Ceramic fluorescent luminescent material and method of preparation and use

Abstract

The application relates to a ceramic fluorescent light-emitting material and a preparation method and application thereof. The preparation method of the ceramic fluorescent light-emitting material comprises the following steps: (a) heating a nitric acid aqueous solution to a first predetermined temperature, adding rare earth oxide Tb4O7 to react, and obtaining a colorless transparent solution; (b) performing acid removal treatment, evaporating the solution, adding deionized water to dissolve, and removing excessive nitric acid; (c) adding Al(NO3)3.9H2O, H3BO3 and citric acid according to a predetermined molar ratio, adding into the solution, and reacting at a predetermined temperature to obtain a gel; and (d) drying and grinding the gel, and performing high-temperature sintering to obtain the ceramic fluorescent light-emitting material. The prepared ceramic fluorescent light-emitting material can be used to prepare a fluorescent light-emitting material for a self-luminous cold light source, and the light-emitting efficiency of the self-luminous cold light source is improved.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent material preparation technology, specifically relating to a ceramic fluorescent luminescent material, its preparation method and application, and particularly its use in preparing fluorescent materials for self-luminous cold light sources. Background Technology

[0002] Isotope energy is a clean, safe, and highly efficient new energy source, and radiation light sources prepared by exciting fluorescent materials with beta rays are one application form of isotope energy. This self-luminous material system offers stable light intensity, requires no external power supply, and is maintenance-free, unaffected by temperature, humidity, altitude, or operating techniques. Therefore, it is an excellent luminescent system for illumination in dark conditions and with limited field of view, and has promising application prospects.

[0003] Currently, traditional self-emissive cold light sources are tritium sources, constructed by coating the inside of a glass tube with a uniform luminescent material, forming a luminescent layer. Because beta rays have a shallow penetration depth, the thickness of the luminescent surface is critical. A thicker luminescent layer will absorb some photon energy, reducing overall luminescence performance. Furthermore, as it is a surface-emitting layer, only beta rays near the luminescent surface are likely to be absorbed by the luminescent material; beta rays decaying in other parts of the tube are unlikely to reach the luminescent layer to excite the luminescent material. Therefore, current traditional self-emissive cold light sources have relatively low brightness and significant size constraints, requiring further improvement. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. This invention provides a ceramic fluorescent luminescent material, its preparation method, and its application, particularly relating to the use of ceramic fluorescent luminescent materials in the preparation of fluorescent materials for self-emissive cold light sources. The traditional synthesis method for ceramic fluorescent luminescent materials (e.g., ceramic fluorescent powders) is the high-temperature solid-state method; however, the high-temperature solid-state method suffers from drawbacks such as high sintering temperature, non-uniformity, and difficulty in controlling morphology and size. In contrast, the ceramic fluorescent luminescent material prepared by the sol-gel method of this invention exhibits good dispersibility, good uniformity, and a high phase transition temperature; the method is simple and highly feasible. The provided ceramic fluorescent luminescent material, with its modified garnet structure, exhibits excellent radiation resistance, high light output, and strong X-ray absorption capability, meeting the requirements of volumetric radiation light sources for high luminous efficiency, high transmittance of the self-emission spectrum, and radiation resistance. It also facilitates the miniaturization of light source components. Furthermore, the simple operation and suitability for large-scale industrial production are of great significance.

[0005] The self-luminescent cold light source fluorescent material prepared by applying the prepared ceramic fluorescent luminescent material uses silica wet gel as the self-luminescent cold light source matrix. The scintillation polycrystalline ceramic luminescent material is uniformly dispersed in the silica aerogel three-dimensional framework, and its porosity can reach more than 80%, so that the luminescent material can fully contact and absorb the β radiation source, thereby improving the luminescent efficiency of the self-luminescent cold light source.

