A Cr3+-doped garnet-structured near-infrared long-afterglow luminescent material and its preparation and application

Abstract

The application relates to the field of near-infrared long-afterglow fluorescent powder preparation and relates to a Cr 3+ doped garnet structure matrix near-infrared long-afterglow luminescent material, preparation and application thereof, which has the following general chemical formula: A 1‑c Zn c B2Ga 4‑4x‑4y C 4y Ge 1‑z D z O 12 :xCr 3+ , 0<=y<=0.5, 0<=z<=0.5, 0<=c<=0.5, wherein 0.1at%<=x<=20at%, A is at least one of second main group elements, B is at least one of rare earth elements, C includes trivalent ions of Al or In, D includes tetravalent ions of Si, Ti or Zr, and the luminescent center is Cr 3+ . Compared with the prior art, the application has the advantages that the afterglow characteristics and luminescent spectrum of the material can be regulated by doping ions with different valences, the material has better performance, and the material can be widely used in the fields of medicine and military, etc.

Description

Technical Field

[0001] This invention relates to the field of near-infrared long-afterglow phosphor preparation, and particularly to a Cr... 3+ Near-infrared long afterglow luminescent materials with doped garnet structure matrix and their preparation and application. Background Technology

[0002] Long-afterglow luminescent materials are a class of photoluminescent materials that can store a portion of the light energy acquired under appropriate light source excitation and slowly release the stored energy in the form of light after excitation stops. Due to their unique luminescent properties, they are widely used in indicator lighting, such as instrument indication, nighttime emergency indication, and architectural decoration. With further development, their applications have expanded to bioimaging and defense. Traditional luminescent materials used in biomedical imaging and diagnosis employ instantaneous excitation and imaging during diagnosis, which can cause unnecessary light damage to the organism and background interference. However, the probes of long-afterglow luminescent materials, due to their afterglow characteristics, can be excited in vitro and then injected into the body for use, achieving in vivo excitation-free detection methods, thus effectively avoiding light damage to the organism and background interference. Current research and applications of long-afterglow materials mainly focus on the visible light range, with SrAl2O4:Eu being a representative example. 2+ ,Dy 3+ CaAl2O4:Eu 2+ ,Nd 3+ Rare-earth ion-doped oxide long-afterglow luminescent materials emit light primarily concentrated in the visible light spectrum. These materials are further enhanced by co-doping with Dy. 3+ This aluminate matrix acts as a new trap center, allowing the sample to maintain high luminescence efficiency while enhancing afterglow duration. Furthermore, this aluminate matrix can be used to synthesize more diverse matrices by changing the raw material ratio, providing impetus for the exploration of luminescent materials with better performance. However, these materials still suffer from narrow luminescence ranges and poor resistance to water, acids, and alkalis, requiring further improvements to meet commercialization requirements.

[0003] Near-infrared long-persistence materials, with emission wavelengths in the 650-950nm biological first transmission window, are used in medical imaging and possess stronger tissue penetration and anti-interference properties compared to visible light long-persistence materials. In the second biological window (1000-1700nm), biological tissues exhibit weak absorption and scattering, thus luminescent materials in this band also possess stronger penetration and higher imaging resolution. However, the luminescence intensity and afterglow time of near-infrared long-persistence materials are inferior to those of visible light long-persistence materials, and they require higher-quality matrix carriers, limiting their widespread application. Currently available matrices, nitride-type matrices such as BaAlSi5O2N7 have drawbacks due to their demanding synthesis processes; sulfide-type matrices such as Y2O2S and CuInS2 also suffer from chemical instability and are prone to deliquescence, producing toxic substances, making them unsuitable as matrices for near-infrared long-persistence materials. Therefore, finding long-persistence luminescent materials that combine performance, ease of preparation, and environmental friendliness is particularly necessary.

