CN115321580A

CN115321580A - Long-afterglow material of rare earth element doped fluoride and preparation method and application thereof

Info

Publication number: CN115321580A
Application number: CN202210830578.4A
Authority: CN
Inventors: 杨黄浩; 陈秋水; 何聿; 江浩
Original assignee: Fuzhou University
Current assignee: Fuzhou Lunqin Technology Co ltd
Priority date: 2022-07-14
Filing date: 2022-07-14
Publication date: 2022-11-11
Anticipated expiration: 2042-07-14
Also published as: CN115321580B

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to a size-adjustable rare earth element doped fluoride long-afterglow material, and a large-scale preparation method and application thereof, wherein the preparation method comprises the following steps: under the condition of not containing any ligand, mixing rare earth salt, sodium fluoride and ammonium fluoride with water, adjusting the pH of the solution to be neutral, adding an alcohol solvent to carry out hydrothermal reaction to obtain beta-NaReF ₄ Long afterglow materials of the type; wherein the Re is selected from at least one of yttrium, scandium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, promethium, dysprosium, holmium, erbium, thulium, ytterbium, praseodymium, lutetium, and terbium;the molar ratio of the sodium fluoride to the ammonium fluoride is 1: (0 to 9). The preparation method of the rare earth element doped fluoride long-afterglow material provided by the invention can be suitable for mass production, the single-time production product can reach 26g, and the yield is about 95%.

Description

Long-afterglow material of rare earth element doped fluoride and preparation method and application thereof

Technical Field

The invention belongs to the technical field of luminescent materials, and particularly relates to a size-adjustable rare earth element doped fluoride long afterglow material, and a mass preparation method and application thereof.

Background

The 7 electron orbitals of the lanthanide rare earth ion 4f layer endow 1600 electron energy levels and 20 more than ten thousand energy level transitions thereof, and is a huge luminous treasure house. The rare earth ions can be doped into a substrate as a luminescent center, and have the excellent performances of narrow emission line, large Stokes shift, long luminescent life and tunable luminescent wavelength from ultraviolet light to infrared light. The host of the current light emitting material is of oxide, sulfide, nitride, fluoride, or the like. Wherein the fluoride matrix has a low phonon vibrational energy: (<350cm ^-1 ) The energy loss caused by non-radiative relaxation transition can be effectively reduced, and the luminous efficiency is good, so that the luminous material has great potential in the aspects of biomedicine, photoelectric devices, anti-counterfeiting fields and the like.

With AReF ₄ Rare earth doped fluoride micro-nano materials represented by (A is an alkali metal element, and Re is a rare earth element) are widely concerned and developed. Recent researches show that the rare earth doped fluoride material has excellent long-afterglow luminescence performance under the action of X-rays, so that the rare earth doped fluoride material has a large application space in the fields of biomedical imaging, industrial flaw detection and the like. The mass preparation of the rare earth doped fluoride material is an important link for promoting the further productive transformation of the rare earth doped fluoride material.

Most of the laboratory-level synthesis methods can only carry out small-scale synthesis, and the single yield is less than one gram, so that the industrial requirements cannot be met. Currently, the most common synthesis methods in laboratories mainly include coprecipitation, hydrothermal, high-temperature thermal decomposition, and the like. The coprecipitation method has low yield, long time consumption, high cost and large waste gas emission, and limits the industrial application of the coprecipitation method; the trifluoroacetate used as a raw material in the high-temperature thermal decomposition method generates a large amount of toxic hydrofluoric acid gas at high temperature, and the required strict reaction conditions of anhydrous, oxygen-free and high temperature are not favorable for production safety. Therefore, the problems of low yield, high cost, serious pollution and the like existing in the two synthesis methods need to be solved urgently. The rare earth luminescent material synthesized by the hydrothermal method has the advantages of high purity, good crystal form and good monodispersity, the reaction temperature is low, and the size and the shape of the product are easy to control. In addition, the hydrothermal method is very suitable for industrialized large-scale production due to the characteristics of simple and convenient operation, simple instrument, high yield, environmental friendliness and the like.

Disclosure of Invention

In order to overcome the defects of the prior art, the technical problems to be solved by the invention are as follows: provides a preparation method of the long afterglow material capable of producing the rare earth element doped fluoride in large scale, the long afterglow material prepared by the preparation method and the application thereof.

In order to solve the technical problem, the invention provides a preparation method of a long afterglow material of rare earth element doped fluoride, which comprises the steps of mixing rare earth salt, sodium fluoride and ammonium fluoride with water under the condition of not containing any ligand, adjusting the pH value of the solution to be neutral, adding an alcohol solvent to carry out hydrothermal reaction to obtain beta-NaReF ₄ Long afterglow materials of the type;

wherein the Re is selected from at least one of yttrium, scandium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, promethium, dysprosium, holmium, erbium, thulium, ytterbium, praseodymium, lutetium, and terbium;

the molar ratio of the sodium fluoride to the ammonium fluoride is 1: (0 to 9).

Further provides the long afterglow material of the rare earth element doped fluoride prepared by the preparation method.

And the application of the long afterglow material of the rare earth element doped fluoride in biological marking, X-ray detection, display and imaging.

The invention has the beneficial effects that: the preparation method of the rare earth element doped fluoride long-afterglow material provided by the invention can obtain the beta-NaReF with excellent luminescence property by adjusting the proportion of the sodium fluoride and the ammonium fluoride without adding any ligand ₄ The long afterglow material and the ligand-free system can reduce the material consumption, increase the output in certain container and raise the quality of the productCan effectively reduce the cost of raw materials and realize the simplification of the synthesis process, which is a key technical problem from the synthesis stage in a laboratory to the industrialized mass preparation. Meanwhile, the traditional ligand is abandoned, so that the growth limitation of the product can be effectively improved, and the size of the product is increased to a micron level to a certain extent, thereby further improving the luminescence property of the long-afterglow material. Moreover, the long afterglow material is synthesized under the condition of no ligand, namely the product is not modified by the ligand, so that the direct in-situ modification can be realized without an additional ligand removing step in the application process of the product, the application process is greatly simplified, and the product loss in the ligand removing process is reduced.

