Rare earth doped multicolor wide temperature long afterglow luminescent material, preparation method and application thereof

Abstract

The application discloses a rare earth doped multicolor wide-temperature long afterglow luminescent material, a preparation method and application thereof, and the material has a chemical formula of LaF3:Ln 3+ (Ln 3+ =Tb 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Dy 3+ , Er 3+ , Tm 3+ ) and belongs to the application field of rare earth luminescent materials. The LaF3:Ln 3+ fluorescent material prepared by the application has a significant long afterglow phenomenon in a wide temperature range after X-ray irradiation. Data results show that the LaF3:Tb 3+ fluorescent material has a significant afterglow phenomenon in a wide temperature range of 80 K-500 K, the afterglow at a 300 K shallow trap energy level lasts for about 48 hours, and the energy stored in a 420 K deep trap energy level has a significant thermal excitation luminescence phenomenon. In addition, other rare earth doped LaF3 also has a significant long afterglow emission after X-ray irradiation, and the temperature range can cover 80 K-300 K. Based on this, the application shows the application of the material in X-ray afterglow imaging and thermal anti-counterfeiting, and indicates that the material has potential application value in the field of optical information storage.

Description

TECHNICAL FIELD

[0001] The present application belongs to the application field of rare earth luminescent materials, and particularly relates to a kind of rare earth doped multi-color wide temperature long afterglow luminescent material and a preparation method and application thereof. BACKGROUND

[0002] Long afterglow luminescent materials have the ability to store excitation light energy and continue to emit light for a long time after the excitation source stops. Due to their fascinating properties, long afterglow materials have been widely used in the fields of display, anti-counterfeiting, information storage, night vision, and biological labeling. It is generally believed that the main elements that can affect the persistent luminescence of long afterglow materials include two: luminescent centers and traps. Luminescent centers can spontaneously radiate and release fluorescence after being excited. Common luminescent centers are usually transition metal ions or lanthanide ions, such as Mn 2+ , Cr 3+ , or Eu 2+ , Ce 3+ , etc. In afterglow materials, traps that can capture carriers (electrons or holes) mainly come from intrinsic defects, doping defects of the crystal, and anion vacancy defects induced by high-energy radiation. These traps slowly release carriers after excitation, thereby achieving persistent luminescence.

[0003] Temperature dependence is a key characteristic of long afterglow materials. By precisely controlling the temperature, the release rate of traps to electrons can be effectively adjusted, thereby optimizing the application performance of long afterglow materials in energy storage. Currently, most researches mainly focus on low-temperature or high-temperature long afterglow materials at specific temperatures to achieve energy storage at specific temperatures. However, long afterglow materials with a wide temperature response range can exhibit long afterglow luminescence phenomena in a wide temperature range from low temperature to high temperature, which makes them have greater potential in realizing complex multi-temperature energy storage. However, it is difficult to construct traps for wide temperature long afterglow materials, and therefore there are fewer related research reports. In addition, the effect of constructing traps by specific rare earth ion doping depends largely on the type of rare earth ion, which limits the further development of long afterglow materials as the luminescence of existing long afterglow materials is usually single. Therefore, it is particularly important to develop a long afterglow material with a wide temperature response and multi-color luminescence characteristics. SUMMARY

[0004] The present application provides a kind of rare earth doped multi-color wide temperature long afterglow luminescent material and a preparation method and application thereof, and its chemical formula is LaF3:Ln 3+ (Ln 3+ =Tb 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Dy3+ Er 3+ , Tm 3+ This material possesses a simple synthesis method and excellent chemical stability. By replacing different rare-earth ions, multicolor long-afterglow luminescence effects can be achieved. Furthermore, based on a unique X-ray induced anion vacancy mechanism, the afterglow phenomenon can be effectively exhibited over a wider temperature range. With appropriate processing, this material can be applied to fields such as X-ray afterglow imaging and thermal anti-counterfeiting, demonstrating significant application value.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a class of rare-earth-doped multicolor wide-temperature long-afterglow luminescent materials, the specific process of which is as follows:

