Rare earth doped luminescent material and preparation method and application thereof

Abstract

The invention discloses a rare earth doped luminescent material and a preparation method and application thereof, and belongs to the technical field of luminescent material preparation. The general chemical formula of the rare earth doped luminescent material provided by the invention is Cs2NaHoCl6: aTm < 3 + > and bYb < 3 + >, Tm < 3 + > and Yb < 3 + > replace part of Ho < 3 + >, a and b are respectively molar doping concentrations of Tm < 3 + > and Yb < 3 + >, and a is greater than or equal to 0.5% and less than or equal to 30%, b is greater than or equal to 10% and less than or equal to 90%, and a + blt is satisfied; 100%. The rare earth doped luminescent material provided by the invention realizes efficient excitation of near-infrared second window laser, shows excellent luminous intensity, and has excellent temperature sensing performance and multi-mode optical anti-counterfeiting capability. The preparation method of the material is simple and convenient, water is used as a unique solvent, reaction conditions are mild, and the product is high in purity and good in crystallinity.

Description

Technical Field

[0001] This invention relates to the field of luminescent material preparation technology, and in particular to a rare earth-doped luminescent material, its preparation method, and its application. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In the field of temperature sensing and optical anti-counterfeiting luminescent materials, developing materials that combine multi-mode luminescence with excellent environmental stability is an important research direction. Currently, high-sensitivity optical temperature sensing materials based on the fluorescence intensity ratio principle are mostly limited to ultraviolet light or traditional short-wavelength near-infrared light (such as 980nm) as their excitation source. These wavelengths have limited penetration ability in biological tissues and may affect the accuracy of temperature measurement or interfere with living tissues due to significant thermal effects. Therefore, developing temperature sensing materials that can be excited by long-wavelength near-infrared light with stronger tissue penetration and lower thermal effects is key to achieving high-precision in vivo and deep temperature sensing.

[0004] In the field of information security, optical anti-counterfeiting technology based on multi-band excitation enhances security by increasing information dimensionality and decoding complexity. While existing systems can achieve dual-mode anti-counterfeiting using both ultraviolet and a single near-infrared band (such as 980nm) excitation, the evolving counterfeiting techniques place increasingly higher demands on information encoding capacity and system security levels. There is an urgent need to develop new, independent excitation-response channels in the near-infrared region to construct a more logically complex and difficult-to-replicate multi-layered anti-counterfeiting system.

[0005] In addition, the synthesis of existing high-performance luminescent materials often relies on complex hydrothermal or solvothermal methods, which have significant limitations in terms of ease of preparation, environmental friendliness, and large-scale production.

[0006] In summary, developing a luminescent material that is simple and green to synthesize and can be efficiently excited by long-wavelength near-infrared light, thereby simultaneously meeting the requirements of high-performance temperature sensing and multi-dimensional optical anti-counterfeiting, is an urgent problem to be solved. Summary of the Invention

[0007] In view of this, the present invention provides a rare earth-doped luminescent material, its preparation method and application, the present invention by introducing Tm 3+ / Yb 3+ By pairing ions and optimizing their doping concentration, the material was first efficiently excited by 1208nm long-wavelength near-infrared light. It has excellent temperature sensing performance and multi-mode optical anti-counterfeiting capabilities, and its preparation method is green and simple.

[0008] In a first aspect, the present invention provides a rare-earth-doped luminescent material, wherein the general chemical formula of the rare-earth-doped luminescent material is Cs₂NaHoCl₆: aTm 3+ , bYb 3+ , wherein, the Tm 3+ and Yb 3+ Replace part of Ho 3+ a and b are Tm 3+ and Yb 3 + The molar doping concentrations must satisfy the following conditions: 0.5% ≤ a ≤ 30%, 10% ≤ b ≤ 90%, and a + b < 100%.

[0009] Preferably, 5% ≤ a ≤ 20%, 20% ≤ b ≤ 40%.

[0010] Furthermore, 5% ≤ a ≤ 10%, 25% ≤ b ≤ 35%.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned rare-earth-doped luminescent material, comprising the following steps: Cesium source, sodium source, holmium source, thulium source and ytterbium source are dissolved in water in stoichiometric ratio, stirred and reacted, and then dried to obtain the rare earth doped luminescent material.