Drawings

FIG. 1 shows micron-sized NaLuF obtained in example 1 of the present invention ₄ X-ray powder diffractogram of Tb;

FIG. 2 shows the micron-sized NaLuF obtained in example 1 of the present invention ₄ Scanning electron microscopy of Tb;

FIG. 3 shows the micron-sized NaLuF obtained in example 1 of the present invention ₄ Photo of product of Tb;

FIG. 4 shows micron-sized NaLuF obtained in example 1 of the present invention ₄ An X-ray excitation luminescence spectrogram of Tb;

FIG. 5 shows micron-sized NaLuF obtained in example 1 of the present invention ₄ Tb;

FIG. 6 shows NaLuF with different ratios of raw materials obtained in example 2 of the present invention ₄ Tb (scale bar 2 μm);

FIG. 7 shows NaLuF with different ratios of raw materials obtained in example 2 of the present invention ₄ Tb X-ray excitation luminescence spectrum;

FIG. 8 shows NaLuF with different ratios of raw materials obtained in example 2 of the present invention ₄ An X-ray excitation luminescence spectrogram of Tb;

FIG. 9 shows NaLuF with different ratios of raw materials obtained in example 2 of the present invention ₄ Tb;

FIG. 10 shows the different starting materials obtained in example 2 of the present inventionProportioned NaLuF ₄ Tb;

FIG. 11 shows NaLuF with different doping concentrations of rare earth elements and co-doped rare earth elements obtained in example 3 of the present invention ₄ Tb and NaLuF ₄ Transmission electron micrographs of Gd and Tb (scale bars are 2 microns);

FIG. 12 shows NaLuF with different doping concentrations of rare earth elements and co-doped rare earth elements obtained in example 3 of the present invention ₄ Tb and NaLuF ₄ An X-ray excitation luminescence spectrogram of Gd and Tb;

FIG. 13 shows NaLuF with different doping concentrations of rare earth elements and co-doped rare earth elements obtained in example 3 of the present invention ₄ Tb and NaLuF ₄ Gd, tb X-ray afterglow attenuation curve diagram;

FIG. 14 shows EDTA-2Na and CitNa, respectively, obtained in comparative example 1 of the present invention ₃ NaLuF with PEG and OA as ligands ₄ Tb (2 microns on a scale);

FIG. 15 shows EDTA-2Na and CitNa, respectively, obtained in comparative example 1 of the present invention ₃ NaLuF with PEG and OA as ligands ₄ Tb X-ray excitation luminescence spectrum;

FIG. 16 shows EDTA-2Na and CitNa, respectively, obtained in comparative example 1 of the present invention ₃ NaLuF with PEG and OA as ligands ₄ Tb;

FIG. 17 shows NaLuF at different reaction times obtained in example 4 of the present invention ₄ Tb (2 microns on a scale);

FIG. 18 shows NaLuF at different reaction times obtained in example 4 of the present invention ₄ Tb X-ray excitation luminescence spectrum;

FIG. 19 shows NaLuF at various reaction times obtained in example 4 of the present invention ₄ Tb;

FIG. 20 shows NaLuF at different reaction temperatures obtained in example 5 of the present invention ₄ Tb (2 microns on a scale);

FIG. 21 is a graph obtained in example 5 of the present inventionNaLuF at different reaction temperatures ₄ Tb X-ray excitation luminescence spectrum;

FIG. 22 shows NaLuF at different reaction temperatures obtained in example 5 of the present invention ₄ Tb;

FIG. 23 shows NaLuF solutions of different NaOH concentrations obtained in example 6 of the present invention ₄ Tb (2 microns on a scale);

FIG. 24 shows NaLuF solutions with different NaOH concentrations obtained in example 6 of the present invention ₄ Tb X-ray excitation luminescence spectrum;

FIG. 25 shows NaLuF solutions of different NaOH concentrations obtained in example 6 of the present invention ₄ Tb;

FIG. 26 shows different rare earth element doped NaLuF obtained in example 7 of the present invention ₄ A transmission electron microscopy picture of Pr/Nd/Sm/Tb/Dy/Ho/Er/Tm (scale bars are 2 microns);

FIG. 27 shows different rare earth element doped NaLuF obtained in example 7 of the present invention ₄ An X-ray excitation luminescence spectrogram of Pr/Nd/Sm/Tb/Dy/Ho/Er/Tm;

FIG. 28 shows different rare earth element doped NaLuF obtained in example 7 of the present invention ₄ An X-ray afterglow decay curve diagram of Pr/Nd/Sm/Tb/Dy/Ho/Er/Tm;

FIG. 29 shows the NaLuF prepared by high temperature co-precipitation method according to comparative example 2 of the present invention ₄ Transmission electron microscopy of Tb (scale bar 50 nm);

FIG. 30 shows the NaLuF prepared by co-precipitation at high temperature in comparative example 2 of the present invention and the ligand-free concentrated hydrothermal method in this patent ₄ Tb X-ray excitation luminescence spectrum;

FIG. 31 shows the NaLuF prepared by co-precipitation at high temperature in comparative example 2 of the present invention and the ligand-free concentrated hydrothermal method in this patent ₄ Tb.

Detailed Description

In order to explain the technical contents, the objects and the effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.

A preparation method of a rare earth element doped fluoride long afterglow material comprises the steps of mixing rare earth salt, sodium fluoride, ammonium fluoride and water under the condition of not containing any ligand, adjusting the pH value of the solution to be neutral, adding an alcohol solvent for hydrothermal reaction, and obtaining a beta-NaReF 4 type long afterglow material; wherein the Re is selected from at least one of yttrium, scandium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, promethium, dysprosium, holmium, erbium, thulium, ytterbium, praseodymium, lutetium, and terbium; the molar ratio of the sodium fluoride to the ammonium fluoride is 1: (0 to 9).

