Ceramic fluorescent nanocrystalline composite particle and preparation method thereof

Abstract

The invention provides a ceramic fluorescent nanocrystal composite particle and a preparation method thereof, and the composite particle comprises a semiconductor fluorescent material with a plurality of fluorescent nanocrystals and a ceramic material, the ceramic material is selected from any one or combination of the following materials: (a) silicate, aluminate, titanate, nitric oxide and composite ceramic formed by any combination of the materials; (b) a mixture of two or more different oxide materials selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; and (c) multiphase ceramic formed by chemical bonding and / or physical mixing of any material combination in (a) and (b). According to the invention, the ceramic fluorescent nanocrystalline composite particle with strong stability and controllable morphology and the preparation method thereof can be provided.

Description

Technical Field

[0001] The present invention relates to the field of new materials, and particularly to a ceramic fluorescent nanocrystal composite particle and a preparation method thereof. Background Art

[0002] Fluorescent nanomaterials have advantages such as high quantum yield, narrow emission spectrum, tunable luminescent color, and high color purity, and are widely used in the field of optoelectronic devices. Most traditional methods for preparing nanocrystals are carried out in solution, but the obtained materials have poor stability, are easily corroded and decomposed by light, heat, moisture, oxygen, etc. Moreover, current solution synthesis techniques require the use of organic ligands and a large amount of organic solvents or water, and a large amount of waste liquid will be generated during the synthesis and purification processes, causing environmental pollution problems, which directly affect the application prospects of nanocrystals.

[0003] To improve the stability of nanocrystals, inorganic materials (such as SiO 2 , TiO 2 , Al 2 O 3 etc.) are usually used to coat the nanocrystals. For example, a nanocrystal ceramic composite is obtained by the liquid-phase coating method: hydrolyzing the oxide precursor in solution to form an oxide around the nanocrystals for coating. However, the shells formed by these coating techniques are usually relatively loose and cannot completely block the corrosion of fluorescent nanocrystals by moisture or oxygen, and the light and heat stability of fluorescent nanocrystals still cannot meet the requirements of practical applications. In addition, a method of encapsulating nanocrystals inside silica by high-temperature solid-phase synthesis and in-situ encapsulation has emerged. Specifically, mesoporous silica and nanocrystals are mixed and sintered at high temperature. The high temperature causes the silica to soften and collapse, and the nanocrystals are coated with silica, thereby obtaining composite particles with better stability.

[0004] However, in the above high-temperature solid-phase method, due to the poor structural rigidity of mesoporous silica, particle softening may occur during sintering at temperatures above 600 °C, causing nanocrystal growth, losing the quantum size effect, and resulting in a decrease in the fluorescence efficiency of nanocrystals. Moreover, the agglomeration and adhesion between particles may cause the morphology of the finally synthesized composite to be uncontrollable; at the same time, it uses mesoporous silica, and the water and oxygen barrier effects of silica synthesized at relatively low temperatures (300 - 600 °C) are relatively weak, which may affect the stability of the finally formed composite particles. Summary of the Invention

[0005] The present invention is completed in view of the above-mentioned prior art situations, and its purpose is to provide a ceramic fluorescent nanocrystal composite particle with strong stability and controllable morphology and a preparation method thereof.

[0006] To this end, a first aspect of the present invention provides a ceramic fluorescent nanocrystal composite particle, comprising a semiconductor fluorescent material having a plurality of fluorescent nanocrystals and a ceramic material, wherein the ceramic material coats the semiconductor fluorescent material, the semiconductor fluorescent material is dispersed in the ceramic material, and the mass ratio of the semiconductor fluorescent material to the ceramic material is 10:1 to 1:100. The ceramic material is selected from any one or a combination of the following materials: (a) silicate, aluminate, titanate, oxynitride, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, and the oxide materials are selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) a multiphase ceramic formed by combining any material in item (a) and item (b) through chemical bonding and / or physical mixing.

[0007] In the first aspect of the present invention, the ceramic fluorescent nanocrystal composite particle (hereinafter may be simply referred to as the composite particle) comprises a semiconductor fluorescent material and a ceramic material. Among them, the composite particle can have good optoelectronic properties and fluorescent characteristics through the semiconductor fluorescent material. The ceramic material coats the fluorescent nanocrystals, and the ceramic material can play a good protective role on the fluorescent nanocrystal material, reduce the influence of the external environment on the fluorescent nanocrystals, and improve the overall stability. In particular, the selection of the ceramic material can make the ceramic material have a certain rigidity, which helps to maintain a good morphology during high-temperature calcination, and the ceramic material has a stronger effect of isolating water and oxygen, which can help to obtain a composite particle with strong stability. Therefore, a composite particle with strong stability and controllable morphology can be provided.

[0008] In the ceramic fluorescent nanocrystal composite particle according to the first aspect of the present invention, optionally, the ceramic material is made from a ceramic material precursor, and the ceramic material precursor is selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds, and indium-containing compounds. Thus, it is convenient to obtain a ceramic material that can effectively protect the fluorescent nanocrystals.

[0009] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the ceramic material is formed by reacting a ceramic material precursor with a functional additive, wherein the functional additive is selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates, and combinations thereof. In this case, other elements other than the ceramic material precursor can be introduced into the ceramic material through the functional additive to improve the rigidity of the ceramic material. The densification of the microstructure and the multi-phase synergistic effect in the ceramic material can improve the overall stability of the composite particles; and some types of functional additives can form high-melting-point compounds or composite phases with higher chemical properties at high temperatures, which helps to improve the oxidation resistance of the ceramic material, so as to further protect the fluorescent nanocrystals.

[0010] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the particle size of the ceramic fluorescent nanocrystal composite particles is 20 nm to 20 μm, and the density is 10 mg / cm 3 to 10 g / cm 3 . Thus, composite particles of appropriate size can be selected according to actual needs. For example, some small-sized composite particles are convenient for encapsulation and are suitable for applications in fields such as high-quality display (such as backlight, Mini-LED, Micro-LED) and biological imaging.

[0011] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the particle size of the fluorescent nanocrystals is 1 nm to 50 nm. In this case, the fluorescent nanocrystals have good optoelectronic properties and fluorescence characteristics, enabling the overall composite particles to also have good optoelectronic properties and fluorescence characteristics, etc.

[0012] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the plurality of fluorescent nanocrystals are uniformly dispersed inside the ceramic material, and the difference between the particle sizes of any two fluorescent nanocrystals among the plurality of fluorescent nanocrystals is 0 nm to 25 nm. In this case, it is beneficial to further improve the stability of the composite particles, and the fluorescence characteristics of the plurality of nanocrystals have small differences, which can improve the fluorescence color purity of the composite particles.

[0013] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the semiconductor fluorescent material includes fluorescent nanocrystals having a perovskite structure ABX 3 , wherein A is Li, Na, K, Rb or Cs, B is Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba, and X is F, Cl, Br or I.

[0014] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the semiconductor fluorescent material includes a fluorescent nanocrystal having a perovskite structure ABX modified with a perovskite-type or non-perovskite halide 3 wherein the structure of the halide includes, but is not limited to, B′X 2 or A′B′X 3 or A′ 4 B′X 6 or A′ 2 B′X 5 , and A′ is Cs, Rb or K; B′ is different from B and is independently Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba; X is F, Cl, Br or I.