[0012] Preferably, the temperature of the stirring reaction is 10~40℃, and the stirring reaction time is 20~90min.

[0013] Furthermore, the temperature of the stirring reaction is 20~30℃, and the stirring reaction time is 20~40min.

[0014] Preferably, the cesium source is cesium chloride; the sodium source is sodium chloride; the holmium source is holmium chloride; the thulium source is thulium chloride; and the ytterbium source is ytterbium chloride.

[0015] Preferably, the drying temperature is 40~90℃ and the drying time is 1~7 days.

[0016] Thirdly, the present invention provides the application of the above-mentioned rare earth-doped luminescent material or the rare earth-doped luminescent material prepared by the above-mentioned preparation method in optical temperature sensing.

[0017] Fourthly, the present invention provides the application of the above-mentioned rare earth-doped luminescent material or the rare earth-doped luminescent material prepared by the above-mentioned preparation method in optical anti-counterfeiting or information encryption.

[0018] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) The rare earth-doped luminescent material provided by the present invention introduces Tm 3+ / Yb 3+By pairing ions and optimizing their doping concentration, efficient excitation of laser light in the near-infrared second window (1208 nm) was achieved, exhibiting excellent luminescence intensity. This characteristic not only significantly reduces the impact of photothermal effects on the measurement system, but also gives it the unique potential for non-invasive, high-precision temperature sensing in deep biological tissues.

[0019] (2) The rare earth doped luminescent material provided by the present invention has tunable luminescence characteristics in multiple independent bands such as ultraviolet, 980 nm and 1208 nm. It can be used as a key component to construct a multi-dimensional optical response system, which greatly improves the encoding capacity, decryption complexity and overall security in information encryption and advanced anti-counterfeiting applications.

[0020] (3) The method for preparing rare earth doped luminescent materials provided by the present invention uses water as the only solvent and can be completed under mild temperature conditions, avoiding complex hydrothermal processes or the use of organic reagents. It is an environmentally friendly, simple and easy-to-scale green synthesis route, and the product has high purity and good crystallinity. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Obviously, those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0022] Figure 1 These are the emission spectra of the materials prepared in Examples 1-11 of this invention under 980nm laser excitation; Figure 2 This refers to the luminescence intensity at 548 nm of the materials prepared in Examples 1-7 of this invention under 980 nm laser excitation; Figure 3 These are the emission spectra of the materials prepared in Examples 1-11 of this invention under 1208nm laser excitation; Figure 4 This refers to the luminescence intensity at 548 nm of the materials prepared in Examples 1-7 of this invention under 1208 nm laser excitation; Figure 5 These are the emission spectra of the materials prepared in Examples 12-22 of this invention under 980nm laser excitation; Figure 6 This refers to the luminescence intensity at 548 nm of the materials prepared in Examples 12-22 of this invention under 980 nm laser excitation; Figure 7These are the emission spectra of the materials prepared in Examples 12-22 of this invention under 1208nm laser excitation; Figure 8 This refers to the luminescence intensity at 546 nm of the materials prepared in Examples 12-22 of this invention under 1208 nm laser excitation; Figure 9 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ Scanning electron microscope images of the material; Figure 10 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ X-ray diffraction pattern of the material; Figure 11 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The fluorescence spectrum of the material under 980nm laser irradiation as a function of temperature; Figure 12 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The relationship between fluorescence intensity at 491 nm and temperature under 980 nm laser irradiation; Figure 13 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The relationship between fluorescence intensity at 549 nm and temperature under 980 nm laser irradiation; Figure 14 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The relationship between fluorescence intensity at 661 nm and temperature under 980 nm laser irradiation; Figure 15 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The relationship between fluorescence intensity at 807 nm and temperature under 980 nm laser irradiation; Figure 16 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+The fluorescence spectrum of the material under 1208nm laser irradiation as a function of temperature; Figure 17 The Cs2NaHoCl6:10%Tm prepared in Example 16 of this invention is an example of this invention. 3+ 30%Yb 3+ The relationship between fluorescence intensity at 547 nm and temperature under 1208 nm laser irradiation; Figure 18 It is an anti-counterfeiting image of the "starfish" pattern preset in the application example of the present invention, excited by 980nm laser, 365nm LED, and 254nm LED. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] This invention provides a rare-earth-doped luminescent material, the general chemical formula of which is Cs₂NaHoCl₆:aTm 3+ , bYb 3+ , wherein, the Tm 3+ and Yb 3+ Replace part of Ho 3+ a and b are Tm 3+ and Yb 3+ The molar doping concentrations must satisfy the following conditions: 0.5% ≤ a ≤ 30%, 10% ≤ b ≤ 90%, and a + b < 100%.