[0006] Specifically, the present invention provides the following technical solution:

[0007] The first aspect of the present invention provides a method for preparing a ceramic fluorescent luminescent material, comprising:

[0008] (a) Heat the aqueous nitric acid solution to a first predetermined temperature, add rare earth oxide Tb4O7 to react, and obtain a colorless and transparent solution;

[0009] (b) The solution obtained in step (a) is subjected to acid removal treatment, the solution is evaporated to dryness, and deionized water is added to dissolve it in order to remove excess nitric acid;

[0010] (c) Add Al(NO3)3·9H2O, H3BO3 and citric acid according to a predetermined molar ratio, and react at a predetermined temperature to obtain a gel;

[0011] (d) The gel is dried, ground, and sintered at high temperature to obtain the ceramic fluorescent luminescent material.

[0012] According to embodiments of the present invention, the preparation method of the ceramic fluorescent luminescent material described above may further include the following technical features:

[0013] According to some embodiments of the present invention, the volume fraction of the nitric acid aqueous solution used in step (a) is 40% to 65%.

[0014] According to some embodiments of the present invention, the first predetermined temperature in step (a) is 80 to 110 degrees Celsius.

[0015] According to some embodiments of the present invention, the reaction time is 0.5 to 2 hours.

[0016] According to some embodiments of the present invention, in step (c), the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 is (2-4):(17-20):(30-35):(0.4-3).

[0017] According to an embodiment of the present invention, in step (d), the heating rate of the high-temperature sintering is 10-20℃ / min, the temperature is raised to 500℃-800℃ and held, then raised to 1000℃-1500℃ and held, and then cooled to obtain the ceramic fluorescent luminescent material.

[0018] A second aspect of the present invention provides a ceramic fluorescent luminescent material, which is prepared according to the preparation method described in any one of the first aspects.

[0019] A third aspect of the present invention provides the use of a ceramic fluorescent luminescent material in the preparation of a fluorescent luminescent material for a self-emissive cold light source, wherein the ceramic fluorescent luminescent material is the ceramic fluorescent luminescent material described in the second aspect.

[0020] A fourth aspect of the present invention provides a method for preparing a fluorescent luminescent material for a self-emissive cold light source, comprising:

[0021] (1) Mix anhydrous ethanol, tetraethyl orthosilicate, deionized water and ceramic fluorescent luminescent material, and stir to obtain a suspension;

[0022] (2) Add ammonia water to the suspension and stir until it becomes gel-like. Then pour it into a mold to solidify and obtain solidified silica wet gel.

[0023] (3) The solidified silica wet gel was immersed in anhydrous ethanol and a supercritical reaction was carried out under nitrogen conditions in order to obtain the fluorescent light-emitting material for the self-luminous cold light source.

[0024] The ceramic fluorescent luminescent material is the ceramic fluorescent luminescent material obtained in the second aspect above.

[0025] According to embodiments of the present invention, the preparation method of the fluorescent luminescent material for the self-emissive cold light source described above may further include the following technical features:

[0026] According to some embodiments of the present invention, the volume ratio of anhydrous ethanol: tetraethyl orthosilicate: deionized water: ceramic fluorescent luminescent material in step (1) is (3-5): 1: 1: (0.15-0.4);

[0027] According to some embodiments of the present invention, the volume ratio of ammonia and tetraethyl orthosilicate in step (2) is (0.15-0.5):1, and the concentration of ammonia is 1-4 mol / L.

[0028] According to an embodiment of the present invention, the temperature of the supercritical reaction in step (3) is 200 to 350 degrees Celsius, and the time of the supercritical reaction is 4 to 10 hours.

[0029] The beneficial effects achieved by this invention are as follows:

[0030] (1) The method for preparing ceramic fluorescent luminescent materials provided by the present invention produces ceramic fluorescent luminescent materials with good dispersibility, good uniformity, and high phase transition temperature. The provided preparation method is simple and highly feasible.

[0031] (2) The self-luminous cold light source fluorescent material prepared by the present invention adopts the method of loading ceramic fluorescent material on silicon oxide framework, so that the ceramic fluorescent material can fully contact the β-ray radiation source and maximize its luminous efficiency. At the same time, silicon oxide aerogel has high light transmittance. When the thickness is about 1 cm, the average light transmittance in the wavelength range of 500-600 nm is 72.4%-75.8%, which can guide the light inside the framework and reduce light loss. In addition, the ceramic fluorescent material based on garnet structure has radiation resistance, which can effectively extend the life of the light source affected by the material life.