[0015] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the semiconductor fluorescent material includes a fluorescent nanocrystal having a binary structure D n+ Y n- wherein n is an integer from 1 to 10, the molar ratio of element D to Y is 1:1, and D is Zn, Cd, Hg, Al, Ga or In, and Y is S, Se, Te, N, P, As or Sb.

[0016] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the semiconductor fluorescent material includes a fluorescent nanocrystal having a ternary compound type structure G + M 3+ (N 2- ) 2 wherein G + is Cu + or Ag + ; M 3+ is In 3+ 、Ga 3+ or Al 3+ ; N 2- is S 2- or Se 2- , and the molar ratio of G + , M 3+ and N 2- is 0.5:0.5:1.

[0017] In the ceramic fluorescent nanocrystal composite particles according to the first aspect of the present invention, optionally, the semiconductor fluorescent material includes a structure with a general formula of R 2 ZF 6 :Mn 4+ or TZF 6 :Mn 4+fluoride, where R is Li, Na, K, Rb or Cs, T is Ba or Zn, and Z is Si, Ti, Ge or Sn.

[0018] The second aspect of the present invention provides a method for preparing ceramic fluorescent nanocrystal composite particles, comprising the following steps: preparing a mesoporous material, adding the mesoporous material, a functional additive and a fluorescent nanocrystal precursor into a solvent and mixing them, wherein the mass ratio of the fluorescent nanocrystal precursor to the mesoporous material is from 10:1 to 1:100; drying the mixed solution to obtain a mixture powder, the mixture powder comprising mesoporous microspheres, and the functional additive and the fluorescent nanocrystal precursor being present in the mesoporous channels of the mesoporous microspheres; calcining the mixture powder at a predetermined temperature for a predetermined time to obtain ceramic fluorescent nanocrystal composite particles, the fluorescent nanocrystals generated by the fluorescent nanocrystal precursor being dispersed in the ceramic material formed by the reaction of the mesoporous material and the functional additive, the ceramic material coating the fluorescent nanocrystals, and the ceramic material being selected from any one or a combination of the following materials: (a) silicate, aluminate, titanate, oxynitride, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, the oxide materials being selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) a multiphase ceramic formed by combining any material in item (a) with any material in item (b) through chemical bonding and / or physical mixing.

[0019] In the second aspect of the present invention, when the mixture powder is calcined at a predetermined temperature, the fluorescent nanocrystal precursor migrates into the pores of the mesoporous microspheres due to heat and cools to generate fluorescent nanocrystals in the subsequent process; the internal pores of the mesoporous microspheres melt and collapse during sintering to enclose the fluorescent nanocrystals located in the pores therein, thereby realizing the coating of the ceramic microspheres on the fluorescent nanocrystals. In particular, the ceramic material formed by the reaction of the mesoporous material and the functional additive has a certain rigidity, which helps to maintain a good morphology during high-temperature calcination, and the ceramic material has a stronger effect of isolating water and oxygen, which helps to obtain composite particles with strong stability. Thus, through the preparation method according to the second aspect of the present invention, ceramic fluorescent nanocrystal composite particles with strong stability and controllable morphology can be prepared.

[0020] In the preparation method according to the second aspect of the present invention, optionally, the functional additive is selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates, and combinations thereof. In this case, other elements other than the ceramic material precursor can be introduced into the ceramic material through the functional additive, improving the rigidity of the ceramic material. The densification of the microstructure and the multiphase synergistic effect in the ceramic material can improve the overall stability of the composite particles; and some types of functional additives can form high-melting-point compounds or composite phases with higher chemical properties at high temperatures, which helps to improve the oxidation resistance of the ceramic material, so as to further protect the fluorescent nanocrystals; in addition, the functional additive can also play a certain fluxing role in promoting the melting and collapse of the mesoporous microspheres at high temperatures.

[0021] In the preparation method according to the second aspect of the present invention, optionally, the molar ratio of the functional additive to the fluorescent nanocrystal precursor is from 0.1:1 to 10:1. Thereby, it is possible to easily obtain composite particles with suitable properties.

[0022] In the preparation method according to the second aspect of the present invention, optionally, the mesoporous material is made of a ceramic material precursor, and the ceramic material precursor is selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds, and indium-containing compounds. Thereby, it is possible to easily and effectively protect the fluorescent nanocrystals.

[0023] In the preparation method according to the second aspect of the present invention, optionally, the step of preparing the mesoporous material includes: mixing the ceramic material precursor with a surfactant, centrifuging to obtain a precipitate after hydrolysis for a predetermined time, and sequentially performing drying and calcination for a predetermined time under a predetermined temperature condition to obtain the mesoporous material.

[0024] In the preparation method according to the second aspect of the present invention, optionally, the fluorescent nanocrystal precursor includes an AX precursor, a BX 2 precursor, and one or more of B'X 2 precursors, wherein A is Li, Na, K, Rb, or Cs, B' is different from B, and each is independently Ge, Sn, Pb, Cu, Mn, Ca, Sr, or Ba, and X is F, Cl, Br, or I.

[0025] In the preparation method according to the second aspect of the present invention, optionally, the fluorescent nanocrystal precursor includes a cation precursor and an anion precursor with a molar ratio of 1:1, and the cation precursor is used to provide cation D i+, where i is an integer from 1 to 10, and the cation precursor is selected from oxides, nitrides, phosphides, sulfides, selenides, hydrochlorides, acetates, carbonates, sulfates, phosphates, nitrates and hydrates of the following elements: Zn, Cd, Hg, Al, Ga, In elements; the anion precursor is used to provide anion Y n- , where n is an integer from 1 to 10, and the anion precursor is selected from the simple substances and inorganic salts of the following elements: S, Se, Te, N, P, As, Sb.

[0026] In the preparation method according to the second aspect of the present invention, optionally, the particle size of the mesoporous microspheres is 20 nm to 20 μm, and the pore size is 2 nm to 50 nm. In this case, by selecting mesoporous microspheres of appropriate size, it is possible to facilitate the preparation of composite particles of a predetermined size, and the pore size of the mesopores can affect the size of the nanocrystals. Specifically, during high-temperature calcination, the pores soften, and the fluorescent nanocrystal precursors continuously melt and vaporize and crystallize in the pores. Some nanocrystals will grow beyond the limitation of the pore size and be larger than the pore size of the pores, and some nanocrystals will be smaller than the pore size of the pores. Therefore, by selecting appropriate particle sizes and pore sizes of the mesoporous microspheres, it is possible to facilitate the preparation of nanocrystals with sizes within a predetermined range.

[0027] In the preparation method according to the second aspect of the present invention, optionally, the predetermined temperature is 300 °C to 1600 °C, and the predetermined time is 1 minute to 600 minutes. In this case, it can promote the crystallization of the fluorescent nanocrystal precursors in the pores to generate fluorescent nanocrystals, and it can also facilitate the melting and collapse of the mesopores of the mesoporous microspheres to densely coat the fluorescent nanocrystals; in addition, high-temperature calcination in the temperature range above 600 °C helps to form high-melting-point compounds to facilitate the protection of the fluorescent nanocrystals and improve the overall stability of the composite particles.