[0025] This invention chooses Cs₂NaHoCl₆ as the matrix material because it possesses a stable cubic double perovskite structure, which can provide a suitable octahedral crystal field environment for trivalent rare earth ions. This invention uses Tm 3+ and Yb 3+ Replacing part of Ho in the crystal lattice 3+ The site can achieve solid solution doping without severely damaging the main crystal lattice, thereby ensuring that the resulting material can maintain excellent phase purity and structural stability.

[0026] In the rare earth-doped luminescent material of the present invention, Yb 3+ As the primary sensitizing ion, an appropriate doping concentration enables effective absorption of excitation light and provides the foundation for the energy transfer network; Tm 3+ As a key intermediate activating ion, its concentration range is set to ensure that it can effectively receive Yb. 3+ The energy can be efficiently transferred to the luminous center Ho. 3+At the same time, it avoids luminescence quenching caused by its own excessive concentration.

[0027] In optional embodiments of the present invention, 5% ≤ a ≤ 20%, 20% ≤ b ≤ 40%. More preferably, 5% ≤ a ≤ 10%, 25% ≤ b ≤ 35%. In one or more embodiments of the present invention, a = 10%, b = 30%. A suitable doping concentration range can further ensure the sensitized ions (Yb 3+ ), intermediate ions (Tm) 3+ ) and luminescent central ion (Ho) 3+ The spatial distance and interaction strength among the three elements reach an optimal synergistic state, thereby enabling the material to exhibit significantly enhanced luminescence intensity and efficiency at the target excitation wavelength.

[0028] The present invention also provides a method for preparing the above-mentioned rare-earth-doped luminescent material, comprising the following steps: Cesium source, sodium source, holmium source, thulium source and ytterbium source are dissolved in water in stoichiometric ratio, stirred and reacted, and then dried to obtain the rare earth doped luminescent material.

[0029] The preparation method of the present invention uses water as a green solvent to uniformly mix all metal ions constituting the target product in the form of soluble salts at the molecular / ionic level. Then, through a gentle evaporation and drying process, the solution is driven to become supersaturated, thereby inducing crystallization and finally obtaining rare earth-doped luminescent materials with good crystallinity and high purity.

[0030] In an optional embodiment of the present invention, the temperature of the stirring reaction is 10~40℃, more preferably 20~30℃, and preferably carried out at room temperature. The stirring reaction time is 20~90min, more preferably 20~40min.

[0031] In an optional embodiment of the present invention, the cesium source is cesium chloride (CsCl); the sodium source is sodium chloride (NaCl); the holmium source is holmium chloride (HoCl3); the thulium source is thulium chloride (TmCl3); and the ytterbium source is ytterbium chloride (YbCl3). All raw materials provide chloride ions (Cl... - The chlorides are completely identical to the anions in the target product, thus avoiding the introduction of foreign heteroatoms at the source and greatly ensuring the phase purity of the final product. Furthermore, chlorides exhibit good solubility in aqueous systems, are chemically stable, do not readily undergo complex hydrolysis reactions, and easily form the target crystalline phase.

[0032] To accurately control the doping concentration, the purity of the raw materials used should not be less than 99.9%. Holmium source, thulium source, and ytterbium source can be anhydrous chloride or trichloride hydrate (such as HoCl3·6H2O, TmCl3·6H2O, YbCl3·6H2O, etc.). This invention does not impose any special restrictions on this.

[0033] In optional embodiments of the present invention, the drying temperature is 40-90°C, more preferably 50-80°C; the drying time is 1-7 days, more preferably 3-6 days, and even more preferably 4-6 days. The drying process is a gentle solvent evaporation and crystallization process, ensuring that the solvent is removed slowly, uniformly, and completely, thereby obtaining a product with good crystallinity and few defects.

