Ultra-wideband near-infrared luminescent material and preparation method and application thereof

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to an ultra-wideband near-infrared luminescent material as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a magnesium source, a gallium source, a tin source, a chromium source and a nickel source, grinding, sintering, crushing and carrying out secondary grinding to obtain the near-infrared luminescent material, the near-infrared light-emitting material is of a spinel structure; the chemical general formula is Mg (5-y) Ga (2-x) Sn2O12: xCr < 3 + >, yNi < 2 + >, wherein 0.005 < = x < = 0.3, and 0 < = y < = 0.06. According to the near-infrared luminescent material, the emission spectrum coverage range can be widened, continuous ultra-wideband emission of 700-1650 nm is achieved, and the accumulated half-peak width reaches 590 nm.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to an ultra-wideband near-infrared luminescent material and a preparation method and application thereof. Background Art

[0002] Near-infrared light (700-1700 nm) has received extensive attention in scientific research and industry in recent years due to its potential application value in biomedicine, food safety, environmental monitoring and other fields. In particular, near-infrared light has shown important commercial prospects in the fields of cosmetic medicine, food safety testing, optical communications, night vision monitoring, and precision agriculture. Near-infrared light can penetrate objects such as skin and plants to achieve non-destructive testing and deep component analysis. Therefore, in non-invasive detection technology, especially for the analysis of the components of complex organisms, the advantages of near-infrared light are particularly prominent.

[0003] One of the keys to near-infrared light sources is light-emitting diode (LED) technology, especially near-infrared phosphor-converted LED (NIR-PC-LED). This technology combines the emission of near-infrared light with the fluorescence conversion effect, making it an ideal near-infrared light source. Its working principle is to use phosphors to convert short-wavelength light into long-wavelength near-infrared light, thereby achieving emission control of near-infrared light. Compared with traditional light sources, near-infrared phosphor-converted LED has higher efficiency, longer service life and better stability. Therefore, it is widely regarded as an important technical path for future near-infrared light sources.

[0004] However, there are still many technical challenges to achieve efficient and broadband near-infrared phosphors. In particular, how to extend the emission wavelength of the phosphor to more than 1000 nm and maintain high emission efficiency and good spectral continuity throughout the entire band. Currently, the emission wavelength of many near-infrared luminescent materials is usually difficult to exceed 1000 nm, which poses a great obstacle to accurate spectral analysis and in-depth detection of organic components.

[0005] For example, the existing Chinese patent (CN 116769483 A) discloses a novel garnet structure broadband near-infrared luminescent material and a light source made thereof, the chemical formula of which is A x B 3-x Mg x C 2-x (Si,Ge)3O 12 : a Ce 3+ , b Cr 3+ , cM, M is one or a combination of Ni, Yb, Nd, Dy and Er, and its emission wavelength is successfully increased to more than 1000 nm by co-doping with multiple ions, meeting the requirements of some near-infrared spectra. However, the luminescent material still exhibits a relatively serious narrow-band discontinuity phenomenon in the 900-1100 nm band, which makes it impossible to accurately identify organic components. In the fields of food freshness, non-destructive testing of organic matter, photothermal therapy, etc., high-performance near-infrared light sources with a wider emission range are required. However, the existing near-infrared phosphors have the defects of narrow emission band and insufficient half-peak width, which seriously hinders the development prospects of near-infrared phosphor conversion light-emitting diode technology. Summary of the invention

[0006] The purpose of the present invention is to provide an ultra-wideband near-infrared luminescent material and a preparation method and application thereof to solve the problems in the prior art. The present invention can broaden the emission spectrum coverage range and achieve continuous ultra-wideband emission of 700-1650 nm, with emission peaks at 820 nm and 1450 nm, and the cumulative half-peak width reaches 590 nm.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention provides an ultra-wideband near-infrared luminescent material, wherein the near-infrared luminescent material has a spinel structure; the chemical formula of the near-infrared luminescent material is Mg 5-y Ga 2-x Sn2O 12 :xCr 3+ ,yNi 2+ ; Among them, 0.005≤x≤0.3, 0≤y≤0.06.

