyl formate, benzyl formate, ethyl acetate, ethyl acetoacetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, methyl amyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, propyl propionate, n-butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, n-butyl butyrate, methyl lactate, ethyl lactate, n-butyl lactate, amyl lactate, diethyl oxalate, dibutyl oxalate, diamyl oxalate, diethyl carbonate, tributyl phosphate, ethyl benzoate, isoamyl benzoate, ethyl salicylate, N,N-dimethylformamide, N,N-diisopropylethylamine, acetonitrile, benzene, toluene, m-xylene, tetrahydrofuran, 1,4-dioxane, acetone, cyclohexane, n-hexane, n-pentane, isooctanol, n-butanol, tert-butanol, 1,3-butanediol, 1,2-propanediol, n-propanol, isopropanol, isoamyl alcohol, n-pentanol, N-ethyl-2-pyrrolidone, N,N,N',N'-tetramethylethylenediamine, triethylamine, 2,6-dimethylpyridine, pyridine, diethylamine, 3,5-dimethylaniline, 2,6-dimethylaniline, 3,5-dimethylaniline, 3-methylaniline, octylamine, aniline, or a mixed solution obtained by mixing one or two of them. Further preferably, the organic solvent is a mixed solution obtained by mixing one or two of methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isoamyl formate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, propyl propionate, n-butyl propionate, ethyl acetate, N,N-dimethylformamide, acetonitrile, toluene, tetrahydrofuran, 1,4-dioxane, acetone, cyclohexane, and xylene. The organic solvents used in the present invention are all products sold on the current market. For example, m-xylene sold by Shanghai Merck Chemical Technology Co., Ltd. under the trade name of m-xylene.

[0122] In the present invention, the boron or nitrogen hetero multiple resonance fused ring monomer acts as a luminescent monomer to emit light and regulate the morphology of the microspheres, ensuring the light emission of the luminescent microspheres and the morphology of the microspheres. The boron or nitrogen hetero multiple resonance fused ring monomer is preferably any one or more of the structures shown in A1~1 to E13~3. Further preferably, the boron or nitrogen hetero multiple resonance fused ring monomer is selected from any one or more of the structures shown in a~1 to e~7. The boron or nitrogen hetero multiple resonance fused ring monomers can all be synthesized and obtained with reference to the above-mentioned literature.

[0123] In the present invention, the polyfunctional olefin monomers play a role in increasing the crosslinking degree, forming a three-dimensional network structure, and improving the chemical stability, thermal stability, and mechanical strength of the polymer microspheres during the preparation of the polymer microspheres. The polyfunctional olefin monomers are preferably selected from divinylbenzene, 4,4

[0124] '-divinyl-1,1'-biphenyl, 1,4-diamino-2,5-divinylbenzene, 4,4'-divinylthiodiphenyl ether, 3,6-divinyl-9H-carbazole, 4,4'-divinyl-2,2'-bipyridine, 1,4-dialdehyde-2,5-divinylbenzene, 2,5-divinyl-1,4-benzenedicarboxylic acid, 1,4-dibromo-2,5-divinylbenzene, 5,5-divinyl-2,2'-bipyridine, divinyl terephthalate, diallyl terephthalate, 2,4-divinylpyridine, 3-buten-2-vinylbenzene, 9,10-divinylanthracene, p,p'-divinyl-1,2-diphenylethane, vinyltrimethoxysilane, triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, 3(ethoxy)trimethylolpropane triacrylate, 6(ethoxy)trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, or diethylene glycol dimethacrylate. Further preferably, the polyfunctional olefin monomers are selected from divinylbenzene, vinyltrimethoxysilane, triallyl isocyanurate, or trimethylolpropane triacrylate. The polyfunctional olefin monomers used in the present invention are all products currently sold on the market, such as divinylbenzene sold by Shanghai Aladdin Biochemical Technology Co., Ltd. under the trade name divinylbenzene.

