High-temperature-resistant rare earth luminescent material and preparation method thereof

Abstract

This invention discloses a high-temperature resistant rare-earth luminescent material and its preparation method, belonging to the technical field of rare-earth luminescent materials. Its general chemical formula is: Sr 1‑a‑b‑0.5x Mg a Al 2‑(x+y) Si x B y O4:Eu 2+ b Where 0.03≤a≤0.12, 0.02≤b≤0.08, 0.002≤x≤0.01, 0.002≤y≤0.008; its preparation adopts a sol-gel method combined with a segmented high-temperature calcination process, finally obtaining a high-temperature resistant rare-earth luminescent material. This invention utilizes Si 4+ and B 3+ Collaborative replacement of AI 3+ Lattice sites were introduced, and Sr vacancies were used for charge compensation in Eu. 2+ The surrounding structure is a high-rigidity, low-defect local structure, which solves the technical problem that existing rare earth luminescent materials are prone to thermal quenching and significant decrease in luminescence intensity at high temperatures, and significantly improves the thermal stability and high-temperature luminescence performance of the material.

Description

Technical Field

[0001] This invention belongs to the field of rare earth luminescent materials technology, specifically relating to a high-temperature resistant rare earth luminescent material and its preparation method. Background Technology

[0002] Rare earth luminescent materials are widely used in fluorescent lamps, LEDs, and displays due to their high luminous efficiency, high color purity, and long lifespan. However, existing rare earth luminescent materials, especially commonly used aluminate, silicate, nitride, and oxide-based luminescent materials, generally exhibit "thermal quenching" under high-temperature conditions. This means that as the temperature increases, their luminous intensity decreases significantly, their emission spectrum undergoes a redshift or blueshift, and their color coordinates drift. This leads to a decrease in the luminous efficiency of lighting devices, unstable color temperature, and a shortened lifespan. The fundamental reason for this is that high temperatures intensify the lattice vibrations of rare earth ions, triggering nonradiative transitions. At the same time, internal defects in the material (such as oxygen vacancies) become energy dissipation centers at high temperatures, accelerating luminous decay.

[0003] In the existing technology, heat resistance is mainly improved by doping inert matrix or coating the surface with silicon dioxide, but such methods have obvious defects: (1) Simple physical mixing or coating makes it difficult to achieve chemical synergy between components, resulting in poor interface stability at high temperature; (2) Inert matrix may hinder the energy transfer of rare earth ions and reduce luminescence efficiency; (3) Conventional preparation processes (such as solid-state method) require high-temperature sintering, which can easily lead to abnormal grain growth and exacerbate thermal quenching.

[0004] Therefore, there is an urgent need to develop a rare earth luminescent material with intrinsic high heat resistance, stable luminescence at high temperatures, and high efficiency. Summary of the Invention

[0005] Given the significant thermal quenching effect of existing rare-earth luminescent materials, especially aluminate phosphors used in high-power LEDs, leading to decreased luminous efficiency and stability at high temperatures, this invention provides a high-temperature resistant rare-earth luminescent material and its preparation method. The core innovation of this invention lies in: designing a specific ratio of Si... 4+ and B 3+ The collaborative part replaces AI 3+ The invention utilizes lattice sites and introduces Sr vacancies for charge compensation, achieving atomic-level lattice stabilization through "rigidity enhancement, stress coordination, and defect repair" during high-temperature calcination. Simultaneously, the invention employs a sol-gel preparation process to form a uniform and controllable precursor network at the molecular scale, followed by segmented temperature and atmosphere-controlled calcination to simultaneously complete the Eu process. 3+ The precise construction of efficient reduction and synergistic substitution structures fundamentally suppresses lattice relaxation and luminescence quenching at high temperatures, significantly improving the thermal stability and high-temperature luminescence performance of the material.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a high-temperature resistant rare-earth luminescent material with the general chemical formula: Sr 1-a-b-0.5x Mg a Al 2-(x+y) Si x B y O4:Eu 2+ b , where a, b, x, and y represent the molar number of the corresponding ions, satisfying: 0.03≤a≤0.12, 0.02≤b≤0.08, 0.002≤x≤0.01, 0.002≤y≤0.008.