[0008] Preferably, the excitation wavelength range of the near-infrared luminescent material is 400-650 nm.

[0009] Preferably, the emission wavelength range of the near-infrared luminescent material is 700-1650 nm.

[0010] In a second aspect, the present invention provides a method for preparing an ultra-wideband near-infrared luminescent material, comprising: mixing a magnesium source, a gallium source, a tin source, a chromium source and a nickel source, and obtaining the near-infrared luminescent material after grinding, sintering, crushing and secondary grinding.

[0011] Preferably, the magnesium source is an oxide containing magnesium.

[0012] Preferably, the gallium source is a gallium-containing oxide.

[0013] Preferably, the tin source is a tin-containing oxide.

[0014] Preferably, the chromium source is a chromium-containing oxide.

[0015] Preferably, the selected nickel source is a nickel-containing oxide.

[0016] In a third aspect, the present invention provides an application of an ultra-wideband near-infrared luminescent material in the field of luminescent materials; the near-infrared luminescent material is used to prepare a near-infrared light source.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention can tune the emission spectrum characteristics by controlling the ratio of each element, and can simultaneously obtain two emission peaks of 820nm and 1450nm under blue light excitation, thereby obtaining a continuous ultra-wideband near-infrared emission. 3+ , so that the emission spectrum of the near-infrared luminescent material under blue light excitation covers 700~1200 nm, the optimal emission wavelength is 820 nm, and the half-peak width is 270 nm. 3+ and Ni 2+ Co-doping makes Cr 3+ As a sensitizer to Ni 2+ Energy transfer is performed, and Cr is retained under blue light excitation. 3+ and Ni 2+ The emission band forms a dual-mode broadband near-infrared emission of 820 nm and 1450 nm. The emission spectrum covers 700~1650 nm. The intensity and position of the emission wavelength are adjustable, and the cumulative half-peak width reaches 590 nm, which greatly broadens the application range of fluorescent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 The excitation spectrum of the near-infrared luminescent material obtained in Example 1 of the present invention at a monitoring wavelength of 820 nm; Figure 2 The emission spectrum of the near-infrared luminescent material obtained in Example 1 of the present invention under 400 nm ultraviolet light excitation; Figure 3 The excitation spectrum of the near-infrared luminescent material obtained in Example 2 of the present invention at a monitoring wavelength of 1450 nm; Figure 4 The emission spectrum of the near-infrared luminescent material obtained in Example 2 of the present invention under 650 nm red light excitation; Figure 5 This is the X-ray diffraction (XRD) spectrum of the near-infrared luminescent material obtained in Example 3 of the present invention; Figure 6 The photo of the near-infrared luminescent material and the prepared near-infrared light source obtained in Example 2 of the present invention; Figure 7 This is a photo of a near-infrared light source prepared by the near-infrared luminescent material obtained in Example 2 of the present invention being used for information encryption and biological imaging; Figure 8 The near-infrared light source prepared from the near-infrared luminescent material obtained in Example 2 of the present invention is used for non-destructive detection of the spectrum of organic components. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0023] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0024] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings: The first object of the present invention is to provide an ultra-wideband near-infrared luminescent material, wherein the near-infrared luminescent material has a spinel structure; the chemical formula of the near-infrared luminescent material is Mg5-y Ga 2-x Sn2O 12 :xCr 3+ ,yNi 2+ ; Among them, 0.005≤x≤0.3, 0≤y≤0.06.

[0026] The excitation wavelength range of the near-infrared luminescent material is 400-650 nm, which can match ultraviolet light, blue light or red light sources; the emission wavelength range of the near-infrared luminescent material is 700-1650 nm, which can cover near-infrared region I to near-infrared region II.