[0028] According to the present disclosure, it is possible to provide a ceramic fluorescent nanocrystal composite particle with strong stability and controllable morphology and a preparation method thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of the preparation method of the ceramic fluorescent nanocrystal composite particle involved in the example of the present invention.

[0030] Figure 2 is CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 optical photograph of the composite particle.

[0031] Figure 3 is CsPbBr of Example 1 of the present invention 3 -SiO2 / CaSiO 3 XRD pattern of the composite particles.

[0032] Figure 4 It is CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 TEM and mapping images of the composite particles.

[0033] Figure 5 It is CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 XPS spectra of Si and Ca elements of the composite particles.

[0034] Figure 6 It is CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 Comparison of fluorescence spectra between the composite particles and commercially available silicate green phosphors.

[0035] Figure 7 It is CsPbBr of Example 2 of the present invention 3 -K(AlSi 3 O 8 ) XRD pattern of the composite particles.

[0036] Figure 8 It is CsPbBr of Example 3 of the present invention 3-x I x -SiO 2 / Al 2 O 3 Optical photograph of the composite particles.

[0037] Figure 9 It is CsPbBr of Example 3 of the present invention 3-x I x -SiO 2 / Al 2 O 3 Fluorescence spectrum of the composite particles.

[0038] Figure 10 It is CsPbBr of Example 4 of the present invention 3 -Y 3 Al 5 O 12 Optical photograph of the composite particles. Detailed implementation manners

[0039] All references cited in this disclosure are incorporated herein by reference in their entirety as if fully set forth. Unless otherwise defined, the technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0040] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are assigned to the same components, and repeated descriptions are omitted. In addition, the drawings are only schematic diagrams, and the dimensional ratios between components or the shapes of components, etc. may be different from the actual ones.

[0041] The first aspect of the present disclosure relates to a ceramic fluorescent nanocrystal composite particle. The ceramic fluorescent nanocrystal composite particle involved in the present disclosure has strong stability and good fluorescence effect. In the present disclosure, the ceramic fluorescent nanocrystal composite particle may be simply referred to as "composite particle", and may also be called ceramic / fluorescent nanocrystal composite particle, ceramic fluorescent material, ceramic composite particle, ceramic fluorescent particle, nanocomposite particle, semiconductor composite fluorescent material, composite fluorescent material, composite luminescent material, etc.

[0042] The composite particle related to the first aspect of the present disclosure has good fluorescence characteristics and stability, and can be applied to fields such as the display field, the fluorescence imaging field, and the lighting field. For example, the composite particle can be used as a raw material for preparing a color conversion layer, a raw material for preparing a semiconductor nanocrystal ink, a raw material for preparing a biological imaging fluorescent probe, etc. In particular, the composite particle can be applied in fields such as high-quality display fields (such as backlight, Mini-LED, Micro-LED) and biological imaging.

[0043] The second aspect of the present disclosure relates to a preparation method of a ceramic fluorescent nanocrystal composite particle. The preparation method of the ceramic fluorescent nanocrystal composite particle related to the second aspect of the present disclosure may be simply referred to as "preparation method". By the preparation method related to the second aspect of the present disclosure, a composite particle with strong stability can be obtained.

[0044] Hereinafter, with reference to the accompanying drawings, the composite particle and its preparation method related to the present disclosure will be described.

[0045] In this embodiment, the composite particle may include a semiconductor fluorescent material (in the present disclosure, the semiconductor fluorescent material will be simply referred to as "fluorescent material" hereinafter) and an oxide material. Among them, the fluorescent material may have a plurality of fluorescent nanocrystals (in the present disclosure, the fluorescent nanocrystals will be simply referred to as "nanocrystals" hereinafter). Thereby, the composite particle can have good fluorescence characteristics. In the present disclosure, the nanocrystals may also be called quantum dots.

[0046] In some examples, the composite particles may include a ceramic material. The ceramic material may coat the fluorescent material. In this case, the ceramic material can provide good protection for the fluorescent material, reduce the influence of the external environment on the fluorescent material, and improve the overall stability. In some examples, the ceramic material may densely coat the fluorescent material, and a plurality of nanocrystals may be dispersed inside the ceramic material. In some examples, the fluorescent material may be dispersed in the ceramic material. Thereby, it is helpful to obtain composite particles with uniform fluorescence characteristics. In some examples, the fluorescent material may be uniformly dispersed in the ceramic material. Thereby, the nanocrystals can be protected by the oxide material, and it is beneficial to further improve the overall stability of the composite particles.

[0047] In some examples, the composite particles may be composed of a fluorescent material and a ceramic material. Among them, the fluorescent material may be in the form of nanocrystals. In other words, the fluorescent material may be composed of a plurality of fluorescent nanocrystals.

[0048] In some examples, the ceramic material may be selected from any one or a combination of silicates, aluminates, titanates, oxynitrides, and composite ceramics formed by any combination of the above materials. In some examples, the ceramic material may include a mixture of two or more different oxide materials. Among them, the oxide material may be selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides. In some examples, the ceramic material may be selected from any one or a combination of the following materials: (a) silicates, aluminates, titanates, oxynitrides, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, and the oxide material is selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) a multiphase ceramic formed by chemically bonding and / or physically mixing any material in item (a) and item (b). In this case, the selection of the ceramic material can make the ceramic material have a certain rigidity, help maintain a good morphology during high-temperature calcination, and the ceramic material has a stronger effect of isolating water and oxygen, which can help obtain composite particles with strong stability.

[0049] In some examples, the ceramic material may be made from a ceramic material precursor. Among them, the ceramic material precursor may be selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds, and indium-containing compounds. Thereby, it is convenient to obtain a ceramic material that can effectively protect the fluorescent nanocrystals.

[0050] In some examples, the ceramic material can be formed by reacting a ceramic material precursor with a functional additive. Among them, the functional additive can be selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates, and combinations thereof. In this case, other elements other than the ceramic material precursor can be introduced into the ceramic material through the functional additive, improving the rigidity of the ceramic material. The densification of the microstructure and the multiphase synergistic effect in the ceramic material can improve the overall stability of the composite particles. Moreover, some types of functional additives can form high-melting-point compounds or composite phases with higher chemical properties at high temperatures, which helps to improve the oxidation resistance of the ceramic material, so as to further protect the fluorescent nanocrystals.

[0051] In some examples, the particle size of the composite particles can be from 20 nm to 20 μm. For example, the particle size of the composite particles can be 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 1000 nm, 2000 nm, 5000 nm, 10000 nm, 15000 nm, or 20000 nm (i.e., 20 μm). It should be noted that the particle size of the composite particles can refer to the diameter of the composite particles. In this case, composite particles of appropriate sizes can be selected according to actual needs. For example, some small-sized composite particles are convenient for encapsulation and can be easily applied in fields such as high-quality display (such as backlight, Mini-LED, Micro-LED) and bioimaging. Among them, small-sized (nanoscale) composite particles are convenient for solution processing (for example, they can be evenly dispersed in a solution), and thus can be applied in fields such as high-quality display fields such as Micro-LED and bioimaging fields. Specifically, in the field of bioimaging, the smaller the fluorescent composite particles, the easier it is to enter cells. In the display field, the quality of the color conversion film prepared from small-sized composite particles as the raw material for the color conversion film is better (more uniform), which can meet the requirements of the imaging field. In some examples, the particle size of the composite particles can be from 20 nm to 500 nm. In some examples, the particle size of the composite particles can be from 20 nm to 100 nm. In some examples, the particle size of the composite particles can be from 1 μm to 20 μm.