[0032] (3) The fluorescent light-emitting material for the self-luminous cold light source can be excited by β-rays. Therefore, its β-ray source is not limited to one type. It can be used for a variety of materials such as tritium and krypton 85. Moreover, its emission color is determined by the rare earth elements added. The fluorescence excited by terbium aluminum garnet with added terbium is green, and it will turn red after adding dysprosium. The color of the light source can be changed according to the needs, and the application range is wider. Attached Figure Description

[0033] Figure 1 The TG-DSC test (maximum phase transition temperature ~897.3℃) of the ceramic fluorescent luminescent material provided according to an embodiment of the present invention is shown.

[0034] Figure 2 This is a β-ray diffraction pattern of a ceramic fluorescent luminescent material provided according to an embodiment of the present invention.

[0035] Figure 3 These are scanning electron microscope images of ceramic fluorescent luminescent materials provided according to embodiments of the present invention. The left image is the sample of Example 2; the right image is the sample of Example 4.

[0036] Figure 4 The PL spectrum (excitation wavelength 275 nm) of the ceramic fluorescent luminescent material provided according to an embodiment of the present invention is shown.

[0037] Figure 5 The cathode fluorescence spectrum of the ceramic fluorescent luminescent material provided according to an embodiment of the present invention (Sample 2). Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0039] This invention provides a method for preparing a ceramic fluorescent luminescent material, comprising:

[0040] (a) Heat the nitric acid aqueous solution to a first predetermined temperature, add rare earth oxide Tb4O7 to react until a colorless and transparent solution is obtained;

[0041] (b) The solution obtained in step (a) is subjected to acid removal treatment in order to remove excess nitric acid;

[0042] (c) Add Al(NO3)3·9H2O, H3BO3 and citric acid according to a predetermined molar ratio, and react at a predetermined temperature to obtain a gel;

[0043] (d) The gel is dried, ground, and sintered at high temperature to obtain the ceramic fluorescent luminescent material.

[0044] The nitric acid aqueous solution used in step (a) should be slightly in excess. According to the specific embodiment, the volume fraction of the nitric acid aqueous solution used in step (a) is 40% to 65%, for example, 50%. If the volume fraction of the nitric acid aqueous solution is too low, it cannot react sufficiently with Tb4O7; conversely, if the volume fraction is too high, the subsequent acid removal process will take a long time.

[0045] According to a specific implementation, the first predetermined temperature in step (a) is 80 to 110 degrees Celsius;

[0046] According to specific embodiments, the reaction time is 0.5 to 2 hours. For example, a reaction time of 1 hour can yield a colorless and transparent solution.

[0047] According to the specific implementation method, the acid removal process in step (b) makes the solution pH neutral. During acid removal, the solution can be evaporated to dryness first, and then deionized water solution can be added, repeating this process 2 to 3 times to remove excess nitric acid.

[0048] According to a specific embodiment, in step (c), the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid, and H3BO3 is 3:(17-20):32:(0.4-3). These substances and their relative proportions have a significant impact on the properties and structure of the final material. If the ratio of the precursors in the sol and gel deviates, it may lead to several adverse consequences, such as uneven composition, phase transition or phase separation, or failure to obtain the target compound. According to a preferred embodiment, the molar ratios of Tb4O7, Al(NO3)3·9H2O, citric acid, and H3BO3 are 3:19.6:32:0.4, 3:18.8:32:1.2, and 3:18.0:32:2.0, respectively.

[0049] According to a specific embodiment, in step (d), the heating rate of the high-temperature sintering is 10-20℃ / min, the temperature is raised to 500℃-800℃ and held, then raised to 1000℃-1500℃ and held, and finally cooled to obtain the ceramic fluorescent luminescent material. According to a preferred embodiment, the heating rate of the high-temperature sintering is 10℃ / min, the temperature is raised to 600℃ and held for 1 hour, then raised to 1200℃ and held for 3 hours, and finally cooled naturally to obtain the ceramic fluorescent luminescent material.

[0050] The ceramic fluorescent luminescent material obtained by the above preparation method can be used to prepare fluorescent luminescent materials for self-luminous cold light sources.