[0027] The ultra-wide near-infrared luminescent material of the present invention is designed based on the energy transfer effect. By controlling the ratio of each element to tune the emission spectrum characteristics, two emission peaks of 820 nm and 1450 nm can be obtained simultaneously under blue light excitation, thereby obtaining a continuous ultra-wideband near-infrared emission. 3+ and Ni 2+ Determines the luminescent properties of the luminescent material. 3+ As an activator, there is no Ni 2+ When Cr is excited by blue light, the emission spectrum covers 700~1200 nm, the optimal emission wavelength is 820 nm, and the half-peak width is 270 nm. 3+ and Ni 2+ When co-doped, Cr 3+ As a sensitizer to Ni 2+ Energy transfer is performed, and Cr is retained under blue light excitation. 3+ and Ni 2+ The emission band forms a dual-mode broadband near-infrared emission of 820 nm and 1450 nm. The emission spectrum covers 700~1650 nm. The intensity and position of the emission wavelength are adjustable, and the cumulative half-peak width reaches 590 nm, which greatly broadens the application range of fluorescent materials.

[0028] The second object of the present invention is to provide a method for preparing an ultra-wideband near-infrared luminescent material, comprising: mixing a magnesium source, a gallium source, a tin source, a chromium source and a nickel source, and obtaining the near-infrared luminescent material after grinding, sintering, crushing and secondary grinding. The present invention combines mechanical grinding with a high-temperature solid-phase reaction method to obtain the Cr 3+ 、Ni 2+ Uniform doping into Mg5Ga2Sn2O 12 In the matrix material, Cr 3+ →Ni 2+ Energy transfer channel, forming Cr 3+ and Ni 2+ Dual-mode emission greatly increases the luminous range; by controlling the element ratio, Cr 3+ and Ni2+ The co-doped near-infrared luminescent material greatly increases its half-peak width under blue light excitation, achieving continuous ultra-wideband emission from 700 to 1650 nm.

[0029] Among them, the particle size of the near-infrared luminescent material is 3~9 μm. This particle size range can optimize the surface and volume effects of the near-infrared luminescent material, thereby improving its luminous efficiency.

[0030] The grinding is performed by wet ball milling or dry ball milling, both of which can increase the specific surface area of ​​the material and improve the luminous efficiency of the near-infrared luminescent material by grinding the particles into finer particles.

[0031] The sintering method is high-temperature sintering, specifically: heating from room temperature to 1400~1600 ℃ at a heating rate of 5~10 ℃ / min, and keeping warm for 3~6 hours. Cooling down to 500 ℃ at a cooling rate of 5~10 ℃ / min, and then naturally cooling to room temperature. Slow heating helps to avoid stress concentration and uneven heating of materials caused by too fast temperature changes. 1400~1600 ℃ is the optimal temperature for materials such as ceramics, metals and alloys to obtain high density during heat treatment. This temperature helps to fully diffuse the solid phase between the particles of the material, thereby promoting closer contact between the particles, and finally forming a dense structure, improving the mechanical properties, density and permeability resistance of the material.

[0032] In addition, the magnesium source is an oxide containing magnesium; preferably, the magnesium source is magnesium oxide. The gallium source is an oxide containing gallium; preferably, the gallium source is gallium oxide. The tin source is tin dioxide. The chromium source is an oxide containing chromium; preferably, the chromium source is chromium oxide. The selected nickel source is an oxide containing nickel; preferably, the nickel source is nickelous oxide. The above substances all have fewer impurities at high purity, which can improve the purity of the luminescent material and thus improve the luminescent performance.

[0033] The third object of the present invention is to provide an application of an ultra-wideband near-infrared luminescent material in the field of luminescent materials, wherein the near-infrared luminescent material is used to prepare a portable near-infrared light source, and the near-infrared light source also includes a blue light emitting diode with a luminescent wavelength of 420-480 nm or a red light emitting diode with a luminescent wavelength of 600-650 nm. The near-infrared light source prepared based on the near-infrared fluorescent luminescent material provided by the present invention can emit continuous ultra-wideband near-infrared emission of 700-1650 nm under 440 nm blue light excitation, and the half-peak width reaches 590 nm, which is suitable for non-destructive detection of organic components, information encryption and biological imaging.

