A luminescent material of superfine rare earth doped divalent metal phosphate, a manufacturing method and a luminescent device

Abstract

This invention relates to the field of luminescent materials technology, and discloses an ultrafine rare-earth-doped divalent metal phosphate luminescent material, its manufacturing method, and a luminescent device. The preparation method includes the following steps: S1, preparing Eu 3+ The process involves: S1) Doping barium zinc phosphate luminescent material and grinding it into luminescent particles; S2) Preparing an aluminum sol; S3) Slowly adding the pretreated luminescent material powder into the aluminum sol, allowing the sol particles to be uniformly adsorbed onto the surface of the luminescent material to form composite particles with an Al2O3 coating; S4) Continuing to stir or allow the sol layer coated on the surface of the luminescent material to undergo further hydrolysis and condensation reactions to form a wet gel layer; S5) Drying the wet gel layer and then placing it in a muffle furnace for low-temperature heat treatment to form discontinuous pores. This application enhances the vibration resistance and broadens the divergence angle of the luminescent material by forming a discontinuous porous structure between the core and shell, thereby improving the service life of the luminescent material and expanding its application range.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, and in particular to an ultrafine rare earth-doped divalent metal phosphate luminescent material, its manufacturing method, and a luminescent device. Background Technology

[0002] Luminescent materials play a crucial role in numerous fields, including industrial manufacturing, lighting displays, and consumer electronics, particularly in applications such as automotive dashboards, home appliance status indicators, and LED display backlight modules. Currently, although aluminate systems hold a large market share due to their superior performance, phosphate-based luminescent materials continue to attract widespread attention due to their unique advantages. However, some existing problems urgently need to be addressed to meet the higher performance requirements of modern technologies for luminescent materials.

[0003] Traditional phosphate luminescent materials have poor moisture resistance and are prone to deliquescence, which leads to a rapid decline in luminescent performance and severely limits their lifespan in high humidity environments. At the same time, their narrow luminescent angle makes it impossible to achieve uniform brightness distribution in scenarios requiring wide-angle observation, such as car dashboards, which seriously affects user experience and application effectiveness.

[0004] Existing coating technologies attempt to address these issues by adding a protective layer to the surface of luminescent materials. However, these technologies often only improve a single property to a certain extent and cannot simultaneously meet the comprehensive requirements of luminescent materials for high brightness, wide viewing angle, and long lifespan in complex environments such as high humidity and strong vibration.

[0005] Therefore, a new solution is urgently needed to address the above problems. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides an ultrafine rare earth-doped divalent metal phosphate luminescent material, its manufacturing method, and a luminescent device.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material, comprising the following steps:

[0008] S1, Preparation of Eu 3+ A luminescent material doped with barium zinc phosphate is ground to obtain luminescent particles.

[0009] S2. Dissolve aluminum alkoxide in an anhydrous organic solvent and add an alcohol solution containing a catalyst to obtain aluminum sol;

[0010] S3. Add the luminescent particles from step S1 to the aluminum sol and stir continuously to make the sol particles uniformly adsorbed on the surface of the luminescent particles, thus obtaining composite particles with an Al2O3 coating.

[0011] S4. Let it stand, allowing the sol layer coating the surface of the luminescent particles to undergo further hydrolysis and condensation reaction to form a wet gel layer;

[0012] S5. The wet gel layer is dried and subjected to low-temperature heat treatment, with the temperature controlled at 300-600℃, to form discontinuous pores between the Al2O3 coating layer and the luminescent particle core.

[0013] In a preferred embodiment of the present invention, step S1 specifically includes the following steps:

[0014] S11. Take barium carbonate, ammonium dihydrogen phosphate, basic zinc carbonate and Eu2O3 powder for later use; wherein, the molar ratio of the components satisfies: barium carbonate: basic zinc carbonate: ammonium dihydrogen phosphate = 1:1:2, and Eu2O3 is 2-18 mol% of the total substance concentration;

[0015] S12. Grind the powder from step S11 into granules to ensure uniform mixing;

[0016] S13. The sample powder in step S12 is sintered at high temperature, with the sintering temperature set at 930-970℃ and the holding time at 8h.

