Blue light excited near-infrared fluorescent material, preparation method thereof and light emitting device

Abstract

The application relates to the technical field of light-emitting materials, and provides a blue light excited near-infrared fluorescent material, a preparation method of the near-infrared fluorescent material and a light-emitting device. The near-infrared fluorescent material comprises a compound with a chemical general formula A2BM 1‑x F6:xCr 3+ , ACM 1‑x F6:xCr 3+ and A3B3M 2‑x F 12 :xCr 3+ at least one of the compounds, wherein: the A position and the B position each independently comprise at least one of a monovalent alkali metal element and an ammonium ion group; the C position comprises at least one of a divalent alkaline earth metal element; the M position comprises at least four elements selected from Zn, Mg, Al, Ga, Sc, In, Ti, Zr, Hf, Sn, Ge, Y, Gd, La, Lu and Sb; the molar percentage content of each element contained in the M position is close, and the molar percentage content of each element is within the range of 5% to 35%. The near-infrared fluorescent material has good light-emitting performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of luminescent materials, and particularly relates to a blue-light-excited near-infrared fluorescent material and a preparation method thereof, and a light-emitting device. BACKGROUND

[0002] Due to the significant ability of penetrating biological tissues and the characteristics of being absorbed by certain substances (characteristic absorption signals covering C-H, O-H and N-H normal vibration modes), near-infrared light is widely used in food ingredient analysis, plant lighting, biomedical imaging and night vision. Compared with traditional near-infrared light sources and near-infrared LEDs, the combination of blue LEDs and broadband near-infrared fluorescent powder will be an ideal way to build small, portable, energy-efficient near-infrared light sources. Its production equipment and technology are basically the same as those of white light LEDs, which can effectively reduce research and production costs and make it easier to popularize the technology.

[0003] At present, the main active ions that can realize near-infrared emission are rare earth ions and transition metal ions. Among them, Cr 3+ With its unique luminescent characteristics (in an octahedral weak crystal field environment, it shows broadband excitation and tunable near-infrared emission), it stands out among many ions and becomes the main doping ion of near-infrared fluorescent powder. In recent years, some excellent near-infrared luminescent materials have been reported, such as: Ca3Sc2Si3O 12 :Cr 3+ , Na3Al2Li3F 12 :Cr 3+ , and Cs2NaGaF6:Cr 3+ However, the parity-forbidden d-d electron transition of Cr 3+ determines that its transition rate is small, it is difficult to improve the luminescent efficiency, and the large Stokes shift from blue light to near-infrared light makes it still a considerable challenge to obtain a broadband near-infrared fluorescent powder with good thermal quenching resistance and high luminescent efficiency at the same time. SUMMARY

[0004] The purpose of the present application is to provide a blue-light-excited near-infrared fluorescent material and a preparation method thereof, and a light-emitting device, aiming to solve the problem of simultaneously obtaining a near-infrared fluorescent powder with good luminescent efficiency.

[0005] To achieve the above application purpose, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the present application provides a blue-light-excited near-infrared fluorescent material, which comprises a chemical general formula A2BM 1- x F6:xCr 3+ , ACM 1-x F6:xCr3+ and A3B3M 2-x F 12 : xCr 3+ , wherein: A site comprises at least one of monovalent alkali metal elements and ammonium ion groups; B site comprises at least one of monovalent alkali metal elements and ammonium ion groups; C site comprises at least one of divalent alkali earth metal elements; M site comprises at least four elements of Zn, Mg, Al, Ga, Sc, In, Ti, Zr, Hf, Sn, Ge, Y, Gd, La, Lu and Sb; each element in M site has a close molar percentage content, and the molar percentage content of each element is in the range of 5% to 35%; 0.01 ≤ x ≤ 0.35.

[0007] The present application introduces high-entropy design into fluoride matrix system, enriches the selectivity of composition elements and stoichiometric ratio, adjusts the local structure of light emitting units (i.e. [CrF6] 3- octahedron, which can effectively improve the quantum efficiency of near-infrared fluorescent materials, broaden the spectrum and move the emission peak wavelength to the long wave, and the thermal stability can also be kept at a high level, and the excellent comprehensive performance is conducive to expanding its application in the near-infrared field.

[0008] In a second aspect, the present application provides a preparation method of the blue light excited near-infrared fluorescent material, which comprises the following steps: obtaining raw material components according to the stoichiometric ratio of the chemical formula of the blue light excited near-infrared fluorescent material described above; the raw material components comprise Cr element raw material components, M site raw material components and A site raw material components, and further comprise B site raw material components and / or C site raw material components; and performing hydrothermal treatment on the raw material components to obtain the blue light excited near-infrared fluorescent material.

[0009] The present application adopts hydrothermal method, and the synthesis method is relatively simple and has high synthesis efficiency. The hydrothermal method can provide a mild synthesis environment and improve the ion diffusion rate. The supercritical high-temperature reaction environment for a long time under the hydrothermal condition can generate sufficient reaction activity, so that the reaction is sufficient, and the Cr 3+ ions are stably and effectively doped into the matrix lattice. In addition, it is safer under the closed hydrothermal condition due to the long-time use of toxic fluoride-containing acidic aqueous solution.

[0010] In a third aspect, the present application provides a light emitting device, which comprises a light source and a light emitting material excited by the light source, and the light emitting material comprises the blue light excited near-infrared fluorescent material described above, or comprises the blue light excited near-infrared fluorescent material obtained by the preparation method described above.

[0011] The near-infrared fluorescent material provided by the application or the near-infrared fluorescent material prepared by the application has high luminous efficiency, and the thermal stability can also be kept at a high level, and the excellent comprehensive performance is beneficial to expand the application in the near-infrared field, so that the light emitting device has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0013] Figure 1 is the near-infrared pc-LED device prepared by the embodiment 10 of the application and the electroluminescence spectrum.

