Method for preparing fluorescent powder by adopting solution method

Abstract

The invention discloses a method for preparing fluorescent powder by adopting a solution method, and belongs to the technical field of fluorescent powder. The fluorescent powder is prepared by adopting a solution method process, and the method comprises the following steps: 1) adding an organic fluorinated metal salt, a perovskite type material and a divalent metal salt into a polar organic solvent, and fully stirring at a certain temperature to obtain a clear and transparent solution A; 2) adding a certain amount of porous material into the solution, and fully stirring at a certain temperature to obtain a clear and transparent solution B; 3) adding a certain amount of the solution B into the non-polar solution, fully stirring, centrifuging, and subsequently cleaning with the non-polar solution to obtain powder C; and 4) heating a certain amount of C in vacuum for a certain time to obtain fluorescent powder D. By adding the porous material, the nucleation growth of the perovskite is limited in a way that pore gaps of the porous material limit the growth of perovskite crystals, so that a smaller size is obtained; the characteristics of fluorescence intensity, fluorescence stability and the like of the fluorescent powder are enhanced through the proportion of the divalent salt ions doped in the precursor solution.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent powders, and in particular relates to a solution method for preparing fluorescent powders. Background Art

[0002] Phosphor is a luminescent material that can convert external energy into visible light. It is an important supporting material in the field of lighting and display. It is an extremely important material in today's life. As the world pays more attention to energy consumption and environmental impact, traditional lighting materials are gradually being eliminated and replaced by efficient and environmentally friendly alternatives. As an important component of LED lighting and display devices, phosphor can effectively improve light efficiency, reduce energy consumption, and achieve higher color rendering quality.

[0003] At present, most of the preparation of phosphors in industry adopts high-temperature solid-phase method, but this method has high reaction temperature, long reaction time, serious agglomeration phenomenon, and it is difficult to obtain phosphors with small particle size and good dispersibility. In addition, the product after calcination is seriously agglomerated and needs mechanical grinding, which leads to crystal defects of phosphor grains, increases non-radiative luminescent centers, and may also form an amorphous non-luminescent film on the surface of the crystal, which greatly reduces the luminous efficiency of the phosphor. Some phosphors may experience photobleaching and degradation under high temperature, humidity or long-term irradiation, reducing their service life. In addition, the high cost of raw materials and complex preparation process also limit the commercial application of phosphors. In order to overcome these defects, researchers are committed to developing more efficient and environmentally friendly preparation methods to improve the performance and economy of phosphors. Therefore, more research is needed to solve these problems. It is well known that the synthesis method has a great influence on the physical and chemical properties of phosphors. At present, the commonly used preparation methods are: high-temperature solid-phase method, sol-gel method, microwave radiation method, combustion method, hydrothermal synthesis method, spray pyrolysis method and chemical co-precipitation method. Summary of the invention

[0004] In view of this, it is necessary to provide a method for preparing phosphor to address the above problems.

[0005] The solution method for preparing phosphors according to the present invention has many significant advantages and is a widely used synthesis technology. The method can obtain uniform and controllable particle size, ensuring that the optical properties of the phosphors are optimized. At the same time, by adjusting the reaction conditions, such as temperature, doping ratio and reaction time, the composition and structure of the phosphors can be accurately controlled, thereby improving their fluorescence properties. In addition, the solution method can usually produce products with higher purity because it can effectively reduce the introduction of impurities, and after synthesis, unreacted precursors and by-products can be further removed through steps such as washing and precipitation.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention discloses a method for preparing a phosphor by a solution method, wherein the phosphor can improve its fluorescence characteristics by adjusting the doping ratio of a divalent ion salt; the solution method has the advantages of high efficiency, simplicity, stability, etc. The present invention discloses a method for preparing a phosphor by a solution method, comprising the following steps:

[0008] S1: dissolving an organic fluoride metal salt, a perovskite material, and a divalent metal salt in a polar organic solvent at a molar ratio of X:Y, X:Z, and Y:Z, respectively, to obtain a clear and transparent driving solution; wherein Z controls the doping ratio of the divalent salt ions;

[0009] S2: Take 1 mL of the prepared precursor solution, add an appropriate amount of porous material molecular sieve, and stir at room temperature for at least 1 hour to obtain an intermediate solution;

[0010] S3: Take 4 mL of non-polar solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the non-polar solution, stir for 10 min and centrifuge, discard the supernatant, and wash the precipitate repeatedly with the non-polar solution for 3 times to obtain the initial powder;

[0011] S4: The initial powder prepared in S3 is heated in a vacuum environment at 80-90°C for 6 hours to obtain a phosphor, wherein the vacuum degree is 10 -3 Pa-10 -7 Pa.

[0012] Furthermore, the organic fluorinated metal salt can be a characteristic material such as CF3COOCs, CF3COOK, Eu(CF3COO)3; the perovskite material can be a photoelectric material such as CsPbBr3, CsPbCl3, MAPbBr3; the cation of the divalent metal salt can be Sr 2+ , Mn 2+ 、Cd 2+ , Ca 2+ Etc., cations with a specific energy level structure that can effectively absorb excitation light.