[0051] Therefore, the present invention also provides a method for preparing a fluorescent luminescent material for a self-emissive cold light source, comprising:

[0052] (1) Mix anhydrous ethanol, tetraethyl orthosilicate, deionized water and ceramic fluorescent material, and stir until a suspension is obtained;

[0053] (2) Add ammonia water to the suspension and stir until it becomes gel-like. Then pour it into a mold to solidify and obtain solidified silica wet gel.

[0054] (3) The solidified silica wet gel was immersed in anhydrous ethanol and a supercritical reaction was carried out under nitrogen conditions in order to obtain the fluorescent light-emitting material for the self-luminous cold light source.

[0055] The ceramic fluorescent material is obtained by the following method:

[0056] (a) Heat the nitric acid aqueous solution to a first predetermined temperature, add rare earth oxide Tb4O7 to react until a colorless and transparent solution is obtained;

[0057] (b) The solution obtained in step (a) is subjected to acid removal treatment in order to remove excess nitric acid;

[0058] (c) Add Al(NO3)3·9H2O, H3BO3 and citric acid according to a predetermined molar ratio, and react at a predetermined temperature to obtain a gel;

[0059] (d) The gel is dried, ground, and sintered at high temperature to obtain the ceramic fluorescent luminescent material.

[0060] According to a specific embodiment, the volume ratio of anhydrous ethanol: tetraethyl orthosilicate: deionized water: ceramic fluorescent luminescent material in step (1) is (3-5):1:1:(0.15-0.4). According to a preferred embodiment, the volume ratio of anhydrous ethanol: tetraethyl orthosilicate: deionized water: ceramic fluorescent luminescent material is 4:1:1:0.28. During stirring, an electromagnetic stirrer can be used until the liquid becomes a uniform suspension.

[0061] According to a specific embodiment, the volume ratio of ammonia to tetraethyl orthosilicate in step (2) is (0.15–0.5):1, and the concentration of ammonia is 1–4 mol / L. According to a preferred embodiment, the volume ratio of ammonia to tetraethyl orthosilicate is 0.24:1, and the concentration of ammonia is 2 mol / L. The solidification time can be 30–60 minutes.

[0062] According to a specific embodiment, the temperature of the supercritical reaction in step (3) is 200–350 degrees Celsius, and the time of the supercritical reaction is 4–10 hours. According to a preferred embodiment, in step (3), the solidified aerogel is placed in a reaction vessel, anhydrous ethanol is poured in to submerge the solidified aerogel, nitrogen gas at about 10 MPa is introduced, and then a supercritical reaction is carried out at 250 degrees Celsius for 6 hours. The pressure is released to obtain the fluorescent luminescent material for the self-luminous cold light source.

[0063] The technical solution of the present invention will be described below through specific embodiments. It should be noted that these embodiments are only used to facilitate understanding by those skilled in the art and should not be regarded as a limitation on the scope of protection of the present invention. The reagents used in the embodiments are all commonly used reagents in the art and can be obtained by commercial purchase or self-preparation.

[0064] Example 1

[0065] Example 1 provides a method for preparing a ceramic fluorescent luminescent material, comprising the following steps:

[0066] (a) Measure 20 ml of HNO3 with a volume fraction of 50% and heat it to 90°C. Weigh 0.7016 g of rare earth oxide Tb4O7 and add it to HNO3. Mix and stir for 1 h to obtain a colorless and transparent solution.

[0067] (b) Evaporate the solution to dryness, add deionized water to dissolve, repeat 2-3 times to remove excess HNO3;

[0068] (c) According to the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 of 3:19.6:32:0.4, weigh 2.2989 g of Al(NO3)3·9H2O, 2.1019 g of citric acid and 0.0078 g of H3BO3 respectively, add them to the solution and stir for 1 h. Then react the mixed solution at 80 °C for 3-4 h to obtain a light yellow gel.

[0069] (d) The pale yellow gel was dried and ground at 150°C to obtain precursor powder; the obtained precursor powder was sintered at high temperature. First, the temperature was raised to 600°C at a rate of 10°C / min and held for 1 hour, then raised to 1200°C and held for 3 hours, and finally cooled naturally to obtain ceramic fluorescent luminescent material.

