Inorganic near-infrared fluorescent material, preparation method and application thereof

Abstract

The application discloses an inorganic near-infrared fluorescent material and a preparation method and application thereof, relates to the technical field of luminescent materials, and has the chemical formula Mg(CrM) x Ti 1‑ x O3; wherein, 0

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of luminescent materials, in particular to an inorganic near-infrared fluorescent material and a preparation method and application thereof. BACKGROUND

[0002] The near-infrared fluorescent material can absorb ultraviolet or visible light and convert it into low-energy near-infrared photons, and has important applications in food detection, night vision, non-destructive detection, biomedical imaging and other fields.

[0003] Traditional inorganic near-infrared fluorescent materials can be divided into two categories: rare earth ion doped fluorescent materials and transition metal ion doped fluorescent materials. The rare earth ion doped fluorescent materials mostly use Nb 3+ , Yb 3+ as the luminescent center, and the excitation efficiency of the rare earth ions is low, and the luminescent spectrum is narrow; the transition metal ion doped fluorescent materials mostly use Cr 3+ as the luminescent center, and the luminescent peak is mostly concentrated in the range of 750-850nm, thus limiting its application in the imaging field.

[0004] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0005] Based on the above shortcomings of the prior art, the purpose of the present application is to provide an inorganic near-infrared fluorescent material and a preparation method and application thereof, aiming to solve the problems of the prior art that the luminescent spectrum of the inorganic near-infrared fluorescent material is narrow, the luminescent peak range is less than 850nm, and the application in the imaging field is limited.

[0006] The technical scheme of the present application is as follows:

[0007] In a first aspect of the present application, an inorganic near-infrared fluorescent material is provided, wherein the chemical formula of the inorganic near-infrared fluorescent material is Mg(CrM) x Ti 1-x O3; wherein 0

[0008] Optionally, M is at least one of Li, Na and K.

[0009] In a second aspect of the present application, a preparation method of the inorganic near-infrared fluorescent material of the present application is provided, wherein the method comprises the following steps:

[0010] According to the preparation method of the inorganic near-infrared fluorescent material of the present application, Mg(CrM) x Ti 1-xThe inorganic near-infrared fluorescent material is prepared by mixing a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source in a stoichiometric ratio of elements in O3, sintering at a first preset temperature for a first preset time, and then sintering at a second preset temperature for a second preset time.

[0011] Optionally, the preparation method of the inorganic near-infrared fluorescent material specifically comprises the following steps:

[0012] According to Mg(CrM) x Ti 1-x The inorganic near-infrared fluorescent material is prepared by mixing a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source in a stoichiometric ratio of elements in O3, sintering at a first preset temperature for a first preset time, and then sintering at a second preset temperature for a second preset time.

[0013] The inorganic near-infrared fluorescent material is prepared by mixing a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source in a stoichiometric ratio of elements in O3, sintering at a first preset temperature for a first preset time, and then sintering at a second preset temperature for a second preset time.

[0014] The inorganic near-infrared fluorescent material is prepared by mixing a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source in a stoichiometric ratio of elements in O3, sintering at a first preset temperature for a first preset time, and then sintering at a second preset temperature for a second preset time.

[0015] Optionally, ethanol is added in the first grinding process, and the first grinding time is 15-30 min; ethanol is added in the second grinding process, and the second grinding time is 15-30 min.

[0016] Optionally, the magnesium source comprises magnesium oxide; the titanium source comprises titanium dioxide; and the chromium source comprises chromium trioxide.

[0017] Optionally, the alkali metal source comprises lithium carbonate, sodium carbonate or potassium carbonate.

[0018] Optionally, the first preset temperature is 900 DEG C, and the first preset time is 3 h.

[0019] Optionally, the second preset temperature is 1300 DEG C, and the second preset time is 2 h.

[0020] In a third aspect, the application provides a use of the inorganic near-infrared fluorescent material prepared by the above preparation method in the field of near-infrared imaging.