[0014] Figure 2 is the excitation and emission spectrum of the single-matrix sample Cs2NaGaF6:0.20Cr 3+ and the high-entropy sample Cs2NaMF6:0.20Cr 3+ .

[0015] Figure 3 is the morphology and element distribution of the high-entropy sample Cs2NaMF6:0.20Cr 3+ provided by the embodiment 4 of the application. Figure 3 In (a), the morphology under the 10-micron scale is shown, Figure 3 In (b), the morphology under the 3-micron scale is shown, Figure 3 In (c), the element distribution of the sample is shown, Figure 3 In (d), the Cs element distribution of the sample is shown, Figure 3 In (e), the F element distribution of the sample is shown, Figure 3 In (f), the Na element distribution of the sample is shown, Figure 3 In (g), the Ga element distribution of the sample is shown, Figure 3 In (h), the Cr element distribution of the sample is shown, Figure 3 In (i), the Al element distribution of the sample is shown, Figure 3 In (j), the In element distribution of the sample is shown, Figure 3 In (k), the Sc element distribution of the sample is shown.

[0016] Figure 4 is the Raman spectrum of the single-matrix sample Cs2NaGaF6:0.20Cr 3+ and the high-entropy sample Cs2NaMF6:0.20Cr 3+ .

[0017] Figure 5 The matrix sample is Cs2NaGaF6:0.20Cr. 3+ And the high-entropy sample Cs2NaMF6:0.20Cr 3+ The crystal structure diagram, in which, Figure 5 In the middle (a), it represents Cs2NaGaF6:0.20Cr 3+ Crystal structure diagram, Figure 5 (b) indicates Cs2NaGaF6:0.20Cr 3+ The coordination environment of each cation. Figure 5 (c) indicates Cs2NaGaF6:0.20Cr 3+ A schematic diagram of the layered structure. Figure 5 (d) indicates Cs2NaMF6:0.20Cr 3+ Crystal structure diagram, Figure 5 (e) indicates Cs2NaMF6:0.20Cr 3+ A schematic diagram of the layered structure. Figure 5 (f) indicates Cs2NaMF6:0.20Cr 3+ The coordination environment of each cation.

[0018] Figure 6 The different Cr provided in Embodiment 5 of this application 3+ XRD pattern of a high-entropy sample with varying doping levels. Figure 6 In this context, "Calculated Cs2NaGaF6" indicates the calculated standard Cs2NaMF6:0.20Cr 3+ Phase cards were used in this application because no standard cards were known; these cards were well-matched with the diffraction peaks and the high-entropy fluoride near-infrared phosphor Cs₂NaMF₆:Cr. 3+ The CIF file of the isomorphic Cs2NaGaF6 is the basic model. Using ICSD 55698, and then modifying the model using the crystal structure visualization software VESTA, a theoretical model of the high-entropy fluoride Cs2NaMF6 with the same crystal structure was constructed. Finally, the corresponding theoretical standard card (Calculated Cs2NaMF6) was derived. (For analysis and comparison)

[0019] Figure 7 Single matrix sample Cs2KGaF6:0.20Cr 3+ And the high-entropy sample Cs2KMF6:0.20Cr 3+ The emission spectrum.

[0020] Figure 8 High-entropy sample Cs2K(Al) 0.30 Ga0.30 In 0.2 Sc 0.2 ) 0.80 F6: 0.20Cr 3+ of the three-dimensional crystal structure. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved in the present application clearer, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0022] In the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents that the associated objects before and after it are in an "or" relationship.

[0023] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or the like means any combination of these items, including any combination of single item or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can represent a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, and c can be single or multiple.

[0024] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-mentioned processes does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence. The execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0025] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0026] The weight of the related components mentioned in the embodiment specification of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of each component. Therefore, as long as the content of the related components in the embodiment specification of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the embodiment specification of the present application. Specifically, the mass mentioned in the embodiment specification of the present application can be μg, mg, g, kg and other mass units commonly known in the chemical field.

[0027] The terms "first", "second" are only for descriptive purposes, to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. For example, without departing from the scope of the present application, the first XX can also be referred to as the second XX, and similarly, the second XX can also be referred to as the first XX. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0028] The first aspect of the embodiment of the present application provides a blue light excited near-infrared fluorescent material, which comprises a compound of the general formula A2BM 1-x F6:xCr 3+ , ACM 1-x F6:xCr 3+ and A3B3M 2-x F 12 :xCr 3+ , wherein:

[0029] The A site comprises at least one of monovalent alkali metal elements and ammonium ion groups;

[0030] The B site comprises at least one of monovalent alkali metal elements and ammonium ion groups;

[0031] The C site comprises at least one of divalent alkali earth metal elements;

[0032] The M site comprises at least four elements of Zn, Mg, Al, Ga, Sc, In, Ti, Zr, Hf, Sn, Ge, Y, Gd, La, Lu and Sb; the molar percentage content of each element contained in the M site is close, and the molar percentage content of each element is within the range of 5% to 35%;

[0033] 0.01≤x≤0.35.

[0034] The embodiment of the present application introduces high-entropy design into the fluoride matrix system, enriches the selectivity of composition elements and stoichiometric ratio, and adjusts the local structure of the luminescent unit (i.e. [CrF6] 3-Octahedron, which can effectively improve the quantum efficiency of near-infrared fluorescent materials, broaden the spectrum and make the emission peak wavelength move towards long wave, and the thermal stability can also be kept at a high level, and the excellent comprehensive performance is conducive to expanding its application in the near-infrared field.