[0007] (1) Dissolve the soluble salts of La and Ln in deionized water to obtain rare earth ion salt solutions, and dissolve the fluoride ion salt in deionized water to obtain fluoride ion salt solutions; then, transfer the fluoride ion salt solution to the rare earth ion salt solution, stir evenly, and then transfer it to a hydrothermal reactor, heat to 200~220℃ and maintain for 10~15 hours. After the reaction is completed, centrifuge, collect the solid and dry it to obtain the chemical formula LaF3:Ln. 3+ Rare earth doped materials, dopant ion Ln 3+ For Tb 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Dy 3+ Er 3+ , Tm 3+ One or more of the following;

[0008] (2) The material obtained in step (1) is irradiated with X-rays to obtain the final product.

[0009] Further, in step (1), the soluble salt of La refers to a mixture of one or more of La(NO3)3, LaCl3, and La(CH3COO)3 in any proportion, and the soluble salt of Ln refers to a mixture of one or more of Ln(NO3)3, LnCl3, and Ln(CH3COO)3 in any proportion; the soluble salt of Ln accounts for 0.2% to 20% of the total molar amount of the soluble salts of La and Ln.

[0010] Further, in step (1), the fluoride salt is one or a mixture of two of NH4F and NH4HF2 in any proportion, and the molar amount of the fluoride salt is three times the total molar amount of the soluble salts of La and Ln.

[0011] Preferably, in step (1), the concentration of the rare earth ion salt in the rare earth ion salt solution is 0.1-0.5 mmol / mL, and the concentration of the fluoride ion salt in the fluoride ion salt solution is 1-5 mmol / mL.

[0012] Further, in step (2), the X-ray irradiation refers to irradiation for 1-6 minutes at a current of 100 muA and a voltage of 30-70 kV.

[0013] The rare earth-doped multi-color wide-temperature long-persistence luminescent material prepared by the preparation method has the advantages that the LaF3:Tb 3+ has a long-persistence phenomenon at 80-500 K, and the LaF3:Tb 3+ has a long-persistence phenomenon at 80-300 K.

[0014] The rare earth-doped multi-color wide-temperature long-persistence luminescent material has the advantages of wide temperature range, long persistence, and multi-color.

[0015] A LaF3:Ln film containing the rare earth-doped multi-color wide-temperature long-persistence luminescent material has the advantages of wide temperature range, long persistence, and multi-color. 3+ The PDMS film is prepared as follows:

[0016] The LaF3:Ln film is prepared as follows: 3+ The prepared powder is mixed with PDMS at a mass ratio of 1:2-4, mechanically stirred, and then dropped onto a substrate to spin-coat the LaF3:Ln film. 3+ The PDMS film is dried, peeled off from the substrate, and obtained.

[0017] A security label capable of thermal-induced security printing and containing the rare earth-doped multi-color wide-temperature long-persistence luminescent material has the advantages of wide temperature range, long persistence, and multi-color.

[0018] The LaF3:Ln film is prepared as follows: 3+ The prepared powder is molded into a shape through a mold and shaped through an adhesive.

[0019] The present application has the advantages of finding a long-persistence luminescent material which is easy to synthesize, has high stability, and has a simple structure. The material can realize multi-color long-persistence luminescence through different rare earth ion doping, and solve the problem of single color of general long-persistence luminescent materials. In addition, the long-persistence luminescence of the material is induced by X, so that the intensity of X can effectively improve the intensity of the long-persistence luminescence. Importantly, the long-persistence phenomenon of the material can cover a wider temperature range. Among them, the Tb 3+The long-afterglow luminescence of this material can cover a temperature range of 80 K-500 K, while the long-afterglow luminescence of other rare earth ions can cover a temperature range of 80 K-300 K. This solves the problem that common long-afterglow materials can only be used at specific temperatures. Based on these excellent properties, after encapsulating this material with commonly used PDMS into a film, afterglow imaging after X-ray excitation can be achieved. The advantage of this imaging is that the imaging information can be retained on the film for a long time, eliminating the harm of repeated X-ray irradiation. In addition, the material can be made into anti-counterfeiting labels by simply molding it with a mold. After being charged with X-rays, the material stores some electrons in deep traps, which makes the anti-counterfeiting label exhibit bright fluorescent emission at high temperatures, thereby achieving the purpose of anti-counterfeiting. Attached Figure Description

