Self-activated near-infrared fluorescent powder as well as preparation method and application thereof

Abstract

The invention discloses self-activated near-infrared fluorescent powder as well as a preparation method and application thereof, and belongs to the field of near-infrared luminescent materials. The general chemical formula of the self-activated near-infrared fluorescent powder is BaAl2B2O7: xLi < + >, x represents the mole number of doped monovalent lithium ions, and x is more than 0 and less than or equal to 0.10. A high-temperature solid-phase method is adopted, the preparation process is simple, synthesis raw materials are easy to obtain, operation is easy, the preparation cost is low, and the method is environmentally friendly and low in cost. According to the self-activated near-infrared fluorescent powder prepared by the preparation method disclosed by the invention, by introducing Li < + >, lattice defects are generated in a borate matrix material, the concentration of interstitial oxygen defects is regulated and controlled (the defect concentration is increased), the emission intensity is enhanced through defect engineering, adjustable emission is shown in a range of 710-780nm, and the thermal stability is greatly improved; the prepared self-activated near-infrared fluorescent powder can better meet the actual requirements of NIR LED application.

Description

Technical Field

[0001] The present invention relates to the field of near-infrared luminescent materials, and particularly to a self-activated near-infrared phosphor and its preparation method and application. Background Art

[0002] Near-infrared luminescent materials have important research significance in photoconversion luminescent materials. They have the characteristics of being fast, non-invasive, and non-destructive, and are widely used in fields such as food quality assessment, drug component analysis, medical imaging, and night vision. Traditional near-infrared light sources, such as halogen lamps and tungsten halogen lamps, have disadvantages such as large volume, low efficiency, high cost, and narrow emission peaks, which limit their applications. Currently, the emergence of near-infrared light-emitting diodes (NIRpc-LEDs) overcomes the wavelength limitations of traditional infrared light sources, and has the characteristics of high efficiency, durability, and environmental friendliness, and is expected to become a substitute for traditional light sources. NIR pc-LEDs are integrated with near-infrared phosphors and LED chips, and the near-infrared phosphors determine the performance of NIRpc-LEDs. Therefore, the development of high-performance, broadband near-infrared phosphors is crucial for this technology.

[0003] Currently, the reported near-infrared luminescent phosphors mainly use rare earth ions and transition metal ions as activators. However, phosphors doped with rare earth ions (such as Pr 3+ , Nd 3+ , Yb 3+ , etc.) not only have relatively high costs, but also have problems such as weak absorption and narrow emission bands. Among transition metal ions, phosphors doped with Cr 3+ and Mn 4+ have lower costs and wider near-infrared emission spectra, but their luminescence highly depends on the crystal field strength within the host lattice, which makes it challenging to control their emission wavelengths. In addition, Cr 3+ and Mn 4+ are not suitable for some fields with high safety requirements. Nowadays, the demand for non-toxic and low-cost near-infrared luminescent materials is increasing.

[0004] Different from doped phosphors, the luminescence of self-activated phosphors is caused by directly forming structural defect-type luminescence centers in the matrix, and has characteristics such as low cost, high excitation threshold, less reabsorption overlap, and low sintering temperature, and has received more and more attention. Currently, some achievements have been made in the development of near-infrared self-activated phosphors, such as CaLaMgTaO6, SrLaMgTaO6, and Na2ZrTeO6. However, these phosphors have some disadvantages, such as relatively low emission efficiency, single emission wavelength, and poor thermal stability, and it is difficult to meet the actual application requirements of near-infrared pc-LED devices.

[0005] Therefore, how to obtain a self-activated near-infrared phosphor with high luminous efficiency, tunable spectrum and good thermal stability is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] To solve the above problems existing in the prior art, the object of the present invention is to provide a self-activated near-infrared phosphor, its preparation method and application, which can effectively solve the problems of low luminous efficiency, single emission wavelength and poor thermal stability of the phosphor existing in the prior art.

[0007] To achieve the above object or other objects, the present invention is realized by the following technical solutions.

[0008] A self-activated near-infrared phosphor has a chemical general formula of BaAl2B2O7:xLi + , where x represents the molar number of monovalent lithium ion doping, and 0 < x ≤ 0.10.

[0009] Preferably, x is selected from any one of the values 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10.