[0021] The inorganic near-infrared fluorescent material provided by the application has excellent near-infrared luminescence performance under ultraviolet-visible light excitation, a wide emission band range (750-1200 nm), a peak position at 866 nm, a photoluminescence quantum yield of 31.55%, and reaches the commercial standard, and can be applied to the field of near-infrared imaging. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Crystal structure diagram of the inorganic near-infrared fluorescent material prepared in Example 3.

[0023] Figure 2 XRD diagram of the inorganic near-infrared fluorescent material prepared in Example 3.

[0024] Figure 3 Element distribution diagram of the inorganic near-infrared fluorescent material prepared in Example 3.

[0025] Figure 4 XPS diagram of the inorganic near-infrared fluorescent material prepared in Example 3.

[0026] Figure 5 Fluorescence excitation spectrum diagram of the inorganic near-infrared fluorescent material prepared in Example 3, Example 7, Example 8 and Comparative Example 1.

[0027] Figure 6 Fluorescence emission spectrum diagram of the inorganic near-infrared fluorescent material prepared in Example 3 and Comparative Example 1 under 315 nm excitation wavelength.

[0028] Figure 7 Fluorescence emission spectrum diagram of the inorganic near-infrared fluorescent material prepared in Example 3 and Comparative Example 1 under 728 nm excitation wavelength. DETAILED DESCRIPTION

[0029] The present application provides an inorganic near-infrared fluorescent material and a preparation method and application thereof. In order to make the purpose, technical scheme and effects of the present application more clear and definite, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application.

[0031] The present application provides an inorganic near-infrared fluorescent material, wherein the chemical formula of the inorganic near-infrared fluorescent material is Mg(CrM) x Ti 1-x O3; wherein 0 < x ≤ 0.06, and M is at least one alkali metal.

[0032] The inorganic near-infrared fluorescent material provided by the embodiment has excellent near-infrared luminescence performance under ultraviolet-visible light (315 nm, 514 nm, 728 nm) excitation, a wide emission band range (750-1200 nm), a peak position at 866 nm, a photoluminescence quantum yield of 31.55%, and reaches a commercial standard, and can be applied to the field of near-infrared imaging.

[0033] In the embodiment, the chemical formula of the inorganic near-infrared fluorescent material is Mg(CrM) x Ti 1-x O3, that is, MgCr x M x Ti 1-x O3, which can be represented as MgTiO3:Cr 3+ ,M + For example, when M is Na, the inorganic near-infrared fluorescent material can be represented as MgTiO3:Cr 3+ ,Na + .

[0034] In some embodiments, M is at least one of Li, Na and K, for example, the chemical formula of the inorganic near-infrared fluorescent material is Mg(CrLi) x Ti 1-x O3, Mg(CrNa) x Ti 1-x O3, Mg(CrK) x Ti 1-x O3, Mg(CrLi 0.5 Na 0.5 ) x Ti 1-x O3, and the like.

[0035] The embodiment also provides a preparation method of the inorganic near-infrared fluorescent material as described above.

[0036] According to the stoichiometric ratio of each element in Mg(CrM) x Ti 1-x O3, a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source are mixed, sintered at a first preset temperature for a first preset time, and then sintered at a second preset temperature for a second preset time to obtain the inorganic near-infrared fluorescent material.

[0037] The preparation method is simple, the cost is low, the raw materials used in the preparation method can all be commercially available and low-cost raw materials, the prepared inorganic near-infrared fluorescent material has the characteristics of good thermal stability, has excellent near-infrared luminescence performance under ultraviolet-visible light (315 nm, 514 nm, 728 nm) excitation, has a wide emission band range, the peak position is at 866 nm, the photoluminescence quantum yield is 31.55%, reaches the commercial standard, and can be applied to the field of near-infrared imaging.

[0038] In the embodiment of the application, the magnesium source and the titanium source are used as the matrix components, and the chromium source and the alkali metal source are used as the doped ion components. In the sintering process, chromium ions and alkali metal ions replace titanium ions and are doped into MgTiO3.