[0020] Figure 1 For the present invention, LaF3: x%Tb 3+ (x = 0.2-20) X-ray diffraction pattern of powder;

[0021] Figure 2 Different concentrations of LaF3 in this invention: x%Tb 3+ (x = 0.2-20) Comparison of luminescence intensity of powders under X-ray excitation;

[0022] Figure 3 In the middle: (a) and (b) are LaF3: 5%Tb of the present invention. 3+ (c) Afterglow duration at 30 ℃ and 220 ℃; (d) Crystal morphology of the material synthesized at 220 ℃;

[0023] Figure 4 In the middle: (a) is LaF3:5%Tb at room temperature. 3+ (a) Long afterglow decay curves, with insets showing afterglow photographs and afterglow spectra at 20 seconds and 10 hours; (b) LaF3:5%Tb detected by Edinburgh FLS1000. 3+ Afterglow spectrum after 48 hours;

[0024] Figure 5 The present invention is LaF3:5%Tb 3+ Long afterglow decay curves at temperatures ranging from 80 K to 500 K;

[0025] Figure 6 In the middle: (a) LaF3:5%Tb under different X-ray intensities at room temperature 3+ (a) Long afterglow decay curve; (b) LaF3:5%Tb irradiated for different X-ray exposure times at room temperature. 3+ The long afterglow decay curve;

[0026] Figure 7LaF3:5%Ln doped with different rare earth ions 3+ LaF3:5%Ln doped with different rare earth ions 3+ Color coordinates of their emission spectra

[0027] Figure 8 LaF3:5%Ln doped with different rare earth ions 3+ Long afterglow decay curves after X-ray excitation, monitoring temperature from 80 K to 300 K, Figure 8 The attached figure is the afterglow luminescence photo of the corresponding rare earth;

[0028] Figure 9 LaF3:5%Tb doped with different rare earth ions 3+ @PDMS film afterglow imaging flow chart; (b) LaF3:5%Tb 3+ Afterglow imaging actual effect image; (c) LaF3:5%Tb 3+ Thermal release curve with temperature change; (d) LaF3:5%Tb 3+ Comparison of afterglow intensity after repeated charging and thermal release; (e) LaF3:5%Tb 3+ Thermal anti-counterfeiting flow chart; (f) LaF3:5%Tb 3+ LaF3:5%Sm 3+ Thermal anti-counterfeiting effect diagram with temperature color change. DETAILED DESCRIPTION

[0029] The technical solutions of the present application will be further described in detail below in combination with the drawings and examples, but the protection scope of the present application is not limited thereto.

[0030] Example 1

[0031] A preparation method of a kind of rare earth doped multi-color wide temperature long afterglow luminescent material, comprising the following steps:

[0032] LaF3: Ln 3+ LaF3:5%Ln doped with different rare earth ions are synthesized by hydrothermal synthesis method. Specifically, 0.95 mmol La (NO3) 3·6H2O and 0.05 mmol Ln (NO3) 3·6H2O are dissolved in 10 mL deionized water to obtain a Ln (NO3) 3·6H2O solution. 3 mmol NH4F is dissolved in 3 mL deionized water to obtain an NH4F solution. Then, the NH4F solution is transferred to the Ln (NO3) 3·6H2O solution, stirred and kept for 5 minutes. Next, the reaction solution is poured into a 25 mL hydrothermal reactor, heated to 220 ℃ and kept for 12 hours. After the reaction is completed, centrifugation is performed, the solid is collected, and vacuum drying is performed at 70 ℃ for 12 h to obtain LaF3:5%Ln.3+ , the rare earth ion Ln is one of Tb 3+ , Pr 3+ , Nd 3+ , Sm 3+ , Dy 3+ , Er 3+ , Tm 3+ .