[0008] Furthermore, the Sr, Mg, Al, and Eu elements are derived from strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate, respectively; the B element is derived from boric acid; and the Si element is derived from tetraethyl orthosilicate.

[0009] This invention also provides a method for preparing a high-temperature resistant rare-earth luminescent material, comprising the following steps:

[0010] S1. Preparation of precursor solution: Accurately weigh strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, and tetraethyl orthosilicate as raw materials according to the molar ratio of the general chemical formula. Dissolve strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate in deionized water to obtain a mixed solution. Then add citric acid as a complexing agent. The molar ratio of citric acid to total metal ions is 1.5:1. Stir until completely dissolved to obtain solution A.

[0011] S2. Preparation and aging of sol: Under continuous stirring, solution A was transferred to a constant temperature water bath and the temperature was maintained at 60-70℃. Then, tetraethyl orthosilicate and boric acid solutions were slowly added dropwise. After the addition was completed, the pH of the system was adjusted to 3.5 with dilute ammonia. Under these conditions, tetraethyl orthosilicate and boric acid underwent controlled hydrolysis and condensation reaction with metal ions complexed with citric acid. After continuous stirring for 4-6 hours, a homogeneous and transparent sol was obtained.

[0012] S3. Gelation and drying: Pour the sol obtained in step S2 into an open petri dish and let it stand at 60-80℃ for 24-48 hours to allow it to slowly evaporate and complete the gelation process, obtaining a wet gel. Then, place the wet gel in a forced-air drying oven, program the temperature to 120℃, and maintain it for 24 hours to completely remove moisture and most of the organic matter, obtaining a fluffy and porous dry gel precursor.

[0013] S4. Segmented High-Temperature Calcination: The dry gel precursor is placed in an alumina crucible and then placed in a high-temperature tube furnace. It is first pre-calcined in air at 550-650℃ for 3-4 hours to remove residual organic components and initially form a crystal structure, obtaining the pre-calcined product. Then, under a reducing atmosphere, the pre-calcined product is heated to 1350-1450℃ at a programmed heating rate of 3-5℃ / min and held at this temperature for 5-7 hours. During the high-temperature solid-phase process, the reducing atmosphere releases rare earth ions (Eu). 3+ Restored to its effective luminescent valence state Eu 2+ At the same time, high temperature drives Si 4+ and B 3+ Diffusion and co-entry into Al 3+ Lattice sites, Si 4+ The substitution of B enhances lattice rigidity and induces Sr vacancies to achieve charge compensation, while B 3+ The substitution of ions harmonizes lattice stress and fills voids, with all three working synergistically at the luminescent center Eu. 2+ The surrounding structure forms a localized structure with high rigidity, low defects, and charge balance. This structure significantly suppresses lattice vibrations at high temperatures, thereby increasing the thermal quenching temperature of the material.

[0014] S5. Post-processing: After calcination, the product is naturally cooled to room temperature. The calcined product is then taken out, lightly ground and sieved. Afterward, it is washed multiple times with anhydrous ethanol and deionized water to remove surface impurities and unreacted raw materials. Finally, it is dried at 100°C to obtain the high-temperature resistant rare earth luminescent material.

[0015] Furthermore, the boric acid solution mentioned in step S2 refers to boric acid dissolved in deionized water, wherein the mass-to-volume ratio of boric acid to deionized water is 1g:8mL.

[0016] Further, the reducing atmosphere in step S4 is an N2 / H2 mixture, wherein the volume fraction of H2 is 5%-10%.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] (1) This invention fundamentally improves the thermal stability of materials through a "synergistic lattice substitution" strengthening mechanism. This invention does not involve a simple functional superposition of known ions, but rather creatively integrates Si... 4+ and B 3+ As a structural unit, the matrix is ​​modified at the atomic level, wherein Si 4+ The substitution of ions enhances lattice rigidity and induces the formation of Sr vacancies to balance the charge. This cation vacancy compensation mechanism exhibits extremely high thermodynamic stability under reducing atmospheres, avoiding the problem of interstitial oxygen easily escaping at high temperatures; while B 3+The substitution of ions harmonizes lattice stress and fills defects. The synergistic effect of these three factors creates a highly rigid, low-defect local microenvironment around the luminescent center Eu²⁺, effectively suppressing defects caused by heterovalent substitution, making the overall lattice more stable, and significantly increasing the thermal quenching temperature of the material.