[0010] A method for preparing a self-activated near-infrared phosphor includes the following steps:

[0011] (1) For the chemical general formula BaAl2B2O7:xLi + , 0 < x ≤ 0.10, according to the stoichiometric ratio of Ba 2+ , Al 3+ , BO3 3- , Li + in the chemical general formula, successively weigh the compounds containing Ba 2+ , the compounds containing Al 3+ , the compounds containing BO3 3- , the compounds containing Li + , add anhydrous ethanol and mix and grind to obtain a mixture;

[0012] (2) Calcinate and grind the mixture obtained in step (1) in an air atmosphere to obtain the self-activated near-infrared phosphor.

[0013] Preferably, the compound containing Ba 2+ is selected from one or more of BaCO3, Ba(OH)2, Ba(NO3)2. More preferably, the compound containing Ba 2+ is selected from BaCO3.

[0014] Preferably, the compound containing Al 3+ is selected from one or more of Al2O3, Al(NO3)3, Al(OH)3. More preferably, the compound containing Al3+ The compound is selected from Al2O3 or Al(OH)3.

[0015] Preferably, the Li-containing + compound is selected from one or more of Li2O, Li2CO3, and Li(OH). More preferably, the Li-containing + compound is selected from Li2O and / or Li2CO3. More preferably, the Li-containing + compound is selected from Li2CO3.

[0016] Preferably, the BO3-containing 3- compound is selected from H3BO3 and / or K2B4O7·10H2O. More preferably, the BO3-containing 3- compound is selected from H3BO3.

[0017] Preferably, the addition amount of absolute ethanol in step (1) is 20-70% of the total mass of the compound raw materials. More preferably, the addition amount of absolute ethanol is 30-60% of the total mass of the compound raw materials. More preferably, the addition amount of absolute ethanol is 40-50% of the total mass of the compound raw materials.

[0018] Preferably, the grinding time in step (1) is 20-40 min. More preferably, the grinding time in step (1) is 25-35 min. More preferably, the grinding time in step (1) is 28-33 min. In the present invention, in order to reduce the particle size and improve the mixing uniformity in step (1), grinding is carried out after mixing, which can not only increase the contact area of reactants, shorten the diffusion distance, but also improve the mixing uniformity, promote crystallization and reduce agglomeration. Preferably, the particle size of the obtained mixture after grinding is less than 50 μm.

[0019] Preferably, the calcination temperature in step (2) is 600-900 °C, and the calcination time is 6-12 h. More preferably, the calcination temperature in step (2) is 650-850 °C, and the calcination time is 7-11 h. More preferably, the calcination temperature in step (2) is 700-800 °C, and the calcination time is 8-10 h.

[0020] The present invention also provides an application of the above self-activated near-infrared phosphor in the field of near-infrared luminescent materials.

[0021] The present invention adopts the high-temperature solid-phase method, and the preparation process is simple, the synthesis raw materials are easy to obtain, easy to operate, and the preparation cost is low; in addition, it can effectively avoid the use of toxic organic solvents and the pollution problem of waste liquid generation, which is not only environmentally friendly but also low in cost. In the present invention, borate is used as the matrix material. The preparation process of borate is simple, the synthesis temperature is low, the light transmittance is good, the optical damage threshold is high, the thermal stability is good, the structure is rich and diverse, and the selection range is wide, which is an excellent luminescent matrix material.

[0022] The self-activated near-infrared phosphor prepared by the present invention generates lattice defects in the borate matrix material by introducing Li + , regulates the concentration of interstitial oxygen defects (the defect concentration increases), enhances the emission intensity through defect engineering, exhibits adjustable emission in the range of 710-780 nm, and greatly improves the thermal stability. The prepared self-activated near-infrared phosphor can better meet the actual requirements of NIR LED applications. Description of the Drawings

[0023] Figure 1 SEM image of the near-infrared phosphor prepared in Comparative Example 1;

[0024] Figure 2 SEM image of the self-activated near-infrared phosphor prepared in Example 7;

[0025] Figure 3 X-ray diffraction spectra of the self-activated near-infrared phosphors prepared in Comparative Example 1 and Examples 1-7;

[0026] Figure 4 Excitation spectra of the self-activated near-infrared phosphors prepared in Comparative Example 1 and Examples 1-7 obtained at emission wavelengths of 780 nm and 720 nm, respectively;

[0027] Figure 5 Emission spectra of the self-activated near-infrared phosphors prepared in Comparative Example 1 and Examples 1-7 obtained at excitation wavelengths of 330 nm and 270 nm, respectively;

[0028] Figure 6 Emission spectra of the near-infrared phosphor prepared in Comparative Example 1 at different temperatures (excitation wavelength: 330 nm);