[0070] The final phase transition temperature of the ceramic fluorescent luminescent material obtained in Example 1 is 934.2℃.

[0071] Example 2

[0072] Example 2 provides a method for preparing a ceramic fluorescent luminescent material, comprising:

[0073] (a) Measure 20 ml of HNO3 with a volume fraction of 50% and heat it to 90°C. Weigh 0.6005 g of rare earth oxide Tb4O7 and add it to HNO3. Mix and stir for 1 h to obtain a colorless and transparent solution.

[0074] (b) Evaporate the solution to dryness, add deionized water to dissolve, repeat 2-3 times to remove excess HNO3;

[0075] (c) According to the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 of 3:18.8:32:1.2, weigh 1.8874 g of Al(NO3)3·9H2O, 1.7990 g of citric acid and 0.0199 g of H3BO3 respectively, add them to the solution and stir for 1 h. Then react the mixed solution at 80 °C for 3-4 h to obtain a light yellow gel.

[0076] (d) The pale yellow gel was dried and ground at 150°C to obtain precursor powder; the obtained precursor powder was sintered at high temperature. First, the temperature was raised to 600°C at a rate of 10°C / min and held for 1 hour, then raised to 1200°C and held for 3 hours, and finally cooled naturally to obtain ceramic fluorescent luminescent material.

[0077] The final phase transition temperature of the ceramic fluorescent luminescent material obtained in Example 2 is 921.8℃.

[0078] Example 3

[0079] Example 3 provides a method for preparing a ceramic fluorescent luminescent material, comprising the following steps:

[0080] (a) Measure 20 ml of HNO3 with a volume fraction of 50% and heat it to 90°C. Weigh 0.6013 g of rare earth oxide Tb4O7 and add it to HNO3. Mix and stir for 1 h to obtain a colorless and transparent solution.

[0081] (b) Evaporate the solution to dryness, add deionized water to dissolve, repeat 2-3 times to remove excess HNO3;

[0082] (c) According to the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 of 3:18.0:32:2.0, weigh 1.8094 g of Al(NO3)3·9H2O, 1.8014 g of citric acid and 0.0332 g of H3BO3 respectively, add them to the solution and stir for 1 h; then react the mixed solution at 80 °C for 3-4 h to obtain a light yellow gel;

[0083] (d) The pale yellow gel was dried and ground at 150°C to obtain precursor powder; the obtained precursor powder was sintered at high temperature. First, the temperature was raised to 600°C at a rate of 10°C / min and held for 1 hour, then raised to 1200°C and held for 3 hours, and finally cooled naturally to obtain ceramic fluorescent luminescent material.

[0084] The final phase transition temperature of the ceramic fluorescent material obtained in Example 3 is 899.5℃.

[0085] Example 4

[0086] Example 4 provides a method for preparing a ceramic fluorescent luminescent material, comprising the following steps:

[0087] (a) Measure 20 ml of 50% HNO3 and heat it to 90°C. Weigh 0.4060 g of rare earth oxide Tb4O7 and add it to HNO3. Mix and stir for 1 h to obtain a colorless and transparent solution.

[0088] (b) Evaporate the solution to dryness, add deionized water to dissolve, repeat 2-3 times to remove excess HNO3;

[0089] (c) According to the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 of 3:16.8:32:3.2, weigh 1.1403 g of Al(NO3)3·9H2O, 1.2163 g of citric acid and 0.0359 g of H3BO3 respectively, add them to the solution and stir for 1 h. Then react the mixed solution at 80 °C for 3-4 h to obtain a light yellow gel.

[0090] (d) The pale yellow gel was dried and ground at 150°C to obtain precursor powder; the obtained precursor powder was sintered at high temperature. First, the temperature was raised to 600°C at a rate of 10°C / min and held for 1 hour, then raised to 1200°C and held for 3 hours, and finally cooled naturally to obtain ceramic fluorescent luminescent material.

[0091] The final phase transition temperature of the ceramic fluorescent luminescent material obtained in Example 4 is 897.3℃.