[0033] By changing the doping ratio of Ln(NO3)3·6H2O, i.e. the molar ratio of La(NO3)3·6H2O and Ln(NO3)3·6H2O, for example, when the doping ratio of Ln(NO3)3·6H2O is 10%, the amount of La(NO3)3·6H2O added is 0.9 mmol and the amount of Ln(NO3)3·6H2O added is 0.1 mmol, other doping ratios of LaF3:Ln 3+ , the present application specifically synthesizes LaF3:0.2%Ln 3+ , LaF3:0.5%Ln 3+ , LaF3:1.0%Ln 3+ , LaF3:2.5%Ln 3+ , LaF3:5.0%Ln 3+ , LaF3:10%Ln 3+ , LaF3:15%Ln 3+ , LaF3:20%Ln 3+ .

[0034] Taking Tb(NO3)3·6H2O as an example, the X-ray diffraction pattern of the synthesized LaF3: x%Tb 3+ (x = 0.2-20) powder is shown in Figure 1 , and it can be seen from Figure 1 that the X-ray diffraction pattern thereof corresponds to the standard structure PDF #32-0483, proving that it has a good hexagonal phase structure. By doping Tb ions, the lattice of LaF3 will shrink, resulting in the overall diffraction angle being shifted to a high angle, proving the successful incorporation of rare earth ions.

[0035] Figure 2 The comparison of the luminescence intensity of the synthesized LaF3: x%Tb 3+ (x = 0.2-20) powder under X-ray excitation is shown in Figure 2 It can be seen from Figure 2 that when the content of rare earth ion doping is gradually increased, the overall luminescence intensity shows a trend of first increasing and then decreasing, and in the present application, the optimal doping concentration of rare earth ions is about 5%.

[0036] Figure 7 (a) is LaF3:5%Ln doped with different rare earth ions in the present application3+ (Ln 3+ = Tb 3+ , Pr 3+ , Nd 3+ ,Sm 3+ , Dy 3+ , Er 3+ , Tm 3+ ) in X-ray excitation. The tube voltage of X-ray is 50 kV, the tube current is 100 μA, and the irradiation time is 1 minute. Figure 7 (b) LaF3: 5%Ln 3+ The color coordinate spectrum corresponding to the emission spectrum of the above data proves the multi-color emission ability of the above materials in X-ray excitation.

[0037] Figure 8 (a)-(f) show the emission spectra of LaF3: 5%Ln 3+ (Ln 3+ = Pr 3+ , Nd 3+ ,Sm 3+ , Dy 3+ , Er 3+ , Tm 3+ ) in X-ray excitation. The tube voltage of X-ray is 50 kV, the tube current is 100 μA, and the irradiation time is 1 minute. Different temperatures are achieved on the temperature-variable stage built in FLS1000 by controlling the injection rate of liquid nitrogen and the electric heating rate of the sample stage. The above data show that the above rare earth ions can basically cover the temperature range from low temperature 80 K to room temperature 300 K. Figure 8 The photographs of afterglow luminescence of LaF3: Ln 3+ doped with different rare earth ions show the characteristics of afterglow multi-color. The above data show that LaF3 can be doped with different rare earth ions to effectively adjust the afterglow color, which is of great significance to overcome the problem that only single color afterglow can be achieved in traditional materials.

[0038] Example 2

[0039] Effect of different synthesis temperatures on the afterglow performance of LaF3: 5%Tb 3+ : 5%Tb

[0040] Two 0.95 mmol La(NO3)3·6H2O and 0.05 mmol Tb(NO3)3·6H2O were taken respectively and dissolved in 10 mL deionized water to obtain Ln(NO3)3·6H2O solution. 3 mmol NH4F was dissolved in 3 mL deionized water to obtain NH4F solution. Then, the NH4F solution was transferred to the Ln(NO3)3·6H2O solution, stirred and kept for 5 minutes. Next, the reaction solution was poured into a 25 mL hydrothermal reactor, heated to 30 ℃ for 12 hours and 220 ℃ for 12 hours respectively. After the reaction, centrifugation, solid vacuum drying, i.e. LaF3: 5%Tb 3+ .