[0039] In the embodiment of the application, the alkali metal acts as a fluxing agent and also plays a charge compensation role. Specifically, Cr 3+ replaces Ti 4+ , which is a heterovalent substitution. If the alkali metal is not added, defects will be generated, thereby affecting the luminescent efficiency and thermal stability. Therefore, the embodiment of the application adds the alkali metal to maintain the valence balance through charge compensation.

[0040] Taking M as Na as an example, the charge compensation process is: Cr 3+ + Na + → Ti 4+ , that is to say, in this process, one Cr 3+ and one Na + jointly replace one Ti 4+ .

[0041] In some embodiments, the preparation method of the inorganic near-infrared fluorescent material specifically comprises the following steps:

[0042] According to the stoichiometric ratio of each element in Mg(CrM) x Ti 1-x O3, a magnesium source, a titanium source, a chromium source and an excess of at least one alkali metal source (at least one alkali metal source is additionally added by 3% to 5% of the total mass of the magnesium source, the titanium source and the chromium source) are mixed, and then a first mixture is obtained after first grinding;

[0043] The first mixture is sintered at a first preset temperature for a first preset time, and then a second mixture is obtained after second grinding;

[0044] The second mixture is sintered at a second preset temperature for a second preset time to obtain the inorganic near-infrared fluorescent material.

[0045] In the embodiment, the alkali metal source is excessive, that is, it can be understood that the magnesium source, the titanium source, the chromium source and the excess of at least one alkali metal source are mixed according to the stoichiometric ratio of each element in Mg(CrM) x Ti1-x The stoichiometric ratio of each element in O3, the magnesium source, the titanium source, the chromium source and the at least one alkali metal source are mixed, and then an additional 3% to 5% of the total mass of the magnesium source, the titanium source and the chromium source is added to the at least one alkali metal source.

[0046] In some embodiments, the first grinding is performed in the presence of ethanol, and the first grinding is performed for 15 to 30 minutes; the second grinding is performed in the presence of ethanol, and the second grinding is performed for 15 to 30 minutes.

[0047] In some embodiments, the magnesium source comprises magnesium oxide; the titanium source comprises titanium dioxide; and the chromium source comprises at least one of chromium trioxide.

[0048] In some embodiments, the alkali metal source comprises lithium carbonate, sodium carbonate or potassium carbonate.

[0049] In some embodiments, the first preset temperature is 900°C, and the first preset time is 3 hours.

[0050] In some embodiments, the second preset temperature is 1300°C, and the second preset time is 2 hours.

[0051] The present application also provides an application of the inorganic near-infrared fluorescent material prepared by the preparation method as described above in the field of near-infrared imaging. The inorganic near-infrared fluorescent material has the characteristics of good thermal stability, excellent near-infrared luminescence performance under ultraviolet-visible light (315 nm, 514 nm, 728 nm) excitation, a wide emission band range, a peak position at 866 nm, a photoluminescence quantum yield of 31.55%, and reaches the commercial standard, and thus can be applied in the field of near-infrared imaging.

[0052] Different substances have different absorption degrees of near-infrared light due to different densities, thicknesses and uneven distribution of the substances. Correspondingly, the attenuation degrees of near-infrared light penetrating objects are different, and the difference (distribution state) of the infrared energy reflected or radiated by the scene or different parts of the scene can be recorded by using this principle, and is converted into a two-dimensional visible image in a certain way, which is called near-infrared imaging. In the case of a certain thickness, the dark area in the image indicates that the area has a strong absorption of near-infrared light; on the contrary, the bright area in the image indicates that the area has a weak absorption of near-infrared light, and the observer can determine the properties of the object by combining the image with the density and thickness of the object.

[0053] Specifically, the inorganic near-infrared fluorescent material can be applied to the fields of food detection, night vision, plant growth, non-destructive detection, biomedical imaging and the like. In addition, the inorganic near-infrared fluorescent material can form a clear image under visible light excitation, and a fluorescent conversion light emitting diode can be prepared.