[0017] S14. After sintering, allow the temperature to cool naturally to 180-200℃, then remove the sample and allow it to cool completely.

[0018] S15. Grind the cooled sample to a particle size of 1-5 μm to obtain luminescent particles.

[0019] In a preferred embodiment of the present invention, in step S2, the aluminum alkoxide is aluminum isopropoxide, the anhydrous organic solvent is anhydrous ethanol, and the catalyst is nitric acid or hydrochloric acid.

[0020] In a preferred embodiment of the present invention, in step S3, the stirring speed is 60-100 rpm and the stirring time is 3-5 h.

[0021] In a preferred embodiment of the present invention, the settling time in step S4 is 24-48 hours.

[0022] In a preferred embodiment of the present invention, in step S5, the drying process adopts room temperature and pressure drying or supercritical drying, the low temperature heat treatment temperature is 350-500℃, and the holding time is 1-2h, so as to remove residual organic solvents and hydroxyl groups and form discontinuous pores.

[0023] In a preferred embodiment of the present invention, Eu 3+ The preferred doping concentration is 18 mol%.

[0024] In a preferred embodiment of the present invention, the thickness of the Al2O3 coating layer in step S3 is 50-100 nm.

[0025] On the other hand, this application provides an ultrafine rare earth-doped divalent metal phosphate luminescent material, which is prepared based on the manufacturing method described above.

[0026] In addition, the present invention provides a light-emitting device comprising the above-mentioned ultrafine rare earth-doped divalent metal phosphate light-emitting material, wherein the light-emitting device is an automotive dashboard, indicator light, or backlight device.

[0027] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0028] (1) This invention utilizes Eu 3+ By constructing an Al2O3 coating layer on the surface of barium zinc phosphate luminescent particles and forming nanoscale discontinuous pores, the light scattering performance of the material is significantly improved. Through the synergistic effect of the pores and the nanoscale roughness of the Al2O3 surface, light that was originally concentrated in a small angle is scattered to a larger angle, greatly expanding the emission radiation angle to a wide range. In application scenarios such as automotive dashboards, this solves the problem of severe attenuation of the lateral viewing angle, significantly improves the brightness uniformity when observing at large angles, and directly enhances the applicability and visual effect of luminescent materials in multi-angle lighting needs.

[0029] (2) This invention precisely controls the pore parameters, maintaining the continuity of the Al2O3 coating layer while fully stimulating the light scattering effect to achieve an ultra-wide radiation angle. It also utilizes the stress-buffering properties of the pores to block crack propagation paths. Compared to traditional dense coating layers, the discontinuous pores effectively block environmental water and oxygen from eroding the luminescent center, while simultaneously buffering mechanical vibration and thermal stress, significantly improving the stability and reliability of the material under high temperature, high humidity, and strong vibration environments. This structural optimization not only extends the material's service life but also ensures high-brightness red light output even under harsh operating conditions, solving the technical bottlenecks of traditional phosphate phosphors' hygroscopicity and narrow viewing angle. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating the steps of a preferred embodiment of the present invention;

[0032] Figure 2 For Eu3+ XRD pattern of luminescent material with 18% doping;

[0033] Figure 3 Emission spectra of luminescent materials at different sintering temperatures;

[0034] Figure 4 Emission spectra of luminescent materials at different heat preservation times;

[0035] Figure 5 For different Eu 3+ Emission spectrum of luminescent materials with varying doping levels;

[0036] Figure 6 For Eu 3+ Color coordinate diagram of luminescent material with 18% doping. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0039] Exemplary method:

[0040] like Figure 1 As shown, a method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material includes the following steps:

[0041] S1. Preparation of Eu using high-temperature solid-state reaction 3+ The luminescent particles to be treated are obtained by doping barium zinc phosphate with the powder and grinding it to a particle size of 5-20 μm.

