Near-infrared fluorescent powder as well as preparation method and application thereof

Abstract

The invention provides near-infrared fluorescent powder as well as a preparation method and application thereof. The chemical formula of the near-infrared fluorescent powder is A < 3-y > L < ny > B < x-0.5 z > M < 5-2x-0.5 z > C < x > Cr < z > O < 12 >, wherein 0 lt; x is less than or equal to 2, 0lt; y is less than or equal to 0.5, 0lt; zlt, zlt; 0.10, A is selected from any one or a combination of at least two of Gd, Y, Lu or Sc, Ln is selected from any one or a combination of at least two of Yb, Nd or Er, B is selected from any one or a combination of at least two of Mg, Zn or Ca, M is selected from any one or a combination of at least two of B, Al or Ga, and C is selected from any one or a combination of at least two of Si, Ge or Ti. The near-infrared fluorescent powder disclosed by the invention expands the emission range, and is high in luminous efficiency and good in thermal stability.

Description

Technical Field

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

[0002] Near infrared (NIR) shows unique value in many applications. It can be divided into three types according to the characteristics of near infrared light, which are the main factors determining its performance. The first is lighting application, which mainly utilizes the characteristics of near infrared wavelength. Its invisibility or absorption matching makes it used in plant growth light, anti-counterfeiting, night vision, etc. The second is detection application, which mainly utilizes the band range of 700-1200nm, covering some characteristic absorption signals of CH, OH and NH, and can detect various important organic compounds. Therefore, the wider the emission range of the near infrared light source, the stronger the detection capability. The last application is related to short-wave infrared light, with a typical wavelength of 950-2000nm, which can be easily generated by lanthanide ions with 4f internal transitions (such as Yb 3+ ,Nd 3+ and Er 3+ ) is produced. This part of near-infrared has unique applications in the fields of optical communication, bio-imaging, etc. The light-emitting diodes (LEDs) converted by near-infrared phosphors have the advantages of compact structure and economic friendliness, and their performance is heavily dependent on the phosphors. Therefore, it is of great practical significance to develop efficient phosphors so that near-infrared LEDs can meet the above-mentioned various applications.

[0003] Cr 3+ Since its excitation band is very compatible with commercial blue LED chips, it has incomparable advantages in efficiency and spectral tunability. 3+ When doped to the octahedral position, its 3d 3 Electron formation 4 A2 ground state, near-infrared emitting excited state 2 E and 4 T2, corresponding to narrowband or broadband emission, respectively.

[0004] CN108424770A discloses a Cr-doped garnet-type near-infrared luminescent material, the general chemical formula of which is Ca 2+x Ln 1-x-y Zr 2-x Al3O 12 :xCr 3+ ,yCe 3+ , Ln is Y 3+ 、Lu 3+ and Gd 3+ The preparation method is to weigh the Ca 2+ Compounds containing Ln3+ Compounds containing Zr 4+ Compounds containing Al 3+ Compounds containing Cr 3+ Compounds and Ce 3+ The compound is ground and mixed evenly to obtain a mixture; the mixture is calcined at 1400-1650°C in a reducing atmosphere for 3-8 hours to obtain a sintered body; the sintered body is ground, washed, filtered and dried to obtain a near-infrared phosphor with broadband emission characteristics. The preparation method of the phosphor is simple, pollution-free, low-cost and has stable chemical properties, making the material a very practical near-infrared phosphor luminescent material with broadband emission characteristics.

[0005] CN112779010A discloses a Cr-doped garnet-type near-infrared luminescent material, the general structural formula of which is A 3-x Q x L 5-y-z M y O 12:z Cr 3+ , A element is a rare earth element, selected from one or more of La, Lu and Y; Q element is selected from one or more of Sr and Ba; L element is a third main group element, selected from Al or Ga; M element is one or more of Ge, Ti, Zr, Sn, Si and Hf. The preparation method is to mix a compound containing A element, a compound containing Q element, a compound containing L element, a compound containing M element and a chromium source compound to obtain a mixture; calcining the mixture at 1400-1600°C for 2-8h to obtain a luminescent material. The near-infrared luminescent material emits 650-800nm ​​near-infrared light under the excitation of a near-ultraviolet chip or a blue light chip as a light source, and the main emission peak is located near 710nm. The excitation band overlaps with the emission peak of the blue light chip, and can be excited by the blue light chip and the near-ultraviolet chip. It has excellent luminescence performance and can be used as a new type of near-infrared luminescent material. It can be assembled with a blue light chip into a high-brightness near-infrared LED, and can be used for plant lighting, etc.