[0054] The application will be further described below through specific examples.

[0055] In the following examples, each raw material and equipment used, unless otherwise specified, is a commercially available product that can be obtained through commercial channels.

[0056] Example 1

[0057] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0058] According to the stoichiometric ratio of each element in Mg(CrNa) 0.002 Ti 0.998 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added to an agate mortar, then an appropriate amount of anhydrous ethanol is added, and grinding is performed for 30 min to obtain a first mixture;

[0059] The first mixture is transferred to a corundum crucible and placed in a muffle furnace together for pre-sintering at 900℃ for 3 hours. After cooling to room temperature, an appropriate amount of anhydrous ethanol is added to the pre-sintered product, and grinding is performed for 30 min to obtain a second mixture;

[0060] The second mixture is placed in a muffle furnace for sintering at 1300℃ for 2 hours (i.e., secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrNa) 0.002 Ti 0.998 O3 in a powder state is obtained.

[0061] Example 2

[0062] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0063] According to the stoichiometric ratio of each element in Mg(CrNa) 0.005 Ti 0.995 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added to an agate mortar, then an appropriate amount of anhydrous ethanol is added, and grinding is performed for 30 min to obtain a first mixture;

[0064] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0065] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrNa) 0.005 Ti 0.995 O3 in a powder state.

[0066] Example 3

[0067] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0068] According to the stoichiometric ratio of each element in Mg(CrNa) 0.01 Ti 0.99 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0069] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0070] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrNa) 0.01 Ti 0.99 O3 in a powder state.

[0071] Example 4

[0072] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0073] According to the stoichiometric ratio of each element in Mg(CrNa) 0.02 Ti 0.98 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0074] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0075] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrNa) 0.02 Ti 0.98 O3 in a powder state.

[0076] Example 5

[0077] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0078] According to the stoichiometric ratio of each element in Mg(CrNa) 0.04 Ti 0.96 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0079] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0080] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrNa) 0.04 Ti 0.96 O3 in a powder state.

[0081] Example 6

[0082] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0083] According to the stoichiometric ratio of each element in Mg(CrNa) 0.06 Ti 0.94 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0084] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0085] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrLi) 0.06 Ti 0.94 O3 in a powder state.

[0086] Example 7

[0087] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0088] According to the stoichiometric ratio of each element in Mg(CrLi) 0.01 Ti 0.99 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0089] The first mixture is transferred into a corundum crucible and placed into a muffle furnace together for pre-sintering at 900°C for 3 hours. After cooling to room temperature, a proper amount of absolute ethyl alcohol is added to the pre-sintered product and grinded for 30 minutes to obtain a second mixture;

[0090] The second mixture is placed into a muffle furnace for sintering at 1300°C for 2 hours (i.e. secondary sintering). After cooling to room temperature, the inorganic near-infrared fluorescent material Mg(CrLi) 0.01 Ti 0.99 O3 in a powder state.

[0091] Example 8

[0092] The present example provides a preparation method of an inorganic near-infrared fluorescent material, comprising the following steps:

[0093] According to the stoichiometric ratio of each element in Mg(CrK) 0.01 Ti 0.99 O3, magnesium oxide, titanium dioxide and chromium sesquioxide are added into an agate mortar, and then a proper amount of absolute ethyl alcohol is added and grinded for 30 minutes to obtain a first mixture;

[0094] The first mixture was transferred to a corundum crucible and placed in a muffle furnace for pre-calcination at 900°C for 3 hours. After cooling to room temperature, an appropriate amount of anhydrous ethanol was added to the pre-calcined product and ground for 30 minutes to obtain a second mixture;

[0095] The second mixture is placed in a muffle furnace and sintered at 1300°C for 2 hours (i.e., secondary sintering), and then cooled to room temperature to obtain the inorganic near-infrared fluorescent material Mg(CrK). 0.01 Ti 0.99 O3, which is in powder form.