[0052] In some examples, the composite particles can be spherical. That is to say, in some examples, the ceramic material can be in the form of a solid sphere, and multiple nanocrystals can be dispersed inside the ceramic material. It should be noted that from a microscopic perspective, the composite particles are not completely regular spheres, and such composite particles that are roughly spherical also fall within the scope of "being spherical" as described in the present disclosure. In the present disclosure, the composite particles can also be referred to as composite fluorescent microspheres or composite fluorescent nanospheres, referring to small-sized and roughly spherical composite particles, and the terms microspheres and nanospheres do not imply a limitation on the size of the composite particles.

[0053] In some examples, the density of the composite particles can be 10 mg / cm 3 to 10 g / cm 3 . The specific density can be selected as needed and is related to the components of the ceramic material. In this case, the density of the composite particles can reflect the compactness of the ceramic material coating the fluorescent material. Compared with a loose shell, in the present disclosure, the dense coating of the fluorescent material by the ceramic material can help improve the stability of the fluorescent material. In other words, the dense coating of the fluorescent material by the ceramic material can improve the overall stability of the composite particles. In some examples, the density of the composite particles can be 1 g / cm 3 to 10 g / cm 3 .

[0054] In some examples, the mass ratio of the fluorescent material to the ceramic material can be from 10:1 to 1:100. For example, the mass ratio of the fluorescent material to the ceramic material can be 10:1, 5:1, 2:1, 1:1, 1:2, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100. In this case, the ceramic material can provide good protection for the fluorescent material; in addition, the optoelectronic properties and fluorescence characteristics of the composite particles can be adjusted by regulating the mass ratio of the fluorescent material to the ceramic material.

[0055] In some examples, the particle size of the nanocrystals can be from 1 nm to 50 nm. For example, the particle size of the nanocrystals can be 1 nm, 2 nm, 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm or 50 nm. In this case, the nanocrystals can have good optoelectronic properties and fluorescence characteristics, and thus the composite particles as a whole can also have good optoelectronic properties and fluorescence characteristics. In some examples, the particle size of the nanocrystals can be from 5 nm to 30 nm.

[0056] In some examples, the nanocrystals can be spherical. It should be noted that from a microscopic perspective, the nanocrystals are not completely regular spheres, and such nanocrystals that are roughly spherical also fall within the scope of "being spherical" as described in the present disclosure.

[0057] In some examples, limited by the preparation process, the particle sizes of multiple nanocrystals can be different. Among them, in some examples, the difference between the particle sizes of any two nanocrystals among the multiple nanocrystals can be from 0 nm to 25 nm. In other words, in some examples, the difference between the particle sizes of any two nanocrystals among the multiple nanocrystals can be no more than 25 nm. In this case, it is beneficial to further improve the stability of the composite particles, and the fluorescence property differences of the multiple nanocrystals are small, which can improve the fluorescence color purity of the composite particles.

[0058] In some examples, the distance between the nanocrystals located inside the ceramic material and the outer wall of the composite particle is not less than 2 nm. In other words, the distance between the nanocrystals located inside the ceramic material and the outer wall of the ceramic material is not less than 2 nm. In this case, it is convenient to protect the nanocrystals by coating them with the ceramic material.

[0059] In some examples, limited by the synthesis process of the composite particles, there may also be some nanocrystals on the outer wall of the ceramic material. For example, some nanocrystals can be embedded on the outer wall of the ceramic material. Since these nanocrystals located on the outer wall of the ceramic material are exposed to the environment, the stability of this part of the nanocrystals is not strong. In the present disclosure, the influence of the nanocrystals located inside the ceramic material on the overall optoelectronic properties and fluorescence properties of the composite particles is mainly considered.

[0060] In some examples, the fluorescent material can include fluorescent nanocrystals having a perovskite structure ABX 3 . In other words, the nanocrystals can have a perovskite structure ABX 3 . Wherein A is Li, Na, K, Rb or Cs, B is Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba, and X is F, Cl, Br or I.

[0061] In some examples, the semiconductor fluorescent material can include fluorescent nanocrystals having a perovskite structure ABX 3 modified by perovskite-type or non-perovskite halides. Among them, the structure of the halide can include but is not limited to B′X 2 or A′B′X 3 or A′ 4 B′X 6 or A′ 2 B′X 5 , and A′ is Cs, Rb or K; B′ is different from B and is independently Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba; X is F, Cl, Br or I.

[0062] In some examples, the fluorescent material can include those having a binary structure D n+ Y n-fluorescent nanocrystals. In other words, the nanocrystals can have a binary structure D n+ Y n- , where n is an integer from 1 to 10, the molar ratio of element D to Y is 1:1, and D is Zn, Cd, Hg, Al, Ga or In, and Y is S, Se, Te, N, P, As or Sb.

[0063] In some examples, the fluorescent material can include a ternary compound type structure G of Group IB-ⅢA-ⅥA + M 3+ (N 2- ) 2 fluorescent nanocrystals. In other words, the nanocrystals can have a ternary compound type structure G of Group IB-ⅢA-ⅥA + M 3+ (N 2- ) 2 , where G + is Cu + or Ag + ; M 3+ is In 3+ 、Ga 3+ or Al 3+ ; N 2- is S 2- or Se 2- , and the molar ratio of G + , M 3+ and N 2- is 0.5:0.5:1.

[0064] In some examples, the fluorescent material can include fluorides with the structural general formula of R 2 ZF 6 :Mn 4+ or TZF 6 :Mn 4+ , where R is Li, Na, K, Rb or Cs, T is Ba or Zn, and Z is Si, Ti, Ge or Sn.

[0065] In some examples, preferably, the composite particles may include a semiconductor fluorescent material having a plurality of fluorescent nanocrystals and a ceramic material. The ceramic material coats the semiconductor fluorescent material, and the semiconductor fluorescent material is dispersed in the ceramic material. The mass ratio of the semiconductor fluorescent material to the ceramic material is from 10:1 to 1:100. The ceramic material is selected from any one or a combination of the following materials: (a) silicates, aluminates, titanates, oxynitrides, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, and the oxide materials are selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) a multiphase ceramic formed by chemically bonding and / or physically mixing any material in item (a) and item (b). In this case, the composite particles include a fluorescent material and a ceramic material. Among them, the composite particles can have good optoelectronic properties and fluorescent characteristics through the fluorescent material. The ceramic material coats the fluorescent nanocrystals, and the ceramic material can play a good protective role on the fluorescent nanocrystal material, reduce the influence of the external environment on the fluorescent nanocrystals, and improve the overall stability. In particular, the selection of the ceramic material can make the ceramic material have a certain rigidity, which helps to maintain a good morphology during high-temperature calcination, and the ceramic material has a stronger effect of isolating water and oxygen, which can help to obtain composite particles with strong stability. Thus, a composite particle with strong stability and controllable morphology can be provided.