[0004] Garnet structural material (its general chemical formula is A3B2C3O) 12 It belongs to the cubic crystal system, and its space group is . Its structure consists of three polyhedra: dodecahedron (A), octahedron (B), and tetrahedron (C). Due to its high structural rigidity, numerous doping substitution sites, and good crystallinity, it is one of the most researched luminescent materials. Cr 3+ The ion is a transition metal ion with the electronic configuration [Ar]3d. 3 It is easily affected by the matrix crystal field, leading to different energy level splitting. Based on this characteristic, the splitting can be achieved by changing the Cr... 3+ The crystal field environment is used to modulate the emission spectrum of the sample, so that Cr 3+ Garnets are often used as luminescent centers in near-infrared fluorescent materials, and the complexity of their structure provides excellent conditions for spectral modulation. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a Cr 3+This invention relates to near-infrared long-afterglow luminescent materials with a doped garnet matrix and their preparation and application. Based on the garnet structure, adjustments were made to the (A) position, where Group II elements such as Ca and Sr, and rare earth elements such as Y and Gd co-occupy the (A) position, Ga occupies the (B) position, and Ge is introduced at the (C) position. This invention achieves additional ion doping at the (A), (B), and (C) positions by selectively replacing A (Group II elements) with zinc ions, Ga ions with Al or In ions, and Ge ions with Si, Ti, or Zr ions. This further increases the complexity of the cation arrangement, thereby modulating the afterglow characteristics and emission spectrum of the synthesized material, resulting in better performance.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A type of Cr 3+ Doped garnet-structured matrix near-infrared long-afterglow luminescent materials have the following general chemical formula: A 1- c Zn c B2Ga 4-4x-4y C 4y Ge 1-z D z O 12 :xCr 3+ , 0≤y≤0.5, 0≤z≤0.5, 0≤c≤0.5,

[0008] Wherein, 0.1at% ≤ x ≤ 20at%, A is at least one element from Group II, B is at least one rare earth element, C includes trivalent ions of Al or In, D includes tetravalent ions of Si, Ti, or Zr, and the luminescent center is Cr. 3+ .

[0009] A type of Cr 3+ A method for preparing near-infrared long-afterglow luminescent materials with a doped garnet structure matrix includes the following steps:

[0010] S1: Weigh the raw materials according to the stoichiometric ratio of each substance in the general chemical formula, grind and mix them evenly to obtain the precursor;

[0011] S2: Load the precursor into the crucible and pre-sinter it;

[0012] S3: Take out the sample obtained from the pre-sintering in step S2, grind it, put it back into the crucible, and calcine it to obtain the target compound. After washing, centrifuging, and drying the target compound, the Cr is obtained. 3+ Garnet-structured matrix near-infrared long afterglow luminescent material.

[0013] Furthermore, the raw materials include: compounds containing Group II main elements, compounds containing rare earth elements, compounds containing chromium, compounds containing germanium, compounds containing gallium, compounds containing aluminum, and compounds containing silicon.

[0014] The compound containing a Group 2 element includes at least one of oxides, nitrates, carbonates, or hydroxides containing a Group 2 element; the raw material for the rare earth element compound is at least one of rare earth oxides, rare earth nitrates, or rare earth carbonates; the raw material for the chromium compound is at least one of chromium oxide, chromium nitrate, or chromium carbonate; the raw material for the germanium compound is at least one of germanium oxide, germanium nitrate, or germanium hydroxide; the raw material for the gallium compound is at least one of gallium oxide, gallium nitrate, potassium carbonate, or gallium hydroxide; the raw material for the aluminum compound is at least one of aluminum oxide, aluminum nitrate, or aluminum hydroxide; and the raw material for the silicon compound is at least one of silicon oxide, silicon carbonate, or silicon nitrate.

[0015] Furthermore, in step S2, the pre-sintering temperature is 800-900℃, and the pre-sintering time is 1-4 hours.

[0016] Furthermore, in step S3, the calcination temperature is 1100℃-1500℃, and the calcination time is 9-15 hours.

[0017] Furthermore, in step S3, the drying temperature is 25-250°C.

[0018] Furthermore, in step S3, the centrifugation speed is 10,000-12,000 revolutions per minute, and the centrifugation time is 10-20 minutes.

[0019] Furthermore, in step S2, the heating rate is 3-8℃ / min.

[0020] Furthermore, in step S3, the heating rate is 3-10℃ / min.

[0021] A type of Cr 3+ Applications of doped garnet-structured matrix near-infrared long-afterglow luminescent materials: As a fluorescent material, this material can be used in fingerprint sensing, infrared cameras, and night vision devices; in the medical field, it can be used as a biological probe to detect changes in various tissues in organisms, with the characteristics of clear imaging and minimal damage to biological tissues.

