CN-122012090-A - Perovskite composite fluorescent nano material with double-coating structure and preparation method thereof

Abstract

The invention belongs to the technical field of fluorescent nano materials, and particularly relates to a perovskite composite fluorescent nano material with a double-coating structure and a preparation method thereof. The traditional fluorescent conversion material has low quantum yield and insufficient fluorescence stability. Aiming at the problems, the invention provides a perovskite composite fluorescent nanomaterial with a double-coating structure, which is prepared by uniformly dispersing and distributing ABX 3 perovskite nanocrystals in an A 4 BX 6 perovskite crystal to form an ABX 3 -A 4 BX 6 composite perovskite crystal, and densely coating the surface of the ABX 3 -A 4 BX 6 composite perovskite crystal by a shell formed by mesoporous SiO 2 particles. The mesoporous silica (SiO 2 ) shell at the outermost layer forms a compact physical and chemical barrier, can effectively isolate the contact between the internal perovskite crystal and moisture and oxygen in the external environment, and greatly inhibits the luminescence quenching and structural degradation of the perovskite material caused by deliquescence and oxidation. The ABX 3 nanocrystalline is uniformly limited in the A 4 BX 6 matrix lattice with more stable chemical property and wide band gap, so that the unification of high luminous performance and high stability is realized.

Inventors

• BAO ZHEN
• ZHAO KAI
• PAN YUXIN
• WU ZHANPENG
• CHENG MEILING
• LIU QI

Assignees

• 常州大学

Dates

Publication Date

20260512

Application Date

20260120

Claims (10)

1. 1. A perovskite composite fluorescent nano material with a double-coating structure is characterized by having a structural general formula of ABX 3 -A 4 BX 6 @SiO 2 , wherein A is one or two of Cs + 、Rb + , B is one or two of Pb 2+ 、Sn 2+ , X is one or more than two of Cl - 、Br - 、I - , ABX 3 serving as a luminescence center is a perovskite nanocrystal, and ABX 3 -A 4 BX 6 @SiO 2 is a perovskite composite fluorescent nano material formed by uniformly dispersing and distributing ABX 3 perovskite nanocrystals in A 4 BX 6 perovskite crystals, and the surface of the ABX 3 -A 4 BX 6 perovskite crystals is densely coated by a shell formed by mesoporous SiO 2 particles.
2. 2. A double-coated perovskite composite fluorescent nanomaterial according to claim 1, wherein ABX 3 perovskite nanocrystals have a particle size of no more than 50 nm.
3. 3. A double-coated perovskite composite fluorescent nanomaterial according to claim 1, wherein the particle size of the ABX 3 -A 4 BX 6 composite perovskite crystals is greater than ABX 3 perovskite nanocrystals and no more than 10 μm.
4. 4. The double-coated perovskite composite fluorescent nanomaterial of claim 1, wherein the ABX 3 -A 4 BX 6 @SiO 2 perovskite composite fluorescent nanomaterial has a particle size greater than ABX 3 -A 4 BX 6 composite perovskite crystals and no greater than 100 μm.
5. 5. The perovskite composite fluorescent nanomaterial with a double coating structure according to claim 1, wherein mesoporous SiO 2 particles have a size ranging from 50nm to 100 μm.
6. 6. The perovskite composite fluorescent nanomaterial with double coating structure according to any one of claims 1 to 5, wherein the preparation method comprises the following steps: (1) According to the stoichiometric number, respectively weighing metal halides corresponding to A, B in ABX 3 -A 4 BX 6 , mixing and grinding uniformly to obtain mixed powder; (2) Uniformly mixing the mixed powder with mesoporous SiO 2 particles, sintering at high temperature, and cooling to room temperature to obtain sintered powder; (3) And washing, drying and grinding the sintered powder in sequence to obtain the perovskite composite fluorescent nano material with the double-coating structure.
7. 7. The double-coated perovskite composite fluorescent nanomaterial according to claim 6, wherein the mass ratio of the mixed powder to the mesoporous SiO 2 particles in the step (2) is 1:4.
8. 8. The perovskite composite fluorescent nanomaterial with a double-coating structure according to claim 6, wherein the high-temperature sintering and heat preservation time is 0.1-12 h.
9. 9. The double-coated perovskite composite fluorescent nanomaterial of claim 6, wherein ABX 3 -A 4 BX 6 is at least one of CsPbBr 3 /Cs 4 PbBr 6 、CsPbCl 1.5 Br 1.5 /Cs 4 PbCl 3 Br 3 、CsPbI 1.5 Br 1.5 /Cs 4 PbI 3 Br 3 、Cs 0.5 Rb 0.5 PbBr 3 /Cs 2 Rb 2 PbBr 6 .
10. 10. An optical display screen, characterized in that the perovskite composite fluorescent nanomaterial with a double-coating structure as claimed in any one of claims 1 to 5 is adopted as a fluorescent color conversion material for the display screen.