[0125] According to the present invention, when the reaction monomers, initiator, and organic solvent are within the above ranges, if the amount of the luminescent monomer is 1 to 50 mg, luminescent microspheres with good morphology and relatively uniform particle sizes are obtained; if the amount of the luminescent monomer is greater than 50 mg, the luminescent microspheres are prone to agglomeration, or the particle sizes of the generated microspheres are uneven; if the amount of the luminescent monomer is less than 1 mg, the luminescence emission of the luminescent microspheres is weak, and the particle sizes of the generated microspheres are uneven. Therefore, it is appropriate that the amount of the luminescent monomer is 1 to 50 mg, and more preferably 1 to 30 mg.

[0126] When the ratios of the reaction monomers, luminescent monomer, and organic solvent are within the above ranges, if the amount of the initiator is less than 0.1, the particle sizes of the synthesized microspheres are uneven or no product precipitates; if the amount of the initiator is higher than 2, the particle sizes of the generated microspheres are smaller. Therefore, it is appropriate that the amount of the initiator is 0.1 to 2, and preferably 0.5 to 1.

[0127] The present invention can control the particle size and surface morphology of microspheres by regulating the ratio between different types of organic solvents; increase the yield by regulating the amount of initiator; and control the luminescence emission and morphology of microspheres by regulating the amount of luminescent monomer.

[0128] In steps I-B to VI-B, when the polymerization reaction temperature is within the above range, if the polymerization reaction time is less than 2 hours, the microsphere yield is low or there is no product; if the polymerization reaction time is more than 8 hours, it will result in non-uniform particle size of the microspheres. Therefore, the polymerization reaction time of 2 to 8 hours is appropriate, and more preferably 3 to 4 hours.

[0129] In steps I-B to VI-B, the purpose of washing with ethyl acetate during centrifugation after the reaction is to remove unreacted reaction monomers, luminescent monomers and initiators; washing 3 times ensures that there are no other impurities in the product. The purpose of drying is to obtain dry luminescent microsphere powder for convenient further detection or application.

[0130] According to the present invention, the morphology and luminescence emission of the luminescent microspheres obtained in step B were tested and analyzed by scanning electron microscopy and luminescence spectrometer. The results show that the particle size range of the luminescent microspheres is from 0.2 to 8 μm, and the surface of the microspheres is smooth or rough.

[0131] The present invention will be further described in detail below with specific examples and comparative examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the conditions not specified are the conventional conditions in the industry.

[0132] The boron or nitrogen hetero multiple resonance fused ring monomers used in the following examples can all be synthesized and obtained with reference to the above literature.

[0133] Example 1

[0134] Step A: Prepare mixed solution I

[0135] Dissolve acrylonitrile and azobisisobutyronitrile in ethyl acetate, and then add luminescent monomer a-15 with the structural formula of formula (I) to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, luminescent monomer and ethyl acetate is 6.4:0.5:0.002:80; the luminescent monomer used is:

[0136]

[0137] Step B: Prepare luminescent microspheres

[0138] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product, the luminescent microspheres.

[0139] Detect the photophysical properties of the luminescent microspheres prepared in Example 1 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0140] Example 2

[0141] Step A: Prepare the mixed solution I

[0142] Dissolve acrylonitrile and azodiisooctanenitrile in isopentyl acetate, and then add the luminescent monomer b-12 with the structure of formula (II) to prepare the mixed solution I; the weight ratio of acrylonitrile, azodiisooctanenitrile, luminescent monomer and isopentyl acetate is 8:1:0.01:80; the luminescent monomer used is:

[0143]

[0144] Step B: Prepare the luminescent microspheres.

[0145] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 75 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product, the luminescent microspheres.

[0146] Detect the photophysical properties of the luminescent microspheres prepared in Example 2 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0147] Example 3

[0148] Step A: Prepare the mixed solution I

[0149] Dissolve acrylonitrile and azodiisobutyronitrile in butyl acetate, and then add the luminescent monomer c-5 with the structure of formula (III) to prepare the mixed solution I; the weight ratio of acrylonitrile, azodiisobutyronitrile, luminescent monomer and butyl acetate is 7:0.5:0.03:80; the luminescent monomer used is:

[0150]

[0151] Step B: Prepare the luminescent microspheres.