[0006] However, the phosphor in the above method has a low emission half-width in the near-infrared region, a short wavelength, and a small emission coverage range, which limits its application in many fields. Therefore, it is necessary to develop a new near-infrared phosphor so that it has multiple emission bands in the near-infrared region and expands its emission range to meet different applications. Summary of the invention

[0007] The object of the present invention is to provide a near-infrared phosphor having multiple emission bands and a wide emission range, and a preparation method and application thereof.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] One object of the present invention is to provide a near-infrared phosphor, and the chemical formula of the near-infrared phosphor is A 3- y Ln y B x-0.5z M 5-2x-0.5z C x Cr z O 12 .

[0010] Wherein, 0 < x ≤ 2, 0 < y ≤ 0.5, 0 < z < 0.10. Among them, the value of x can be 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2, the value of y can be 0.1, 0.2, 0.3, 0.4 or 0.5, etc., and the value of z can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 or 0.1, etc., but not limited to the listed values. Other unlisted values within the above numerical ranges are equally applicable.

[0011] A is selected from any one or a combination of at least two of Gd, Y, Lu or Sc. Typical but non-limiting examples of the combination are: the combination of Gd and Y, the combination of Y and Lu, the combination of Lu and Sc, or the combination of Gd and Sc, etc.

[0012] Ln is selected from any one or a combination of at least two of Yb, Nd or Er. Typical but non-limiting examples of the combination are: the combination of Yb and Nd, the combination of Nd and Er, or the combination of Yb and Er, etc.

[0013] B is selected from any one or a combination of at least two of Mg, Zn or Ca. Typical but non-limiting examples of the combination are: the combination of Mg and Zn, the combination of Zn and Ca, or the combination of Mg and Ca, etc.

[0014] M is selected from any one or a combination of at least two of B, Al or Ga. Typical but non-limiting examples of the combination are: the combination of B and Al, the combination of Al and Ga, or the combination of B and Ga, etc.

[0015] C is selected from any one or a combination of at least two of Si, Ge or Ti. Typical but non-limiting examples of the combination are: the combination of Si and Ge, the combination of Ge and Ti, or the combination of Si and Ti, etc.

[0016] The present invention utilizes trivalent rare earth ions Ln 3+ with highly efficient near-infrared luminescent energy levels in Yb 3+ , Nd 3+ , Er 3+, by designing Cr 3+ To Ln 3+ By transferring energy between the two, a phosphor with multi-band emission in the near-infrared region is obtained, which expands the emission range and has the advantages of high luminous efficiency and good thermal stability. 3+ To Yb 3+ As an example, Cr 3+ After absorbing the excitation light, it transfers the energy through 2 E2+ 2 F 7 / 2 → 4 A2+ 2 F 5 / 2 Pass to Yb 3+ , producing Yb 3+ The intrinsic emission.

[0017] A second object of the present invention is to provide a method for preparing the near-infrared phosphor as described in the first object, the preparation method comprising:

[0018] The A source, the Ln source, the B source, the M source, the C source and the Cr source are mixed to obtain a mixture, and the mixture is sintered to obtain the near-infrared phosphor.

[0019] The preparation method of the near-infrared fluorescent powder of the present invention has simple process, no pollution and low preparation cost.

[0020] As a preferred technical solution of the present invention, the A source includes any one of A-containing oxides, A-containing hydroxides, A-containing carbonates or A-containing halides, or a combination of at least two of them, wherein typical but non-limiting examples of the combinations include: a combination of A-containing oxides and A-containing hydroxides, a combination of A-containing hydroxides and A-containing carbonates, or a combination of A-containing carbonates and A-containing halides, etc.

[0021] Preferably, the Ln source comprises any one or a combination of at least two of an Ln oxide, an Ln hydroxide or an Ln halide, wherein typical but non-limiting examples of the combination include: a combination of an Ln oxide and an Ln hydroxide, a combination of an Ln hydroxide and an Ln halide, or a combination of an Ln oxide and an Ln halide, etc.

[0022] Preferably, the B source comprises any one of a B-containing oxide, a B-containing hydroxide, a B-containing carbonate or a B-containing halide, or a combination of at least two of them, wherein typical but non-limiting examples of the combination include: a combination of a B-containing oxide and a B-containing hydroxide, a combination of a B-containing hydroxide and a B-containing carbonate, or a combination of a B-containing carbonate and a B-containing halide, etc.

[0023] Preferably, the M source comprises an M-containing oxide and / or an M-containing hydroxide.