Wherein the ligand is selected from at least one of organic additives, surfactants and functional ligands. For example, sodium citrate described in CN111876154A, and organic additives or surfactants for regulating and controlling the size, phase and morphology of nanocrystals such as oleic acid, polyethyleneimine, ethylenediamine tetraacetic acid and cetyltrimethylammonium bromide described in the prior art, and functional ligands for surface modification of long afterglow materials, such as EDTA-2Na, citNa ₃ PEG, OA and the like.

In one embodiment, the rare earth salt is preferably mixed with water and then with sodium fluoride and ammonium fluoride. The rare earth salt is at least one of nitrate, chloride and acetate of rare earth. Illustratively, the rare earth salt is a rare earth nitrate, rare earth chloride or rare earth acetate; or a combination of rare earth nitrate and rare earth chloride, or a combination of rare earth nitrate and rare earth acetate, or a combination of rare earth chloride or rare earth acetate, or a combination of rare earth nitrate, rare earth chloride and rare earth acetate. The choice of salt form for a particular rare earth element can be considered in light of its water solubility. The rare earth element in the present invention may be any rare earth element known to those skilled in the art, and is not particularly limited thereto. Preferably, the rare earth element is selected from at least one of yttrium, scandium, lanthanum, cerium, neodymium, samarium, europium, gadolinium, promethium, dysprosium, holmium, erbium, thulium, ytterbium, praseodymium, lutetium, and terbium. More preferably, the rare earth element comprises at least lutetium or terbium, and more preferably the rare earth element is lutetium and terbium. In one embodiment, when terbium is contained in the rare earth element, the molar content of terbium is preferably 0.5 to 50%, more preferably 0.5 to 40%, still more preferably 5 to 30%, still more preferably 5 to 25%, and most preferably 5 to 20%, and exemplarily 0.5%, 5%, 10%, 15%, 20%, and 25%. In another embodiment, when the rare earth element contains lutetium and terbium, the molar ratio of lutetium to terbium is preferably (3 to 200): 1, more preferably (3 to 100): 1, more preferably (4 to 20): 1, most preferably (4 to 6): illustratively, the molar ratio of lutetium to terbium is 4: 1. 99.5:0.5, 95: 5. 90: 10. 85: 15. 80:20 or 75:25.

wherein, the water is preferably deionized water. The mixing is preferably ultrasonic mixing to facilitate dissolution of the rare earth salt in the water by ultrasonic mixing. The mixing time is preferably 3 to 10min.

The concentration of the rare earth salt in the mixed solution is preferably 0.5 to 10mol/L, more preferably 0.5 to 8mol/L, still more preferably 0.5 to 6mol/L, still more preferably 0.8 to 4mol/L, and most preferably 0.8 to 2mol/L, and illustratively the concentration of the rare earth salt in the mixed solution is 1.25mol/L or 1mol/L.

The inventor finds that the proportion between sodium fluoride and ammonium fluoride is crucial to influence the luminescence property of the long-afterglow material in a synthesis system lacking other ligands, and the proportion among ammonium fluoride, sodium fluoride and rare earth elements also determines the quality of the long-afterglow luminescence property. Preferably, the molar ratio of the rare earth salt to the sodium fluoride is 1: (1-6); more preferably 1: (1 to 2.5), most preferably 1; the mole ratio of the rare earth salt to the ammonium fluoride is 1: (0 to 9), more preferably 1: (2 to 6), preferably 1: (3 to 5), most preferably 1:4. wherein the sodium fluoride and the ammonium fluoride are both mixed in the form of aqueous solutions thereof. Wherein, the concentration of the aqueous solution of sodium fluoride is preferably 0.1 to 1mol/L, and most preferably 0.5 to 1mol/L; the concentration of the aqueous solution of ammonium fluoride is preferably 0.5 to 15mol/L, more preferably 2 to 15mol/L, still more preferably 2 to 10mol/L, still more preferably 3 to 8mol/L, and most preferably 4 to 5mol/L.

In one embodiment, the aqueous solution of sodium fluoride is preferably added dropwise with stirring, and after the addition, the aqueous solution of ammonium fluoride is added dropwise with stirring. Wherein, the sodium fluoride is dripped to obtain a white turbid solution. After the addition of sodium fluoride, the mixture is preferably stirred for 10 to 40min, more preferably for 20 to 30min. After dropwise adding the ammonium fluoride aqueous solution, the solution is in a gel state, and is preferably stirred for 20 to 60min, more preferably for 30 to 50min, and still more preferably for 30 to 40min; the rotation speed of the stirring at this time is preferably 600 to 1000r/min, more preferably 800 to 900r/min.

However, the inventor finds that when the pH value of the solution is adjusted, the pH value is too high or too low, which causes the problem of reducing the luminescence property of the long afterglow material. Therefore, it is necessary to ensure that the pH of the solution is neutral after thorough mixing. The solution pH can thus be adjusted to neutrality by the addition of a pH adjuster. In order to avoid the introduction of impurities during the pH adjustment, the pH adjustment is preferably carried out using an aqueous sodium hydroxide solution having a concentration of 10 to 20 mol/L. Of course, this step of adjusting the pH to neutral may be omitted in certain embodiments, since the pH of the solution itself is near neutral (7) after the components are thoroughly mixed.

After the pH of the solution is adjusted to be neutral, the solution is preferably stirred and then the alcohol solvent is added, and the stirring time is preferably 10 to 30min, and more preferably 10 to 20min. The pressure of the synthesis system during high-temperature reaction is increased by introducing the alcohol solvent, so as to improve the synthesis conditions of hydrothermal reaction at high temperature and high pressure. The alcohol solvent may be any alcohol solvent known to those skilled in the art, and is not limited thereto. Ethanol is preferred. The alcoholic solvent is preferably added in dropwise form. The volume ratio of the solution mixed with the components and subjected to pH adjustment to the alcohol solvent is (2-5): 1, more preferably (2 to 4): 1, most preferably (3 to 4): 1. after the alcohol solvent is added, the hydrothermal reaction is preferably carried out after stirring. The stirring is preferably 10 to 40min, more preferably 20 to 30min.