[0066] According to the first aspect of the present disclosure, a composite particle with strong stability and controllable morphology can be provided.

[0067] As described above, the second aspect of the present disclosure relates to a method for preparing composite particles. Through the preparation method described in the second aspect of the present disclosure, the composite particles described in the first aspect of the present disclosure can be prepared. The description of the fluorescent material and the ceramic material can refer to the above description and will not be repeated here. It should be noted that the composite particles described in the first aspect of the present disclosure can also be prepared by other preparation methods and are not limited to the preparation method described in the second aspect of the present disclosure.

[0068] Figure 1 It is a flowchart of the method for preparing ceramic fluorescent nanocrystal composite particles involved in the examples of the present invention.

[0069] See Figure 1 , in some examples, the preparation method may include mixing a fluorescent nanocrystal precursor and a functional additive with a mesoporous material, followed by drying and calcination to obtain ceramic fluorescent nanocrystal composite particles.

[0070] In some examples, the preparation method may include the following steps: preparing a mesoporous material, adding the mesoporous material, a functional additive, and a fluorescent nanocrystal precursor into a solvent and mixing them; drying the mixed solution to obtain a mixture powder; calcining the mixture powder at a predetermined temperature for a predetermined time to obtain ceramic fluorescent nanocrystal composite particles.

[0071] In some examples, the mixture powder may include mesoporous microspheres (which may also be referred to as ceramic microspheres), and there are a functional additive and a fluorescent nanocrystal precursor in the mesoporous channels of the mesoporous microspheres. In this case, when the mixture powder is calcined at a predetermined temperature, the fluorescent nanocrystal precursor migrates into the channels of the mesoporous microspheres when heated, and fluorescent nanocrystals are formed upon cooling in subsequent processes; the internal channels of the mesoporous microspheres melt and collapse during sintering to encapsulate the fluorescent nanocrystals located in the channels therein, thereby realizing the encapsulation of the fluorescent nanocrystals by the ceramic microspheres.

[0072] In some examples, the fluorescent nanocrystals formed from the fluorescent nanocrystal precursor may be dispersed in the ceramic material formed by the reaction of the mesoporous material and the functional additive. In some examples, the ceramic material may encapsulate the fluorescent nanocrystals.

[0073] In some examples, the ceramic material may be selected from any one or a combination of the following materials: (a) silicates, aluminates, titanates, nitrides, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, and the oxide materials are selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) a multiphase ceramic formed by combining any materials in item (a) and item (b) through chemical bonding and / or physical mixing. In this case, the ceramic material formed by the reaction of the mesoporous material and the functional additive has a certain rigidity, which helps to maintain a good morphology during high-temperature calcination, and the ceramic material has a stronger effect of isolating water and oxygen, which can help to obtain composite particles with strong stability. Thus, through the preparation method according to the second aspect of the present invention, ceramic fluorescent nanocrystal composite particles with strong stability and controllable morphology can be prepared.

[0074] In some examples, the ceramic material may be formed by the reaction of the mesoporous material and the functional additive.

[0075] In some examples, the mesoporous material may be made from a ceramic material precursor. The ceramic material precursor may be selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds, and indium-containing compounds. Thereby, it is possible to facilitate the effective protection of the fluorescent nanocrystals.

[0076] In some examples, the silicon-containing compound can be selected from one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl titanate, and tetrabutyl titanate. The aluminum-containing compound can be selected from one or more of aluminum triethanolate, aluminum isopropoxide, aluminum sec-butoxide, aluminum tert-butoxide, aluminum chloride, aluminum nitrate, and sodium metaaluminate. The titanium-containing compound can be selected from one or more of titanium isopropoxide, tetramethyl titanate, tetraethyl titanate, isopropyl titanate, tetrabutyl titanate, and titanium tetrachloride. The zirconium-containing compound can be selected from one or more of zirconium isopropoxide, zirconium 2-ethylhexanoate, zirconium chloride, zirconyl chloride, zirconium sulfate, and zirconyl sulfate. The zinc-containing compound can be selected from one or more of zinc acetate and zinc nitrate. The tin-containing compound can be selected from one or more of tin acetate, isopropoxy tin, sodium stannate, and tin chloride. The nickel-containing compound can be selected from one or more of nickel acetate, nickel carbonate, nickel sulfate, nickel halide, and nickel nitrate. The lead-containing compound can be selected from one or more of lead citrate, lead acetate, lead carbonate, lead sulfate, and lead nitrate. The cobalt-containing compound can be selected from one or more of cobalt halide, cobalt oxalate, cobalt carbonate, and cobalt sulfate. The cerium-containing compound can be selected from one or more of cerium nitrate, cerium sulfate, cerium oxalate, cerium acetate, cerium carbonate, and cerium phosphate. The chromium-containing compound can be selected from one or more of chromate and chromium halide. The indium-containing compound can be selected from one or more of indium acetate, indium halide, indium sulfate, and indium nitrate.

[0077] In some examples, the steps for preparing the mesoporous material include: mixing the ceramic material precursor with a surfactant, centrifuging to obtain a precipitate after hydrolysis for a predetermined time, and sequentially drying and calcining for a predetermined time under predetermined temperature conditions to obtain the mesoporous material. Thus, it is possible to facilitate the obtaining of the mesoporous material. In some examples, the drying conditions in the steps for preparing the mesoporous material can be 45 °C to 300 °C for 10 minutes to 600 minutes. In some examples, the calcining conditions in the steps for preparing the mesoporous material can be 300 °C to 1600 °C for 1 minute to 600 minutes.

[0078] In some examples, the surfactant can include one or more of alkyl quaternary ammonium salt surfactants, long-chain alkane-based ethylene oxide ethers (C n H 2n+1 (CH 2 CH 2 O) m H, where n and m are positive integers), and poly(ethylene oxide)-poly(propylene oxide) block copolymers. In this case, by changing the surfactant, the size of the formed micelles can be adjusted, thereby adjusting the pore size of the mesopores in the mesoporous microspheres, so as to obtain composite particles with a predetermined morphology subsequently.

[0079] In some examples, the surfactant and the mesoporous material may have a predetermined ratio. The molar ratio of the mesoporous material to the surfactant can be from 0.5:1 to 50:1. Thus, the size of the pores in the mesoporous microspheres can be adjusted by the surfactant.

[0080] In some examples, a catalyst can be added to improve the efficiency of the in-situ hydrolysis synthesis of the oxide material from the ceramic material precursor. In some examples, the catalyst can be selected from one or more of ammonia water, tert-butylamine, n-butylamine, triethanolamine, sodium hydroxide, and potassium hydroxide.

[0081] In some examples, the functional additive can be selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates, and combinations thereof. In this case, other elements other than the ceramic material precursor can be introduced into the ceramic material through the functional additive, improving the rigidity of the ceramic material. The densification of the microstructure and the multi-phase synergistic effect in the ceramic material can improve the overall stability of the composite particles; and some types of functional additives can form high-melting-point compounds or composite phases with higher chemical properties at high temperatures, which helps to improve the oxidation resistance of the ceramic material for further protection of the fluorescent nanocrystals; in addition, the functional additive can also play a certain fluxing role in promoting the melting and collapse of the mesoporous microspheres at high temperatures.