[0152] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 72 °C without stirring, then cool the product to room temperature, centrifuge the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product, luminescent microspheres.

[0153] Detect the photophysical properties of the luminescent microspheres prepared in Example 3 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0154] Example 4

[0155] Step A: Prepare mixed solution I

[0156] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of butyl acetate and N,N-dimethylformamide, and then add the luminescent monomer d-9 with the structure of formula (IV) to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, luminescent monomer, butyl acetate and N,N-dimethylformamide is 3:0.3:0.01:75:5; the luminescent monomer used is:

[0157]

[0158] Step B: Prepare luminescent microspheres.

[0159] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product, luminescent microspheres. See the Figure 1 scanning electron micrograph, and the particle size distribution diagram is shown in Figure 2 .

[0160] According to the results of the scanning electron micrograph and the particle size distribution diagram, it can be concluded that the surface of the microspheres prepared in this example is relatively rough, and the particle size is mainly distributed in the range of 0.28 - 0.42 μm. Use a luminescence spectrometer to detect the quantum efficiency of the microspheres prepared in this example, and the detected quantum efficiency is 12.74%.

[0161] Detect the photophysical properties of the luminescent microspheres prepared in Example 4 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0162] Example 5

[0163] Step A: Prepare mixed solution I

[0164] Dissolve acrylonitrile and azobisisobutyronitrile in ethyl acetate, and then add the luminescent monomer e-5 with the structure of formula (Ⅴ) to prepare mixed solution Ⅰ; the weight ratio of acrylonitrile, azobisisobutyronitrile, luminescent monomer, and ethyl acetate is 6.4:1:0.008:80; the luminescent monomer used is:

[0165]

[0166] Step B: Prepare luminescent microspheres.

[0167] Transfer the mixed solution Ⅰ obtained in Step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge the product, and wash it with ethyl acetate multiple times during centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres. See the scanning electron micrograph in Figure 3 , and see the particle size distribution diagram in Figure 4 .

[0168] According to the results of the scanning electron micrograph and the particle size distribution diagram, it can be concluded that the surface of the microspheres prepared in this example is relatively rough, and the particle size is mainly distributed in the range of 0.47 - 0.57 μm.

[0169] Detect the photophysical properties of the luminescent microspheres prepared in Example 5 of the present invention. The results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0170] Example 6

[0171] Step A: Prepare mixed solution Ⅰ

[0172] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of butyl acetate and acetone, and then add the luminescent monomers b-8 and d-6 with the structures of formula (Ⅱ) and formula (Ⅳ) to prepare mixed solution Ⅰ; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (Ⅱ), the luminescent monomer with the structure of formula (Ⅳ), butyl acetate, and acetone is 8:1.5:0.02:0.01:65:15; the luminescent monomers used are:

[0173]

[0174] Step B: Prepare luminescent microspheres.

[0175] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres. See its scanning electron micrograph in Figure 5 , and see the particle size distribution diagram in Figure 6 . According to the results of the scanning electron micrograph and the particle size distribution diagram, it can be concluded that the surface of the microspheres prepared in this example is relatively rough, and the particle size is mainly distributed in the range of 0.58 - 0.65 μm.

[0176] Detect the photophysical properties of the luminescent microspheres prepared in Example 6 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0177] Example 7

[0178] Step A: Prepare mixed solution I

[0179] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of ethyl acetate and m-xylene, and then add the luminescent monomer a-10 with the structure of formula (I) and divinylbenzene to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (I), divinylbenzene, ethyl acetate and m-xylene is 6:0.5:0.001:1:50:30; the luminescent monomer used is:

[0180]

[0181] Step B: Prepare luminescent microspheres.

[0182] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres. See its scanning electron micrograph in Figure 7 , and see the particle size distribution diagram in Figure 8 . According to the results of the scanning electron micrograph and the particle size distribution diagram, it can be concluded that the surface of the microspheres prepared in this example is relatively rough, and the particle size is mainly distributed in the range of 0.79 - 0.88 μm.