Existing rare earth doped fluorides mainly comprise AB ₃ Type (e.g. YF) ₃ ：Tb ³⁺ ) And ABX ₄ Type (NaLuF) ₄ ：Tb ³⁺ ). In one aspect, AB ₃ Type rare earth doped fluoride compared to ABX ₄ The crystal lattice of the rare earth doped fluoride is soft and the phonon vibration is slightly large, so that the rare earth doped fluoride has the advantages of soft lattice rigidity and slightly large phonon vibrationThe energy loss due to its non-radiative relaxation transition also increases. On the other hand, AB ₃ The luminous center density of the rare earth element doped fluoride is higher, so that the probability of non-radiative relaxation transition among luminous ions is greatly increased, and the luminous performance is reduced. I.e. AB as a whole ₃ The rare earth element doped fluoride has poor luminescence property and poor or no afterglow. And for ABX ₄ The type rare earth element doped fluoride has an alpha type and a beta type, and the beta type has better luminescence property compared with the alpha type. Therefore, the invention avoids preferentially synthesizing alpha-type rare earth element doped fluoride with more stable kinetics under low temperature conditions by increasing the reaction temperature of the hydrothermal reaction. Meanwhile, the high temperature condition is also beneficial to the improvement of the crystallinity of the crystal, and the improvement of the crystallinity can further enhance the luminescence property of the long afterglow material.

Specifically, the hydrothermal reaction is preferably carried out in a reaction vessel. The volume of the solution of the reaction system of the hydrothermal reaction is preferably 10-80%, more preferably 30-80%, even more preferably 50-80%, even more preferably 60-80%, and most preferably 70-80% of the volume of the reaction kettle; the temperature of the hydrothermal reaction is preferably 160 ℃ to 230 ℃, more preferably 180 ℃ to 230 ℃, and further preferably 200 ℃ to 210 ℃. Illustratively, the temperature of the hydrothermal reaction is 200 ℃, 210 ℃, or 220 ℃. The reaction time of the hydrothermal reaction is preferably 2 to 24 hours, more preferably 4 to 20 hours, still more preferably 6 to 18 hours, and most preferably 6 to 12 hours. Illustratively, the reaction time of the hydrothermal reaction is 2h, 4h, 6h, 8h, 10h, 12h, or 16h.

After hydrothermal reaction, preferably centrifuging, washing and drying the suspension particles to obtain the rare earth doped fluoride long afterglow material with adjustable size from nanometer to micrometer level; the washing is preferably one or more of double distilled water, ethanol and toluene; the drying temperature is preferably 50 ℃ to 100 ℃, more preferably 50 ℃ to 80 ℃, and most preferably 60 ℃ to 70 ℃.

A long-afterglow material of rare earth element doped fluoride is prepared by the preparation method. The particle size of the prepared long afterglow material is adjustable within the range of 0.1-10 μm, namely the long afterglow material can be a nano or micron material, and more preferably the particle size is 1-10 μm. The crystal structure of the long afterglow material is hexagonal phase. The long afterglow material has fluorescence and long afterglow luminescence under the excitation of X ray, and the rest glow time can last for more than 30 days.

The long afterglow material provided by the invention has excellent luminescence property and size advantage, and has better water solubility because the material is prepared in a water-ethanol system, so that the material still has great advantage in the application of biological marking, X-ray detection, display and imaging even if the material is not subjected to additional ligand surface modification such as PEG.

Example 1

Example 1:100mmol micron-sized NaLuF ₄ Preparation of Tb

1.1 mixing 80mmol of lutetium nitrate and 20mmol of terbium nitrate powder, dissolving in deionized water to reach a constant volume of 80mL, and ultrasonically dissolving to obtain 1.25 mol.L ^-1 A rare earth nitrate solution.

1.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution obtained in the step 1.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

1.3 Add 80mL of ammonium fluoride solution to the solution of step 1.2 drop-wise, wherein the ammonium fluoride solution concentration is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

1.4 slowly dropwise adding a sodium hydroxide solution to the solution in step 1.3 to a pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

1.5 to the solution in step 1.4, 100mL of absolute ethanol was added dropwise and stirring was continued for 20min.

1.6 transferring the mixed solution obtained in the step 1.5 into a 500mL reaction kettle, and carrying out hydrothermal reaction for 12h at 200 ℃ to obtain a white product. After centrifugation, the product is washed for 3 times by redistilled water and ethanol, and finally the micron-sized NaLuF is obtained ₄ Tb white powder was dried at 60 ℃ for 6h.

Micron-sized NaLuF obtained in example 1 was subjected to X-ray diffraction ₄ Tb white powder was analyzed to obtain the X-ray powder diffraction pattern shown in FIG. 1. As can be seen from FIG. 1, the diffraction peak positions of the two phases are all equal to those of the hexagonal phase of beta-NaLuF ₄ Crystal structured PDF standard card (NaLuF) ₄ : JCPDF No. 27-0726) is a pure hexagonal phase structure without impurity phase. In addition, the high temperature is more beneficial to the improvement of the crystallinity of the crystal, and the improvement of the crystallinity can effectively enhance the luminescence performance, and the product has good crystallinity also can be illustrated from the sharp and high-intensity diffraction peak in fig. 1.

Scanning electron microscope was used to measure the micron-sized NaLuF obtained in example 1 ₄ Tb white powder was analyzed and its scanning electron micrograph, shown in fig. 2, was obtained. As can be seen from FIG. 2, the morphology was rod-like, with a length of 2 to 5 μm.