[0042] S2. Dissolve aluminum alkoxide in an anhydrous organic solvent, and slowly add a water or alcohol mixture containing a catalyst to the solution, controlling the amount of water added, to obtain a partially hydrolyzed, low-crosslinking aluminum sol; wherein the aluminum alkoxide is aluminum isopropoxide, the anhydrous organic solvent is selected from anhydrous ethanol or isopropanol, and the catalyst is dilute nitric acid or hydrochloric acid.

[0043] S3. Slowly add the pretreated luminescent material powder into the aluminum sol and stir gently for 3-5 hours at a stirring speed of 60-100 revolutions per minute, so that the sol particles are uniformly adsorbed on the surface of the luminescent material to form composite particles with an Al2O3 coating layer of 50-100nm thickness.

[0044] S4. Continue stirring or let stand for 24-48 hours to allow the sol layer coated on the surface of the luminescent material to undergo further hydrolysis and condensation reaction to form a wet gel layer.

[0045] S5. After drying the wet gel layer, place the dried powder in a muffle furnace and heat-treat it at a low temperature of 300-600℃ for 1-2 hours to form discontinuous pores between the Al2O3 coating layer and the luminescent particle core.

[0046] Specifically, the preparation of the luminescent material in step S1 includes the following steps:

[0047] S11. Accurately weigh and measure barium carbonate, ammonium dihydrogen phosphate, basic zinc carbonate, and Eu2O3 according to stoichiometric ratios, and control the Eu content. 3+ The doping concentration is 18%.

[0048] S12. Grind the weighed sample powder thoroughly in a grinding mortar until it becomes granular, ensuring that it is mixed evenly.

[0049] S13. Pour the ground powder into a crucible and place it in a high-temperature furnace;

[0050] S14. Set the sintering temperature in the high-temperature furnace to 930-970℃ and the holding time to 8h.

[0051] S15. After the high-temperature furnace sintering is completed and the temperature drops to 180-200℃, take out the sample and cool it.

[0052] S16. Grind the cooled powder to the required particle size to obtain the luminescent particles to be treated, so as to ensure good dispersibility and luminescence performance.

[0053] Based on the above exemplary method, the sol-gel method is used in Eu 3+An Al2O3 coating layer was constructed on the surface of barium zinc phosphate luminescent particles. During low-temperature heat treatment at 350-500℃, the difference in thermal expansion coefficients between the core and Al2O3 induced interfacial micro-stress. Simultaneously, partial hydrolysis of the aluminum sol was controlled to form a low-crosslinking network. This resulted in the formation of nanoscale discontinuous pores at the interface due to solvent evaporation and gel shrinkage during drying. These pores were isolated by the amorphous γ-phase Al2O3 framework and were not interconnected. This coating structure, on the one hand, effectively blocked the erosion of the luminescent centers by environmental water and oxygen in the continuous Al2O3 film, significantly improving the material's lifespan; on the other hand, the discontinuous pores at the interface and... The nano-roughness of the Al2O3 surface synergistically acts as a light scattering center, broadening the radiation angle of the main emission peak (594.6nm red light) while maintaining stable color coordinates. The material of this application is particularly suitable for light-emitting devices such as automotive dashboard indicator lights, multi-angle status lights for home appliances, and LED display backlight modules, where it is not necessary to ensure that the luminescent material maintains a smooth surface to form low light scattering requirements. At the same time, the luminescent material of this application can still maintain high-brightness red light output under strong vibration and high humidity environments through the buffering effect of discontinuous pores between the core and the coating layer, solving the technical bottlenecks of traditional phosphate phosphors being prone to deliquescence and having a narrow viewing angle.

[0054] Example 1:

[0055] Example 1 is the preferred embodiment of this application, and the preparation steps are as follows:

[0056] S1. Accurately weigh 5.03g of barium carbonate, 5.87g of ammonium dihydrogen phosphate, 2.3g of basic zinc carbonate, and 0.81g of Eu₂O₃ according to the stoichiometric ratio, and control the Eu content. 3+ The doping amount is 18%, and the mixture is ground until uniform. The powder is placed in a crucible and sintered in a high-temperature furnace at 950℃ for 8 hours. After the temperature drops to 180-200℃, it is taken out and cooled, and then ground to obtain luminescent core particles with a particle size of 5-20μm.