[0041] Figure 3 (a) (b) shows the influence of the synthesis temperature of the LaF3 powder sample prepared by the hydrothermal synthesis method in the application on the afterglow length. When the synthesis temperature is 30 ℃, the obtained material LaF3: 5%Tb 3+ has no long afterglow performance after X-ray irradiation, while the sample synthesized at 220 ℃ has long afterglow performance after X-ray irradiation, so the afterglow of the sample synthesized at 220 ℃ is much higher than that of the sample synthesized at 30 ℃, wherein the tube voltage of the X-ray is 60 kV, the tube current is 100 μA, and the irradiation time is 5 minutes. Figure 3 (c) is the electron scanning microscope image of the sample synthesized at 220 ℃, and it can be seen that the sample synthesized at 220 ℃ is a good hexagonal crystal structure. Therefore, the optimal synthesis temperature of the material in the application is about 220 ℃.

[0042] From Figure 4 (a), it can be seen that after irradiation for 5 minutes under X-ray with a tube voltage of 60 kV and a tube current of 100 μA, the LaF3: 5%Tb 3+ has a significant decrease in afterglow intensity at room temperature, and then gradually tends to be stable. The afterglow length observed by the human eye in the dark environment can reach about 10 hours, and the drawing shows the afterglow intensity of LaF3: 5%Tb 3+ at 20 seconds and 10 hours. In addition, the afterglow length that can be detected by the Edinburgh FLS1000 spectrometer can reach about 48 hours, as shown in Figure 4 (b).

[0043] Figure 5 shows the afterglow intensity of LaF3: 5%Tb 3+The long afterglow decay curve at a temperature of 80 K-500 K was measured by Edinburgh FLS1000 spectrometer equipped with a variable temperature X-ray luminescence spectrum test system (X-XILS-P70V-5). The X-ray luminescence spectrum test system (X-XILS-P70V-5) generated X-ray as the excitation light source for the Edinburgh FLS1000 spectrometer. The LaF3:5%Tb 3+ was placed on the variable temperature stage in the Edinburgh FLS1000 spectrometer. The temperature of the variable temperature stage was controlled by controlling the injection rate of liquid nitrogen and the electric heating rate of the sample stage to control the cooling and heating of the variable temperature stage, so as to realize the accurate adjustment of the ambient temperature in the range of 80 K-500 K. The X-ray tube voltage was set to 50 kV, and the tube current was 100 μA. After irradiating the above-mentioned material at 80 K, 200 K, 300 K, 400 K and 500 K for 2 minutes respectively, the afterglow performance was observed, and the afterglow intensity was measured by the Edinburgh FLS1000 spectrometer. Figure 5 It can be seen that the LaF3:5%Tb 3+ has excellent long afterglow luminescence properties at low temperature, and the afterglow intensity at high temperature 400 K is also significantly higher than that at room temperature, which proves that it has excellent wide temperature long afterglow characteristics.

[0044] Example 3

[0045] The LaF3:5%Tb 3+ was prepared at 220 ℃. The long afterglow performance of the LaF3:5%Tb 3+ was detected by the X-ray diffractometer at a current of 100 μA and a voltage of 50 kV after irradiation for 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes and 6 minutes.

[0046] Figure 6 (a) shows that when the irradiation time is kept at 2 minutes, the afterglow of the material will gradually increase with the gradual increase of the tube voltage of the X-ray. The inset is the normalized afterglow decay rate change of the luminescence intensity, and it can be seen that the afterglow decay rate will gradually slow down with the increase of the tube voltage. It can be seen that by increasing the irradiation power of the X-ray, not only the afterglow intensity of the material can be improved, but also the release rate of the electrons can be slowed down in a short time, which is mainly because the larger X-ray excitation power increases the number of fluorine ion vacancies and the drift distance of fluorine ions. At the same time, the intensity of the afterglow can also be enhanced by increasing the irradiation time of the X-ray, such as Figure 6(b) shown. It is worth noting that the afterglow intensity does not increase indefinitely by increasing the irradiation time of X-rays, because the afterglow intensity tends to be saturated gradually as the difficulty of generating fluorine ion vacancy increases, as shown in the inset. Thus, the optimal irradiation voltage and current of X-rays in the present application is 50 kV, 100 μA, and the optimal irradiation time is about 5-6 minutes. The above proves that the afterglow phenomenon in the present application is mainly generated by X-ray induced fluorine ion vacancy defects.