Description

Perovskite composite fluorescent nano material with double-coating structure and preparation method thereof Technical Field The invention belongs to the technical field of fluorescent nano materials, and particularly relates to a perovskite composite fluorescent nano material with a double-coating structure and a preparation method thereof. Background With the rapid development of display technology, high resolution, high color gamut and high stability have been the core pursuit of the high-end display field. The front edge technology of Mini/Micro LED, flexible display, laser display and the like has strict requirements on fluorescent color conversion materials, namely the fluorescent color conversion materials are required to have high fluorescence quantum yield and narrow emission half-peak width so as to realize accurate color reduction, a wide color gamut is required to be covered so as to meet the extremely perception requirement of human eyes on color, and meanwhile, the materials are required to keep environmental stability, thermal stability and mechanical reliability in the long-term use process so as to cope with challenges of complex application scenes. However, the traditional fluorescent conversion material has obvious performance short plates, namely rare earth fluorescent powder has limited color gamut coverage and low quantum yield due to the limitation of a crystal structure, and the quantum dot material has tunable luminescence characteristics, but the traditional Cd quantum dot contains heavy metal elements, so that the environment pollution risk exists, and the stability is insufficient due to the fact that a surface ligand is easy to fall off, so that the requirement of high-end display on the reliability of the material is difficult to meet. Metal halide perovskite materials are rapidly becoming a research hotspot as a new generation of fluorescent materials by virtue of their unique optical properties. The luminous wavelength can be continuously adjustable from ultraviolet to near infrared by regulating and controlling the composition of halogen anions (Cl-, br-, I-), the half-peak width of an emission peak can be as narrow as below 20 nm, the color purity is obviously superior to that of the traditional fluorescent material, and the high-end display color gamut standard such as Rec 2020 and the like can be completely covered theoretically. In addition, the perovskite material has a fluorescence quantum yield of nearly 100%, can be prepared by a solution method at low cost, has great application potential in the fields of display, illumination, photoelectric detection and the like, and is regarded as a core candidate of a next-generation fluorescence color conversion material. While perovskite materials have significant advantages in optical properties, their inherent drawbacks severely limit their use in large scale applications. Firstly, in the traditional ABX 3 perovskite crystal structure, the binding force between cations and halogen anions is weak, so that the material is highly sensitive to water vapor and oxygen, the water vapor is easy to invade the inside of the crystal to cause hydrolysis reaction, the lattice structure is destroyed, the fluorescence intensity is quickly attenuated, and the oxygen accelerates the oxidative degradation of the crystal surface, so that the service life of the material is obviously shortened. Secondly, perovskite nanocrystals are susceptible to migration and diffusion of metal cations (such as Pb 2+) and halogen anions during preparation and use, resulting in unbalanced stoichiometric ratio of luminescent centers, thereby causing luminescence wavelength shift and color purity reduction. The stability problem is the first technical bottleneck of the perovskite material from laboratory research to practical industrial application, and needs to be solved through material design and process optimization. Disclosure of Invention The problems in the prior art are that the quantum yield of the traditional fluorescent conversion material is low and the fluorescence stability is insufficient. Aiming at the problems, the invention provides a perovskite composite fluorescent nanomaterial with a double-coating structure, which has a structural general formula of ABX 3-A4BX6@SiO2, wherein A is one or two of Cs +、Rb+, B is one or two of Pb 2+、Sn2+, X is one or more than two elements of Cl -、Br-、I-, ABX 3 serving as a luminescence center is perovskite nanocrystals, and ABX 3-A4BX6@SiO2 is a perovskite composite fluorescent nanomaterial obtained by densely coating the surface of ABX 3-A4BX6 composite perovskite crystals formed by uniformly dispersing and distributing the ABX 3 perovskite nanocrystals in A 4BX6 perovskite crystals by a shell formed by mesoporous SiO 2 particles. Preferably, the ABX 3 perovskite nanocrystals have a particle size of no more than 50: 50 nm. Preferably, the particle size of the ABX 3-A4BX6 composite perovskite crystals is greater