[0057] S2. Dissolve 4.08 g of aluminum isopropoxide (Al(OCH(CH3)2)3) in 40 mL of anhydrous ethanol. Under continuous stirring, slowly add a water / alcohol / catalyst mixture consisting of 0.36 mL of deionized water, 10 mL of anhydrous ethanol, and 2 drops of concentrated nitric acid (approximately 0.1 mL). Control the dropping rate to complete within 1-2 hours, and continuously stir the reaction in a 40°C water bath for 2 hours to finally obtain a clear and stable partially hydrolyzed aluminum sol.

[0058] S3. Add the particles obtained in S1 to the sol and stir at 80 rpm for 4 hours to make the sol be uniformly adsorbed on the particle surface and form a 50-100nm pre-coating layer.

[0059] S4. Let stand for 36 hours to complete the sol-gel conversion and form a dense wet gel layer;

[0060] S5. After drying at room temperature, heat-treat at 450℃ for 1.5h to generate discontinuous pores at the interface between the core and Al2O3, thus obtaining the final product.

[0061] Figure 2 For Eu 3+ XRD pattern of the luminescent material with 18% doping. The figure shows that the prepared luminescent material is pure BaZnP2O7, with no other impurity phases detected, indicating that Eu... 3+ The doping did not change the crystal structure, Eu 3+ It is incorporated into the crystal structure.

[0062] Figure 3 The images show the emission spectra of luminescent materials sintered at different temperatures. Temperature is a crucial factor affecting the luminescent properties of materials; changes in sintering temperature influence the fluorescence characteristics and doping substitution sites of the samples through the crystal structure. 3+ The luminescence intensity of barium zinc phosphate doped luminescent materials first increases and then decreases with increasing temperature, reaching its highest value at 950℃.

[0063] Figure 4 The graphs show the emission spectra of the luminescent material at different heat treatment times. It can be seen from the graphs that at the optimal temperature of 950℃, Eu... 3+ The luminescence intensity of the barium zinc phosphate-doped luminescent material first increases and then decreases with increasing heating time, and the luminescent material exhibits the best performance when the heating time is 8 hours.

[0064] Figure 5 For different Eu 3+ Emission spectrum of the luminescent material with varying doping levels. The figure shows that as Eu increases... 3+ With gradual increase in dopant content, the fluorescence intensity of the luminescent material first increases and then decreases. When Eu... 3+ The luminescent material exhibits optimal performance when its concentration is 18%.

[0065] Figure 6 For Eu 3+ The color coordinates of the luminescent material with a doping concentration of 18% are shown in the figure. As can be seen from the figure, the luminescent material is located in the red luminescent region.

[0066] Example 2:

[0067] The difference between Example 2 and Example 1 lies in reducing the amount of discontinuous porosity. The preparation steps are as follows:

[0068] S1. Accurately weigh 5.03g of barium carbonate, 5.87g of ammonium dihydrogen phosphate, 2.3g of basic zinc carbonate and 0.81g of Eu2O3 according to the stoichiometric ratio, mix and grind until uniform; place the powder in a crucible and sinter in a high-temperature furnace at 950℃ for 8h. After the temperature drops to 180-200℃, take it out and cool it, grind it to obtain luminescent core particles with a particle size of 5-20μm;

[0069] S2. Dissolve aluminum isopropoxide in anhydrous ethanol, slowly add water / alcohol mixture containing dilute nitric acid catalyst, and stir to form a highly cross-linked aluminum sol.

[0070] S3. Add the particles obtained in S1 to the sol and stir at 80 rpm for 4 hours.

[0071] S4. Let stand for 24 hours;

[0072] S5. After drying at room temperature, heat-treat at 400℃ for 1 hour to obtain a final product with reduced porosity.