[0035] Unlike traditional binary solid solution systems, high-entropy materials are composed of five or more near-molar components, which expand the composition range of material design and enrich the development space of materials due to the selectability and diversity of structure, composition and proportion. At the same time, high-entropy materials have high configuration entropy, which can inhibit the phase separation tendency of materials and easily obtain single-structure high-entropy solid solution phase. In addition, high-entropy structure effect can induce local structure distortion and improve system disorder, which is conducive to breaking the parity-forbidden characteristics of Cr 3+ d-d transition and ultimately improving the luminescent efficiency and performance of Cr 3+ activated fluoride near-infrared fluorescent powder.

[0036] The embodiment of the application introduces the high-entropy design concept into the fluoride matrix system, and obtains a high-entropy fluoride matrix by optimizing the composition elements and proportion design. Due to the differences in the radius, valence state of each ion in the matrix, and the significant differences in bond length and bond angle, the [CrF6] 3- octahedron distortion degree increases, which will lead to changes in the local structure around Cr 3+ and a decrease in symmetry, which is conducive to breaking the parity-forbidden characteristics of Cr 3+ d-d transition and ultimately improving the luminescent efficiency and thermal stability performance of Cr 3+ activated fluoride near-infrared fluorescent powder.

[0037] In some embodiments, the element selection principle of the M site includes at least one of the following (1) to (4): (1) the ionic radii of each element should be as close as possible; (2) the electronegativity of the elements is similar; (3) the charge of the lattice site should be balanced; (4) the crystal structure of each element corresponding to the matrix is similar.

[0038] The inorganic fluorescent powder is mainly composed of inorganic crystal material as a matrix and activator ions as a luminescent center, so the above-mentioned "matrix" specific examples are A2BM 1-x F6 and ACM 1-x F6; "lattice site" refers to the M site in each matrix material, that is, the substitution position of the activator ion Cr 3+ .

[0039] In some embodiments, the molar percentage content of each element contained in the M site is close, and the molar percentage content of each element is within the range of 5% to 35%.

[0040] In some embodiments, the element or group at the A site and the element or group at the B site can be the same.

[0041] In some embodiments, the element or group at the A site and the element or group at the B site are different.

[0042] In some embodiments, at least one of the following (1) to (5) is satisfied:

[0043] (1) The monovalent alkali metal element at the A site includes at least one of Li, Na, K, Rb, and Cs;

[0044] (2) The monovalent alkali metal element at the B site includes at least one of Li, Na, K, Rb, and Cs;

[0045] (3) The ammonium group at the A site includes at least one of an ammonium group and a tetramethylammonium group,

[0046] (4) The ammonium group at the B site includes at least one of an ammonium group and a tetramethylammonium group;

[0047] (5) The divalent alkaline earth metal element includes at least one of Ca, Sr, Ba, Mg, and Zn.

[0048] The ion corresponding to the monovalent alkali metal element includes at least one of Li + , Na + , K + , Rb + , and Cs + .

[0049] The ammonium group is NH 4+ ; and the tetramethylammonium group is (CH3)4N + (tetramethylammonium, TMA + ).

[0050] Further, the ion corresponding to the A site includes at least one of Li + , Na + , K + , Rb + , Cs + , NH 4+ , and (CH3)4N + .

[0051] Further, the ion corresponding to the B site includes at least one of Li + , Na + , K + , Rb + , Cs + , NH 4+ , and (CH3)4N + .

[0052] In some embodiments, the divalent alkaline earth metal elements include at least one of Ca, Sr, Ba, Mg, and Zn.

[0053] The ions corresponding to the divalent alkaline earth metal elements include at least one of Ca 2+ , Sr 2+ , Ba 2+ , Mg 2+ , and Zn 2+ .

[0054] Further, the ions corresponding to the C sites include at least one of Ca 2+ , Sr 2+ , Ba 2+ , Mg 2+ , and Zn 2+ .

[0055] In some embodiments, the molar percentage of each element contained in the M sites differs by no more than 10%. In specific examples, the molar percentage of each element contained in the M sites differs by 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, etc.

[0056] In some embodiments, the blue light-excited near-infrared fluorescent material has an excitation light wavelength of 420 nm to 470 nm; and / or, an emission light wavelength of 700 nm to 1000 nm.

[0057] In some embodiments, the compound of the general formula A2BM 1-x F6: xCr 3+ satisfies any one of the following (1) to (2):

[0058] (1) The A sites and the B sites are both K, and the M sites are a combination of four elements of Al, Ga, In, and Sc. Further, the M sites are Al, Ga, In, and Sc, and the molar ratio of each element is 0.30:0.30:0.20:0.20. Further, x is 0.08, and in this case, the chemical formula of the fluorescent material is K3(Al 0.30 , Ga 0.30 , In 0.20 , Sc 0.20 ) 0.92 F6:0.08Cr 3+ .

[0059] (2) The A sites and the B sites are both Na, and the M sites are a combination of five elements of Zn, Al, Ga, Sc, and Ti. Further, the M sites are Zn, Al, Ga, Sc, and Ti, and the molar ratio of each element is 0.20:0.20:0.20:0.20:0.20. Further, x is 0.25, and in this case, the chemical formula of the fluorescent material is Na3(Zn 0.20Al 0.20 Ga 0.20 Sc 0.20 Ti 0.20 ) 0.75 F6:0.25Cr 3+ .

[0060] (3) A is K, B is Li, and M is a combination of five elements of Al, Ga, In, Sc, and Lu. Further, M is Al, Ga, In, Sc, and Lu, and the molar ratio of each element is 0.20:0.20:0.20:0.20:0.20. Still further, x is 0.10, and at this time, the chemical formula of the fluorescent material is K2Li(Al 0.20 Ga 0.20 In 0.20 Sc 0.20 Lu 0.20 ) 0.90 F6:0.10Cr 3+ .