[0019] (2) This invention employs a sol-gel preparation method precisely matched to the structural design, ensuring component uniformity and structural controllability. This invention abandons traditional solid-phase methods or co-precipitation methods that easily lead to component segregation, opting instead for the sol-gel method. This method enables all raw materials to achieve uniform mixing at the molecular / atomic level in solution, resulting in a dry gel precursor with extremely high chemical homogeneity. This facilitates the subsequent high-temperature calcination process of Si... 4+ and B 3+ It can diffuse uniformly and collaboratively into the predetermined Al 3+ Lattice sites provide the perfect premise, solving the problem of precise control over the microstructure of multi-component functional materials.

[0020] (3) The "segmented temperature and atmosphere controlled" high-temperature calcination and post-treatment process of this invention is a key guarantee for achieving high-performance materials. Low-temperature pre-calcination in an air atmosphere thoroughly removes organic matter and initiates initial crystallization, avoiding carbon pollution that may result from direct high-temperature reduction; subsequently, long-term high-temperature calcination is carried out in a precisely controlled N2 / H2 reducing atmosphere, which not only achieves Eu... 3 + Towards efficient luminescent valence state Eu 2+ The reduction process provides the necessary environmental conditions for the formation of Sr vacancies, simultaneously activating luminescent centers, optimizing the crystal structure, and repairing defects. Subsequent processing removes surface impurities and reduces the surface defect state density. The synergistic effect of the entire process results in a material that not only possesses excellent high-temperature luminescence performance but also exhibits superior anti-aging properties and environmental stability, meeting the requirements for long-term use under harsh conditions. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0022] Figure 1 The X-ray diffraction pattern of the high-temperature resistant rare-earth luminescent material prepared in Example 2 of the present invention;

[0023] Figure 2 The emission spectrum of the high-temperature resistant rare earth luminescent material prepared in Example 2 of the present invention is shown. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0026] The materials used in the following implementations, including strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, tetraethyl orthosilicate, and other materials unless otherwise specified, are all new materials purchased from the market.

[0027] Example 1: This example provides a high-temperature resistant rare-earth luminescent material with the general chemical formula: Sr 1-a-b- 0.5x Mg a Al 2-(x+y) Si x B y O4:Eu 2+ b Where a, b, x, and y represent the molar number of the corresponding ions, in this embodiment a = 0.03, b = 0.05, x = 0.002, and y = 0.002, i.e., the general chemical formula is: Sr 0.919 Mg 0.03 Al 1.996 Si 0.002 B 0.002 O4:Eu 2+ 0.05 .

[0028] This invention also provides a method for preparing a high-temperature resistant rare-earth luminescent material, comprising the following steps:

[0029] S1. Preparation of precursor solution: According to the molar ratio of the general chemical formula, accurately weigh strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, and tetraethyl orthosilicate as raw materials. Dissolve the calculated amounts of strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate in an appropriate amount of deionized water to obtain a mixed solution. Then add citric acid as a complexing agent. The molar ratio of citric acid to total metal ions is 1.5:1. Stir until completely dissolved to obtain solution A.

[0030] S2. Preparation and aging of sol: Under continuous stirring, solution A was transferred to a constant temperature water bath and the temperature was maintained at 60℃. Then, tetraethyl orthosilicate and boric acid solution were slowly added dropwise. After the addition was completed, the pH value of the system was adjusted to 3.5 with dilute ammonia water and stirred continuously for 6 hours to obtain a homogeneous and transparent sol.

[0031] S3. Gelation and drying: Pour the sol obtained in step S2 into an open petri dish and let it stand at 60°C for 48 hours to allow it to slowly evaporate and complete the gelation process, resulting in a wet gel. Then, place the wet gel in a forced-air drying oven, program the temperature to 120°C, and maintain it for 24 hours to obtain a fluffy and porous dry gel precursor.