[0022] Cr 3+Ions, acting as luminescent centers, typically emit infrared light. This wavelength can be used in fingerprint and facial recognition sensors to enhance recognition accuracy, and its emission wavelength can be used in devices such as night vision devices and infrared cameras. In the medical field, afterglow properties are often used as biological probes to track and detect changes in tissues and chemical components within organisms. They offer clear imaging with minimal tissue damage and can also be used in photodynamic therapy, providing continuous treatment to deep tissues without an external excitation source, thus reducing wounds on the skin surface.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) Cr prepared in this invention 3+ Gallium germanate near-infrared long afterglow luminescent materials have a simple synthesis process, long afterglow time, can be excited by ultraviolet and blue light, and emit light in the infrared band between 650-1150nm.

[0025] (2) By using different ion doping methods and changing the concentration of doped ions, this invention can influence the Cr content. 3+ The crystal field environment at the luminescent center can thus regulate the intensity, wavelength range, and afterglow time of the luminescence.

[0026] (3) This invention selects gallium germanate with a garnet structure as the luminescent matrix, which has a simple synthesis process, is easy and safe to operate, has low equipment requirements, has a wide range of raw material sources, and is suitable for industrial production. The long afterglow material of this invention exhibits broadband emission in the near-infrared region, covering a range of 650-1150nm, completely covering the first biological window, and some of the emission bands are located in the second biological window with stronger penetration and higher medical imaging resolution, while also having excellent afterglow time. Attached Figure Description

[0027] Figure 1 X-ray diffraction pattern of the near-infrared long-afterglow luminescent material prepared in Example 1;

[0028] Figure 2 The diffuse reflectance spectrum of the near-infrared long-afterglow luminescent material prepared in Example 1;

[0029] Figure 3 The emission spectrum of the near-infrared long-afterglow luminescent material prepared in Example 1;

[0030] Figure 4 The afterglow decay curve of the near-infrared long afterglow luminescent material prepared in Example 1;

[0031] Figure 5 The emission spectra of the near-infrared long-afterglow luminescent material samples prepared in Example 1 and Example 6 are compared.

[0032] Figure 6 Comparison of afterglow decay curves of near-infrared long-afterglow luminescent material samples prepared in Example 1 and Example 6;

[0033] Figure 7 The emission spectra of the near-infrared long afterglow luminescent material samples prepared in Example 1 and Example 7 are compared. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] The following embodiments are implemented based on the above-described technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0036] The following are more detailed implementation examples, which further illustrate the technical solution of the present invention and the technical effects that can be obtained.

[0037] This invention modifies the garnet structure, with Group II elements such as Ca and Sr, and rare earth elements such as Y and Gd occupying position (A), Ga occupying position (B), and Ge introduced at position (C). This invention achieves additional ion doping at positions (A), (B), and (C) by selectively replacing A (Group II elements) with zinc ions, Ga ions with Al or In ions, and Ge ions with Si, Ti, or Zr ions. This further increases the complexity of the cation arrangement, thereby improving the afterglow characteristics and emission spectrum of the synthesized material, resulting in better performance. When no additional ions are doped, the chemical formula of this invention is: AB₂Ga₄GeO₄. 12 xCr 3+ The general chemical formula after doping is: A 1-c Zn c B2Ga 4-4x-4y C 4y Ge 1- z D z O 12 :xCr 3+ , 0≤y≤0.5, 0≤z≤0.5, 0≤c≤0.5, 0.1at%≤x≤20at%.

[0038] Example 1

[0039] This embodiment provides a Cr 3+ Doped garnet-structured matrix near-infrared long-afterglow luminescent materials and their preparation, this embodiment excluding Cr 3+Apart from this, no additional ions were doped at positions (A), (B), and (C). The material is in powder form and has the following molecular formula: CaY2Ga 3.96 GeO 12 1at%Cr 3+ .

[0040] The preparation method is as follows:

[0041] (1) Based on the stoichiometric ratio of each substance according to the molecular formula, calcium carbonate, yttrium trioxide, gallium trioxide, germanium dioxide, and chromium trioxide, all with a purity of 99.9% or higher, were used as raw materials, with masses of 0.2488 g, 0.5612 g, 0.9224 g, 0.2601 g, and 0.0076 g, respectively. The precursors were obtained by grinding and mixing them evenly in an agate mortar.

[0042] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 900°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 1 hour, then cool it to room temperature with the furnace.

[0043] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1450°C at a rate of 5°C / min under air atmosphere. After holding at this temperature and calcining for 10 hours, the mixture was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 10000 r / min for 20 min. The powder was then dried at 100°C to obtain the CaY2Ga4GeO of this embodiment. 12 1at%Cr 3+ Near-infrared long afterglow luminescent materials.