FIG. 3 shows micron-sized NaLuF obtained in example 1 ₄ Tb white powder product picture, single pass yield was about 26g, yield was about 95%.

The micron-sized NaLuF obtained in example 1 was subjected to X-ray excitation luminescence spectroscopy ₄ Tb white powder was analyzed to obtain its X-ray excited luminescence spectrum as shown in FIG. 4. FIG. 4 is NaLuF ₄ The fluorescence emission pattern of Tb material corresponds to Tb ³⁺ Four characteristic emission peaks of ⁵ D ₄ → ⁷ F ₆ ， ⁵ D ₄ → ⁷ F ₆ ， ⁵ D ₄ → ⁷ F ₆ And ⁵ D ₄ → ⁷ F ₆ wherein the insert in the upper right corner of FIG. 4 is NaLuF ₄ Fluorescence photograph of Tb powder in excited state.

FIG. 5 is NaLuF of example 1 ₄ An X-ray afterglow attenuation curve diagram of Tb material, and long-afterglow material excited by 50kv and 80mA silver target for 3min. It can be seen that the long afterglow intensity remains more than 1000 times the baseline after 10min from the end of excitation, indicating that it has excellent and persistent long afterglow luminescence properties.

Example 2: 100mmol NaLuF with different raw material ratios ₄ Preparation of Tb

2.1 mixing 80mmol of lutetium nitrate and 20mmol of terbium nitrate powder, dissolving in deionized water, diluting to 100mL, and ultrasonically dissolving to obtain 1 mol. L ^-1 A rare earth nitrate solution.

2.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution in the step 2.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

2.3 dropping 60mL of ammonium fluoride solution into the solution in the step 2.2, wherein the concentration of the ammonium fluoride solution is 15 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

2.4 slowly dropwise adding sodium hydroxide solution into the solution in step 2.3 to pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

2.5 Add 100mL of absolute EtOH drop wise to the solution from step 2.4 and continue stirring for 20min.

2.6 transferring the mixed solution obtained in the step 2.5 into a 500mL reaction kettle, and carrying out a hydrothermal reaction for 12h at 200 ℃ to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

2.7, comparing the performances of the products with different raw material ratios to obtain the optimal performance ratio: repeating the steps 2.1-2.6, wherein the other conditions are completed under the same condition except that the molar ratio of the sodium fluoride to the ammonium fluoride is adjusted. That is, the optimum ratio of the rare earth salt to the sodium fluoride and the ammonium fluoride is determined by adjusting the amount of the sodium fluoride or the ammonium fluoride in step 2.2 or step 2.3 while keeping the total amount of the rare earth salt constant. Finally obtaining products with different molar ratios of sodium fluoride to ammonium fluoride, wherein the products are respectively (molar mass ratio, sodium fluoride: ammonium fluoride): a-1; b-1; c-1; d-1; e-1; f-1; g-4; h-2; i-3; j-3; k-4; l-5; m-5; and n-6.

NaLuF prepared in different ratios of the raw materials obtained in example 2 was subjected to a transmission electron microscope ₄ Tb is analyzed separately to obtain its transmission electron microscope pictureAs shown in fig. 6. As can be seen from fig. 6, naLuF with a molar ratio of sodium fluoride to ammonium fluoride of 1 ₄ Tb is limited in growth due to the fact that a fluorine source is small and the solubility of ammonium fluoride in ethanol is poor, so that the morphology of Tb is about 100 nanometers, and the morphologies of the rest experimental groups with different proportions are all irregular rods, and the length of Tb is between 1 and 6 micrometers. Wherein, naLuF with the molar ratio of sodium fluoride to ammonium fluoride of 1 ₄ Tb is in the shape of short rod and 2-5 mu m in length.

NaLuF prepared in example 2 by using X-ray excited luminescence spectroscopy in different ratios ₄ Tb was analyzed separately to obtain the X-ray excited luminescence spectra as shown in FIGS. 7 and 8 (the luminescence intensities of different raw material ratios listed in the figures gradually increase from bottom to top). As can be seen from fig. 7 and 8, in all the above-mentioned ratios, when the molar ratio of sodium fluoride to ammonium fluoride is 1.

FIGS. 9 and 10 (in which the afterglow intensities at different raw material ratios listed in the figure are gradually increased from bottom to top) show the NaLuF in example 2 at different raw material ratios ₄ X-ray afterglow attenuation curve diagrams of Tb materials, long afterglow materials are excited for 3min by rays under silver targets of 50kv and 80 mA. It can be seen that in all the above-mentioned formulations, when the molar ratio of sodium fluoride to ammonium fluoride is 1.

Example 3: 100mmol NaLuF with different doping concentrations of rare earth elements and co-doped different rare earth elements ₄ Tb and NaLuF ₄ Preparation of Gd and Tb

3.1 mixing 99.5mmol lutetium nitrate and 0.5mmol terbium nitrate powder, dissolving in deionized water to constant volume of 80mL, and ultrasonically dissolving to obtain 1.25 mol. L ^-1 A rare earth nitrate solution.

3.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution of step 3.1 ^-1 To obtain a white turbid solution, and continuously stirring for 20min.

3.3 dropping 80mL of ammonium fluoride solution into the solution in the step 3.2, wherein the concentration of the ammonium fluoride solution is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

3.4 slowly dropwise adding sodium hydroxide solution into the solution in step 3.3 to pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

3.5 Add 100mL of absolute ethanol dropwise to the solution from step 3.4 and continue stirring for 20min.

3.6 transferring the mixed solution obtained in the step 3.5 into a 500mL reaction kettle, and carrying out hydrothermal reaction for 12h at 200 ℃ to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

3.7 comparing the performances of the products of different doping concentrations of the rare earth elements and the co-doping of different rare earth elements to obtain the optimal doping concentration of Tb: changing the molar ratio of the rare earth salt added in the step 3.1, and repeating the steps 3.2-3.6 to finally obtain products of different doping concentrations (molar concentrations) of the rare earth elements and codoping of different rare earth elements, wherein the products are respectively as follows: a-0.5%; b-5% Tb; c-10% Tb; d-15% Tb; e-20% Tb; f-25% of Tb; g-5% Gd-15%; h-5% Gd-20% Tb; i-10% Gd-20% Tb.