[0082] In some examples, the mass ratio of the fluorescent nanocrystal precursor to the mesoporous material can be from 10:1 to 1:100. For example, the molar ratio of the fluorescent nanocrystal precursor to the mesoporous material can be 10:1, 5:1, 2:1, 1:1, 1:2, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, or 1:100. Thus, it is possible to easily obtain composite particles with suitable properties. In some examples, the molar ratio of the functional additive to the fluorescent nanocrystal precursor can be from 0.1:1 to 10:1. For example, the molar ratio of the functional additive to the fluorescent nanocrystal precursor can be 0.1:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1. Thus, it is possible to easily obtain composite particles with suitable properties.

[0083] In some examples, the mass ratio of the functional additive to the mesoporous microspheres can be from 1:10 to 1:1. For example, the mass ratio of the functional additive to the mesoporous microspheres can be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, or 1:1. Thus, it is possible to easily obtain a ceramic material with suitable properties.

[0084] In some examples, the particle size of the mesoporous microspheres can be from 20 nm to 20 μm, and the pore size can be from 2 nm to 50 nm. In this case, by selecting mesoporous microspheres of appropriate sizes, it is convenient to prepare composite particles of a predetermined size, and the pore size of the mesopores can affect the size of the nanocrystals. Specifically, during high-temperature calcination, the pore channels soften, and the fluorescent nanocrystal precursors continuously melt and vaporize and crystallize within the pore channels. Some of the nanocrystals will grow beyond the limitation of the pore size and be larger than the pore size of the pore channels, while some nanocrystals will be smaller than the pore size of the pore channels. Therefore, by selecting appropriate particle sizes and pore sizes of the mesoporous microspheres, it is convenient to prepare nanocrystals with sizes within a predetermined range.

[0085] In some other examples, the ceramic material can also be directly formed by the decomposition and recombination of a ceramic material precursor. For example, after selecting the type of ceramic material, the corresponding ceramic material precursor can be directly decomposed and recombined to form it.

[0086] In some examples, the predetermined temperature for calcining the mixture powder can be from 300 °C to 1600 °C, and the predetermined time can be from 1 minute to 600 minutes. Among them, the predetermined temperature is related to the type of the oxide precursor. Specifically, the predetermined temperature is not lower than the collapse temperature of the mesopore channels in the oxide microspheres. In this case, it can promote the crystallization of the fluorescent nanocrystal precursors within the pore channels to generate fluorescent nanocrystals, and it can also facilitate the melting and collapse of the mesopore channels of the mesoporous microspheres to densely coat the fluorescent nanocrystals; in addition, high-temperature calcination in the temperature range above 600 °C can help form high-melting-point compounds to facilitate the protection of the fluorescent nanocrystals and improve the overall stability of the composite particles. In some examples, the calcination conditions of the mixture powder can be from 300 °C to 800 °C. In some examples, the calcination conditions of the mixture powder can be from 600 °C to 1200 °C. In some examples, the calcination conditions of the mixture powder can be from 600 °C to 1600 °C.

[0087] In some examples, after the calcination of the mixture powder is completed, the product can be ground and washed. Specifically, the product can be ground, and after grinding, it is added to water for washing, centrifuged, and the supernatant is removed. The operations of washing and centrifuging are repeated multiple times, and finally, the precipitate obtained after multiple centrifugations is dried to obtain the composite particles. Thereby, the unstable nanocrystals and / or precursors on the surface of the product can be removed.

[0088] In some other examples, the fluorescent material precursor can also be directly mixed with the pre-synthesized ceramic material and calcined to obtain composite particles. In some other examples, the fluorescent material can also be directly mixed with the ceramic material and calcined to cause the ceramic material to melt and collapse to coat the fluorescent material to obtain composite particles.

[0089] In summary, through the preparation method according to the second aspect of the present disclosure, composite particles with strong stability and controllable morphology can be prepared, and the composite particles have good optoelectronic properties and fluorescence characteristics.

[0090] Hereinafter, the ceramic fluorescent nanocrystal composite particles and the preparation method thereof provided by the present invention will be described in detail with reference to embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0091] It should be noted that in the embodiments of the present disclosure, unless otherwise specified, the reagents and instruments used are all commercially available products.

[0092] Embodiment

[0093] Embodiment 1: CsPbBr 3 -SiO 2 / CaSiO 3 Composite particles

[0094] (1) Preparation of mesoporous SiO 2 Materials: Add 1 g of cetyltrimethylammonium bromide (CTAB), 0.1 g of poloxamer 188 (F127), 0.4 g of sodium hydroxide and 480 mL of water into a 1000 mL beaker, stir at 80 °C for 0.5 h, add 15 mL of tetraethyl orthosilicate (TEOS), continue heating and stirring for 6.5 h, stop the reaction, after the solution returns to room temperature, centrifuge to obtain the precipitate, and then wash it twice with 100 mL of ethanol (95%) each time, dry it at 70 °C, place the ground solid powder in a corundum crucible, and calcine it in a muffle furnace at 550 °C for 6 h.

[0095] (2) Filling CsPbBr 3 Fluorescent nanocrystal precursor and functional additive: Add 0.6 mmol of cesium bromide, 0.54 mmol of lead bromide, 0.75 mmol of calcium bromide, 0.75 mmol of potassium bromide, 0.06 mmol of barium bromide and 100 mL of water into a 500 mL beaker, and add 1 mL of hydrobromic acid solution (mass fraction about 2%), stir until dissolved, add 1 g of the above mesoporous SiO 2 Material, heat and stir at 80 °C to evaporate the water, then transfer it to an oven and dry it at 70 °C, place the ground solid powder in a corundum crucible, calcine it in a muffle furnace at 600 °C for 40 min and then cool it down to 500 °C at a programmed rate and keep it warm for 2 h, and then terminate the program and let it cool down naturally to obtain the CsPbBr 3 -SiO 2 / CaSiO 3 Composite particles of Embodiment 1.

[0096] For the CsPbBr prepared in Embodiment 1 3 -SiO 2 / CaSiO3 The composite particles were subjected to XRD (X-ray diffraction), TEM (transmission electron microscopy), mapping (elemental distribution), XPS (X-ray photoelectron spectroscopy), and fluorescence spectroscopy tests.

[0097] Figure 2 is the CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 Optical photograph of the composite particles. CsPbBr 3 -SiO 2 / CaSiO 3 The composite particles presented a yellowish-green powder form (the original color of the sample could not be seen due to the grayscale photograph).

[0098] Figure 3 Shows the CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 XRD pattern of the composite particles. From Figure 3 it can be known that the obtained CsPbBr 3 -SiO 2 / CaSiO 3 composite particles presented a perovskite structure of orthorhombic system (PDF card #97-009-7851), fully proving that CsPbBr 3 nanocrystals were formed under the high-temperature calcination environment. At the same time, Figure 3 also showed the diffraction peaks of CaSiO 3 , proving that CaSiO 3 compound was formed in the experiment of Example 1.