[0061] (4) A is Cs, B is Na, and M is a combination of four elements of Al, Ga, In, and Sc. Further, M is Al, Ga, In, and Sc, and the molar ratio of each element is 0.25:0.25:0.25:0.25. Still further, x is 0.20, and at this time, the chemical formula of the fluorescent material is Cs2Na(Al 0.25 Ga 0.25 In 0.25 Sc 0.25 ) 0.80 F6:0.20Cr 3+ .

[0062] (5) A is Rb, B is K, and M is a combination of seven elements of Al, Ga, In, Y, Gd, Sc, and Lu. Further, M is Al, Ga, In, Y, Gd, Sc, and Lu, and the molar ratio of each element is 0.15:0.15:0.15:0.10:0.15:0.15:0.15. Still further, x is 0.12, and at this time, the chemical formula of the fluorescent material is Rb2K(Al 0.15 Ga 0.15 In 0.15 Y 0.10 Gd 0.15 Sc 0.15 Lu 0.15 ) 0.88 F6:0.12Cr 3+ .

[0063] (6) A site is Cs, B site is Na, M site is a combination of four elements of Al, Ga, In and Sc. Further, M site is Al, Ga, In and Sc, and the molar ratio of each element is 0.25:0.25:0.25:0.25. At this time, the chemical formula of the fluorescent material is Cs2Na(Al 0.25 ,Ga 0.25 ,In 0.25 ,Sc 0.25 ) 1-x F6:xCr 3+ .

[0064] In some embodiments, the compound has a chemical formula of ACM 1-x F6:xCr 3+ , and satisfies:

[0065] A site is Li, B site is Sr, M site is a combination of five elements of Al, Ga, In, Gd and Sc. Further, M site is Al, Ga, In, Gd and Sc, and the molar ratio of each element is 0.20:0.20:0.20:0.20:0.20. Further, x is 0.15. At this time, the chemical formula of the fluorescent material is LiSr(Al 0.20 ,Ga 0.20 ,In 0.20 ,Gd 0.20 ,Sc 0.20 ) 0.85 F6:0.15Cr 3+ .

[0066] In some embodiments, the compound has a chemical formula of A3B3M 2-x F 12 :xCr 3+ , and satisfies:

[0067] A site is Na, B site is Li, M site is a combination of four elements of Al, Ga, In and Sc. Further, M site is Al, Ga, In and Sc, and the molar ratio of each element is 0.30:0.30:0.20:0.20. Further, x is 0.09. At this time, the chemical formula of the fluorescent material is Li3Na3(Al 0.30 ,Ga 0.30 ,In 0.20 ,Sc 0.20 ) 1.91 F6:0.09Cr 3+ .

[0068] The second aspect of the embodiments of the present application provides a preparation method of a blue light excited near-infrared fluorescent material, which comprises the following steps:

[0069] The raw material components are obtained according to the stoichiometric ratio of the chemical formula of the blue light excited near-infrared fluorescent material; the raw material components include Cr element raw material components, M site raw material components, and A site raw material components, and further include B site raw material components and / or C site raw material components;

[0070] The raw material components are subjected to hydrothermal treatment to obtain the blue light excited near-infrared fluorescent material.

[0071] The embodiment of the present application adopts a hydrothermal method, and the synthesis method is relatively simple and has high synthesis efficiency. The hydrothermal method can provide a mild synthesis environment and improve the ion diffusion rate. The supercritical high-temperature reaction environment for a long time under the hydrothermal condition can generate sufficient reaction activity, so that the reaction is sufficient, and the Cr 3+ ions are stably and effectively doped into the matrix lattice. In addition, it is safer under the closed hydrothermal condition because of the long-time use of toxic fluoride-containing acidic aqueous solution.

[0072] In some embodiments, the raw material components satisfy at least one of the following (1) to (5):

[0073] (1) The Cr element raw material components include at least one of chromium chloride, chromium nitrate, chromium hydroxide, chromium fluoride, and chromium oxide;

[0074] (2) The M site raw material components include at least one of an oxide, a fluoride, and a metal salt;

[0075] (3) The A site raw material components include at least one of a fluoride and a carbonate;

[0076] (4) The B site raw material components include at least one of a fluoride and a carbonate;

[0077] (5) The C site raw material components include at least one of a fluoride and a carbonate.

[0078] The embodiment of the present application selects each raw material component, which has low cost and high solubility in a solvent, so as to participate in the reaction and improve the reaction efficiency.

[0079] In the embodiment of the present application, the M site raw material components include at least one of an oxide, a fluoride, and a metal salt. The "fluoride" refers to a compound composed of a fluoride ion and a corresponding metal ion; the "metal salt" refers to a salt compound composed of a metal ion and an acid radical ion. The "oxide" refers to an oxide formed by the metal ion; and the metal ion is at least one of Zn, Al, Ga, Sc, In, Ti, Y, Gd, La, Lu, and Sb. Further, the metal salt includes at least one of a sulfate, a nitrate, and a carbonate.

[0080] In the embodiment of the present application, in the A site raw material components, the "fluoride" refers to a compound composed of a fluoride ion (F- ) or a hydrogen bifluoride ion (HF2 - ) and a cation. Further, the cation is an ion corresponding to the monovalent alkali metal element or the ammonium group at the A site in the chemical formula. In specific examples, the fluoride includes at least one of LiF, NaF, KF, RbF, CsF, NH4F, (CH3)4NF, NH4HF2, and KHF2. The carbonate in the A site raw material component is a carbonate corresponding to the monovalent alkali metal element or the ammonium group at the A site.