[0183] Detect the photophysical properties of the luminescent microspheres prepared in Example 7 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0184] Example 8

[0185] Step A: Prepare mixed solution I

[0186] Dissolve acrylonitrile and 2,2'-azobis(2-methylbutyronitrile) in a mixed solvent of butyl acetate and m-xylene, and then add the luminescent monomer a-11 with the structure of formula (I) and vinyltrimethoxysilane to prepare mixed solution I; the weight ratio of acrylonitrile, 2,2'-azobis(2-methylbutyronitrile), the luminescent monomer with the structure of formula (I), vinyltrimethoxysilane, butyl acetate and m-xylene is 6:0.5:0.01:2:50:30; the luminescent monomer used is:

[0187]

[0188] Step B: Prepare luminescent microspheres.

[0189] Transfer the mixed solution I obtained in Step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 78 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it with ethyl acetate multiple times during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres. See its scanning electron micrograph in Figure 9 , and see the particle size distribution diagram in Figure 10 . According to the results of the scanning electron micrograph and the particle size distribution diagram, it can be concluded that the surface of the microspheres prepared in this example is relatively rough, and the particle size is mainly distributed in the range of 0.57 - 0.74 μm.

[0190] Detect the photophysical properties of the luminescent microspheres prepared in Example 8 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0191] Example 9

[0192] Step A: Prepare mixed solution I

[0193] Dissolve acrylonitrile and 2,2'-azobisisobutyronitrile in a mixed solvent of butyl acetate and acetonitrile, and then add the luminescent monomer a-9 with the structure of formula (I) and triallyl isocyanurate to prepare mixed solution I; the weight ratio of acrylonitrile, 2,2'-azobisisobutyronitrile, the luminescent monomer with the structure of formula (I), triallyl isocyanurate, butyl acetate and acetonitrile is 5:1:0.01:3:65:15;

[0194] The luminescent monomer used is:

[0195] Step B: Prepare luminescent microspheres.

[0196] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it with ethyl acetate multiple times during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0197] Detect the photophysical properties of the luminescent microspheres prepared in Example 9 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0198] Example 10

[0199] Step A: Prepare mixed solution I

[0200] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of isopentyl acetate and acetone, and then add the luminescent monomer b-6 with the structure of formula (II) and triallyl isocyanurate to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (II), triallyl isocyanurate, isopentyl acetate and acetone is 8:1:0.02:1:65:15; the luminescent monomer used is:

[0201]

[0202] Step B: Prepare luminescent microspheres.

[0203] Transfer the mixed solution I obtained in step A to a three-necked flask, carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring, then cool the product to room temperature, centrifuge out the product, and wash it with ethyl acetate multiple times during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0204] Detect the photophysical properties of the luminescent microspheres prepared in Example 10 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0205] Example 11

[0206] Step A: Prepare mixed solution I

[0207] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of isopentyl acetate and m-xylene, and then add the luminescent monomer c-3 with the structure of formula (III) and divinylbenzene to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (III), divinylbenzene, isopentyl acetate and m-xylene is 4:1:0.05:4:60:20; the luminescent monomer used is:

[0208]

[0209] Step B: Preparation of luminescent microspheres.

[0210] Transfer the mixed solution I obtained in Step A to a three-necked flask, carry out a polymerization reaction at a temperature of 67 °C without stirring for 3 h, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0211] Example 12

[0212] Step A: Preparation of mixed solution I

[0213] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of ethyl acetate and 1,4-dioxane, and then add the luminescent monomer e-7 with the structure of formula (V) and ethylene glycol dimethacrylate to prepare mixed solution I; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (V), ethylene glycol dimethacrylate, ethyl acetate and 1,4-dioxane is 5:0.5:0.05:1:60:20; the luminescent monomer used is:

[0214]

[0215] Step B: Preparation of luminescent microspheres.