[0073] Example 3:

[0074] S1, Same as Example 1;

[0075] S2, Same as Example 1;

[0076] S3, Same as Example 1;

[0077] S4, Same as Example 1;

[0078] S5. After drying at room temperature, heat-treat at 450℃ for 2 hours.

[0079] Example 4:

[0080] The difference between Example 4 and Example 1 lies in the increase of discontinuous porosity. The preparation steps are as follows:

[0081] S1, Same as Example 1;

[0082] S2. Dissolve aluminum isopropoxide in anhydrous ethanol, slowly add water / alcohol mixture containing dilute nitric acid catalyst, and stir to form a low cross-linking aluminum sol.

[0083] S3, Same as Example 1;

[0084] S4. Let stand for 48 hours;

[0085] S5. After drying at room temperature, heat-treat at 500℃ for 1.5 hours.

[0086] Comparative Example 1:

[0087] S1, Same as Example 1;

[0088] S2. Dissolve aluminum isopropoxide in anhydrous ethanol, add excess water and dilute nitric acid, and hydrolyze thoroughly to form a highly cross-linked sol.

[0089] S3. Add the core particles to the sol and stir at 80 rpm for 4 hours;

[0090] S4. Let stand for 12 hours;

[0091] S5. After drying at room temperature, heat-treat at 1200℃ for 2 hours to form a non-porous α-Al2O3 continuous coating layer.

[0092] Performance testing:

[0093] Light scattering performance testing: A rotating sample stage integrating sphere spectrometer equipped with a 650nm laser light source was used, matched with the main emission peak at 594.6nm. Each sample was pressed into a pellet. A 10mm × 1mm disk; the laser is incident perpendicularly on the center of the sample, and the rotating stage scans from -90° to +90° in 10° steps; the intensity of the emitted light at each angle is recorded, and a polar coordinate radiogram is plotted; the full width at half maximum (FWHM) and the relative intensity attenuation rate at ±60° are calculated.

[0094] Humid heat aging test: Using a constant temperature and humidity chamber and a fluorescence spectrophotometer, the sample was placed in an environment of 85℃ / 85%RH; it was taken out every 24 hours and the luminescence intensity at 594.6nm was measured with excitation light at 393.5nm; after 500 hours, the intensity retention rate was calculated.

[0095] Vibration stability test: An electromagnetic vibration table and scanning electron microscope were used. The sample was fixed on the vibration table and subjected to random vibration at 20-2000 Hz (PSD = 0.04g). 2 / Hz); after 24 hours, SEM was used to observe the peeling and cracking of the coating layer; the luminescence intensity decay rate after vibration was tested.

[0096] Pore ​​structure testing: Scanning electron microscopy was used to observe the sample cross-section, SEM was used to observe the pore morphology at the interface, and porosity was statistically analyzed.

[0097] The light scattering performance test results are shown in Table 1 below:

[0098] Table 1. Results of Light Scattering Performance Test

[0099]

[0100] The results of the damp heat aging and vibration stability tests are shown in Table 2 below:

[0101] Table 2 Results of Damp Heat Aging and Vibration Stability Tests

[0102]

[0103]

[0104] The test data results for the pore structure are shown in Table 3 below:

[0105] Table 3. Results of Pore Structure Test Data

[0106] sample Average pore size Porosity Pore ​​morphology Example 1 50-200nm 18％ isolated discontinuous Example 2 30-80nm 6％ Sparse dots Example 3 50-200nm 19％ Evenly dispersed Example 4 80-300nm 25％ Local connectivity Comparative Example 1 - ＜0.5％ Non-porous

[0107] Based on the above performance test results, it can be seen that, compared with Comparative Example 1, Example 1 outperforms Comparative Example 1 in all tests. In terms of optical performance, the interface pores and surface roughness of Example 1 work together to form a highly efficient scattering center, which greatly expands the emission radiation angle from the narrow viewing angle of traditional coatings to a wide-angle range, significantly improving the brightness uniformity when observing at large angles and solving the problem of severe lateral viewing angle attenuation in application scenarios such as automotive dashboards. In terms of environmental stability, the discontinuous pores both block the water and oxygen permeation path and buffer thermal stress, enabling the material to effectively resist deliquescence failure in high temperature and high humidity environments. At the same time, by absorbing mechanical vibration energy, it avoids cracking of the coating layer, significantly improving the product's lifespan reliability under harsh working conditions.