[0034] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0035] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0036] Example 1 A Cr 3+ Doped near-infrared luminescent material, chemical formula is Mg5Ga 1.9 Sn2O 12 :0.1Cr 3+ , the material is light green solid powder. The preparation method is as follows: (1) Raw materials include: MgO: 0.4030 g, Ga2O3: 0.3561 g, SnO2: 0.6028 g, Cr2O3: 0.0152 g, a total of 1.3771 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1400 °C at a heating rate of 10 °C / min, and then kept at this temperature for 6 h, then cooled to 500 °C at a cooling rate of 5 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ Doped with near-infrared luminescent materials.

[0037] The near-infrared luminescent material obtained in this embodiment is subjected to emission spectrum test, such as Figure 1 and Figure 2 As shown, the emission spectrum of the near-infrared luminescent material obtained in this example under 424 nm blue light excitation has a maximum emission wavelength of 820 nm, a spectrum spanning 700-1200 nm, and a half-peak width of 270 nm.

[0038] Example 2 A Cr 3+ , Ni 2+ Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.99 Ga1.9 Sn2O 12 :0.1Cr 3+ , 0.01Ni 2+ The preparation method is as follows: (1) Raw materials include: MgO: 0.4021 g, Ga2O3: 0.3561 g, SnO2: 0.6028 g, Cr2O3: 0.0152 g, NiO: 0.0015 g, totaling 1.3777 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1450 °C at a heating rate of 8 °C / min, and then kept at this temperature for 3 h, then decreased to 500 °C at a cooling rate of 6 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0039] The near-infrared luminescent material obtained in this embodiment was subjected to an excitation spectrum test. Figure 3 As shown, the results show that the obtained near-infrared luminescent material can be effectively excited between 400 and 650 nm. In addition, Figure 4 : is the emission spectrum of the near-infrared luminescent material obtained in this example under 424 nm blue light excitation, the emission spectrum spans 700-1650 nm, consists of two broadband emission peaks at 820 nm and 1450 nm, and the total half-peak width reaches 590 nm; Figure 6 The photos of the near-infrared luminescent material and the prepared near-infrared light source obtained in this example; Figure 7 This is a photo of the near-infrared light source prepared by the near-infrared luminescent material obtained in this example being used for information encryption and biological imaging; Figure 8 The near-infrared light source prepared from the near-infrared luminescent material obtained in this example is used for non-destructive detection of the spectrum of organic components.

[0040] Example 3 A Cr 3+ , Ni 2+ Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.97 Ga 1.9 Sn2O 12 :0.1Cr 3+ , 0.03Ni 2+ The preparation method is as follows: (1) Raw materials include: MgO: 0.4006 g, Ga2O3: 0.3561 g, SnO2: 0.6028 g, Cr2O3: 0.0152 g, NiO: 0.0045 g, a total of 1.3792 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1500 °C at a heating rate of 5 °C / min, and then kept at this temperature for 3 h, then cooled to 500 °C at a cooling rate of 7 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0041] The near-infrared luminescent material obtained in this embodiment was subjected to emission spectrum test. Figure 5 As shown, the results show that the emission spectrum of the near-infrared luminescent material ranges from 700 to 1650 nm, exhibiting two broadband emission peaks at 820 nm and 1450 nm.