[0216] Transfer the mixed solution I obtained in Step A to a three-necked flask, carry out a polymerization reaction at a temperature of 67 °C without stirring for 3 h, then cool the product to room temperature, centrifuge out the product, and wash it repeatedly with ethyl acetate during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0217] Detect the photophysical properties of the luminescent microspheres prepared in Example 12 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0218] Example 13

[0219] Step A: Preparation of mixed solution I

[0220] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of isopentyl acetate and cyclohexane, add the luminescent monomer b-7 with the structure of formula (Ⅱ), the luminescent monomer d-3 with the structure of formula (Ⅳ), and trimethylolpropane triacrylate to prepare mixed solution Ⅰ; the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (Ⅱ), the luminescent monomer with the structure of formula (Ⅲ), trimethylolpropane triacrylate, isopentyl acetate and cyclohexane is 7:0.5:0.003:0.003:1:45:35; the luminescent monomers used are:

[0221]

[0222] Step B: Prepare luminescent microspheres.

[0223] Transfer the mixed solution Ⅰ obtained in Step A to a three-necked flask, carry out a polymerization reaction at a temperature of 67 °C without stirring for 3 h, then cool the product to room temperature, centrifuge the product, and wash it with ethyl acetate multiple times during centrifugation until all unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0224] Detect the photophysical properties of the luminescent microspheres prepared in Example 13 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0225] Example 14

[0226] Step A: Prepare mixed solution Ⅰ

[0227] Dissolve acrylonitrile and azobisisobutyronitrile in a mixed solvent of isopentyl acetate and tetrahydrofuran, and then add the luminescent monomer a-4 with the structure of formula (Ⅰ), two luminescent monomers b-13 and b-14 with the structure of formula (Ⅱ), and vinyltrimethoxysilane to prepare mixed solution Ⅰ;

[0228] Among them, the weight ratio of acrylonitrile, azobisisobutyronitrile, the luminescent monomer with the structure of formula (Ⅰ), two luminescent monomers with the structure of formula (Ⅱ), vinyltrimethoxysilane, isopentyl acetate and tetrahydrofuran is 6:0.5:0.001:0.001:0.001:2:45:35; the luminescent monomers used are:

[0229]

[0230] Step B: Prepare luminescent microspheres.

[0231] Transfer the mixed solution Ⅰ obtained in step A to a three-necked flask, and carry out a polymerization reaction for 3 h at a temperature of 67 °C without stirring. Subsequently, cool the product to room temperature, centrifuge the product, and wash it with ethyl acetate multiple times during centrifugation until the unreacted monomers and initiators are completely removed. Dry the product obtained by suction filtration in a vacuum drying oven at 40 °C for 8 hours to finally obtain the product of luminescent microspheres.

[0232] Detect the photophysical properties of the luminescent microspheres prepared in Example 14 of the present invention. The detection results are shown in Table 1, and Table 1 shows the photophysical properties of the luminescent microspheres prepared in the examples of the present invention.

[0233] Table 1 Photophysical properties of the luminescent microspheres prepared in the examples of the present invention

[0234]

[0235] For acrylonitrile, luminescent monomers, initiators, organic solvents, and polyfunctional olefin monomers used in the above examples, their types, mass ratios, preparation conditions, etc. can also be any type or any value within the above-defined ranges, and no further examples are given here.