[0081] In the embodiments of the present application, the "fluoride" in the B site raw material component refers to a compound composed of a fluoride ion (F - ) or a hydrogen bifluoride ion (HF2 - ) and a cation. Further, the cation is an ion corresponding to the monovalent alkali metal element or the ammonium group at the B site in the chemical formula. In specific examples, the fluoride includes at least one of LiF, NaF, KF, RbF, CsF, NH4F, (CH3)4NF, NH4HF2, and KHF2. The carbonate in the B site raw material component is a carbonate corresponding to the monovalent alkali metal element or the ammonium group at the B site.

[0082] In the embodiments of the present application, the "fluoride" in the C site raw material component refers to a compound composed of a fluoride ion (F - ) or a hydrogen bifluoride ion (HF2 - ) and a metal ion. Further, the cation is an ion corresponding to the divalent alkaline earth metal element at the C site in the chemical formula. In specific examples, the fluoride includes at least one of CaF2, CsF2, BaF2, MgF2, and ZnF2. The carbonate in the C site raw material component is a carbonate corresponding to the divalent alkali metal element at the C site.

[0083] In some embodiments, the solvent used in the hydrothermal treatment includes an acidic aqueous solution containing fluorine.

[0084] In the embodiments of the present application, the acidic aqueous solution containing fluorine is used to dissolve various raw materials, provide a reaction environment, and also provide a fluorine source, thereby stabilizing the generated fluoride fluorescent material.

[0085] Further, the acidic aqueous solution containing fluorine is an aqueous solution of hydrogen fluoride.

[0086] Further, the acidic aqueous solution containing fluorine is an aqueous solution composed of an acid and a fluorine source. The acid includes at least one of hydrofluoric acid, nitric acid, hydrochloric acid, and phosphoric acid. The fluorine source includes at least one of a fluoride and a hydrogen fluoride; the fluoride includes HF; and the hydrogen fluoride includes NH4HF2.

[0087] In some embodiments, the acidic aqueous solution containing fluorine has a mass percentage concentration of 10% to 49%.

[0088] In some embodiments, the control parameters in the hydrothermal treatment step include:

[0089] The temperature of the hydrothermal treatment is 160°C to 240°C, and / or the time of the hydrothermal treatment is 6h to 24h.

[0090] The reaction temperature can affect the luminescent intensity of the fluorescent material, and by reasonably selecting the reaction temperature, the luminescent intensity of the fluorescent material can be further improved.

[0091] In some embodiments, the step of subjecting the raw material components to hydrothermal treatment includes:

[0092] The order of adding the raw material components and the solvent is controlled to meet the requirement that the A-site raw material component is added last among the B-site raw material component and the C-site raw material component.

[0093] The order of adding the other raw material components (M-site raw material component, Cr element raw material component) and the solvent is not limited, and it is only required that the A-site raw material component is added last among the B-site raw material component and the C-site raw material component. The combination of the A-site raw material component and the B-site raw material component, or the combination of the A-site raw material component and the C-site raw material component can act as a precipitant, which is beneficial to promoting the reaction to proceed smoothly and generate the target product.

[0094] In the embodiments of the present application, if a compound with the chemical formula of A2BM 1-x F6:xCr 3+ is prepared, then the A-site raw material component and the B-site raw material component are added last; if a compound with the chemical formula of A3B3M 2-x F 12 :xCr 3+ is prepared, then the A-site raw material component and the B-site raw material component are added last; if a compound with the chemical formula of ACM 1-x F6:xCr 3+ is prepared, then the A-site raw material component and the C-site raw material component are added last.

[0095] In some embodiments, the step of subjecting the raw material components to hydrothermal treatment includes:

[0096] First, the M-site raw material component and the solvent used in the hydrothermal treatment are mixed; then the Cr element raw material component is added and mixed; and then the A-site raw material component and at least one of the B-site raw material component and the C-site raw material component are added and mixed to obtain a mixed material;

[0097] The mixed material is subjected to hydrothermal treatment.

[0098] In specific examples, a compound with the chemical formula of A2BM 1-xF6:xCr 3+ The compound is prepared by first adding the M-site raw material component and the solvent used for hydrothermal treatment, and then mixing it; then adding the Cr element raw material component and mixing it; then adding the A-site raw material component and the B-site raw material component and mixing it to obtain a mixture; and then subjecting the mixture to hydrothermal treatment.

[0099] In a specific example, a preparation of chemical formula ACM was prepared. 1-x F6:xCr 3+ The compound is prepared by first adding the M-site raw material component and the solvent used for hydrothermal treatment, and then mixing it; then adding the Cr element raw material component and mixing it; then adding the A-site raw material component and the C-site raw material component and mixing it to obtain a mixture; and then subjecting the mixture to hydrothermal treatment.

[0100] In a specific example, a preparation with the general chemical formula A3B3M was prepared. 2-x F 12 :xCr 3+ The compound is prepared by first adding the M-site raw material component and the solvent used for hydrothermal treatment, and then mixing it; then adding the Cr element raw material component and mixing it; then adding the A-site raw material component and the B-site raw material component and mixing it to obtain a mixture; and then subjecting the mixture to hydrothermal treatment.

[0101] In a specific example, a preparation with the general chemical formula A2BM was prepared. 1-x F6:xCr 3+ The compound and its general chemical formula are ACM 1-x F6:xCr 3 + The compound is prepared by first adding the M-site raw material component and the solvent used for hydrothermal treatment, and then mixing it; then adding the Cr element raw material component and mixing it; then adding the A-site raw material component, B-site raw material component and C-site raw material component and mixing them to obtain a mixture; and then subjecting the mixture to hydrothermal treatment.

[0102] In a specific example, a preparation with the general chemical formula A2BM was prepared. 1-x F6:xCr 3+ The compound and its general chemical formula are A3B3M 2-x F 12 :xCr 3+ The compound is prepared by first adding the M-site raw material component and the solvent used for hydrothermal treatment, and then mixing it; then adding the Cr element raw material component and mixing it; then adding the A-site raw material component and the B-site raw material component and mixing it to obtain a mixture; and then subjecting the mixture to hydrothermal treatment.