[0099] Figure 4 Shows the CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 TEM and mapping images of the composite particles. From Figure 4 it can be seen that the CsPbBr 3 -SiO 2 / CaSiO 3 composite particles were microspheres with a diameter of 200 - 300 nm (good morphology), CsPbBr 3 was densely coated with SiO 2 / CaSiO 3 , and the mapping image showed that the elemental distribution of CsPbBr 3 nanocrystals and other flux substances was uniform.

[0100] Figure 5This is the CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 XPS spectra of Si and Ca elements of the composite particles. From the 2p XPS spectrum of Si, the binding energy of 103.41 eV of Si is assigned to SiO 2 , but the peak at 347.31 eV in the Ca 2p shows the formation of CaSiO 3 , a small amount of CaSiO 3 can increase the rigidity of the material shell and help improve the overall stability of the material.

[0101] Figure 6 Shows the CsPbBr of Example 1 of the present invention 3 -SiO 2 / CaSiO 3 Comparison chart of fluorescence spectra of composite particles and commercially available silicate green fluorescent powder. From Figure 6 it can be seen that the CsPbBr obtained in Example 1 3 -SiO 2 / CaSiO 3 composite particles have a narrow full width at half maximum and great application potential.

[0102] Example 2: CsPbBr 3 -K(AlSi 3 O 8 ) composite particles

[0103] (1) Preparation of mesoporous SiO 2 / Al 2 O 3 material: Add 1 g of CTAB, 0.1 g of F127, 480 mL of water and 1 mL of n-butylamine to a 1000 mL beaker. After stirring at 60 °C for 0.5 h, add 15 mL of TEOS, continue heating and stirring for 5.5 h, add 3 mmol of aluminum isopropoxide, continue heating and stirring for 1 h, stop the reaction, wait for the solution to return to room temperature, centrifuge to collect the precipitate, dry at 70 °C, grind and calcine at 800 °C for 6 h.

[0104] (2) Filling CsPbBr 3 fluorescent nanocrystal precursors and functional additives: Add 0.6 mmol of cesium bromide, 0.54 mmol of lead bromide, 0.75 mmol of calcium bromide, 0.75 mmol of potassium bromide, 0.06 mmol of barium bromide and 100 mL of water to a 500 mL beaker, and add 1 mL of hydrobromic acid solution (mass fraction about 2%), stir until dissolved, and add the above mesoporous SiO 2 / Al 2 O 31 g of the material was heated and stirred at 80 °C to volatilize the moisture, and then transferred to an oven and dried at 70 °C. The ground solid powder was placed in a corundum crucible and calcined in a tubular furnace at 720 °C for 40 min and then cooled naturally, and then calcined in a muffle furnace at 600 °C for 2 h to obtain the CsPbBr of Example 2 3 -K(AlSi 3 O 8 ) composite particles.

[0105] Figure 7 is the XRD pattern of the CsPbBr 3 -K(AlSi 3 O 8 ) composite particles of Example 2 of the present invention. It can be seen from Figure 7 that the material shows the diffraction peaks of K(AlSi 3 O 8 )(PDF#97-003-5334) and CsPbBr 3 (PDF#97-009-7851), indicating the successful preparation of the CsPbBr 3 -K(AlSi 3 O 8 ) composite particles.

[0106] Example 3: CsPbBr 3-x I x -SiO 2 / Al 2 O 3 composite particles

[0107] (1) Preparation of mesoporous SiO 2 / Al 2 O 3 material: 1 g of CTAB, 0.1 g of F127, 480 mL of water and 1 mL of n-butylamine were added to a 1000 mL beaker, stirred at 60 °C for 0.5 h, then 15 mL of TEOS was added, and stirring was continued for 5.5 h. 3 mmol of aluminum isopropoxide was added, and stirring was continued for 1 h. The reaction was stopped. After the solution returned to room temperature, the precipitate was collected by centrifugation and dried at 70 °C, and then calcined at 800 °C for 6 h after grinding.

[0108] (2) Filling CsPbBr 3-x I x fluorescent nanocrystal precursors and functional additives: 0.6 mmol of cesium bromide, 0.54 mmol of lead bromide, 0.75 mmol of calcium bromide, 0.06 mmol of barium bromide and 100 mL of water were added to a 500 mL beaker, and 1 mL of hydrobromic acid solution (mass fraction about 2%) was added and stirred until dissolved. The above mesoporous SiO 2 / Al 2 O3 1 g of ceramic material was heated and stirred at 80 °C. After most of the water was evaporated, 0.75 mmol of potassium iodide and 3 mmol of ammonium iodide were added. Heating and stirring were continued to evaporate the water, and then it was transferred to an oven and dried at 70 °C. After grinding, it was calcined in a tubular furnace at 720 °C for 1 h in an argon atmosphere, and then the program was terminated and it was cooled naturally to obtain CsPbBr of Example 3 3-x I x -SiO 2 / Al 2 O 3 composite particles.

[0109] Figure 8 It is CsPbBr of Example 3 of the present invention 3-x I x -SiO 2 / Al 2 O 3 Optical photograph of the composite particles. CsPbBr 3-x I x -SiO 2 / Al 2 O 3 The composite particles presented a reddish-brown powder (the original color of the sample could not be seen due to the grayscale photograph).

[0110] Figure 9 It is CsPbBr of Example 3 of the present invention 3-x I x -SiO 2 / Al 2 O 3 Fluorescence spectrum of the composite particles, with a central wavelength of 666 nm and a full width at half maximum of about 35 nm.

[0111] Example 4: CsPbBr 3 -Y 3 Al 5 O 12 composite particles

[0112] 1.5 g of F127, 40 mL of tetrahydrofuran and 0.5 mL of ammonia water were added to a beaker and stirred until the solution was clear. 0.6 mmol of CsBr and 0.6 mmol of PbBr 2 were added, and it was stirred at room temperature for 30 min. Then, 1.5 mmol of Y(NO 3 ) 3 ·6H 2 O and 1.5 mmol of Al(NO 3 ) 3 ·9H 2O was added to the above solution to form a mixed solution, which was then evaporated at 40 °C for 20 h and then at 80 °C for 8 h to form a white powder. The powder was transferred to a corundum crucible and calcined at 1000 °C for 1 h. After natural cooling, it was taken out and ground, and repeatedly washed 3 times with deionized water. The precipitate was collected by centrifugation, and then the precipitate was placed in a constant temperature drying oven at 70 °C for drying to obtain the CsPbBr of Example 5 3 -Y 3 Al 5 O 12 composite particles.

[0113] Figure 10 Figure 4 shows the CsPbBr of Example 4 of the present invention 3 -Y 3 Al 5 O 12 optical photograph of the composite particles.

[0114] The performance and parameters of the composite particles obtained in each example were detected, and the results are shown in Table 1.

[0115] Table 1

[0116]

[0117] As can be seen from Table 1, the composite particles obtained in each example all have excellent light stability, that is, through the dense coating of nanocrystals by ceramic materials, the stability of nanocrystals can be improved and their service life can be extended.

[0118] In summary, according to the present disclosure, a ceramic fluorescent nanocrystal composite particle with strong stability and controllable morphology and its preparation method can be provided.

[0119] Although the present invention has been specifically described above in conjunction with the accompanying drawings and examples, it can be understood that the above description does not limit the present invention in any form. Those skilled in the art can make deformations and changes to the present invention according to needs without departing from the essence and scope of the present invention, and these deformations and changes all fall within the scope of the present invention.