Claims

1. A narrow-band luminescent microsphere, characterized in that: The luminescent microsphere is obtained by precipitation polymerization of acrylonitrile monomer and boron or nitrogen multiple resonance condensed ring monomer through free radical polymerization. Wherein, the boron or nitrogen multiple resonance fused ring monomer is selected from one or more of the structures shown in general formula (I), (II), (III), (IV) and (V): In formulas (I) to (V), X1 and X2 are each independently selected from O, S, Se, Te or N; Y1 is selected from a single bond, -CR 1 R 2 -、-C=O-、-SiR 1 R 2 -、-NR 1 -、-POR 1 -, -O-, -S-, -Se-, -S=O- and -SO2-; wherein R 1 and R 2 Each is independently selected from H, D, a substituted or unsubstituted C1-C30 straight-chain hydrocarbon group, a substituted or unsubstituted C1-C30 branched hydrocarbon group, a substituted or unsubstituted C1-C30 halogenated alkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C60 aromatic group, or a substituted or unsubstituted C5-C60 heteroaromatic group; a, b and c are each independently an integer of 0 to 3; q is 0 or 1; Z is B or N; Ar1 to Ar5 are each independently selected from a substituted or unsubstituted C6 to C60 aryl ring or a substituted or unsubstituted C3 to C60 heteroaryl ring; wherein the heteroatoms of the heteroaryl ring are independently selected from Si, Ge, N, P, O, S or Se; R1~R3 ​​are each independently selected from H, D, F, Cl, Br, I, -CN, -NO2, -CF3, -OH, -SH, -NH2, a C1~C30 straight-chain alkyl group, a C3~C30 branched-chain alkyl group, a C3~C30 cycloalkyl group, a C1~C30 alkoxy group, a C1~C30 alkylthio group, a C1~C30 alkylamino group, a C6~C60 aryl group, a C6~C60 aromatic ether group, a C3~C60 heteroaryl group or a C3~C60 heteroaromatic ether group; wherein the heteroatoms of the heteroaromatic group are independently selected from Si, Ge, N, P, O, S or Se.

2. The narrow-band luminescent microsphere according to claim 1, characterized in that: Multifunctional vinyl monomers can also be added during the polymerization reaction.

3. The narrow-band luminescent microsphere according to claim 1, characterized in that: The particle size distribution is 0.2-8 μm, and the dispersion coefficient is 0.1-1.

4. The narrow-band luminescent microsphere according to claim 1, characterized in that: The Ar1, Ar2, Ar3, Ar4 and Ar5 are each independently selected from one of the following structures:

5. The narrow-band luminescent microsphere according to claim 1, characterized in that: The boron or nitrogen multiple resonance fused ring monomer is selected from any one or more of the structures shown in A1-1 to E13-3: Among them, R1~R 15 Each is independently selected from H, D, F, Cl, Br, I, -CN, -NO2, -CF3, -OH, -SH, -NH2, a C1-C30 straight-chain alkyl group, a C3-C30 branched-chain alkyl group, a C3-C30 cycloalkyl group, a C1-C30 alkoxy group, a C1-C30 alkylthio group, a C1-C30 alkylamino group, a C6-C60 aryl group, a C6-C60 aromatic ether group, a C3-C60 heteroaryl group or a C3-C60 heteroaromatic ether group; wherein the heteroatoms of the heteroaromatic group are independently selected from Si, Ge, N, P, O, S or Se.

6. The narrow-band luminescent microsphere according to claim 1, characterized in that: The boron or nitrogen multiple resonance fused ring monomer is selected from any one or more of the structures shown in a~1 to e~7:

7. A method for preparing the narrow-band luminescent microspheres according to claim 2, characterized in that: The preparation method comprises any one of methods (I) to (VI): The method (I) is to polymerize acrylonitrile and any one of the boron or nitrogen multiple resonance fused ring monomers having structures represented by formula (I) to formula (V) to obtain copolymerized luminescent microspheres, comprising the following steps: IA. Preparation of mixture solution I Dissolving acrylonitrile and an initiator in an organic solvent, and then adding any one of boron or nitrogen multi-resonance fused ring monomers having structures represented by formula (I) to formula (V) to obtain a mixture solution I; IB. Preparation of luminescent microspheres The mixture solution I obtained in step IA is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours, and then the product is cooled to room temperature, filtered or centrifuged to remove the product, and washed with ethyl acetate several times during the filtration or centrifugation process to completely remove the unreacted monomer and initiator, and the product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres; The method (II) is to polymerize two different types of monomers of acrylonitrile and the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formula (I) to (V) to obtain ternary copolymerized luminescent microspheres, comprising the following steps: Ⅱ-A. Preparation of Mixture Solution I Dissolving acrylonitrile and an initiator in an organic solvent, and then adding two different types of monomers of the boron or nitrogen multiple resonance fused ring monomers of the structures represented by formulas (I) to (V) to obtain a mixture solution I; Ⅱ-B. Preparation of luminescent microspheres The mixture solution I obtained in step II-A is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours, and then the product is cooled to room temperature, filtered or centrifuged to remove the product, and washed with ethyl acetate several times during the filtration or centrifugation process to completely remove the unreacted monomer and initiator, and the product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres; The method (III) is to use acrylonitrile and any one of the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formula (I) to formula (V) to polymerize with a multifunctional olefin monomer to obtain a ternary copolymerized luminescent microsphere, comprising the following steps: III-A. Preparation of mixture solution I Dissolving acrylonitrile and an initiator in an organic solvent, then adding any one of the boron or nitrogen multi-resonance fused ring monomers of the structures represented by formula (I) to formula (V), and then adding a multifunctional olefin monomer to obtain a mixture solution I; Ⅲ-B. Preparation of luminescent microspheres The mixture solution I obtained in step III-A is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours, and then the product is cooled to room temperature, filtered or centrifuged to remove the product, and washed with ethyl acetate several times during the filtration or centrifugation process to completely remove the unreacted monomer and initiator, and the product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres; The method (IV) is to use acrylonitrile and two different types of monomers among the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formula (I) to (V) to polymerize with a multifunctional olefin monomer to obtain a quaternary copolymerized luminescent microsphere, comprising the following steps: IV-A. Preparation of Mixture Solution I Dissolving acrylonitrile and an initiator in an organic solvent, then adding two different types of monomers of the boron or nitrogen multiple resonance fused ring monomers of the structures represented by formula (I) to formula (V), and finally adding a multifunctional olefin monomer to obtain a mixture solution I; IV-B. Preparation of luminescent microspheres The mixture solution I obtained in step IV-A is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours, and then the product is cooled to room temperature, filtered or centrifuged to remove the product, and washed with ethyl acetate several times during the filtration or centrifugation process to completely remove the unreacted monomer and initiator, and the product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres; The method (V) is to polymerize three monomers of different types among acrylonitrile and the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formula (I) to (V) to obtain quaternary copolymerized luminescent microspheres, comprising the following steps: Ⅴ-A. Preparation of Mixture Solution I Dissolving acrylonitrile and an initiator in an organic solvent, and then adding three different types of monomers of the boron or nitrogen multiple resonance fused ring monomers of the structures represented by formula (I) to formula (V) to obtain a mixture solution I; Ⅴ-B. Preparation of luminescent microspheres The mixture solution I obtained in step V-A is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours, and then the product is cooled to room temperature, filtered or centrifuged to remove the product, and washed with ethyl acetate several times during the filtration or centrifugation process to completely remove the unreacted monomer and initiator, and the product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres; The method (VI) is to use acrylonitrile and three different types of monomers of the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formula (I) to formula (V) to polymerize with multifunctional olefin monomers to obtain five-membered copolymerized luminescent microspheres, comprising the following steps: VI-A. Preparation of Mixture Solution I Dissolving acrylonitrile and an initiator in an organic solvent, then adding three different types of monomers of the boron or nitrogen multi-resonance fused ring monomers of the structures represented by formula (I) to formula (V), and finally adding a multifunctional olefin monomer to obtain a mixture solution I; VI-B. Preparation of luminescent microspheres The mixture solution I obtained in step VI-A is transferred to a three-necked flask, and a polymerization reaction is carried out at a temperature of 65-90° C. without stirring for 2-8 hours. The product is then cooled to room temperature, filtered or centrifuged, and washed with ethyl acetate several times during the filtration or centrifugation process until unreacted monomers and initiators are completely removed. The product obtained by filtration is dried in a vacuum drying oven at 40-60° C. for 6-12 hours to finally obtain the product luminescent microspheres.