[0032] S4. Segmented high-temperature calcination: The dry gel precursor is placed in an alumina crucible and then placed in a high-temperature tube furnace. It is first pre-calcined in air at 550°C for 4 hours to obtain the pre-calcined product. Then, the pre-calcined product is heated to 1350°C at a heating rate of 3°C / min under the protection of a N2 / H2 mixed reducing atmosphere (H2 volume fraction is 5%), and held at this temperature for 7 hours.

[0033] S5. Post-processing: After calcination, the product is naturally cooled to room temperature. The calcined product is then taken out, lightly ground and sieved. It is then washed three times alternately with anhydrous ethanol and deionized water, and finally dried at 100°C to obtain the high-temperature resistant rare earth luminescent material.

[0034] Example 2: This example provides a high-temperature resistant rare-earth luminescent material with the general chemical formula: Sr 1-a-b- 0.5x Mg a Al 2-(x+y) Si x B y O4:Eu 2+ b Where a, b, x, and y represent the molar number of the corresponding ions, in this embodiment a = 0.07, b = 0.06, x = 0.006, and y = 0.005, i.e., the general chemical formula is: Sr 0.8345 Mg 0.07 Al 1.989 Si 0.006 B 0.005 O4:Eu 2+ 0.06 .

[0035] This invention also provides a method for preparing a high-temperature resistant rare-earth luminescent material, comprising the following steps:

[0036] S1. Preparation of precursor solution: Accurately weigh strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, and tetraethyl orthosilicate as raw materials according to the molar ratio of the general chemical formula. Dissolve the calculated amounts of strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate in an appropriate amount of deionized water to obtain a mixed solution. Then add citric acid as a complexing agent. The molar ratio of citric acid to total metal ions is 1.5:1. Stir until completely dissolved to obtain solution A.

[0037] S2. Preparation and aging of sol: Under continuous stirring, solution A was transferred to a constant temperature water bath and the temperature was maintained at 65°C. Then, tetraethyl orthosilicate and boric acid solution were slowly added dropwise. After the addition was completed, the pH value of the system was adjusted to 3.5 with dilute ammonia water and stirred continuously for 5 hours to obtain a homogeneous and transparent sol.

[0038] S3. Gelation and drying: Pour the sol obtained in step S2 into an open petri dish and let it stand at 70°C for 36 hours to allow it to slowly evaporate and complete the gelation process, resulting in a wet gel. Then, place the wet gel in a forced-air drying oven, program the temperature to 120°C, and maintain it for 24 hours to obtain a fluffy and porous dry gel precursor.

[0039] S4. Segmented high-temperature calcination: The dry gel precursor is placed in an alumina crucible and then placed in a high-temperature tube furnace. It is first pre-calcined in air at 600°C for 3.5 hours to obtain the pre-calcined product. Then, the pre-calcined product is heated to 1400°C at a heating rate of 4°C / min under the protection of a N2 / H2 mixed reducing atmosphere (H2 volume fraction of 7%), and held at this temperature for 6 hours.

[0040] S5. Post-processing: After calcination, the product is naturally cooled to room temperature. The calcined product is then taken out, lightly ground and sieved. It is then washed three times alternately with anhydrous ethanol and deionized water, and finally dried at 100°C to obtain the high-temperature resistant rare earth luminescent material.

[0041] Example 3: This example provides a high-temperature resistant rare-earth luminescent material with the general chemical formula: Sr 1-a-b- 0.5x Mg a Al 2-(x+y) Si x B y O4:Eu 2+ b Where a, b, x, and y represent the molar number of the corresponding ions, in this embodiment a = 0.12, b = 0.08, x = 0.01, and y = 0.008, i.e., the general chemical formula is: Sr 0.795 Mg 0.12 Al 1.982 Si 0.01 B0.008 O4:Eu 2+ 0.08 .

[0042] This invention also provides a method for preparing a high-temperature resistant rare-earth luminescent material, comprising the following steps:

[0043] S1. Preparation of precursor solution: Accurately weigh strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, and tetraethyl orthosilicate as raw materials according to the molar ratio of the general chemical formula. Dissolve the calculated amounts of strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate in an appropriate amount of deionized water to obtain a mixed solution. Then add citric acid as a complexing agent. The molar ratio of citric acid to total metal ions is 1.5:1. Stir until completely dissolved to obtain solution A.