[0024] Preferably, the C source includes any one or a combination of at least two of C-containing oxides, C-containing hydroxides, C-containing carbonates, or C-containing halides. Typical but non-limiting examples of the combination include: the combination of C-containing oxides and C-containing hydroxides, the combination of C-containing hydroxides and C-containing carbonates, or the combination of C-containing carbonates and C-containing halides, etc.

[0025] Preferably, the Cr source includes any one or a combination of at least two of Cr-containing oxides, Cr-containing hydroxides, Cr-containing carbonates, or Cr-containing halides. Typical but non-limiting examples of the combination include: the combination of Cr-containing oxides and Cr-containing hydroxides, the combination of Cr-containing hydroxides and Cr-containing carbonates, the combination of Cr-containing carbonates and Cr-containing halides, or the combination of Cr-containing oxides and Cr-containing halides, etc.

[0026] As a preferred technical solution of the present invention, the stoichiometric ratios of the A source, Ln source, B source, M source, C source, and Cr source are (3 - y):y:(x - 0.5z):x:z, where 0 < x ≤ 2, 0 < y ≤ 0.5, 0 < z < 0.10. Here, the value of x can be 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, or 2, the value of y can be 0.1, 0.2, 0.3, 0.4, or 0.5, etc., and the value of z can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1, etc. However, it is not limited to the listed values, and other unlisted values within the above numerical ranges are equally applicable.

[0027] As a preferred technical solution of the present invention, the mixing includes grinding.

[0028] As a preferred technical solution of the present invention, the sintering temperature is 1300 - 1550 °C. The temperature can be 1300 °C, 1350 °C, 1400 °C, 1450 °C, 1500 °C, or 1550 °C, etc. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0029] In the present invention, the sintering temperature is 1300 - 1550 °C. If the sintering temperature is higher than 1550 °C, the phosphor will stick to the bottom of the crucible and cannot be taken out because the temperature reaches the melting point of the phosphor. If it is lower than 1300 °C, the near-infrared phosphor cannot be synthesized because the raw materials cannot react at low temperatures.

[0030] Preferably, the sintering time is 2 - 8 h. The time can be 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, or 8 h, etc. However, it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0031] Preferably, the sintering atmosphere includes an air atmosphere.

[0032] As a preferred technical solution of the present invention, after the sintering, grinding, washing, drying and sieving are carried out in sequence to obtain the near-infrared phosphor.

[0033] As a preferred technical solution of the present invention, the preparation method comprises:

[0034] A source A, a source Ln, a source B, a source M, a source C and a source Cr having a stoichiometric ratio of (3-y):y:(x-0.5z):x:z are mixed to obtain a mixture, and the mixture is sintered at 1300 to 1550° C. for 2 to 8 hours to obtain the near-infrared phosphor, wherein 0 <x≤2,0<y≤0.5,0<z<0.10。

[0035] A third object of the present invention is to provide an application of the near-infrared phosphor as described in the first object, wherein the near-infrared phosphor is applied in the technical field of luminescent materials.

[0036] The near-infrared fluorescent powder of the present invention is used for plant lighting, night vision, non-destructive testing, anti-counterfeiting or biomedicine.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The near-infrared phosphor of the present invention realizes broadband absorption of near-ultraviolet and blue light and multi-band emission in the near-infrared region. The present invention utilizes trivalent rare earth ions Ln 3+ Yb with high-efficiency near-infrared luminescence level 3 + 、Nd 3+ , Er 3+ , by designing Cr 3+ To Ln 3+ By using the energy transfer between the two, a phosphor with multi-band emission in the near-infrared region is obtained in the garnet matrix, which expands the emission range and broadens its emission band, and has high luminous efficiency and good thermal stability.

[0039] (2) The method for preparing the near-infrared phosphor of the present invention is simple, pollution-free and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is an emission spectrum diagram of the near-infrared phosphor obtained in Example 1 of the present invention;

[0041] Figure 2 This is an emission spectrum diagram of the near-infrared phosphor obtained in Example 3 of the present invention;

[0042] Figure 3This is an emission spectrum diagram of the near-infrared phosphor obtained in Example 4 of the present invention;

[0043] Figure 4 This is the emission spectrum of the near-infrared phosphor obtained in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] Example 1

[0046] This embodiment provides a chemical formula of Y 2.99 Nd 0.01 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared phosphor.