[0042] Example 4 A Cr 3+ , Ni 2+ Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.96 Ga 1.9 Sn2O 12 :0.1Cr 3+ , 0.04Ni 2+ The preparation method is as follows: (1) Raw materials include: MgO: 0.3998 g, Ga2O3: 0.3561 g, SnO2: 0.6028 g, Cr2O3: 0.0152 g, NiO: 0.0060 g, totaling 1.3799 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1550 °C at a heating rate of 6 °C / min, and then kept at this temperature for 3 h, then cooled to 500 °C at a cooling rate of 8 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0043] Example 5 A Cr 3+ , Ni 2+Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.95 Ga 1.9 Sn2O 12 :0.1Cr 3+ , 0.05Ni 2+ The preparation method is as follows: (1) Raw materials include: MgO: 0.3990 g, Ga2O3: 0.3561 g, SnO2: 0.6028 g, Cr2O3: 0.0152 g, NiO: 0.0075 g, a total of 1.3806 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1600 °C at a heating rate of 10 °C / min, and then kept at this temperature for 3 h, then cooled to 500 °C at a cooling rate of 9 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0044] Example 6 A Cr 3+ , Ni 2+ Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.94 Ga 1.7 Sn2O 12 :0.3Cr 3+ , 0.06Ni 2+ The preparation method is as follows: (1) The raw materials include: MgO: 0.3982 g, Ga2O3: 0.3186 g, SnO2: 0.6028 g, Cr2O3: 0.0456 g, NiO: 0.0090 g, a total of 1.3742 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1500 °C at a heating rate of 9 °C / min, and then kept at this temperature for 5 h, then reduced to 500 °C at a cooling rate of 10 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0045] Example 7 A Cr 3+ , Ni 2+Co-doped continuous broadband near-infrared luminescent material, the material is solid powder, the chemical formula is Mg 4.94 Ga 1.995 Sn2O 12 :0.005Cr 3+ , 0.06Ni 2+ The preparation method is as follows: (1) Raw materials include: MgO: 0.3982 g, Ga2O3: 0.3739 g, SnO2: 0.6028 g, Cr2O3: 0.0008 g, NiO: 0.0090 g, a total of 1.3847 g. The above raw materials are fully mixed, ground, loaded into an alumina crucible, and then transferred to a muffle furnace. The temperature is increased from room temperature to 1500 °C at a heating rate of 8 °C / min, and then kept at this temperature for 5 h, then cooled to 500 °C at a cooling rate of 10 °C / min, and then cooled to room temperature with the furnace; (2) The product obtained in step (1) is crushed, ball-milled, washed three times with anhydrous ethanol, dried, and sieved to obtain a Cr 3+ 、Ni 2+ Co-doped near-infrared luminescent materials.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-broadband near-infrared luminescent material, characterized in that: The near-infrared luminescent material has a spinel structure; the chemical formula of the near-infrared luminescent material is Mg 5-y Ga 2-x Sn2O 12 :xCr 3+ ,yNi 2+ ; Among them, 0.005≤x≤0.3, 0≤y≤0.

06.

2. The ultra-wideband near-infrared luminescent material according to claim 1, characterized in that: The excitation wavelength range of the near-infrared luminescent material is 400-650 nm.

3. The ultra-wideband near-infrared luminescent material according to claim 1, characterized in that: The emission wavelength range of the near-infrared luminescent material is 700-1650 nm.

4. The method for preparing the ultra-wideband near-infrared luminescent material according to any one of claims 1 to 3, characterized in that: include: A magnesium source, a gallium source, a tin source, a chromium source and a nickel source are mixed, and the near-infrared luminescent material is obtained after grinding, sintering, crushing and secondary grinding.

5. The preparation method according to claim 4, characterized in that: The magnesium source is an oxide containing magnesium.

6. The preparation method according to claim 4, characterized in that: The gallium source is a gallium-containing oxide.

7. The preparation method according to claim 4, characterized in that: The tin source is a tin-containing oxide.

8. The preparation method according to claim 4, characterized in that: The chromium source is a chromium-containing oxide.

9. The preparation method according to claim 4, characterized in that: The nickel source selected is a nickel-containing oxide.

10. Application of the ultra-wideband near-infrared luminescent material according to any one of claims 1 to 3 in the field of luminescent materials; the near-infrared luminescent material is used to prepare a near-infrared light source.

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