[0103] The third aspect of the embodiment of the present application provides a light-emitting device, comprising a light source and a light-emitting material excited by the light source, wherein the light-emitting material comprises the blue-light-excited near-infrared fluorescent material described above or the blue-light-excited near-infrared fluorescent material prepared by the method described above.

[0104] The near-infrared fluorescent material provided by the embodiment of the present application or the near-infrared fluorescent material prepared by the method has high light-emitting efficiency and high thermal stability, and the excellent comprehensive performance is conducive to expanding the application in the near-infrared field, so the light-emitting device has a good application prospect.

[0105] The embodiment is described below in combination with specific examples.

[0106] Example 1

[0107] The embodiment provides a blue-light-excited near-infrared fluorescent material, which has a chemical formula of K3(MAl 0.30 ,Ga 0.30 ,In 0.20 ,Sc 0.20 ) 0.92 F6:0.08Cr 3+ , and a specific preparation method is as follows:

[0108] According to the stoichiometric ratio, 0.1159 g of AlF3, 0.1293 g of Ga2O3, 0.1277 g of In2O3, 0.0634 g of Sc2O3, 0.0436 g of CrF3 and 2.905 g of KF are weighed.

[0109] First, the raw materials AlF3, Ga2O3, In2O3 and Sc2O3 are sequentially added to the reaction container; then 6 mL of HF is added, and mechanical stirring is performed for 10 min; then CrF3 is added, and stirring is continued for 5 min; then KF is added to the above solution, and stirring is continued at room temperature for 25 min.

[0110] Then, the reaction container is placed in a high-pressure kettle and transferred to a reaction device, and incubated at 160°C for 12 h.

[0111] After the reaction is completed and cooled to room temperature, the green product is collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a drying box at 65°C for 6 h, and finally the high-entropy sample is obtained, which is the blue-light-excited near-infrared fluorescent material K3(MAl 0.30 ,Ga 0.30 ,In 0.20 ,Sc 0.20 ) 0.92 F6:0.08Cr 3+ , which is abbreviated as K3MF6:0.08Cr 3+ .

[0112] Example 2

[0113] This example provides a blue light excited near-infrared fluorescent material, which has a chemical formula of: Na3(Zn 0.20 ,Al 0.20 ,Ga 0.20 ,Sc 0.20 ,Ti 0.20 ) 0.75 F6:0.25Cr 3+ , and the specific preparation method is as follows:

[0114] According to the stoichiometric ratio, 0.2813g of Al(NO3)3·9H2O, 0.0703g of Ga2O3, 0.0517g of Sc2O3, 0.0611g of ZnO, and 0.0599g of TiO2, 0.2752g of (NH4)3CrF6, and 0.6299g of NaF were weighed.

[0115] First, the raw materials Al(NO3)3·9H2O, Ga2O3, Sc2O3, ZnO, and TiO2 were sequentially added to the reaction container; then 6mL of HF was added, and mechanical stirring was performed for 15min; then (NH4)3CrF6 was added, and stirring was continued for 5min; then NaF was added to the above solution, and stirring was continued at room temperature for 20min.

[0116] Then the reaction container was placed in an autoclave and transferred to a reaction device, and incubated at 200℃ for 10h.

[0117] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 20mL of acetic acid and anhydrous ethanol for 3 times, and finally placed in a 60℃ drying box for drying for 8h, and finally a high-entropy sample was obtained, which was a blue light excited near-infrared fluorescent material Na3(Zn 0.20 ,Al 0.20 ,Ga 0.20 ,Sc 0.20 ,Ti 0.20 ) 0.75 F6:0.25Cr 3+ , which is abbreviated as Na3MF6:0.25Cr 3+ .

[0118] Example 3

[0119] This example provides a blue light excited near-infrared fluorescent material, which has a chemical formula of: K2Li(Al 0.20 ,Ga 0.20 ,In 0.20 ,Sc 0.20 ,Lu 0.20 ) 0.90 F6:0.10Cr 3+The specific preparation method is shown as follows:

[0120] According to the stoichiometric ratio, the corresponding raw materials 0.0756 g of AlF3, 0.0843 g of Ga2O3, 0.1249 g of In2O3, 0.0621 g of Sc2O3, 0.1791 g of Lu2O3, 0.2001 g of Cr(NO3)3·9H2O, 0.7810 g of KHF2 and 0.1297 g of LiF were weighed.

[0121] First, the raw materials AlF3, Ga2O3, In2O3, Sc2O3 and Lu2O3 were added in the reaction container; then 5 mL of HF was added and stirred for 5 min; Cr(NO3)3·9H2O was added and stirred for 15 min; then KHF2 and LiF were added in the above solution and stirred for 30 min at room temperature,

[0122] Then the reaction container was placed in the autoclave and transferred to the reaction equipment, and incubated at 180℃ for 15 h.

[0123] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a 65℃ drying box for 8 h, and finally the high-entropy sample was obtained, which was a blue light excited near-infrared fluorescent material K2Li(Al 0.20 ,Ga 0.20 ,In 0.20 ,Sc 0.20 ,Lu 0.20 )0.90F6:0.10Cr 3+ , which is abbreviated as K2LiMF6:0.10Cr 3+ .