[0047] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0048] Y2O3, Nd2O3, MgO, Ga2O3, GeO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.99:0.01:0.96:2.96:1:0.08 to obtain a mixture, the mixture is sintered at 1400°C for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0049] The emission spectrum of the near-infrared phosphor obtained in this embodiment is shown in FIG. Figure 1 As shown by Figure 1 It can be seen that the near-infrared phosphor Y 2.99 Nd 0.01 Mg 0.96 Ga 2.96 Ge 0.08 O 12 In the near-infrared region of 600-1500nm, two-band emission is achieved, namely 600-1200nm and 1300-1500nm.

[0050] Example 2

[0051] This embodiment provides a chemical formula of Gd 2.99 Nd 0.01 Mg 0.96 Ga 2.96 SiCr 0.08 O 12 Near-infrared phosphor.

[0052] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0053] Y2O3, Nd2O3, MgO, Ga2O3, SiO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.99:0.01:0.96:2.96:1:0.08 to obtain a mixture, the mixture is sintered at 1500°C for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0054] Example 3

[0055] This embodiment provides a chemical formula of Y 2.5 Er 0.5 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared fluorescent materials.

[0056] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0057] Y2O3, Er2O3, MgO, Ga2O3, GeO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.5:0.5:0.96:2.96:1:0.08 to obtain a mixture, the mixture is sintered at 1400°C for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0058] The emission spectrum of the near-infrared phosphor obtained in this embodiment is shown in FIG. Figure 2 As shown by Figure 2 It can be seen that the near-infrared phosphor Y 2.5 Er 0.5 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Two-band emission is achieved in the near-infrared region of 600-1600nm, namely 600-1200nm and 1400-1600nm.

[0059] Example 4

[0060] This embodiment provides a chemical formula of Y 2.97 Yb 0.03 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared phosphor.

[0061] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0062] Y2O3, Yb2O3, MgO, Ga2O3, GeO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.97:0.03:0.96:2.96:1:0.08 to obtain a mixture, the mixture is sintered at 1400°C for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0063] The emission spectrum of the near-infrared phosphor obtained in this embodiment is shown in FIG. Figure 3 As shown by Figure 3 It can be seen that the near-infrared phosphor Y 2.97 Yb 0.03 Mg 0.96 Ga 2.96 Ge 0.08 O 12 In the near-infrared region of 600-1200nm, two-band emission is achieved, namely 600-900nm and 900-1200nm.

[0064] Example 5

[0065] This embodiment provides a chemical formula of Y 2.96 Nd 0.01 Yb 0.03 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared phosphor.

[0066] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0067] Y2O3, Nd2O3, Yb2O3, MgO, Ga2O3, GeO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.96:0.01:0.03:0.96:2.96:1:0.08 to obtain a mixture, and the mixture is sintered at 1400°C for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0068] Example 6

[0069] This embodiment provides a chemical formula of Y 2.47 Yb 0.03 Er 0.5 Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared phosphor.

[0070] This embodiment also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0071] Y2O3, Yb2O3, Yb2O3, MgO, Ga2O3, GeO2 and Cr2O3 are ground and mixed according to a stoichiometric ratio of 2.47:0.03:0.5:0.96:2.96:1:0.08 to obtain a mixture, and the mixture is sintered at 1400° C. for 4 hours in an air atmosphere, and then ground, washed, dried and sieved in sequence to obtain a near-infrared phosphor.

[0072] Comparative Example 1

[0073] This comparative example provides a chemical formula of Y3Mg 0.96 Ga 2.96 Ge 0.08 O 12 Near-infrared phosphor.

[0074] This comparative example also provides a method for preparing the above-mentioned near-infrared phosphor, the preparation method comprising:

[0075] Y2O3, MgO, Ga2O3, GeO2, and Cr2O3 are ground and mixed according to a stoichiometric ratio of 3:0.96:2.96:1:0.08 to obtain a mixture, the mixture is sintered at 1400°C for 4 hours in an air atmosphere, and then ground, washed, dried, and sieved in sequence to obtain a near-infrared phosphor.

[0076] The emission spectrum of the near-infrared phosphor obtained in this comparative example is shown in FIG. Figure 4 As shown by Figure 4 It can be seen that the near-infrared phosphor Y3Mg 0.96 Ga 2.96 Ge 0.08 O 12 There is only a single-band emission in the near-infrared region of 600-1200nm.

[0077] The emission bands of the near-infrared phosphors prepared in Examples 1-6 and Comparative Example 1 were tested. The testing method is as follows: The emission spectrum of the obtained phosphors was tested using FLS1000.