[0029] Figure 7 Emission spectra of the self-activated near-infrared phosphor prepared in Example 1 at different temperatures (excitation wavelength: 270 nm);

[0030] Figure 8 Emission spectra of the self-activated near-infrared phosphor prepared in Example 7 at different temperatures (excitation wavelength: 270 nm);

[0031] Figure 9 Electron paramagnetic resonance spectra of the self-activated near-infrared phosphors prepared in Comparative Example 1, Example 1, and Example 7 under 254 nm irradiation;

[0032] Figure 10 Thermoluminescence spectra of the self-activated near-infrared phosphors prepared in Comparative Example 1 and Example 7;

[0033] Figure 11 Application of the self-activated near-infrared phosphor prepared in Example 7. Specific implementation manners

[0034] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for describing specific implementation manners and are not intended to limit the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0036] When the embodiments give a numerical range, it should be understood that unless otherwise specified in the present invention, any value at both ends of each numerical range and any value between the two ends can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, based on the understanding of those skilled in the art of the prior art and the description of the present invention, can also use any methods, devices, and materials similar to or equivalent to the methods, devices, and materials described in the embodiments of the present invention to implement the present invention.

[0037] Example 1:

[0038] BaAl2B2O7:0.04Li +

[0039] Using Ba(OH)2, Al2O3, Li2CO3, and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula and grind them. Add anhydrous ethanol accounting for 40% of the total mass of the above raw materials, and mix and grind for 30 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 750 °C for 10 h. Then cool to room temperature, and grind the calcined block sample into powder to obtain the required self-activated near-infrared phosphor.

[0040] Example 2

[0041] BaAl2B2O7:0.05Li +

[0042] Using Ba(NO3)2, Al(NO3)3, Li2CO3 and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 30% of the total mass of the above raw materials, and grind for 28 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 700 °C for 8 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0043] Example 3

[0044] BaAl2B2O7:0.06Li +

[0045] Using BaCO3, Al(OH)3, Li2O and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 45% of the total mass of the above raw materials, and grind for 25 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 800 °C for 10 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0046] Example 4

[0047] BaAl2B2O7:0.07Li +

[0048] Using BaCO3, Al(OH)3, Li2CO3 and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 60% of the total mass of the above raw materials, and grind for 33 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 650 °C for 9 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0049] Example 5

[0050] BaAl2B2O7:0.08Li +

[0051] Using BaCO3, Al(OH)3, Li2CO3 and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 45% of the total mass of the above raw materials, and grind for 35 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 800 °C for 11 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0052] Example 6

[0053] BaAl2B2O7:0.09Li +

[0054] Using BaCO3, Al(OH)3, Li2CO3 and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 20% of the total mass of the above raw materials, and grind for 20 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 600 °C for 7 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0055] Example 7

[0056] BaAl2B2O7:0.10Li +

[0057] Using BaCO3, Al(OH)3, Li2CO3 and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 50% of the total mass of the above raw materials, and grind for 40 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 850 °C for 11 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0058] Example 8

[0059] BaAl2B2O7:0.10Li +

[0060] Using BaCO3, Al(OH)3, Li(OH) and K2B4O7·10H2O as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, put them into an agate mortar, add anhydrous ethanol accounting for 70% of the total mass of the above raw materials, and grind for 40 minutes to fully mix the raw materials. Calcinate the uniformly mixed reactants in an air atmosphere at 900 °C for 11 h. Let it cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required self-activated near-infrared phosphor.

[0061] Comparative Example 1

[0062] BaAl2B2O7

[0063] Using Ba2CO3, Al(OH)3, and H3BO3 as raw materials, weigh the raw materials according to the molar amounts expressed by the chemical formula, add anhydrous ethanol accounting for 50% of the total mass of the above raw materials, and grind for 20 minutes to fully mix the raw materials. Calcinate the well-mixed reactants in an air atmosphere at 750 °C for 7 h. Cool down to room temperature in a high-temperature tube furnace, and grind the calcined block sample into powder in an agate mortar to obtain the required phosphor.

[0064] Performance Test

[0065] 1. Take the phosphor of Comparative Example 1 and the self-activated near-infrared phosphor obtained in Example 7 for SEM testing. The obtained spectra are respectively as Figure 1 、 2 shown. It can be seen from the figures that the phosphors obtained in Comparative Example 1 and Example 7 are both aggregates of irregularly shaped particles, and the distance between the particles is good, indicating good crystal growth. However, the particle size of the self-activated near-infrared phosphor obtained in Example 7 is finer, with a particle size range of 5 - 10 microns, which is more conducive to improving the luminescence efficiency, dispersion, and uniformity.