[0096] Comparative Example 1

[0097] This comparative example provides a method for preparing an inorganic near-infrared fluorescent material, comprising the following steps:

[0098] According to MgCr 0.01 Ti 0.99 The stoichiometric ratio of each element in O3 was calculated by adding magnesium oxide, titanium dioxide, and chromium oxide into an agate mortar, and then adding an appropriate amount of anhydrous ethanol and grinding for 30 minutes to obtain a first mixture;

[0099] The first mixture was transferred to a corundum crucible and placed in a muffle furnace for pre-calcination at 900°C for 3 hours. After cooling to room temperature, an appropriate amount of anhydrous ethanol was added to the pre-calcined product and ground for 30 minutes to obtain a second mixture;

[0100] The second mixture was placed in a muffle furnace and sintered at 1300°C for 2 hours (i.e., secondary sintering), and then cooled to room temperature to obtain the inorganic near-infrared fluorescent material MgCr 0.01 Ti 0.99 O3, which is in powder form.

[0101] test:

[0102] (1) The crystal structure of the inorganic near-infrared fluorescent material prepared in Example 3 is shown in FIG. Figure 1 As shown by Figure 1 It can be seen that Mg 2+ and Ti 4+ Arranged in layers, each Mg 2+ and Ti 4+ All with 6 O 2- Combined to form a distorted octahedral structure, while Cr 3+ and Na + Then replace Ti 4+ The crystal structures of the inorganic near-infrared fluorescent materials prepared in the remaining examples are the same as that of the inorganic near-infrared fluorescent material in Example 3.

[0103] (2) The inorganic near-infrared fluorescent material prepared in Example 1 to Example 8 was subjected to powder X-ray diffraction (XRD) test, wherein the XRD pattern of the inorganic near-infrared fluorescent material prepared in Example 3 is shown in FIG. 2 (the XRD patterns of the inorganic near-infrared fluorescent materials prepared in the remaining examples are basically the same as this), which is very similar to the XRD pattern obtained by crystal structure fitting, indicating that the inorganic near-infrared fluorescent material prepared in Example 3 is a pure phase and does not need to be further purified. Figure 2

[0104] (3) The inorganic near-infrared fluorescent material prepared in Example 3 was subjected to energy spectrum test, and the element distribution diagrams are shown in FIG. 3, which can prove that it contains Mg, Ti, O, Cr and Na elements. Figure 3

[0105] (4) The inorganic near-infrared fluorescent material prepared in Example 3 was subjected to X-ray photoelectron spectroscopy (XPS) test, and the results are shown in FIG. 4, which has Mg 1s peak, Na 1s peak, Cr 2p peak, O 1s peak and Ti 2p peak. Figure 4

[0106] (5) The fluorescence excitation spectrum diagrams of the inorganic near-infrared fluorescent materials prepared in Example 3, Example 7, Example 8 and Comparative Example 1 were tested, and the results are shown in FIG. 5, which can be seen that the fluorescence excitation peaks of the inorganic near-infrared fluorescent materials prepared in Example 3, Example 7 and Example 8 are three, which are located at 315 nm, 514 nm and 728 nm respectively, and the excitation waveband covers ultraviolet and visible light. Compared with the inorganic near-infrared fluorescent material prepared in Comparative Example 1, the inorganic near-infrared fluorescent materials prepared in Example 3, Example 7 and Example 8 have stronger ultraviolet and red light absorption. Figure 5

[0107] (6) The fluorescence emission spectrum diagrams (excitation wavelength is 315 nm) of the inorganic near-infrared fluorescent materials prepared in Example 3 and Comparative Example 1 were tested, and the results are shown in FIG. 6, which can be seen that the fluorescence emission peak of the inorganic near-infrared fluorescent material prepared in Example 3 is located at 866 nm, and the emission waveband is 750-1200 nm, which has a very wide emission range. Figure 6

[0108] In addition, through calculation, the photoluminescence quantum yield of the inorganic near-infrared fluorescent material prepared in Example 3 is 31.55% (when the excitation wavelength is 520 nm), which reaches the standard of commercial inorganic near-infrared fluorescent powder, indicating that the inorganic near-infrared fluorescent material provided by the present application has commercial potential. Compared with the inorganic near-infrared fluorescent material prepared in Example 3, the fluorescence emission peak intensity of the inorganic near-infrared fluorescent material prepared in Comparative Example 1 is lower.