[0078] The test results of Examples 1-6 of the present invention and Comparative Example 1 are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] From the data in Table 1, we can see that:

[0083] (1) As can be seen from Examples 1-6, the near-infrared phosphor of the present invention realizes multi-band emission in the near-infrared region. 3+ Yb with high-efficiency near-infrared luminescence level 3+ 、Nd 3+ , Er 3+ , by designing Cr 3+ To Ln 3+ By transferring energy between the two, a phosphor with multi-band emission in the near-infrared region is obtained in the garnet matrix, which expands the emission range and broadens its emission band.

[0084] (2) By comparing Example 4 with Example 5, it can be found that the Ln doped in Example 4 is Yb, while the Ln doped in Example 5 is Yb and Nd. The addition of Nd makes the emission peak broader.

[0085] (3) By comparing Example 5 with Example 6, it can be found that the Ln doped in Example 5 is Yb and Nd, while the Ln doped in Example 6 is Yb and Er. It can be seen that the difference in Ln will lead to different emission peaks;

[0086] (4) By comparing Example 4 with Comparative Example 1, it can be found that since no Yb is added to Comparative Example 1, the emission at 900-1200 nm is relatively weak, and the addition of Yb enhances the emission at 900-1200 nm.

[0087] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A near-infrared phosphor, characterized in that: The chemical formula of the near-infrared phosphor is A 3-y Ln y B x-0.5z M 5-2x- 0.5z C x Cr z O 12 ; Among them, 0 < x ≤ 2, 0 < y ≤ 0.5, 0 < z < 0.10, A is selected from any one or a combination of at least two of Gd, Y, Lu or Sc, Ln is selected from any one or a combination of at least two of Yb, Nd or Er, B is selected from any one or a combination of at least two of Mg, Zn or Ca, M is selected from any one or a combination of at least two of B, Al or Ga, and C is selected from any one or a combination of at least two of Si, Ge or Ti.

2. The near-infrared phosphor according to claim 1, characterized in that: The Ln is selected from a combination of at least two of Yb, Nd or Er.

3. A method for preparing the near-infrared phosphor according to claim 1 or 2, characterized in that: The preparation method includes: Mixing an A source, an Ln source, a B source, an M source, a C source and a Cr source to obtain a mixture, and sintering the mixture to obtain the near-infrared phosphor.

4. The preparation method according to claim 3, characterized in that: The A source includes any one or a combination of at least two of an A-containing oxide, an A-containing hydroxide, an A-containing carbonate or an A-containing halide; Preferably, the Ln source includes any one or a combination of at least two of an Ln-containing oxide, an Ln-containing hydroxide or an Ln-containing halide; Preferably, the B source includes any one or a combination of at least two of a B-containing oxide, a B-containing hydroxide, a B-containing carbonate or a B-containing halide; Preferably, the M source includes an M-containing oxide and / or an M-containing hydroxide; Preferably, the C source includes any one or a combination of at least two of a C-containing oxide, a C-containing hydroxide, a C-containing carbonate or a C-containing halide; Preferably, the Cr source includes any one or a combination of at least two of a Cr-containing oxide, a Cr-containing hydroxide, a Cr-containing carbonate or a Cr-containing halide.

5. The preparation method according to claim 3 or 4, characterized in that: The stoichiometric ratio of the A source, the Ln source, the B source, the M source, the C source and the Cr source is (3 - y):y:(x - 0.5z):x:z, where 0 < x ≤ 2, 0 < y ≤ 0.5, 0 < z < 0.

10.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The mixing includes grinding.

7. The preparation method according to any one of claims 3 to 6, characterized in that: The sintering temperature is 1300 - 1550 °C; Preferably, the sintering time is 2 - 8 h; Preferably, the sintering atmosphere includes an air atmosphere.

8. The preparation method according to any one of claims 3 to 7, characterized in that: After the sintering, grinding, washing, drying and sieving are carried out in sequence to obtain the near-infrared phosphor.

9. The preparation method according to any one of claims 3 to 8, characterized in that: The preparation method includes: Mixing an A source, an Ln source, a B source, an M source, a C source and a Cr source with a stoichiometric ratio of (3 - y):y:(x - 0.5z):x:z to obtain a mixture, and sintering the mixture at 1300 - 1550 °C for 2 - 8 h to obtain the near-infrared phosphor, where 0 < x ≤ 2, 0 < y ≤ 0.5, 0 < z < 0.

10.

10. Use of the near-infrared phosphor according to claim 1 or 2, characterized in that: The near-infrared phosphor is applied to the technical field of luminescent materials.

Images