[0034] The present invention also provides the application of the above-mentioned rare earth-doped luminescent material or the rare earth-doped luminescent material prepared by the above-mentioned preparation method in optical temperature sensing.

[0035] The rare-earth-doped luminescent material provided by this invention can generate multiple emission peaks from different thermally coupled energy levels under near-infrared light (980nm and 1208nm) excitation. For example, under 980nm laser excitation, the fluorescence intensity at 491nm, 549nm, 661nm and 807nm changes linearly with increasing temperature, and under 1208nm laser excitation, the fluorescence intensity at 547nm changes linearly with increasing temperature. Therefore, a standard curve between fluorescence intensity and temperature can be obtained, and non-contact measurement of unknown temperature can be achieved by measuring the fluorescence intensity of the material at an unknown temperature.

[0036] This invention also provides applications of the above-mentioned rare-earth-doped luminescent materials or rare-earth-doped luminescent materials prepared by the above-mentioned preparation methods in optical anti-counterfeiting or information encryption. The above-mentioned applications of this invention utilize the multi-mode, multi-wavelength luminescent properties of the materials. The rare-earth-doped luminescent materials provided by this invention can emit visible light of different colors or intensities when excited at different wavelengths (254nm, 365nm, 980nm, 1208nm).

[0037] This invention does not impose any special limitations on specific applications. For example, the material of this invention can be combined with materials that respond to other wavelengths in a specific spatial pattern to create anti-counterfeiting labels or encrypted patterns. The preset "key" is the color that a certain pattern area will display under a certain excitation light. During verification, multiple wavelength excitation light sources (covering ultraviolet to near-infrared) are used to irradiate the area sequentially, and the displayed pattern sequence is compared to see if it is completely consistent with the preset key.

[0038] The technical solution of the present invention will be further described below with reference to specific embodiments. The present invention does not impose any special restrictions on the source of reagents used in the following embodiments; commercially available products well known to those skilled in the art can be used.

[0039] Example 1 This embodiment provides Cs2NaHoCl6: 0.5%Tm 3+ 1%Yb 3+ Material preparation.

[0040] (1) Add 0.3367g cesium chloride (2.0 mmol), 0.0584g sodium chloride (1.0 mmol), 0.05mL 0.1 M thulium chloride aqueous solution (0.005 mmol), 0.010mL 1 M ytterbium chloride aqueous solution (0.010 mmol), and 0.3737g holmium chloride hexahydrate (0.985 mmol) to a test tube. Then add 2mL ultrapure water and a magnetic stir bar, place the tube on a magnetic stirrer, and stir for 30min at room temperature (25±3℃) until the solution is clear.

[0041] (2) Place the clear solution obtained in step (1) into a drying oven at 60℃ and dry for 5 days to obtain a solid. Grind the solid into powder to obtain Cs2NaHoCl6: 0.5%Tm 3+ 1%Yb 3+ Material.

[0042] Examples 2-11 The preparation process of Examples 2 to 11 is the same as that of Example 1, except that the amount of materials used is different. The specific differences are summarized in Table 1.

[0043] Table 1. Materials and molar amounts of ingredients in Examples 1-11

[0044] The emission spectra of the materials prepared in Examples 1-11 under 980nm laser excitation are shown below. Figure 1 As shown, the luminescence intensity at 548 nm of the materials prepared in Examples 1-7 under 980 nm laser excitation is as follows: Figure 2 As shown, it can be seen that when Yb 3+ The luminescence intensity was highest when the molar doping concentration was 30%. The emission spectra of the materials prepared in Examples 1-11 under 1208 nm laser excitation are shown below. Figure 3 As shown, the luminescence intensity at 548 nm of the materials prepared in Examples 1-7 under 1208 nm laser excitation is as follows: Figure 4 As shown, it can be seen that when Yb 3+ The highest luminescence intensity was observed at a molar doping concentration of 60%, followed by a second highest at 30%. Considering all factors, Yb was selected. 3+ The optimal molar doping concentration is 30%.

[0045] Examples 12-22 The preparation process of Examples 12-22 is the same as that of Example 1, except that the amount of materials used is different. The specific differences are summarized in Table 2.