[0013] Furthermore, in S1, 0.3≤X≤0.6, 0.3≤Y≤0.6, and 0≤Z≤0.3.

[0014] Furthermore, the porous material is selected from molecular sieves such as SBA-15, MCM-41, HMS, TUD-1, etc.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention discloses a method for preparing phosphors by a solution method, which has many significant advantages and is expected to become a widely used synthesis technology. The method can obtain a uniform and controllable particle size, ensuring that the optical properties of the phosphors are optimized. At the same time, by adjusting the reaction conditions, such as temperature, doping ratio and reaction time, the composition and structure of the phosphors can be accurately controlled, thereby improving their fluorescence properties. In addition, the solution method can usually produce products with higher purity because it can effectively reduce the introduction of impurities, and after synthesis, unreacted precursors and by-products can be further removed through steps such as washing and precipitation.

[0017] 2. The solution method has strong adaptability and can use a variety of inorganic salts and metal organic compounds as precursors. It is suitable for different types of fluorescent materials, such as rare earth-doped oxides and sulfides. At the same time, the reaction conditions of this method are usually mild, which can reduce energy consumption and reduce the impact on the environment, in line with the concept of green chemistry. Finally, the solution method is easy to achieve large-scale production, suitable for industrial needs, and has a high degree of automation, suitable for application in modern production lines. In summary, the solution method for preparing phosphors is not only flexible in process, but also has the advantages of high efficiency, environmental protection and sustainability, making it an ideal choice for the preparation of phosphors.

[0018] 3. The porous material molecular sieve added during the preparation process can confine the nucleation and growth of perovskite to the pores of the porous material, and limit the growth of perovskite crystals through the pores of the porous material to obtain a smaller size. At the same time, the pore walls of the porous material isolate the air, preventing water and oxygen in the air from contacting the perovskite, preventing the decomposition of the perovskite crystals, and improving the stability of the phosphor.

[0019] 4. The divalent salt ions doped in the present invention usually have specific energy level structures, which can effectively absorb the excitation light. On the one hand, after the doped ions are excited, the electrons transition from the ground state to the excited state. When the electrons fall back to the ground state, they release energy in the form of fluorescence. The proper design of this energy level improves the absorption efficiency of the phosphor at the wavelength of the excitation light, thereby enhancing the light effect. At the same time, the doped ions can effectively reduce the light-induced changes in the material structure, inhibit the formation of defects, reduce fluorescence attenuation, and thus stabilize the crystal structure of the material. On the other hand, the doped ions interact with the crystal structure of the matrix, resulting in changes in the crystal field effect. The crystal field effect can affect the energy level splitting of the ions, thereby changing their optical properties, including the emission wavelength and intensity of fluorescence. Reasonable doping ratios and the selection of appropriate ions can optimize these effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a real picture of the phosphor of the present invention at room temperature;

[0021] Figure 2The present invention is a real picture of the phosphor under the condition of continuous high temperature of 235°C for 2 hours;

[0022] Figure 3 The different Sr prepared by the present invention 2+ Doped phosphor in N2 atmosphere, 455nm, 100mW / cm -2 Stability comparison chart under different conditions;

[0023] Figure 4 The different Sr prepared by the present invention 2+ Doped phosphor in air atmosphere, 455nm, 100mW / cm -2 Stability comparison chart under different conditions;

[0024] Figure 5 The different Sr prepared by the present invention 2+ Spectrum of doped phosphors. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0026] The present invention discloses a method for preparing phosphor by solution method, wherein Sr 2+ Taking doping as an example, the perovskite material is CsPbBr3, the divalent metal salt is SrCO3, the porous material is SBA-15 molecular sieve, DMSO is used as the polar organic solvent, and toluene is used as the non-polar solution, including the following steps:

[0027] Example 1

[0028] A method for preparing phosphor by solution method comprises the following steps:

[0029] S1: Dissolve CF3COOCs, CsPbBr3, and SrCO3 in DMSO solution at a molar ratio of 0.4m:0.4m:0.042m to obtain a precursor solution; at this time, Sr in the precursor solution 2+ The doping amount is 5%;

[0030] S2: Take 1 mL of the prepared precursor solution, add 100 mg of SBA-15 molecular sieve into it, stir at room temperature for 1.5 h, and obtain an intermediate solution;

[0031] S3: Take 4 mL of toluene solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the toluene solution, stir for 10 min, centrifuge at 5000 rpm for 3 min, pour out the supernatant, and wash the precipitate with toluene repeatedly for 3 times to obtain the initial powder;

[0032] S4: The initial powder prepared in S3 was heated in a vacuum environment at 90°C for 6 h to obtain a phosphor (5% Sr 2+ ), vacuum degree <10 -4 Pa.