[0124] Example 4

[0125] This example provides a blue light excited near-infrared fluorescent material, which has a chemical formula of Cs2Na(Al 0.25 ,Ga 0.25 ,In 0.25 ,Sc 0.25 ) 0.80 F6:0.20Cr 3+ , and the specific preparation method is shown as follows:

[0126] According to the stoichiometric ratio, the corresponding raw materials 0.0420 g of AlF3, 0.0469 g of Ga2O3, 0.0694 g of In2O3, 0.0345 g of Sc2O3, 0.20 g of Cr(NO3)3·9H2O, 0.1050 g of NaF and 7.595 g of CsF were weighed.

[0127] The raw materials AlF3, Ga2O3, In2O3 and Sc2O3 were first added into a reaction vessel, followed by 5 mL of HF, and stirred for 10 min; then Cr(NO3)3·9H2O was added, and stirring was continued for 25 min; then NaF and CsF were added into the above solution, and stirring was continued at room temperature for 40 min.

[0128] The reaction vessel was then placed in an autoclave and transferred to a reaction device, and incubated at 200°C for 18 h.

[0129] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a 70°C drying oven for 6 h, and finally obtained the high-entropy sample, i.e., the near-infrared fluorescent material Cs2Na(Al 0.25 ,Ga 0.25 ,In 0.25 ,Sc 0.25 ) 0.80 F6:0.20Cr 3+ , which is abbreviated as Cs2NaMF6:0.20Cr 3+ .

[0130] The excitation and emission spectra of the high-entropy sample Cs2NaMF6:0.20Cr 3+ prepared in Example 4 are shown in Figure 2 , the morphology and element distribution map are shown in Figure 3 , and the quantum efficiency is shown in Table 1.

[0131] Table 1 Quantum efficiency

[0132] Sample IQE (%) AE (%) EQE (%) Cs2NaGaF6:0.20Cr 3+ ]]> 85.7 26.1 22.37 Cs2NaMF6: 0.20 Cr 3+ ]]> 97 27.3 26.5

[0133] Note: In Table 1, “IQE” represents internal quantum efficiency, “AE” represents x absorption rate, and “EQE” represents external quantum efficiency.

[0134] As shown in Figure 2 , three typical excitation bands can be observed in the visible light region, among which the strong excitation band centered at 437 nm dominates in the excitation spectrum, indicating that the Cs2NaGaF6:0.20Cr 3+ and Cs2NaMF6:0.20Cr 3+ fluorescent powder can be effectively excited by a commercial InGaN blue light chip. Under 437 nm excitation, the single-matrix Cs2NaGaF6:0.20Cr 3+A broad near-infrared emission band with a peak at 789 nm was obtained in the 650 nm–1100 nm range, with a wide effective wavelength (FWHM) of 117 nm. The high-entropy design at the Ga site increased the disorder of the high-entropy phosphor, leading to enhanced electron-phonon coupling and thus broadening the emission band. Furthermore, Cs₂NaMF₆:₀.₂₀Cr 3+ The peak emission wavelength redshifted from 789 nm to 795 nm, while the integrated emission intensity increased compared to that of a single-matrix Cs₂NaGaF₆:0.20Cr. 3+ The efficiency was improved by 65.3%, which can be attributed to the high-entropy design of Cs2NaMF6:0.20Cr. 3+ Cr 3+ The symmetry of the crystal field environment decreases. Under these conditions, Cr 3+ The probability of dd transitions is increased, thereby improving near-infrared emission.

[0135] like Figure 3 The morphology diagrams show that the sample has high compositional uniformity, confirming the successful synthesis of single-phase high-entropy fluorides.

[0136] In addition, the high-entropy sample Cs2NaMF6:0.20Cr 3+ With a single matrix Cs2NaGaF6:0.20Cr 3+ Raman spectrum

[0137] like Figure 4 As shown, Cs2NaMF6:0.20Cr 3+ With Cs2NaGaF6:0.20Cr 3+ The Raman spectra of Cs2NaMF6:0.20Cr are similar, indicating that... 3+ It has properties similar to Cs2NaGaF6:0.20Cr 3+ Similar vibration modes. However, there are differences between the two. First, Cs2NaMF6:0.20Cr 3+ At 150cm -1 ~300cm -1 The A1g mode shifts towards lower wavenumbers, which can be attributed to the elongation of its associated chemical bonds. Therefore, it can be considered that the increase in lattice parameters caused by the increased average cation radius after high-entropy design at the Ga site ultimately leads to the shift in Raman peaks. Furthermore, with Cs2NaGaF6:0.20Cr... 3+ In comparison, Cs2NaMF6:0.20Cr 3+ In the low-frequency region (150cm) -1 ~300cm -1 The Raman peak shows significant broadening, and at ~223cm -1A new low-frequency mode appeared, indicating an increase in structural disorder after high-entropy design and the presence of high-entropy fluoride Cs2NaMF6:0.20Cr. 3+ It exhibits severe lattice distortion, which is beneficial for enhancing luminescence.

[0138] like Figure 5 The single-matrix Cs2NaGaF6:0.20Cr 3+ And high-entropy sample Cs2NaMF6:0.20Cr 3+ Crystal structure diagram of Cs2NaGaF6:0.20Cr. 3+ Similarly, Cs2NaMF6:0.20Cr 3+ The crystal framework consists of [NaF6] octahedrons, [MF6] octahedrons, and [CsF6] octahedrons. 12 It is composed of polyhedra, with [NaF6] octahedra and [MF6] octahedra stacked along the c-axis to form a three-dimensional layered framework. High-entropy design at the Ga sites introduces multiple principal elements, the impact of which on the overall crystal structure is negligible. Furthermore, as... Figure 5 As shown in (c), in a single matrix, adjacent Cr on the same layer 3+ The minimum distance between ions is Maximum distance is And the adjacent layer Cr 3+ The minimum distance between ions is At this point, the [CrF6] octahedrons are fully separated, with a separation distance of [missing information]. In high-entropy samples (such as...) Figure 5 As shown in (e), in the same layer, Cr 3+ -Cr 3+ The shortest distance between them is The longest distance is Adjacent layer Cr 3+ -Cr 3+ The shortest distance between them is Clearly, in high-entropy samples, due to the local structural modifications caused by the high-entropy of Ga sites, Cr content varies between different layers and adjacent layers. 3+ -Cr 3+ The spacing between them is greater, and the distribution between [CrF6] octahedra is more sparse. The structural constraint effect is more pronounced, therefore, it can partially suppress Cr. 3+ The non-radiative relaxation at the launch center enhances the luminescence efficiency of the fluoride near-infrared phosphor. Therefore, a reasonable high-entropy design can effectively improve the luminescence efficiency of the phosphor.