8. The method for preparing narrow-band luminescent microspheres according to claim 7, characterized in that: In step IA, the mass ratio of acrylonitrile, boron or nitrogen multiple resonance fused ring monomers of structures represented by formulas (I) to (V), initiator and organic solvent is 1 to 10: 0.001 to 0.05: 0.1 to 2: 80; In step II-A, the mass ratio of acrylonitrile, two monomers of different types among the boron or nitrogen multiple resonance fused ring monomers of the structures shown in formulas (I) to (V), the initiator and the organic solvent is 1 to 10: 0.001 to 0.05: 0.001 to 0.05: 0.1 to 2: 80; In step III-A, the mass ratio of acrylonitrile, boron or nitrogen multi-resonance fused ring monomers of structures represented by formula (I) to (V), multifunctional olefin monomers, initiator, and organic solvent is 1-10: 0.001-0.05: 1-10: 0.1-2: 80; In step IV-A, the mass ratio of acrylonitrile, two different types of monomers among the boron or nitrogen multiple resonance fused ring monomers of the structures represented by formula (I) to formula (V), the multifunctional olefin monomer, the initiator and the organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 1-10: 0.1-2: 80; In step V-A, the mass ratio of acrylonitrile, three monomers of different types among the boron or nitrogen multiple resonance fused ring monomers of structures represented by formula (I) to formula (V), initiator and organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.001-0.05: 0.1-2: 80; In step VI-A, the mass ratio of acrylonitrile, three monomers of different types among the boron or nitrogen multi-resonance fused ring monomers of formula (I) to (V), multi-functional olefin monomers, initiator and organic solvent is 1-10: 0.001-0.05: 0.001-0.05: 0.001-0.05: 1-10: 0.1-2:

80.

9. The method for preparing narrow-band luminescent microspheres according to claim 7, characterized in that: In step IA to step VI-A, The initiator is azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate or azobisisobutyramidine hydrochloride; The organic solvent is methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, isobutyl formate, isoamyl formate, benzyl formate, ethyl acetate, ethyl acetoacetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, methyl amyl acetate, cycloethyl acetate, methylcyclohexyl acetate, benzyl acetate, methyl propionate, ethyl propionate, propyl propionate, n-butyl propionate, amyl propionate, methyl butyrate, ethyl butyrate, n-butyl butyrate, methyl lactate, ethyl lactate, n-butyl lactate, amyl lactate, diethyl oxalate, dibutyl oxalate, diamyl oxalate, diethyl carbonate, tributyl phosphate, ethyl benzoate, A mixed solution obtained by mixing one or two of isoamyl benzoate, ethyl salicylate, N,N-dimethylformamide, N,N-diisopropylethylamine, acetonitrile, benzene, toluene, m-xylene, tetrahydrofuran, 1,4-dioxane, acetone, cyclohexane, n-hexane, n-pentane, isooctyl alcohol, n-butanol, tert-butanol, 1,3-butanediol, 1,2-propylene glycol, n-propanol, isopropanol, isopentanol, n-pentanol, N-ethyl-2-pyrrolidone, N,N,N',N'-tetramethylethylenediamine, triethylamine, 2,6-lutidine, pyridine, diethylamine, 3,5-dimethylaniline, 2,6-dimethylaniline, 3,5-dimethylaniline, 3-methylaniline, octylamine and aniline.

10. The method for preparing narrow-band luminescent microspheres according to claim 7, characterized in that: In step III-A, step IV-A and step VI-A, the multifunctional olefin monomer is selected from divinylbenzene, 4,4'-divinyl-1,1'-biphenyl, 1,4-diamino-2,5-divinylbenzene, 4,4'-divinylmercaptodiphenyl ether, 3,6-divinyl-9H-carbazole, 4,4'-divinyl-2,2'-bipyridine, 1,4-dialdehyde-2,5-divinylbenzene, 2,5-divinyl-1,4-phthalic acid, 1,4-dibromo-2,5-divinylbenzene, 5,5-divinyl-2,2-bipyridine, divinyl terephthalate, dipropylene terephthalate, 2,4-divinylpyridine, 3-butene-2-vinyl Benzene, 9,10-divinylanthracene, p,p'-divinyl-1,2-diphenylethane, vinyl trimethoxysilane, triallyl isocyanurate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethoxylated trimethylolpropane triacrylate, 3(ethoxy)trimethylolpropane triacrylate, 6(ethoxy)trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate or diethylene glycol dimethacrylate.

Images