[0033] Example 2

[0034] A method for preparing phosphor by solution method comprises the following steps:

[0035] S1: Dissolve CF3COOK, CsPbCl3, and CdCO3 in a DMSO solution at a molar ratio of 0.4m:0.4m:0.141m to obtain a precursor solution; at this time, Cd 2+ The doping amount is 15%;

[0036] S2: Take 1 mL of the prepared precursor solution, add 100 mg of MCM-41 molecular sieve into it, stir at room temperature for 1.5 h, and obtain an intermediate solution;

[0037] S3: Take 4 mL of toluene solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the toluene solution, stir for 10 min, centrifuge at 5000 rpm for 3 min, pour out the supernatant, and wash the precipitate with toluene repeatedly for 3 times to obtain the initial powder;

[0038] S4: The initial powder prepared in S3 was heated in a vacuum environment at 90°C for 6 h to obtain a phosphor (15% Cd 2+ ), vacuum degree <10 -4 Pa.

[0039] Example 3

[0040] A method for preparing phosphor by solution method comprises the following steps:

[0041] S1: Dissolve Eu(CF3COO)3, MAPbBr3, and CaCO3 in DMSO solution at a molar ratio of 0.4m:0.4m:0.267m to obtain a precursor solution; at this time, Ca 2+ The doping amount is 25%;

[0042] S2: Take 1 mL of the prepared precursor solution, add 100 mg of HMS molecular sieves into it, stir at room temperature for 1.5 h, and obtain an intermediate solution;

[0043] S3: Take 4 mL of toluene solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the toluene solution, stir for 10 min, centrifuge at 5000 rpm for 3 min, pour out the supernatant, and wash the precipitate with toluene repeatedly for 3 times to obtain the initial powder;

[0044] S4: The initial powder prepared in S3 was heated in a vacuum environment at 90°C for 6 h to obtain a phosphor (25% Ca 2+ ), vacuum degree <10 -4 Pa.

[0045] Comparative Example

[0046] A method for preparing phosphor by solution method comprises the following steps:

[0047] S1: Dissolve CF3COOCs and CsPbBr3 in DMSO solution at a molar ratio of 0.4m:0.4m to obtain a precursor solution without Sr 2+ doping;

[0048] S2: Take 1 mL of the prepared precursor solution, add 100 mg of SBA-15 molecular sieve into it, stir at room temperature for 1.5 h, and obtain an intermediate solution;

[0049] S3: Take 4 mL of toluene solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the toluene solution, stir for 10 min, centrifuge at 5000 rpm for 3 min, pour out the supernatant, and wash the precipitate with toluene repeatedly for 3 times to obtain the initial powder;

[0050] S4: The initial powder prepared in S3 was heated in a vacuum environment at 90°C for 6 h to obtain a phosphor (without Sr 2+ Doping), vacuum degree <10 -4 Pa.

[0051] The different Sr 2+ The fluorescence effect, stability and PL spectrum of the doped phosphors are compared. 2+ Doping has a significant optimizing effect on the fluorescent effect, stability and luminous intensity of the phosphor; compared with the most commonly used high-temperature solid-phase method for synthesizing phosphors, the solution method for synthesizing phosphors of the present invention has milder reaction conditions, low energy consumption, less impact on the environment, is easy to achieve large-scale production, is suitable for industrial needs, and has a high degree of automation, suitable for application in modern production lines.

[0052] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing phosphor by solution method, characterized in that: The following steps are involved: S1: dissolving an organic fluoride metal salt, a perovskite material, and a divalent metal salt in a polar organic solvent at a molar ratio of X:Y, X:Z, and Y:Z, respectively, to obtain a clear and transparent driving solution; S2: Take 1 mL of the prepared precursor solution, add an appropriate amount of porous material molecular sieve, and stir at room temperature for at least 1 hour to obtain an intermediate solution; S3: Take 4 mL of non-polar solution and 200 uL of intermediate solution respectively, add the intermediate solution dropwise into the non-polar solution, stir for 10 min and centrifuge, discard the supernatant, and wash the precipitate repeatedly with the non-polar solution for 3 times to obtain the initial powder; S4: The initial powder prepared in S3 is heated in a vacuum environment at 80-90°C for 6 hours to obtain a phosphor, wherein the vacuum degree is 10 -3 Pa-10 -7 Pa.

2. The method for preparing phosphor by solution method according to claim 1, characterized in that: The organic fluoride metal salts are CF3COOCs, CF3COOK, Eu(CF3COO)3 and other characteristic materials; the perovskite materials are CsPbBr3, CsPbCl3, MAPbBr3 and other photoelectric materials; the cation of the divalent metal salt is Sr 2+ , Mn 2+ 、Cd 2+ , Ca 2+ wait.

3. The method for preparing phosphor by solution method according to claim 1, characterized in that: In S1, 0.3≤X≤0.6, 0.3≤Y≤0.6, and 0≤Z≤0.3.

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