[0047] Example 4

[0048] A LaF3: Tb that can perform afterglow imaging 3+ @PDMS film, the preparation method is as follows:

[0049] LaF3: 5%Tb 3+ Mechanical grinding for 30 minutes to obtain micron-sized powder. Then the prepared powder is mixed with PDMS at a mass ratio of 1:3, mechanically stirred for 6 hours, and finally the mixture is dropped onto a glass substrate and spin-coated into LaF3: Tb 3+ @PDMS film. After drying at 60°C for 30 minutes, the film with a thickness of 1.2 mm is peeled off from the glass substrate.

[0050] Example 5

[0051] A security label that can perform thermally induced anti-counterfeiting, the preparation method is as follows:

[0052] LaF3: 5%Tb 3+ Mechanical grinding for 30 minutes to obtain micron-sized powder. Then the prepared powder is shaped by a mold and shaped by UV glue or other types of adhesives.

[0053] Figure 9 (a) is a LaF3: Tb that can perform afterglow imaging in Example 4 of the present application 3+ @PDMS film. The schematic diagram shows that the paperclip is placed on the LaF3: Tb 3+ @PDMS film, when X-rays pass through the card screen, the image of the paperclip can be stored on the LaF3: Tb 3+ @PDMS film.

[0054] As Figure 9 (b) shown, the LaF3: Tb 3+ @PDMS film has good flexibility and can be folded at any angle, which makes it have more rich application scenarios. The dashed line range is the actual effect display of the present application. From left to right are the paperclip placed on the LaF3: Tb 3+The sun picture on the PDMS film; after X-ray irradiation for 5 minutes with a tube voltage of 50 kV and a tube current of 100 μA, the paperclip image remained on the LaF3: Tb 3+ The image picture on the PDMS film; the gray image of the image picture after RGB chromaticity conversion. It can be seen that due to the excellent long afterglow property of the material, the paperclip image can be effectively imaged on the film.

[0055] Figure 9 (c) LaF3: 5% Tb 3+ The heat release curve of the phosphor with temperature change, which shows that when the LaF3: 5% Tb 3+ The phosphor has a significant luminescence enhancement phenomenon when it is heated to 420 K after being irradiated by X-ray with a tube voltage of 50 kV and a tube current of 100 μA for 5 minutes. The LaF3: 5% Tb 3+ The phosphor is repeatedly irradiated for 8 times (first irradiated by X-ray with a tube voltage of 50 kV and a tube current of 100 μA for 5 minutes, and then heated to 420 K, and the afterglow intensity is observed, and so on for 8 times) under the same irradiation intensity and time, and the results are shown in Figure 9 (d) It can be seen that the LaF3: 5% Tb Figure 9 (d) It can be seen that the LaF3: 5% Tb 3+ The phosphor has very good stability, and the afterglow intensity does not decay after repeated heat release at high temperature, which provides a prerequisite for its practical application. By using this characteristic, the LaF3: 5% Tb 3+ is prepared into a security pattern by a mold, and the specific method is described in Example 5, so as to show the application effect thereof.

[0056] Figure 9 (e) The actual application effect of the security pattern. After being irradiated by X-ray with a tube voltage of 50 kV and a tube current of 100 μA for 5 minutes, the pattern will have a bright afterglow at the beginning, and then the afterglow intensity will be greatly weakened after 10 hours. When the pattern is heated to 420 K, the pattern will restore bright luminescence, and gradually weaken after cooling. Compared with the traditional ultraviolet excitation security pattern, the embodiment of the present application has significant complexity and operability, and greatly improves the difficulty of counterfeiting. The above shows that the potential application value of the material is in the field of energy storage information encryption.