[0092] As shown in Examples 1-4 above, the proportion of H3BO3 was adjusted during the experiment, which altered the microstructure of the ceramic phosphor and thus regulated its luminescence intensity. The samples prepared in Examples 1-4 were then tested and analyzed to obtain... Figure 1-5 The data is as follows:

[0093] Taking Example 4 as an example, Figure 1 Thermogravimetric-Differential Thermal (TG-DSC) curves of the precursor powder prepared by the sol-gel method are shown. Exothermic peaks are observed near 423.8℃ and 462.3℃, mainly due to the combustion of organic components in the precursor powder, corresponding to weight losses of 38.38% and 49.36%, respectively. An exothermic peak appears at 820.5℃, corresponding to the crystallization of the mesophase TAP, with a weight loss of 57.65%. An exothermic peak at 897.3℃ corresponds to the maximum phase transformation rate temperature of the TAG crystalline phase, with a weight loss of 60.46%. Above 900℃, the mass of the powder no longer changes with increasing temperature, indicating that at this stage, the organic matter in the sample has been fully combusted and the mesophase TAP has been completely converted into the final phase TAG.

[0094] Figure 2 These are X-ray diffraction patterns obtained by X-ray excitation of ceramic fluorescent luminescent materials prepared in different embodiments. First, it can be seen that the positions and intensities of the diffraction peaks of the ceramic fluorescent luminescent material powders prepared in each embodiment are similar to those of Tb3Al5O4. 12 The standard card (JCPDS#76-0111) is a perfect match, confirming that the obtained powder is a terbium aluminum garnet structure ceramic fluorescent luminescent material powder (TAG). Meanwhile, from... Figure 2 It can be observed that there are no other impurity peaks or diffraction peaks generated by the intermediate phase in the samples of Examples 1 to 3. It can be determined that the ceramic fluorescent luminescent material powders prepared in Examples 1 to 3 are all TAG phases and do not contain any impurity compounds. There are some TbBo3 peaks in Example 4, indicating that the intermediate phase was not completely removed under the conditions of Example 4.

[0095] Figure 3 These are scanning electron microscope images of the ceramic fluorescent materials prepared in Examples 2 and 4. It can be seen that the powder particle size in Example 2 is relatively uniform and the dispersion is good. In Example 4, it can be seen that some intermediate phases were not completely transformed, and the powder particle size dispersion and uniformity are poor.

[0096] Figure 4These are photoluminescence spectra of ceramic fluorescent materials prepared in different embodiments at an excitation wavelength of 275 nm. The figures show multiple significant emission peaks between 460-640 nm, with the maximum emission wavelength at 543 nm. Subsequent significant emission peaks are also observed at 490 nm, 589 nm, and 625 nm, corresponding to Tb values ​​respectively. 3+ Ionic 5 D4→ 7 F5 leap, 5 D4→ 7 F6 jump, 5 D4→ 7 F4 jump and 5 D4→ 7 The F3 transition is basically consistent with the emission peak position of TAG scintillation powder in the literature (Optical Materials 64 (2017) 557-563).

[0097] Figure 5 The image shows the cathodoluminescence spectrum of the ceramic fluorescent luminescent material prepared in Example 2. This spectrum was obtained by bombarding the ceramic fluorescent luminescent material powder with a 10keV electron beam (simulating β-ray energy range of 5.7-18.6keV). The obtained cathodoluminescence spectrum shows that the powder has multiple significant emission peaks between 460-640nm, with the maximum emission wavelength around 542nm. There are also relatively obvious emission peaks around 490nm, 590nm, and 629nm, which are basically consistent with the photoluminescence spectrum. This proves that the TAG powder also has a radioluminescence effect.

[0098] Taking the ceramic fluorescent luminescent materials prepared in Examples 1-3 above as examples, the ceramic fluorescent luminescent materials are dispersed on silica gel by the sol-gel method to prepare a self-luminous cold light source fluorescent luminescent material, including:

[0099] (a) Mix the corresponding solutions in a volume ratio of anhydrous ethanol: tetraethyl orthosilicate: deionized water: ceramic fluorescent material of 4:1:1:0.28. Stir using an electromagnetic stirrer until the liquid becomes a homogeneous suspension.

[0100] (b) Measure 2 mol / L of ammonia water and add it to the suspension in a volume ratio of 0.24:1 for ammonia water to tetraethyl orthosilicate. Stir until it becomes gel-like, then pour it into a mold and let it stand for 40 minutes to solidify.