[0044] S2. Preparation and aging of sol: Under continuous stirring, solution A was transferred to a constant temperature water bath and the temperature was maintained at 70°C. Then, tetraethyl orthosilicate and boric acid solution were slowly added dropwise. After the addition was completed, the pH value of the system was adjusted to 3.5 with dilute ammonia water and stirred continuously for 4 hours to obtain a homogeneous and transparent sol.

[0045] S3. Gelation and drying: Pour the sol obtained in step S2 into an open petri dish and let it stand at 80°C for 24 hours to allow it to slowly evaporate and complete the gelation process, resulting in a wet gel. Then, place the wet gel in a forced-air drying oven, program the temperature to 120°C, and maintain it for 24 hours to obtain a fluffy and porous dry gel precursor.

[0046] S4. Segmented high-temperature calcination: The dry gel precursor is placed in an alumina crucible and then placed in a high-temperature tube furnace. It is first pre-calcined in air at 650°C for 3 hours to obtain a pre-calcined product. Then, the pre-calcined product is heated to 1450°C at a heating rate of 5°C / min under the protection of a N2 / H2 mixed reducing atmosphere (H2 volume fraction of 10%), and held at this temperature for 7 hours.

[0047] S5. Post-processing: After calcination, the product is naturally cooled to room temperature. The calcined product is then taken out, lightly ground and sieved. It is then washed three times alternately with anhydrous ethanol and deionized water, and finally dried at 100°C to obtain the high-temperature resistant rare earth luminescent material.

[0048] Comparative Example 1: This comparative example provides a rare-earth luminescent material with the general chemical formula: Sr 0.87 Mg 0.07 Al2O4:Eu 2 + 0.06That is, no Si and B elements are introduced; its preparation method is basically the same as that in Example 2, except that tetraethyl orthosilicate and boric acid are not added in steps S1 and S2, and the remaining raw materials and amounts are adjusted proportionally.

[0049] Comparative Example 2: This comparative example provides a rare-earth luminescent material with the general chemical formula: Sr 0.867 Mg 0.07 Al 1.994 B 0.006 O4:Eu 2+ 0.06 That is, no Si element is introduced; its preparation method is basically the same as that in Example 2, except that: tetraethyl orthosilicate is not added in steps S1 and S2, and the remaining raw materials and amounts are adjusted proportionally.

[0050] Comparative Example 3: This comparative example provides a rare-earth luminescent material with the general chemical formula: Sr 0.864 Mg 0.07 Al 1.994 Si 0.006 O4:Eu 2+ 0.06 That is, without the introduction of element B, its preparation method is basically the same as that of Example 2, except that boric acid is not added in steps S1 and S2, and the remaining raw materials and amounts are adjusted proportionally.

[0051] To verify the effectiveness of the present invention, the luminescent materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests:

[0052] Crystal structure analysis: X-ray diffraction was used to test the phase structure of the samples. The results showed that all samples were in the expected SrA₂O₄ phase. Fine-tuning of the lattice parameters due to Si and B doping was observed in the example samples, proving that the dopant ions successfully entered the crystal lattice. Figure 1 The X-ray diffraction pattern of Example 2 is shown.

[0053] Luminescence performance testing: The excitation and emission spectra of the samples were tested using a fluorescence spectrophotometer, wherein the emission spectrum of Example 2 is as follows. Figure 2 As shown. All the sample examples emitted bright green light under near-ultraviolet light excitation, with the emission peak located at 545 nm, corresponding to Eu. 2+ 4f 6 5d 1 →4f 7 The transition indicates that changes in Si and B doping, as well as the doping ratio, did not alter the Eu level. 2+ The luminescent center energy level ensures that the material has good luminescent color purity.