[0046] Table 2 Materials and molar amounts of ingredients in Examples 12-22

[0047] The emission spectra of the materials prepared in Examples 12-22 under 980nm laser excitation are shown below. Figure 5 As shown, the luminescence intensity at 548 nm under 980 nm laser excitation is as follows: Figure 6 As shown, it can be seen that when Tm 3+ The luminescence intensity was highest at a molar doping concentration of 5%, and second highest at 10%. The emission spectra of the materials prepared in Examples 12-22 under 1208 nm laser excitation are shown below. Figure 7 As shown, the luminescence intensity at 546 nm under 1208 nm laser excitation is as follows: Figure 8 As shown, it can be seen that when Tm 3+ The light emission intensity is highest when the molar doping concentration is 10%, and second highest when it is 5%.

[0048] Test case 1. Morphological characteristics The Cs2NaHoCl6 prepared in Example 16: 10%Tm 3+ 30%Yb 3+ The material was tested using scanning electron microscopy, and the results are as follows: Figure 9 As shown in the figure, the prepared Cs2NaHoCl6: 10%Tm 3+ 30%Yb 3+ The material exhibits a blocky structure with some stacking and aggregation between the blocks. Some areas form a layered or radial arrangement. The structure contains a small number of holes or gaps, the surface is relatively flat, and the boundaries of the blocky structure are clear.

[0049] 2. X-ray diffraction (XRD) characterization The Cs2NaHoCl6 prepared in Example 16: 10%Tm 3+ 30%Yb 3+ The material was subjected to XRD testing, such as Figure 10 As shown, the test results are consistent with the standard card (PDF#04-014-4493), indicating that the prepared Cs2NaHoCl6: 10%Tm 3+ 30%Yb 3+ The material is pure phase, free from impurity peaks, has good crystallinity, and high purity.

[0050] Application examples 1. Temperature sensing experiment: The Cs2NaHoCl6 prepared in Example 16: 10%Tm 3+ 30%Yb 3+ The material was placed in a variable-temperature device and heated. Under 980nm laser irradiation, the fluorescence spectrum of the material was measured using a spectrometer, and the fluorescence spectrum as a function of temperature was obtained. Figure 11 As shown, the emission peaks are at 491 nm, 549 nm, 661 nm, and 807 nm. The excitation source used is 980 nm with a power of 1.3 W. Then, the relationship between fluorescence intensity at 491 nm, 549 nm, 661 nm, and 807 nm under 980 nm excitation and temperature is plotted, as shown in the figures. Figure 12 , Figure 13 , Figure 14 , Figure 15 As shown, the fluorescence intensity of the material has a linear relationship with temperature, therefore, the unknown temperature can be tested based on the obtained linear fitting curve.

[0051] The Cs2NaHoCl6 prepared in Example 16: 10%Tm 3+ 30%Yb 3+ The material was placed in a temperature-controlled device and heated. Under 1208nm laser irradiation, the fluorescence spectrum of the material was measured using a spectrometer, and the fluorescence spectrum as a function of temperature was obtained, as shown in the figure. Figure 16 As shown in the figure. The relationship between fluorescence intensity at 547 nm and temperature is shown in the figure. Figure 17 As shown, the fluorescence intensity of the material is linearly related to temperature, so unknown temperatures can be tested based on the obtained linear fitting curve.

[0052] 2. Anti-counterfeiting test Preparation of carbon dot nanoparticles: 0.1 mol citric acid and 20 mL water were added to a beaker and stirred until homogeneous. 0.2 mol ethanolamine was added to the solution, and the mixture was stirred vigorously to obtain a clear solution. The mixture was sealed in an autoclave and heated to 180 °C for 6 hours to obtain a reddish-brown liquid, which is the carbon dot nanoparticle solution.