The products of the rare earth elements obtained in example 3 with different doping concentrations and different co-doping of the rare earth elements were analyzed by a transmission electron microscope, and a transmission electron microscopic image thereof was obtained, as shown in fig. 11. Wherein, the shape and size of the product are irregular rods with the exception of the product b-5 percent Tb of 200-500 nm, and the length is between 1 and 8 mu m. Wherein the Tb doping concentration with the best luminescence property is 15-20%, the shape is a short rod, and the length is 2-6 μm.

The products of different doping concentrations of the rare earth elements and the co-doping of different rare earth elements obtained in example 3 were analyzed by X-ray excited luminescence spectroscopy, respectively, to obtain X-ray excited luminescence spectrograms thereof, as shown in fig. 12. In all the above doping concentrationsWhen the molar ratio of the lutetium nitrate to the terbium nitrate is 1 (4-6), the NaLuF is obtained ₄ Tb (15% -20%) has the optimum fluorescence intensity.

FIG. 13 is the X-ray afterglow decay curve graphs of the rare earth elements obtained in example 3 with different doping concentrations and co-doped products of different rare earth elements, and the long afterglow materials are all excited by rays for 3min under 50kv and 80mA silver targets. It can be seen that in all the doping concentrations, naLuF is obtained when the molar ratio of lutetium nitrate to terbium nitrate is 1 (4-6) ₄ Tb (15-20%), the afterglow performance of said material has optimum value.

Comparative example 1:100mmol NaLuF modified by different ligands ₄ Preparation of Tb

1.1 separately mixing 80mmol of lutetium nitrate, 20mmol of terbium nitrate, 40mmol of EDTA-2Na (disodium ethylenediamine tetraacetate) powder and 200mmol of CitNa ₃ Mixing and dissolving (sodium citrate) powder and 5mmol of PEG (polyethylene glycol-2000) powder in deionized water to reach a constant volume of 80mL, and ultrasonically dissolving to obtain 1.25 mol.L ^-1 A rare earth nitrate solution. In addition, for the OA (oleic acid) ligand, 3g of sodium hydroxide solid was added to the dissolved rare earth nitrate solution and 100mL of absolute ethanol from step 1.5 was added in advance, followed by 40mL of OA ligand.

1.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution of step 1.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

1.3 dropwise adding 80mL of ammonium fluoride solution into the solution obtained in the step 1.2, wherein the concentration of the ammonium fluoride solution is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

1.6 transferring the mixed solution obtained in the step 1.5 into a 500mL reaction kettle, and carrying out hydrothermal reaction for 12h at 200 ℃ to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

NaLuF obtained in comparative example 1 was aligned by a transmission electron microscope ₄ Tb was analyzed and its TEM image was obtained as shown in FIG. 14. Firstly, the EDTA-2Na ligand product is rod-shaped, and the length is 2-3 μm. The phenomenon is mainly caused by that the ligand is adsorbed on the surface of the crystal, the growth rate of the crystal is changed, the growth of the crystal is limited to a certain degree, and the phenomenon influencing the appearance growth is generated. In addition, because different ligands have different growth orientation preference on different crystal faces of the crystal, the EDTA-2Na ligand has more selectivity on the growth of the crystal on the c-axis (100) crystal face, and the appearance is rod-shaped. Second, citNa ₃ The shape of the ligand product is a short flat hexagonal prism, and the size of the ligand product is 1-3 mu m. The appearance of the product is different from that of EDTA-2Na ligand, and the product changes from a rod shape to a short flat hexagonal prism, and the phenomenon is mainly caused by that CitNa is adsorbed on the surface ₃ The crystal growth orientation of the ligand is more favorable for the a-axis (001) crystal face, so that the morphology of the ligand is represented by a short flat hexagonal prism. Thirdly, the shapes of the PEG ligand product and the OA ligand product are both rod-shaped, and the sizes are 2-4 mu m. This phenomenon occurs mainly because the adsorption tendency of the ligand on the crystal side surface lowers the surface energy of the crystal side surface, resulting in a decrease in the growth rate thereof, and finally, it appears as a rod.

NaLuF obtained in comparative example 1 was excited by X-ray emission spectrum ₄ Tb was analyzed to obtain the X-ray excitation luminescence spectrum shown in FIG. 15. As can be seen, the NaLuF with the added ligand ₄ The fluorescence intensity of Tb material is significantly lower than that without ligand.

FIG. 16 is NaLuF of comparative example 1 ₄ An X-ray afterglow attenuation curve graph of Tb material, and the long afterglow material is excited by radiation under 50kv and 80mA silver target for 3min. As can be seen, the NaLuF with the added ligand ₄ The afterglow performance of Tb material is obviously lower than that of ligand-free material.

Example 4: 100mmol NaLuF in different reaction times ₄ Preparation of Tb

4.1 mixing 80mmol of nitreLutetium acid and 20mmol terbium nitrate powder are mixed and dissolved in deionized water to reach a constant volume of 80mL, and ultrasonic dissolution is carried out to obtain 1.25 mol.L ^-1 A rare earth nitrate solution.

4.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution of step 4.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

4.3 Add 80mL of ammonium fluoride solution to the solution of step 4.2 drop-wise, wherein the ammonium fluoride solution concentration is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

4.4 slowly adding sodium hydroxide solution into the solution in the step 4.3 dropwise to the pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

4.5 to the solution in step 4.4, 100mL of absolute ethanol was added dropwise, and stirring was continued for 20min.