Claims

1. A ceramic fluorescent nanocrystalline composite particle, characterized in that: The invention comprises a semiconductor fluorescent material having a plurality of fluorescent nanocrystals, and a ceramic material, wherein the ceramic material covers the semiconductor fluorescent material, the semiconductor fluorescent material is dispersed in the ceramic material, the mass ratio of the semiconductor fluorescent material to the ceramic material is 10:1 to 1:100, and the ceramic material is selected from any one of the following materials or a combination thereof: (a) Silicates, aluminates, titanates, oxynitrides, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, wherein the oxide material is selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) A multiphase ceramic formed by chemical bonding and / or physical mixing of any of the materials in (a) and (b).

2. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The ceramic material is made of a ceramic material precursor, and the ceramic material precursor is selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds and indium-containing compounds.

3. The ceramic fluorescent nanocrystalline composite particles according to claim 2, characterized in that: The ceramic material is formed by the reaction of a ceramic material precursor and a functional additive, wherein the functional additive is selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates and combinations thereof.

4. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The particle size of the ceramic fluorescent nanocrystalline composite particles is 20nm to 20μm, and the density is 10mg / cm 3 Up to 10g / cm 3 .

5. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The particle size of the fluorescent nanocrystal is 1 nm to 50 nm.

6. The ceramic fluorescent nanocrystalline composite particles according to claim 1 or 5, characterized in that: The plurality of fluorescent nanocrystals are uniformly dispersed inside the ceramic material, and a difference between the particle sizes of any two fluorescent nanocrystals among the plurality of fluorescent nanocrystals is 0 nm to 25 nm.

7. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The semiconductor fluorescent material includes fluorescent nanocrystals with a perovskite structure ABX3, wherein A is Li, Na, K, Rb or Cs, B is Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba, and X is F, Cl, Br or I.

8. The ceramic fluorescent nanocrystalline composite particles according to claim 1 or 7, characterized in that: The semiconductor fluorescent material includes fluorescent nanocrystals with a perovskite structure ABX3 modified by a perovskite-type or non-perovskite halide, wherein the structure of the halide includes but is not limited to B′X2 or A′B′X3 or A′4B′X6 or A′2B′X5, and A′ is Cs, Rb or K; B′ and B are different and are independently Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba; X is F, Cl, Br or I.

9. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The semiconductor fluorescent material includes a binary structure D n+ Y n- Fluorescent nanocrystals, wherein n is an integer of 1-10, the molar ratio of element D to Y is 1:1, and D is Zn, Cd, Hg, Al, Ga or In, and Y is S, Se, Te, N, P, As or Sb.

10. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The semiconductor fluorescent material includes a ternary compound type structure G of group IB-IIIA-VIA + M 3+ (N 2- )2 fluorescent nanocrystals, wherein G + Cu + or Ag + ;M 3+ ForIn 3+ , Ga 3+ or Al 3+ ; N 2- For S 2- or Se 2- , and G + 、M 3+ and N 2- The molar ratio is 0.5:0.5:

1.

11. The ceramic fluorescent nanocrystalline composite particle according to claim 1, characterized in that: The semiconductor fluorescent material includes a general structural formula of R2ZF6:Mn 4+ or TZF6:Mn 4+ A fluoride of wherein R is Li, Na, K, Rb or Cs, T is Ba or Zn, and Z is Si, Ti, Ge or Sn.

12. A method for preparing ceramic fluorescent nanocrystalline composite particles, characterized in that: The following steps are involved: Prepare a mesoporous material, add the mesoporous material, a functional additive and a fluorescent nanocrystal precursor into a solvent and mix them, wherein the mass ratio of the fluorescent nanocrystal precursor to the mesoporous material is 10:1 to 1:100; Drying the mixed solution to obtain a mixed powder, wherein the mixed powder includes mesoporous microspheres, and the functional additive and the fluorescent nanocrystal precursor are present in the mesoporous channels of the mesoporous microspheres; The mixture powder is calcined at a predetermined temperature for a predetermined time to obtain ceramic fluorescent nanocrystal composite particles, wherein the fluorescent nanocrystals generated by the fluorescent nanocrystal precursor are dispersed in the ceramic material generated by the reaction of the mesoporous material and the functional additive, and the ceramic material covers the fluorescent nanocrystals, and the ceramic material is selected from any one of the following materials or a combination thereof: (a) Silicates, aluminates, titanates, oxynitrides, and composite ceramics formed by any combination of the above materials; (b) a mixture of two or more different oxide materials, wherein the oxide material is selected from any one of silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, zinc oxide, tin oxide, and transition metal oxides; (c) A multiphase ceramic formed by chemical bonding and / or physical mixing of any of the materials in (a) and (b).

13. The preparation method according to claim 12, characterized in that: The functional additive is selected from any one or more of halogen compounds, lead compounds, bismuth compounds, boron compounds, vanadates, molybdates, tungstates and combinations thereof.

14. The preparation method according to claim 12, characterized in that: The molar ratio of the functional additive to the fluorescent nanocrystal precursor is 0.1:1 to 10:

1.

15. The preparation method according to claim 12, characterized in that: The mesoporous material is made of a ceramic material precursor, and the ceramic material precursor is selected from any one or more of silicon-containing compounds, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, zinc-containing compounds, tin-containing compounds, nickel-containing compounds, lead-containing compounds, cobalt-containing compounds, cerium-containing compounds, chromium-containing compounds and indium-containing compounds.

16. The preparation method according to claim 15, characterized in that: The steps of preparing the mesoporous material include: mixing the ceramic material precursor with a surfactant, hydrolyzing for a predetermined time, centrifuging to obtain a precipitate, and sequentially drying and calcining for a predetermined time under a predetermined temperature condition to obtain the mesoporous material.

17. The preparation method according to claim 12, characterized in that: The fluorescent nanocrystal precursor includes one or more of an AX precursor, a BX2 precursor, and a B′X2 precursor, wherein A is Li, Na, K, Rb or Cs, B′ and B are different and each is independently Ge, Sn, Pb, Cu, Mn, Ca, Sr or Ba, and X is F, Cl, Br or I.

18. The preparation method according to claim 12, characterized in that: The fluorescent nanocrystal precursor comprises a cationic precursor and an anionic precursor in a molar ratio of 1:1, wherein the cationic precursor is used to provide a cationic D i+ , wherein i is an integer of 1 to 10, and the cation precursor is selected from the oxides, nitrides, phosphides, sulfides, selenides, hydrochlorides, acetates, carbonates, sulfates, phosphates, nitrates and hydrates thereof of the following elements: Zn, Cd, Hg, Al, Ga, In elements; the anion precursor is used to provide anions Y n- , wherein n is an integer of 1 to 10, and the anion precursor is selected from the following elements and inorganic salts: S, Se, Te, N, P, As, Sb.

19. The preparation method according to claim 12, characterized in that: The particle size of the mesoporous microspheres is 20 nm to 20 μm, and the pore size is 2 nm to 50 nm.

20. The preparation method according to claim 12, characterized in that: The predetermined temperature is 300° C. to 1600° C., and the predetermined time is 1 minute to 600 minutes.

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