[0066] 2. Conduct X-ray diffraction testing on the phosphor of Comparative Example 1 and the defect engineering-improved self-activated near-infrared phosphors prepared in Examples 1 - 7. The obtained spectra are as Figure 3 shown. It can be seen from the figures that the diffraction peaks of the obtained phosphors are in good agreement with the standard cards, and no impurity peaks appear. This indicates that the synthesized BaAl2B2O7:xLi + phosphor is a pure phase, where x represents the molar number of monovalent lithium ion doping, and 0 ≤ x ≤ 0.10.

[0067] 3. Measure the excitation spectra of the phosphor of Comparative Example 1 and the defect engineering-improved self-activated near-infrared phosphors prepared in Examples 1 - 7 at emission wavelengths of 780 nm and 720 nm respectively, as Figure 4 shown; measure the emission spectra at excitation wavelengths of 270 nm and 330 nm, as Figure 5 shown; it can be seen from the figures that for the defect engineering-improved self-activated near-infrared phosphors prepared in Examples 1 - 7, with the increase in the content of Li + doping, the fluorescence intensity increases, and the strongest emission is obtained when x = 0.10. Specifically, when the fluorescence intensity of the self-activated near-infrared phosphor increases, there is a continuous blue shift in the peak position, accompanied by a broadening of the peak width. Compared with the BaAl2B2O7 matrix, the representative BaAl2B2O7:0.10Li +The PL intensity of the phosphor increased by about 8 times, the PL peak position showed a blue shift of about 69 nm, and the full width at half maximum increased from 85.4 nm to 102.8 nm. The excitation spectra were measured at the strongest emission wavelength, and the excitation peaks corresponding to the defect-engineered improved self-activated near-infrared phosphors prepared in Examples 1-7 also showed a continuous blue shift, and the intensity reached the maximum value at x = 0.10.

[0068] 4. The temperature-dependent emission spectra of the phosphor of Comparative Example 1 and the defect-engineered improved self-activated near-infrared phosphors prepared in Examples 1 and 7 were measured (the test temperatures were 25 °C, 50 °C, 75 °C, 100 °C, 125 °C, and 150 °C), and the test results are shown in Figure 6 、 Figure 7 and Figure 8 respectively. It can be seen from Figure 6 、 Figure 7 and Figure 8 that with the increase of temperature, the intensity of the emission band of the phosphor BaAl2B2O7 prepared in Comparative Example 1 decreased sharply, and the emission intensity at 150 °C was only 37% of the room temperature emission intensity. In contrast, the defect-engineered improved self-activated near-infrared phosphors BaAl2B2O7:0.04Li + and BaAl2B2O7:0.10Li + prepared in Examples 1 and 7 had greatly enhanced thermal stability. At 150 °C, the emission intensities of BaAl2B2O7:0.04Li + and BaAl2B2O7:0.10Li + powders were 81% and 86% of the room temperature emission intensity respectively, and the thermal stability was improved by 44% and 52% compared with the BaAl2B2O7 phosphor.

[0069] 5. The electron paramagnetic resonance spectra of the phosphor of Comparative Example 1 and the defect-engineered improved self-activated near-infrared phosphors prepared in Examples 1 and 7 were measured, and the results are shown in Figure 9 respectively. It can be seen from Figure 9 that in all three samples, a characteristic peak of interstitial oxygen defect with a signal value of 2.005 was observed at 3510 gauss, and the concentration of interstitial oxygen defects increased with the increase of Li + concentration.

[0070] 6. The thermoluminescence spectra of the phosphor of Comparative Example 1 and the defect-engineered improved self-activated near-infrared phosphor prepared in Example 7 were measured, as shown in Figure 10 respectively. It can be seen from Figure 10 that compared with Comparative Example 1, the thermoluminescence spectrum intensity of the defect-engineered improved self-activated near-infrared phosphor prepared in Example 7 was significantly enhanced, and the main peak position shifted towards the high temperature direction. This change indicates that Li +Doping increases the trap depth and the density of trapped charge carriers in deep traps. The shape of the thermoluminescence spectrum curve is composed of traps at different depths. When Li + is incorporated, the peak shape changes, indicating a change in the trap distribution. By fitting the TL curves of the comparative example 1 and the sample of Example 7 with Gaussian peaks, two broad bands (trap 1, trap 2) can be clearly observed in Comparative Example 1, with peak values at 355K and 423K respectively; three broad bands (trap 1, trap 2, trap 3) can be clearly observed in Example 7, with peak values at about 381K, 449K and 536K respectively. After doping 10% of L i+ , a new defect energy level trap 3 is introduced.