[0044] The resulting product CaY2Ga4GeO 12 1at%Cr 3+ Phase analysis was performed using X-ray powder diffraction. (See attached image) Figure 1 Compared with the standard library of garnet structural phases, the sample powder diffraction peaks showed high intensity and no obvious impurities, indicating that the obtained compound was a garnet phase with good crystallinity. Figure 2 The image shows the UV-Vis diffuse reflectance spectrum of the sample. It can be seen from the image that the sample has absorption in the blue light region, which can be matched with commercially available low-cost blue LED chips. Figure 3 The emission spectrum of the sample shows that when excited at 468 nm, the sample can emit near-infrared light in the 800 nm band, which is the first transmission window of a biological system, and the emission spectrum is broadband emission. Figure 4 The afterglow decay curve of the sample shows that the afterglow time exceeds 18000s after 5 minutes of irradiation with a 254nm UV lamp.

[0045] The sample's good afterglow time can be used as a fluorescent marker, which can be used for tissue labeling in vivo after excitation in vitro, reducing the damage of the excitation light source to the tissue in vivo; its near-infrared light penetration can be used for fingerprint and facial recognition, enhancing the accuracy of recognition; its special emission wavelength can be used in night vision devices and infrared cameras.

[0046] Example 2

[0047] This embodiment provides a Cr 3+ In this embodiment, the long afterglow luminescent material doped with gallium germanate, except for Cr... 3+ Apart from this, no additional ions were doped at positions (A), (B), and (C). The material is in powder form and has the following molecular formula: CaGd₂Ga 3.92 Cr 0.08 GeO 12 2at%Cr 3+ .

[0048] The preparation method is as follows:

[0049] (1) Based on the stoichiometric ratio of each substance according to the molecular formula, calcium carbonate, gadolinium trioxide, gallium trioxide, germanium dioxide, and chromium trioxide, all with a purity of 99.9% or higher, were used as raw materials, with masses of 0.2128 g, 0.7707 g, 0.7811 g, 0.2225 g, and 0.0130 g, respectively. The precursors were obtained by grinding and mixing them evenly in an agate mortar.

[0050] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 850°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 2 hours, then cool it to room temperature with the furnace.

[0051] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1150 °C at a heating rate of 5 °C / min under an air atmosphere. After holding at this temperature and calcining for 9 hours, the sample was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 11000 r / min for 15 min. After drying at 100 °C, CaGd2Ga4GeO was obtained. 12 2at%Cr 3+ Near-infrared long afterglow luminescent materials.

[0052] Example 3

[0053] This embodiment provides a Cr 3+ In this embodiment, the long afterglow luminescent material doped with gallium germanate, except for Cr... 3+Apart from this, no additional ions were doped at positions (A), (B), and (C). The material is in powder form and has the following molecular formula: SrGd2Ga 3.8 Cr 0.2 GeO 12 5at%Cr 3+ .

[0054] The preparation method is as follows:

[0055] (1) Based on the stoichiometric ratio of each substance according to the molecular formula, strontium carbonate, gadolinium trioxide, gallium trioxide, germanium dioxide, and chromium trioxide, all with a purity of 99.9% or higher, were used as raw materials, with masses of 0.2994 g, 0.7352 g, 0.7223 g, 0.2122 g, and 0.0308 g, respectively. The precursors were obtained by grinding and mixing them evenly in an agate mortar.

[0056] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 950°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 3 hours, then cool it to room temperature with the furnace.

[0057] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1250 °C at a heating rate of 5 °C / min under air atmosphere. After holding at this temperature and calcining for 11 hours, the sample was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 12000 r / min for 10 min. After drying at 125 °C, SrGd2Ga4GeO was obtained. 12 5at%Cr 3+ Near-infrared long afterglow luminescent materials.

[0058] Example 4

[0059] This embodiment provides a Cr 3+ Doped gallium germanate long afterglow luminescent material, in this embodiment except for Cr 3+ Apart from this, no additional ions were doped at positions (A), (B), and (C). The material is in powder form and has the following molecular formula: SrY₂Ga 3.6 Cr 0.4 GeO 12 10at%Cr 3+ .

[0060] The preparation method is as follows: Based on the stoichiometric ratio of each substance as defined in the molecular formula, strontium carbonate, yttrium trioxide, gallium trioxide, germanium dioxide, and chromium trioxide, all with a purity of 99.9% or higher, were used as raw materials, with mass ratios of 0.3491 g, 0.5339 g, 0.7978 g, 0.2474 g, and 0.0719 g, respectively. The precursor was obtained by grinding and mixing the materials evenly using an agate mortar and pestle.