[0054] Thermal stability test: The change in luminescence intensity of the sample within the range of room temperature (25℃) to 200℃ was tested using a fluorescence spectrometer equipped with a heating stage. The thermal quenching temperature (the temperature at which the luminescence intensity drops to half of the room temperature, T½) was calculated. The test results are shown in the table below:

[0055] Table 1 Thermal stability test results

[0056]

[0057] As can be seen from the data in Table 1, the luminescent materials prepared in Examples 1-3 have significantly higher thermal quenching temperatures than those in Comparative Examples 1-3. Example 2 (optimal doping ratio) achieved a thermal quenching temperature of 192℃ and maintained 82% of its luminescence intensity at 150℃, demonstrating excellent high-temperature resistance. The thermal stability of Comparative Examples 1 (lacking Si and B), 2 (lacking Si), and 2 (lacking B) decreased significantly, proving that Si... 4 The synergistic doping of ⁺ and B³⁺ plays a crucial role in constructing a high-rigidity, low-defect lattice environment, thereby suppressing thermal quenching. In summary, this invention utilizes precisely designed Si… 4+ and B 3+ By employing a synergistic co-doping strategy and combining the advantages of uniform mixing in the sol-gel method, a high-temperature resistant rare-earth luminescent material with excellent thermal stability was successfully prepared.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0059] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-temperature resistant rare-earth luminescent material, characterized in that, Its general chemical formula is: Sr 1-a-b-0.5x Mg a Al 2-(x+y) Si x B y O4:Eu 2+ b Where a, b, x, and y represent the molar number of the corresponding ions, satisfying: 0.03≤a≤0.12, 0.02≤b≤0.08, 0.002≤x≤0.01, 0.002≤y≤0.008; the elements Sr, Mg, Al, and Eu in the chemical formula are derived from strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate; the element B in the chemical formula is derived from boric acid; and the element Si in the chemical formula is derived from tetraethyl orthosilicate.

2. A method for preparing a high-temperature resistant rare-earth luminescent material according to claim 1, characterized in that, Includes the following steps: S1. Preparation of precursor solution: Weigh strontium nitrate, magnesium nitrate, aluminum nitrate, europium nitrate, boric acid, and tetraethyl orthosilicate as raw materials. Dissolve strontium nitrate, magnesium nitrate, aluminum nitrate, and europium nitrate in deionized water to obtain a mixed solution. Then add citric acid to the solution and stir until completely dissolved to obtain solution A. S2. Preparation and aging of sol: Tetraethyl orthosilicate and boric acid solution were slowly added dropwise to solution A. After the addition was completed, the pH of the system was adjusted to 3.5 with dilute ammonia. Under these conditions, tetraethyl orthosilicate and boric acid hydrolyzed and then underwent a condensation reaction with the metal ions complexed with citric acid. The sol was then obtained by continuous stirring. S3. Gelation and drying: The sol obtained in step S2 is allowed to stand to complete the gelation, resulting in a wet gel. Subsequently, the wet gel is dried to obtain a dry gel precursor. S4. Segmented High-Temperature Calcination: The dry gel is first pre-calcined in air at 550-650℃ to obtain a pre-calcined product. Then, the pre-calcined product is calcined at 1350-1450℃ under a reducing atmosphere. During this high-temperature solid-state process, the reducing atmosphere releases rare earth ions (Eu). 3+ Restored to its effective luminescent valence state Eu 2+ At the same time, high temperature drives Si 4+ and B 3+ Diffusion and co-entry into Al 3+ Lattice sites induce the generation of Sr vacancies for charge compensation; S5. Post-processing: After calcination, the product is naturally cooled to room temperature. The calcined product is then removed, lightly ground, sieved, washed, and dried to obtain the high-temperature resistant rare earth luminescent material.

3. The method for preparing a high-temperature resistant rare-earth luminescent material according to claim 2, characterized in that, The molar ratio of citric acid to total metal ions in step S1 is 1.5:

1.

4. The method for preparing a high-temperature resistant rare-earth luminescent material according to claim 2, characterized in that, The boric acid solution mentioned in step S2 refers to boric acid dissolved in deionized water, wherein the mass-volume ratio of boric acid to deionized water is 1g:8mL.

5. The method for preparing a high-temperature resistant rare-earth luminescent material according to claim 2, characterized in that, The reducing atmosphere described in step S4 is a N2 / H2 mixture, wherein the volume fraction of H2 is 5%-10%.

Images