[0071] 7. Take the self-activated near-infrared phosphor obtained in Example 7 and prepare an LED by conventional techniques. Prepare a UV LED chip (wavelength 280nm), BaAl2B2O7:0.10Li + phosphor (Example 7) and two-component PDMS silicone (main agent and curing agent). Weigh 0.2g of BaAl2B2O7:0.10Li + phosphor, 1.62g of the main agent, and 0.18g of the curing agent, then stir evenly for 15 min. Then, use a pipette gun with a measuring range of 100 - 1000 μL to suck and spot twice on the LED chip. After that, dry the LED chip in an oven at 75°C for 2 - 3 h to obtain a near-infrared LED prepared with the BaAl2B2O7:0.10Li + self-activated near-infrared phosphor obtained in Example 7. Use a near-infrared camera and the above-prepared near-infrared LED for illumination to observe an orange, a human body, a picture covered by a 720nm filter, etc. As Figure 11 shown, it can be seen from Figure 11 that the detailed features (such as shape, spots, etc.) of the orange can be clearly observed using the near-infrared camera and the near-infrared LED prepared with the phosphor of Example 7, showing its night vision ability. Under the illumination of the near-infrared LED, the blood vessels of the hand can be clearly observed, indicating that the device has great potential in biological imaging. Finally, the school badge image covered with a 720nm filter has no visible markings under the near-infrared camera; however, under the illumination of the near-infrared LED prepared with the BaAl2B2O7:0.10Li + self-activated near-infrared phosphor, the school badge is clearly visible, indicating that it can be used for the security detection of invisible markers.

[0072] As can be seen from the above embodiments, the present invention provides a defect engineering-improved self-activated near-infrared phosphor and a preparation method thereof. Compared with the matrix, the phosphor after defect engineering improvement has enhanced peak intensity, blue-shifted peak position, broadened full width at half maximum, and enhanced thermal stability. The defect engineering-improved self-activated near-infrared phosphor of the present invention can be effectively excited by short-wave ultraviolet light and exhibits strong emission in the range of 650-800 nm. The prepared phosphor has broad application prospects as a near-infrared emission component in various fields (such as night vision, biological imaging, and concealed security marker detection).

[0073] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A self-activated near-infrared phosphor, characterized in that: Its general chemical formula is BaAl2B2O7:xLi + , wherein x represents the molar number of monovalent lithium ions doped, 0<x≤0.

10.

2. The self-activated near-infrared phosphor according to claim 1, characterized in that: x is any value selected from 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.

10.

3. A method for preparing the self-activated near-infrared phosphor according to claim 1 or 2, characterized in that: The following steps are involved: (1) Chemical formula: BaAl2B2O7:xLi + , 0<x≤0.10, according to the chemical formula Ba 2+ 、Al 3+ , BO3 3- , Li + The stoichiometric ratio of Ba 2+ Compounds containing Al 3+ Compounds containing BO3 3- Compounds containing Li + The compound is added with anhydrous ethanol, mixed and ground to obtain a mixture; (2) The mixture obtained in step (1) is calcined and ground in an air atmosphere to obtain a self-activated near-infrared phosphor.

4. The method according to claim 3, characterized in that The Ba-containing 2+ The compound is selected from one or more of BaCO3, Ba(OH)2, and Ba(NO3)2.

5. The method according to claim 3, characterized in that The Al-containing 3+ The compound is selected from one or more of Al2O3, Al(NO3)3, and Al(OH)3.

6. The method according to claim 3, characterized in that The Li-containing + The compound is selected from one or more of Li2O, Li2CO3, and Li(OH).

7. The method according to claim 3, characterized in that The BO3 3- The compound is selected from H3BO3 and / or K2B4O7·10H2O.

8. The method according to claim 3, characterized in that The amount of anhydrous ethanol added in step (1) is 20 to 70% of the total mass of the compound raw materials.

9. The method according to claim 3, characterized in that In step (2), the calcination temperature is 600-900° C. and the calcination time is 6-12 hours.

10. Use of the self-activated near-infrared phosphor according to claim 1 or 2 in the field of near-infrared luminescent materials.

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