[0061] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 900°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 3 hours, then cool it to room temperature with the furnace.

[0062] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1550 °C at a rate of 5 °C / min under air atmosphere. After holding at this temperature and calcining for 10 hours, the mixture was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 10000 r / min for 15 min. The product was then dried at 250 °C to obtain SrY2Ga4GeO. 12 10at%Cr 3+ Near-infrared long afterglow luminescent materials.

[0063] Example 5

[0064] This embodiment provides a Cr 3+ This embodiment of a gallium germanate long-afterglow luminescent material is doped only with divalent Zn ions. 2+ The emission spectrum was modulated, i.e., y=0, z=0. The material was in powder form and had the following molecular formula: Ca 0.9 Zn 0.1 Y2Ga 3.96 Cr 0.04 GeO 12 1at%Cr 3+ .

[0065] The preparation method is as follows:

[0066] (1) Based on the stoichiometric ratio of each substance determined by the molecular formula, using raw materials of calcium carbonate, yttrium trioxide, zinc oxide, gallium trioxide, germanium dioxide, and chromium trioxide, all with a purity of 99.9% or higher, with masses of 0.2366 g, 0.5618 g, 0.0101 g, 0.9233 g, 0.2603 g, and 0.0076 g respectively, and grinding and mixing them evenly in an agate mortar and pestle, a precursor was obtained.

[0067] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 900°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 4 hours, then cool it to room temperature with the furnace.

[0068] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1600 °C at a rate of 5 °C / min under air atmosphere. After holding at this temperature and calcining for 15 hours, the mixture was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 12000 r / min for 20 min. The powder was then dried at 200 °C to obtain Ca. 0.9 Zn 0.1 Y2Ga 3.96 Cr 0.04 GeO 12 1at%Cr 3+ Near-infrared long afterglow luminescent materials.

[0069] Example 6

[0070] This embodiment provides a Cr 3+ Near-infrared long-afterglow luminescent materials with doped garnet matrix and their preparation, doped only with trivalent Al ions 3+ The emission spectrum is modulated to achieve c=0 and z=0. The material is in powder form with the following molecular formula: CaY₂Ga 3.96 Al 0.4 Cr 0.04 GeO 12 1at%Cr 3+ .

[0071] The preparation method is as follows:

[0072] (1) Based on the stoichiometric ratio of each substance determined by the molecular formula, calcium carbonate, yttrium trioxide, gallium trioxide, germanium dioxide, chromium trioxide, and aluminum trioxide, all with a purity of 99.9% or higher, were used as raw materials with masses of 0.2542 g, 0.5734 g, 0.8472 g, 0.2657 g, 0.0077 g, and 0.0518 g, respectively. After grinding and mixing evenly with an agate mortar, the precursor was obtained.

[0073] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 900°C at a heating rate of 5°C / min under air atmosphere, hold it at that temperature and calcine for 1 hour, then cool it to room temperature with the furnace.

[0074] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1450°C at a rate of 5°C / min under air atmosphere. After holding at this temperature and calcining for 10 hours, the mixture was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 10000 r / min for 20 min. Finally, it was dried at 100°C to obtain the CaY2Ga of this embodiment. 3.96 Al 0.4 Cr 0.04 GeO 12 1at%Cr 3+ Near-infrared long afterglow luminescent materials. Figure 5 The comparison emission spectra of the samples from Example 1 and this example show that Al 3+ The spectrum of the doped sample is approximately blue-shifted by 4 nm compared to the undoped sample; Al doping 3+ The intensity of the resulting spectrum is approximately 90% of that of the undoped sample, and the emission range is wider, indicating that the sample has good spectral tunability. A comparison of the afterglow decay curves with those of Example 1 reveals that the Al-doped sample exhibits better spectral performance. 3+ The afterglow time of the sample was shorter than that of undoped Al. 3+ The sample, approximately 12000s, such as Figure 6 As shown, this indicates that for the more expensive Ga-containing raw materials, partially replacing Cr with the relatively cheaper Al-containing raw materials can have a positive impact. 3+ The performance of doped near-infrared long afterglow luminescent materials is not significantly affected.