[0101] (c) The solidified wet gel is placed in a reaction vessel, anhydrous ethanol is poured in to cover the wet gel, nitrogen gas at about 10 MPa is introduced, and a supercritical reaction is carried out at 250°C for 6 hours. After the pressure is released, the self-luminous cold light source fluorescent material is obtained.

[0102] Characterization of the prepared fluorescent luminescent material revealed that the ceramic fluorescent luminescent material can fully contact the β-ray radiation source to maximize its luminescence efficiency. At the same time, the silica aerogel has high light transmittance, with an average light transmittance of 72.4% to 75.8% in the wavelength range of 500 to 600 nm when the thickness is ~1 cm. It can guide the light inside the skeleton and reduce light loss. Furthermore, the ceramic fluorescent luminescent material based on the garnet structure has radiation resistance, which can effectively extend the lifespan of the light source affected by the material lifespan.

[0103] In the description of this specification, references to terms such as "an embodiment," "some embodiments," "implementation," "specific implementation," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of the present invention.

[0104] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a ceramic fluorescent luminescent material, characterized in that, Ceramic fluorescent luminescent materials are suitable for self-emissive cold light sources, and the method includes: (a) Heating an aqueous nitric acid solution to a first predetermined temperature, adding rare earth oxide Tb4O7 to react, and obtaining a colorless and transparent solution; (b) The solution obtained in step (a) is subjected to acid removal treatment, the solution is evaporated to dryness, and deionized water is added to dissolve it in order to remove excess nitric acid; (c) Add Al(NO3)3·9H2O, H3BO3 and citric acid according to a predetermined molar ratio, and react at a predetermined temperature to obtain a gel; the molar ratio of Tb4O7, Al(NO3)3·9H2O, citric acid and H3BO3 is one of 3:19.6:32:0.4, 3:18.8:32:1.2 and 3:18.0:32:2.0; (d) The gel is dried, ground, and sintered at high temperature to obtain the ceramic fluorescent luminescent material; the heating rate of the high temperature sintering is 10℃ / min, heated to 600℃ and held for 1h, then heated to 1200℃ and held for 3h, and finally cooled naturally to obtain the ceramic fluorescent luminescent material.

2. The preparation method according to claim 1, characterized in that, The volume fraction of the nitric acid aqueous solution used in step (a) is 40% to 65%.

3. The preparation method according to claim 1, characterized in that, In step (a), the first predetermined temperature is 80~110 degrees Celsius.

4. The preparation method according to claim 1, characterized in that, In step (a), the reaction time is 0.5 to 2 hours.

5. A ceramic fluorescent luminescent material, characterized in that, Prepared by the method according to any one of claims 1 to 4.

6. The use of the ceramic fluorescent luminescent material according to claim 5 in the preparation of fluorescent luminescent materials for self-luminous cold light sources.

7. A method for preparing a fluorescent luminescent material for a self-emissive cold light source, characterized in that, include: (1) Mix anhydrous ethanol, tetraethyl orthosilicate, deionized water and ceramic fluorescent luminescent material, and stir to obtain a suspension; (2) Add ammonia water to the suspension and stir until it becomes gel-like. Then pour it into a mold to solidify and obtain solidified silica wet gel. (3) The solidified silica wet gel was immersed in anhydrous ethanol and a supercritical reaction was carried out under nitrogen conditions to obtain the fluorescent light-emitting material for the self-luminous cold light source. The ceramic fluorescent luminescent material is the ceramic fluorescent luminescent material as described in claim 5.

8. The preparation method according to claim 7, characterized in that, The volume ratio of anhydrous ethanol: tetraethyl orthosilicate: deionized water: ceramic fluorescent luminescent material in step (1) is (3~5): 1: 1: (0.15~0.4). The volume ratio of ammonia and tetraethyl orthosilicate in step (2) is (0.15~0.5):1, and the concentration of ammonia is 1~4 mol / L.

9. The preparation method according to claim 7, characterized in that, The temperature of the supercritical reaction in step (3) is 200~350 degrees Celsius, and the time of the supercritical reaction is 4~10 hours.

Images