[0109] ​​​​​(7) The fluorescence emission spectrum of the inorganic near-infrared fluorescent material prepared in Test Example 3 and Comparative Example 1 (excitation wavelength: 728 nm) was tested, and the results are shown in Figure 7 Figure 3. The fluorescence emission band of the inorganic near-infrared fluorescent material prepared in Example 3 was 750-1200 nm, had a very wide emission range, and the fluorescence emission peak intensity of the inorganic near-infrared fluorescent material in Comparative Example 1 was lower than that of the inorganic near-infrared fluorescent material prepared in Example 3.

[0110] In summary, the present application provides an inorganic near-infrared fluorescent material, a preparation method thereof, and an application thereof. The inorganic near-infrared fluorescent material has excellent near-infrared luminescence performance under ultraviolet-visible light (315 nm, 514 nm, 728 nm) excitation, has a wide emission band range (750-1200 nm), has a peak position at 866 nm, has a photoluminescence quantum yield of 31.55%, reaches a commercial standard, and can be applied in the field of near-infrared imaging.

[0111] It should be understood that the application of the present application is not limited to the above examples, and those of ordinary skill in the art can make improvements or changes according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. An inorganic near-infrared fluorescent material, characterized in that: The inorganic near-infrared fluorescent material has a chemical formula of Mg(CrM) x Ti 1-x O3; wherein, 0 < x ≤ 0.06, M is at least one of Li, Na, and K; in the chemical formula, one Cr 3+ substitutes one Ti + together with one M 4+ .

2. A method for producing the inorganic near-infrared fluorescent material according to claim 1, characterized by, The method comprises the following steps: According to the stoichiometric ratio of each element in Mg(CrM) x Ti 1-x O3, the magnesium source, the titanium source, the chromium source and the excess M source are mixed, sintered at a first preset temperature for a first preset time, and then sintered at a second preset temperature for a second preset time to obtain the inorganic near-infrared fluorescent material.

3. The preparation method according to claim 2, characterized in that The preparation method of the inorganic near-infrared fluorescent material comprises the following steps: According to the stoichiometric ratio of each element in Mg(CrM) x Ti 1-x O3, the magnesium source, the titanium source, the chromium source and the excess M source are mixed, and then after the first grinding, a first mixture is obtained; The first mixture is sintered at a first preset temperature for a first preset time, and then is secondly ground to obtain a second mixture; The second mixture is sintered at a second preset temperature for a second preset time to obtain the inorganic near-infrared fluorescent material.

4. The production method according to claim 3, characterized by, Ethanol is added in the first grinding process, and the first grinding time is 15-30 min; ethanol is added in the second grinding process, and the second grinding time is 15-30 min.

5. The production method according to claim 2 or 3, characterized by, The magnesium source comprises magnesium oxide; the titanium source comprises titanium dioxide; and the chromium source comprises chromium trioxide.

6. The production method according to claim 2 or 3, characterized by, The M source comprises lithium carbonate, sodium carbonate or potassium carbonate.

7. The production method according to claim 2 or 3, characterized by, The first preset temperature is 900 DEG C, and the first preset time is 3 h.

8. The production method according to claim 2 or 3, characterized by, The second preset temperature is 1300 DEG C, and the second preset time is 2 h.

9. The inorganic near-infrared fluorescent material according to claim 1, or the inorganic near-infrared fluorescent material prepared by the preparation method according to any one of claims 2-8, is applied in the field of near-infrared imaging.

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