4.6 transferring the mixed solution obtained in the step 4.5 to a 500mL reaction kettle, and performing hydrothermal reactions for 2h, 4h, 6h, 8h, 10h, 12h and 16h at 200 ℃ respectively to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

The products obtained in example 4 at different reaction times were analyzed by transmission electron microscopy, respectively, to obtain a transmission electron micrograph thereof, as shown in fig. 17. Among them, the products of 2h and 4h reaction time have more nano-scale small particles, and the crystal growth may not be complete due to insufficient reaction time. The product with the shape and the size of 1-6 mu m is irregular rod-shaped with the reaction time of 6-16 h.

The products obtained in example 4 with different reaction times were analyzed by X-ray excitation luminescence spectra, respectively, to obtain X-ray excitation luminescence spectra thereof, as shown in fig. 18. When the reaction time is 6-12 h, the fluorescence intensity has the optimal value, and when the reaction time is less than 4h, the fluorescence intensity is greatly reduced due to incomplete reaction.

FIG. 19 is the X-ray afterglow decay curve graphs of products obtained in example 4 with different reaction times, and the long afterglow materials are all excited by radiation at 50kv and 80mA silver targets for 3min. It can be seen that when the reaction time is 6-12 h, the afterglow performance of the material has the optimum value, and when the reaction time is less than 4h, the afterglow performance is greatly reduced due to incomplete reaction.

Example 5: 100mmol NaLuF at different reaction temperatures ₄ Preparation of Tb

5.1 mixing 80mmol of lutetium nitrate and 20mmol of terbium nitrate powder, dissolving in deionized water, fixing the volume to 80mL, and ultrasonically dissolving to obtain 1.25 mol.L ^-1 A rare earth nitrate solution.

5.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution of step 5.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

5.3 dropwise adding 80mL of ammonium fluoride solution into the solution obtained in the step 5.2, wherein the concentration of the ammonium fluoride solution is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

5.4 slowly dropwise adding a sodium hydroxide solution to the solution in step 5.3 to a pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

5.5 Add 100mL of absolute EtOH drop-wise to the solution from step 5.4 and continue stirring for 20min.

5.6 transferring the mixed solution obtained in the step 5.5 into a 500mL reaction kettle, and carrying out hydrothermal reaction at 180 ℃, 200 ℃, 210 ℃ and 220 ℃ for 12h respectively to obtain a white product. After centrifugation, the product is washed for 3 times by redistilled water and ethanol to obtain the NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

The products obtained in example 5 at different reaction temperatures were analyzed by a transmission electron microscope to obtain a transmission electron microscope image, which is shown in fig. 20 and has an irregular rod shape with a morphology size of 2 to 6 μm.

The products of example 5 with different reaction temperatures were analyzed by X-ray excitation luminescence spectra, respectively, to obtain X-ray excitation luminescence spectra, as shown in fig. 21, when the reaction temperature was 200 ℃, the fluorescence intensity had the optimum value.

FIG. 22 is the X-ray afterglow decay curve graphs of products of different reaction temperatures obtained in example 5, and the long afterglow materials are all subjected to radiation excitation for 3min under a silver target of 50kv and 80 mA. It can be seen that the afterglow performance of the material has the best value when the reaction temperature is 200 ℃.

Example 6: 100mmol NaLuF of different sodium hydroxide concentrations ₄ Preparation of Tb

6.1 mixing 80mmol of lutetium nitrate and 20mmol of terbium nitrate powder, dissolving in deionized water to constant volume of 80mL, and ultrasonically dissolving to obtain 1.25 mol.L ^-1 A rare earth nitrate solution.

6.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution of step 6.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

6.3 dropwise adding 80mL of ammonium fluoride solution into the solution obtained in the step 6.2, wherein the concentration of the ammonium fluoride solution is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

6.4 slowly dropwise adding sodium hydroxide solution to the solution in step 6.3 to pH =7 and adding sodium hydroxide solids of 0.3g and 0.6g, respectively, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

6.5 Add 100mL of absolute EtOH drop wise to the solution from step 6.4 and continue stirring for 20min.

6.6 the mixed solution obtained in the step 6.5 is transferred into a 500mL reaction kettle and undergoes a hydrothermal reaction at 200 ℃ for 12h to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

The products with different sodium hydroxide concentrations obtained in example 6 were analyzed by transmission electron microscopy, respectively, to obtain a transmission electron microscopy image, as shown in fig. 23, which has an irregular rod shape with a morphology size of 2 to 6 μm. Different pH values have certain influence on the appearance and the luminous performance of the reaction system, and the appearance of the reaction system gradually appears as long and thin lines along with the increase of the concentration of NaOH.

The products with different sodium hydroxide concentrations obtained in example 6 were analyzed by X-ray excitation luminescence spectroscopy, respectively, to obtain X-ray excitation luminescence spectrograms thereof, as shown in fig. 24, and when the reaction pH =7, the fluorescence intensity had an optimum value.

FIG. 25 is a graph of X-ray afterglow decay curves of products of different sodium hydroxide concentrations obtained in example 6, wherein the long afterglow material is irradiated at 50kv and 80mA silver target for 3min. It can be seen that the afterglow performance of the material has an optimum value when the reaction pH = 7.

Example 7: 100mmol NaLuF doped with different rare earth elements ₄ Preparation of Re

7.1 mixing 99.5mmol of lutetium nitrate and 0.5mmol of praseodymium nitrate, dissolving in deionized water to constant volume of 80mL, and ultrasonically dissolving to obtain 1.25 mol.L ^-1 A rare earth nitrate solution.

7.2 dropping 100mL of a sodium fluoride solution having a concentration of 1 mol. L into the solution in the step 7.1 ^-1 To obtain a white turbid solution, and stirring is continued for 20min.

7.3 dropping 80mL of ammonium fluoride solution into the solution in the step 7.2, wherein the concentration of the ammonium fluoride solution is 5 mol. L ^-1 The solution turns into gel, and the stirring speed is increased to 800 r.min ^-1 Stirring was continued for 30min.