[0057] As described above, different colors of afterglow luminescence can be obtained by doping different rare earths. By using this characteristic, the LaF3: 5% Tb 3+ and LaF3: 5% Sm 3+The mixed phosphor powder can emit multi-color afterglow. Due to the different distribution of traps, the mixed powder is placed on a temperature-variable stage of Edinburgh FLS1000 spectrometer, and the X-ray luminescence spectrum test system (X-XILS-P70V-5) is used to test the luminescence performance of the mixed powder at a tube voltage of 50 kV and a tube current of 100 mu A, while the temperature-variable stage temperature is adjusted from 200 K to 300 K, as shown in Figure 9 (f). Specifically, at a low temperature of 200 K, the afterglow of LaF3: 5%Sm 3+ is dominant, so that orange light emission is exhibited. When the temperature is gradually increased to 300 K, the afterglow of LaF3: 5%Tb 3+ begins to dominate, so that green light emission is converted. Accordingly, the present application provides a case that the composite phosphor powder has a color-changing mechanism with temperature, so that it has better application effect.

[0058] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a rare earth doped multicolor wide temperature long afterglow luminescent material, characterized in that, The specific process is: (1) Dissolve the soluble salt of La and Ln in deionized water to obtain a rare earth ion salt solution, and dissolve the fluoride ion salt in deionized water to obtain a fluoride ion salt solution; then, transfer the fluoride ion salt solution to the rare earth ion salt solution, stir uniformly, and then transfer into a hydrothermal reaction kettle, heat to 200-220℃ and keep for 10-15 hours, after the reaction is completed, centrifugal, collect the solid and dry, to obtain a chemical formula of LaF3:Ln 3+ Rare earth doped material, doping ion Ln 3+ is Pr 3+ , Nd 3+ , Sm 3+ , Dy 3+ , Er 3+ and Tm 3+ ; (2) the material obtained in step (1) is irradiated by X-ray, namely obtained; the irradiation by X-ray refers to irradiation for 1 minute to 6 minutes under 100 uA current and 30 kV to 70 kV voltage.

2. The preparation method of the rare earth-doped multicolor wide-temperature long-afterglow luminescent material according to claim 1, characterized in that, In step (1), the soluble salt of La refers to one or a mixture of two or more of La(NO3)3, LaCl3 and La(CH3COO)3 in any ratio, and the soluble salt of Ln refers to one or a mixture of two or more of Ln(NO3)3, LnCl3 and Ln(CH3COO)3 in any ratio; the soluble salt of Ln accounts for 0.2% to 20% of the total molar amount of the soluble salts of La and Ln.

3. The method for preparing rare-earth-doped multicolor wide-temperature long-afterglow luminescent material according to claim 1, characterized in that, In step (1), the fluoride salt is one or a mixture of two of NH4F and NH4HF2 in any ratio, and the molar amount of the fluoride salt is 3 times the total molar amount of the soluble salts of La and Ln.

4. The rare earth doped multicolor wide temperature long afterglow luminescent material produced by the method of any one of claims 1 to 3, characterized in that, The rare earth ion doped LaF3 has a residual phenomenon at 80 K to 300 K.

5. Application of the rare earth doped multicolor wide-temperature long-afterglow luminescent material in claim 4 in afterglow imaging and thermal anti-counterfeiting.

6. A LaF3:Ln containing rare earth doped multicolor wide temperature long afterglow phosphor material according to claim 4. 3+ @A PDMS film, characterized in that The preparation process is as follows: LaF3: Ln 3+ Mechanical grinding to obtain micron powder, then the prepared powder mixed with PDMS in a mass ratio of 1: (2~4), mechanical stirring, finally the mixture was dropped on the substrate, spin coating into LaF3: Ln 3+ @PDMS film, dried, the film was peeled off from the substrate, ready.

7. A security label capable of thermally induced security against counterfeiting, containing the rare earth doped multicolor wide temperature long afterglow luminescent material according to claim 4, characterized in that, The preparation process is as follows: LaF3: Ln 3+ Mechanical grinding to obtain micron-sized powder, the prepared powder is then molded into shape through a mold and shaped through a binder.

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