[0075] Example 7

[0076] This comparative example provides a Cr 3+ This embodiment of a gallium germanate long-afterglow luminescent material is doped only with tetravalent Si ions. 4+ The emission spectrum was modulated to achieve c=0 and y=0. The material was in powder form and had the following molecular formula: CaY₂Ga 3.96 Cr 0.04 Ge 0.9 Si 0.1 O 12 1at%Cr 3+ .

[0077] The preparation method is as follows:

[0078] (1) Based on the stoichiometric ratio of each substance according to the molecular formula, calcium carbonate, yttrium trioxide, gallium trioxide, germanium dioxide, chromium trioxide, and silicon dioxide, all with a purity of 99.9% or higher, were used as raw materials, with masses of 0.2501 g, 0.5643 g, 0.9275 g, 0.2354 g, 0.0076 g, and 0.0150 g, respectively. After being ground and mixed evenly using an agate mortar, the precursor was obtained.

[0079] (2) Grind the above precursor evenly with 10 ml of anhydrous ethanol in an agate mortar, place it in a corundum crucible, heat it to 1000°C at a heating rate of 5°C / min in air atmosphere, hold it at that temperature and calcine for 4 hours, then cool it to room temperature with the furnace.

[0080] (3) The sample was placed in an agate mortar and ground evenly with 10 ml of anhydrous ethanol. It was then placed back into a corundum crucible and heated to 1500°C at a heating rate of 5°C / min under an air atmosphere. After holding at this temperature and calcining for 12 hours, the sample was cooled to room temperature with the furnace. The resulting product was ground into powder, and an appropriate amount of deionized water was added. The powder was placed in a centrifuge tube and centrifuged at 12000 r / min for 15 min. After drying at 150°C, the CaY2Ga of this comparative example was obtained. 3.96 Cr 0.04 Ge 0.9 Si 0.1 O 12 1at%Cr 3+ Near-infrared long afterglow luminescent materials. Figure 7 The emission spectra of the sample from Example 1 and the sample from this example are compared, revealing that Al doping was present. 3+ The intensity of the resulting spectrum is approximately 91% of that of the undoped sample, indicating that for the more expensive Ge-containing raw material, partially replacing Cr with the relatively cheaper Si-containing raw material is beneficial. 3+ The performance of doped near-infrared long afterglow luminescent materials is not significantly affected.

[0081] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A type of Cr 3+ A doped garnet-structured matrix near-infrared long-afterglow luminescent material, characterized in that, It has the following general chemical formula: A 1-c Zn c B2Ga 4-4x-4y C 4y Ge 1-z D z O 12 :xCr 3+ ,0≤y≤0.5,z=0,c=0; or, A 1-c Zn c B2Ga 4-4x-4y C 4y Ge 1-z D z O 12 :xCr 3+ ,0≤z≤0.5,y=0,c=0; or, A 1-c Zn c B2Ga 4-4x-4y C 4y Ge 1-z D z O 12 :xCr 3+ ,0≤c≤0.5,y=0,z=0; Where 0.1at%≤x≤20at%, A is Ca or Sr, B is Y or Gd, C is a trivalent Al ion, D is a tetravalent Si ion, and the luminescent center is Cr. 3+ .

2. The Cr as described in claim 1 3+ A method for preparing near-infrared long-afterglow luminescent materials with doped garnet structure matrix, characterized in that, Includes the following steps: S1: Weigh the raw materials according to the stoichiometric ratio of each substance in the chemical formula according to claim 1, grind and mix them evenly to obtain the precursor; S2: Load the precursor into the crucible and pre-sinter it; S3: Take out the sample obtained from the pre-sintering in step S2, grind it, and put it back into the crucible for calcination to obtain the target compound. After washing, centrifuging, and drying the target compound, the Cr is obtained. 3+ Near-infrared long afterglow luminescent material with a doped garnet structure matrix.

3. The preparation method according to claim 2, characterized in that, In step S2, the pre-sintering temperature is 800-900℃ and the pre-sintering time is 1-4 hours.

4. The preparation method according to claim 2, characterized in that, In step S3, the calcination temperature is 1100℃-1500℃, and the calcination time is 9-15 hours.

5. The preparation method according to claim 2, characterized in that, In step S3, the drying temperature is 25-250℃.

6. The preparation method according to claim 2, characterized in that, In step S3, the centrifugation speed is 10,000-12,000 revolutions per minute, and the centrifugation time is 10-20 minutes.

7. The preparation method according to claim 2, characterized in that, In step S2, the heating rate is 3-8℃ / min.

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