[0108] Comparing Examples 1-4 reveals that different pore structures also affect performance, and pore characteristics have a decisive impact on performance: when the pore size is too small or the number is insufficient, the improvement in light scattering effect is limited, resulting in a narrowing of the radiation angle; while excessively increasing the pore size or connectivity can further enhance the light diffusion capability, it will weaken the sealing barrier function and induce stress concentration, accelerating performance degradation in a humid and hot coupled environment.

[0109] In summary, this application precisely balances the porosity parameters, maintaining the continuity of the alumina layer while fully stimulating the light scattering effect to achieve an ultra-wide radiation angle. It also utilizes the stress buffering characteristics of the pores to block the crack propagation path, ultimately achieving a triple breakthrough of high brightness, wide viewing angle, and long lifespan in the harsh automotive electronic environment, providing a universal solution for deliquescent fluorescent materials.

[0110] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material, characterized in that, Includes the following steps: S1. Prepare Eu³⁺-doped barium zinc phosphate luminescent material, and grind the luminescent material to obtain luminescent particles; S2. Dissolve aluminum alkoxide in an anhydrous organic solvent and add an alcohol solution containing a catalyst to obtain aluminum sol; S3. Add the luminescent particles from step S1 to the aluminum sol and stir continuously to make the sol particles uniformly adsorbed on the surface of the luminescent particles, thus obtaining composite particles with an Al2O3 coating. S4. Let it stand, allowing the sol layer coating the surface of the luminescent particles to undergo further hydrolysis and condensation reaction to form a wet gel layer; S5. The wet gel layer is dried and subjected to low-temperature heat treatment, with the temperature controlled at 300-600℃, to form discontinuous pores between the Al2O3 coating layer and the luminescent particle core. The drying process employs ambient temperature and pressure drying or supercritical drying, while the low-temperature heat treatment temperature is 350-500℃ and the holding time is 1-2 hours to remove residual organic solvents and hydroxyl groups and form discontinuous pores. In step S2, the aluminum alkoxide is aluminum isopropoxide, the anhydrous organic solvent is anhydrous ethanol, and the catalyst is nitric acid or hydrochloric acid.

2. The method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material according to claim 1, characterized in that, Step S1 specifically includes the following steps: S11, take barium carbonate, ammonium dihydrogen phosphate, basic zinc carbonate, and Eu2O3 powder for later use; wherein, the molar ratio of the components satisfies: barium carbonate: basic zinc carbonate: ammonium dihydrogen phosphate = 1:1:2, and Eu2O3 is 2-18 mol% of the total substance concentration; S12, grind the powder in step S11 into granules to ensure uniform mixing; S13, sinter the sample powder in step S12 at high temperature, setting the sintering temperature to 930-970℃ and the holding time to 8h; S14, after sintering, allow the temperature to cool naturally to 180-200℃, and remove the sample until it is completely cooled; S15, grind the cooled sample to a particle size of 1-5μm to obtain luminescent particles.

3. The method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material according to claim 1, characterized in that, In step S3, the stirring speed is 60-100 rpm and the stirring time is 3-5 h.

4. The method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material according to claim 1, characterized in that, In step S4, the settling time is 24-48 hours.

5. The method for manufacturing an ultrafine rare-earth-doped divalent metal phosphate luminescent material according to claim 1, characterized in that: In step S3, the thickness of the Al2O3 coating layer is 50-100 nm.

6. A luminescent material made of ultrafine rare-earth-doped divalent metal phosphate, characterized in that, The luminescent material is prepared by the manufacturing method described in any one of claims 1-5.

7. A light-emitting device, characterized in that, The light-emitting material includes the ultrafine rare earth-doped divalent metal phosphate as described in claim 6, wherein the light-emitting device is an automotive dashboard, indicator light, or backlight device.

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