7.4 slowly dropwise adding sodium hydroxide solution into the solution in the step 7.3 to pH =7, wherein the concentration of the sodium hydroxide solution is 20mol · L ^-1 Stirring was continued for 10min.

7.5 Add 100mL of absolute ethanol dropwise to the solution from step 7.4 and continue stirring for 20min.

7.6 transferring the mixed solution obtained in the step 7.5 into a 500mL reaction kettle, and carrying out hydrothermal reaction for 12h at 200 ℃ to obtain a white product. After centrifugation, the product was washed 3 times with redistilled water and ethanol to obtain NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

7.7 changing the rare earth salt species added in step 7.1And (3) repeating the step 7.2-7.6, and finally obtaining products doped with different rare earth elements, wherein the products are respectively as follows: a-NaLuF ₄ :0.5％Pr；b-NaLuF ₄ :1％Nd；c-NaLuF ₄ :0.5％Sm；d-NaLuF ₄ :20％Tb；e-NaLuF ₄ :0.5％Dy；f-NaLuF ₄ :1％Ho；g-NaLuF ₄ :1％Er；h-NaLuF ₄ :1％Tm。

The products doped with different rare earth elements obtained in example 7 were analyzed by transmission electron microscopy, respectively, to obtain a transmission electron microscopy image thereof, as shown in fig. 26. Except that the size of the Pr doped product is in the nanometer level, the shape and the size of the other rare earth element doped products are irregular rods with the size of 1-8 mu m.

The products doped with different rare earth elements obtained in example 7 were analyzed by X-ray excited luminescence spectroscopy, respectively, to obtain X-ray excited luminescence spectrograms thereof, as shown in fig. 27. In the figure, the Tb-doped emission curve is reduced by a factor of 0.2 times that of the source Tb. As can be seen from the figure, the fluorescence intensity of Tb doping is much larger than that of other rare earth element doping.

FIG. 28 is the X-ray afterglow decay curve graphs of different rare earth element doped products obtained in example 7, wherein the long afterglow materials are all subjected to ray excitation for 3min under a silver target of 50kv and 80 mA. It can be seen that the afterglow performance of Tb doping is far better than that of other rare earth element doping.

Comparative example 2: high-temperature coprecipitation method for preparing NaLuF ₄ :Tb

2.1 to a 25mL two-neck round bottom flask was added 0.34mmol lutetium acetate, 0.06mmol terbium acetate, 4mL oleic acid, and 6mL octadecene, in that order.

2.2 with stirring, vacuum and heat to 130 ℃.

2.3 after no bubbles on the surface of the liquid, 1mmol of solid sodium hydroxide is quickly added to the flask and immediately evacuated to maintain 130 ℃.

2.4 after no bubble on the surface of the liquid, 1.6mmol of ammonium fluoride solid was quickly added to the flask and immediately evacuated to maintain 130 ℃.

2.5 when no bubble exists on the liquid level, introducing nitrogen into the flask, heating to 300 ℃, and keeping for 1h.

2.6 naturally cooling to room temperature, washing the product with cyclohexane and ethanol for 3 times respectively to obtain the NaLuF ₄ Tb white powder was dried at 60 ℃ for 6h.

NaLuF obtained in comparative example 2 was aligned by a transmission electron microscope ₄ Tb is analyzed to obtain a transmission electron microscope image, and as shown in FIG. 29, the Tb has a hexagonal shape with the appearance of about 24nm, uniform appearance and good dispersibility.

NaLuF obtained in comparative example 2 was aligned with the emission spectrum excited by X-ray ₄ Tb and NaLuF obtained by ligand-free concentrated hydrothermal method in the patent ₄ Tb was analyzed to obtain the X-ray excitation luminescence spectrum shown in FIG. 30. It can be seen that the ligand-free concentrated hydrothermal method employed in this patent produces NaLuF ₄ Tb has higher fluorescence intensity than NaLuF prepared by high-temperature coprecipitation method ₄ :Tb。

FIG. 31 shows NaLuF obtained in comparative example 2 ₄ Tb and NaLuF obtained by the ligand-free concentrated hydrothermal method in this patent ₄ Tb, the long afterglow material is excited by 50kv and 80mA silver target for 3min. It can be seen that the ligand-free concentrated hydrothermal process used in this patent yields NaLuF ₄ Tb has afterglow performance obviously superior to that of NaLuF prepared by high-temperature coprecipitation method ₄ :Tb。

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.

Claims

1. A preparation method of a long afterglow material of rare earth element doped fluoride is characterized in that rare earth salt, sodium fluoride, ammonium fluoride and water are mixed, the pH value of the solution is adjusted to be neutral, then alcohol solvent is added for hydrothermal reaction, and beta-NaReF is obtained ₄ Long afterglow materials of the type;

the molar ratio of the sodium fluoride to the ammonium fluoride is 1: (0 to 9).

2. The method according to claim 1, wherein the rare earth salt is at least one selected from the group consisting of a nitrate, a chloride and an acetate of a rare earth.

3. The method of claim 2, wherein the rare earth salt comprises at least a nitrate, chloride or acetate salt of lutetium and/or terbium.

4. The method according to claim 1, wherein the molar ratio of the rare earth salt to the sodium fluoride is 1: (1-6); the mole ratio of the rare earth salt to the ammonium fluoride is 1: (0 to 9).

5. The method according to claim 1, wherein the volume ratio of the solution after the pH adjustment to the alcohol solvent is (2-5): 1.

6. the preparation method according to claim 1, wherein the reaction temperature of the hydrothermal reaction is 160-230 ℃ and the reaction time is 2-24 h.

7. A long afterglow material of rare earth element doped fluoride, characterized by being prepared by the preparation method of any one of claims 1 to 6.

8. The long afterglow material of claim 7, wherein the particle size of the long afterglow material is 0.1 to 10 μm.

9. Use of the long persistence material of claim 7 or 8 for bio-labeling, X-ray detection, visualization and imaging.