[0053] Zn2GeO4:1%Mn 2+Preparation of nanoparticles: Zn(NO3)2 (1.98 mmol, 99%) and MnCl2 (0.02 mmol, 1%) were added to a beaker, followed by 300 μL of 1% dilute nitric acid and 20 mL of water. The mixture was stirred until homogeneous. 10 mmol of NaOH was dissolved in 10 mL of aqueous solution until completely dissolved. Then, 2 mmol of GeO2 was added to the solution, and the mixture was stirred to obtain a Na2GeO3 solution. 5.5 mL of the Na2GeO3 solution was added to the beaker using a syringe, and the mixture was stirred for 30 min. The pH of the mixture was adjusted to 7.58 using 1% (mass fraction) sodium hydroxide, and the mixture was stirred for 30 min. The mixture was then transferred to a hydrothermal reactor and maintained at 220℃ for 16 h. The resulting solution was centrifuged at 10000 r / min for 10 min, washed with water, and dried to obtain Zn2GeO4:1%MnCl2. 2+ Nanoparticles.

[0054] The anti-counterfeiting experiment is as follows: (1) Take an appropriate amount of polyvinyl alcohol and put it into three beakers containing 20 ml of water respectively. Stir thoroughly to dissolve it, and then add Cs2NaHoCl6 (10% Tm) prepared in Example 16 to each beaker. 3+ 30%Yb 3+ Materials: Zn2GeO4:1%Mn 2 + Different inks were obtained by mixing the powder and carbon nanoparticle solution evenly.

[0055] (2) Prepare suitable cardstock, cover the starfish cutout pattern, coat with the ink obtained above, and dry to obtain the corresponding pattern. When coating, select the central disc area of ​​the starfish and coat it with Cs2NaHoCl6: 10%Tm. 3+ 30%Yb 3+ Materials: Selected brachial regions of starfish were coated with Zn2GeO4:1%Mn 2+ Nanoparticles (emitting green light upon 254nm illumination) are used, while the remaining carpal regions are coated with carbon dot nanoparticles (emitting blue light upon 365nm illumination). This distribution pattern is used as the encryption key. During verification, different wavelengths (254nm, 365nm, 980nm) are used for excitation, the distribution pattern is read, and compared with the preset key. Figure 18 The image shows a preset anti-counterfeiting pattern. The excitation light sources used are 254nm, 365nm, and 980nm, which simultaneously irradiate Zn2GeO4:1%Mn. 2+ Nanoparticle coated region, carbon dot nanoparticle coated region, and Cs2NaHoCl6: 10%Tm 3+ 30%Yb 3+ Material coating area.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rare-earth-doped luminescent material, characterized in that, The rare-earth-doped luminescent material has the general chemical formula Cs₂NaHoCl₆: aTm 3+ , bYb 3+ , wherein, the Tm 3+ and Yb 3+ Replace part of Ho 3+ a and b are Tm 3+ and Yb 3+ The molar doping concentrations are such that: 0.5% ≤ a ≤ 30%, 10% ≤ b ≤ 90%, and a + b < 100%.

2. The rare-earth-doped luminescent material as described in claim 1, characterized in that, 5%≤ a ≤20%, 20%≤ b ≤40%.

3. The rare-earth-doped luminescent material as described in claim 2, characterized in that, 5%≤ a ≤10%, 25%≤ b ≤35%.

4. The method for preparing rare-earth-doped luminescent materials according to any one of claims 1 to 3, characterized in that, Includes the following steps: Cesium source, sodium source, holmium source, thulium source and ytterbium source are dissolved in water in stoichiometric ratio, stirred and reacted, and then dried to obtain the rare earth doped luminescent material.

5. The preparation method according to claim 4, characterized in that, The temperature of the stirring reaction is 10~40℃, and the stirring reaction time is 20~90min.

6. The preparation method according to claim 5, characterized in that, The temperature of the stirring reaction is 20~30℃, and the stirring reaction time is 20~40min.

7. The preparation method according to claim 4, characterized in that, The cesium source is cesium chloride; the sodium source is sodium chloride; the holmium source is holmium chloride; the thulium source is thulium chloride; and the ytterbium source is ytterbium chloride.

8. The preparation method according to claim 4, characterized in that, The drying temperature is 40~90℃, and the drying time is 1~7 days.

9. The application of the rare earth-doped luminescent material as described in any one of claims 1 to 3 or the rare earth-doped luminescent material prepared by the preparation method as described in any one of claims 4 to 8 in optical temperature sensing.

10. The application of the rare earth-doped luminescent material as described in any one of claims 1 to 3 or the rare earth-doped luminescent material prepared by the preparation method as described in any one of claims 4 to 8 in optical anti-counterfeiting or information encryption.

Images