[0139] Example 5

[0140] This embodiment provides a blue light-excited near-infrared fluorescent material with the chemical formula: Cs2Na(Al0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.70 F6:0.30Cr 3+ Cs2Na(Al) 0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.75 F6:0.25Cr 3+ Cs2Na(Al) 0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.80 F6:0.20Cr 3+ Cs2Na(Al) 0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.85 F6:0.15Cr 3+ Cs2Na(Al) 0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.90 F6:0.10Cr 3+ and Cs2Na(Al) 0.25 Ga 0.25 In 0.25 ,Sc 0.25 ) 0.95 F6:0.05Cr 3+ .

[0141] The specific preparation method is the same as in Example 4, except that the amount of Cr(NO3)3·9H2O added is changed according to the stoichiometric ratio. The abbreviations of the high-entropy samples prepared are Cs2NaMF6:0.05Cr 3+ Cs2NaMF6:0.10Cr 3+ Cs2NaMF6:0.15Cr 3+ Cs2NaMF6:0.20Cr 3+ Cs2NaMF6:0.25Cr 3+ and Cs2NaMF6:0.30Cr 3+ .

[0142] The XRD diffraction patterns of the high-entropy samples provided in Example 5 are as follows: Figure 6 As shown. The diffraction peaks of all samples are compared with the theoretical standard card (Calculated Cs2NaMF6 (R3)). _m)) High matching, no impurity phase observed. This result shows that Cr 3+ The entering of Cs2NaMF6 matrix lattice does not change its crystal structure.

[0143] Example 6

[0144] This example provides a blue light excited near-infrared fluorescent material, which has the chemical formula: Rb2K(Al 0.15 ,Ga 0.15 ,In 0.15 ,Y 0.10 ,Gd 0.15 ,Sc 0.15 ,Lu 0.15 ) 0.88 F6:0.12Cr 3+ , and the specific preparation method is as follows:

[0145] According to the stoichiometric ratio, the corresponding raw materials 0.2476 g of Al(NO3)3·9H2O, 0.0619 g of Ga2O3, 0.0916 g of In2O3, 0.0455 g of Sc2O3, 0.0497 g of Y2O3, 0.1197 g of Gd2O3, 0.1313 g of Lu2O3, 0.2401 g of Cr(NO3)3·9H2O, 0.2905 g of KF and 1.1548 g of Rb2CO3 were weighed.

[0146] First, Al(NO3)3·9H2O, Ga2O3, In2O3, Sc2O3, Y2O3, Gd2O3 and Lu2O3 were added in the reaction container; then 8 mL of HF was added and stirred for 15 min; Cr(NO3)3·9H2O was then added, and stirring was continued for 10 min, followed by the addition of KF and Rb2CO3 to the above solution, and stirring was continued at room temperature for 50 min.

[0147] Then the reaction container was placed in an autoclave and transferred to a reaction device, and kept at 220°C for 12 h.

[0148] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 30 mL of acetic acid and anhydrous ethanol for 2 times, and finally placed in a 75°C drying box for drying for 5 h, and finally the high-entropy sample was obtained, which was a blue light excited near-infrared fluorescent material Rb2K(Al 0.15 ,Ga 0.15 ,In 0.15 ,Y 0.10 ,Gd 0.15 ,Sc 0.15 ,Lu 0.15 ) 0.88 F6:0.12Cr 3+ , and is abbreviated as Rb2KMF6:0.12Cr3+ .

[0149] Example 7

[0150] This example provides a blue light excited near-infrared fluorescent material with the chemical formula: Cs2K(Al 0.30 ,Ga 0.30 ,In 0.2 ,Sc 0.2 ) 0.80 F6:0.20Cr 3+ , and the specific preparation method is as shown below:

[0151] According to the stoichiometric ratio, the corresponding raw materials 0.4502 g of Al(NO3)3·9H2O, 0.1125 g of Ga2O3, 0.1110 g of In2O3, 0.0552 g of Sc2O3, 0.20 g of Cr(NO3)3·9H2O, 0.2905 g of KF, and 8.3545 g of CsF were weighed.

[0152] First, Al(NO3)3·9H2O, Ga2O3, In2O3, and Sc2O3 were added to the reaction container, then 5 mL of HF was added, stirred for 8 min, and then Cr(NO3)3·9H2O was added, and stirring was continued for 15 min, then KF and were added to the above solution, and stirring was continued at room temperature for 30 min.

[0153] Then the reaction container was placed in an autoclave and transferred to a reaction device, and incubated at 200°C for 10 h.

[0154] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally placed in a 70°C drying box for drying for 5 h, and finally the high-entropy sample was obtained, which was a blue light excited near-infrared fluorescent material Cs2K(Al 0.30 ,Ga 0.30 ,In 0.2 ,Sc 0.2 ) 0.80 F6:0.20Cr 3+ , which is abbreviated as Cs2KMF6:0.20Cr 3+ .

[0155] The emission spectra of the high-entropy sample Cs2KMF6:0.20Cr 3+ and the single matrix Cs2KGa 0.80 F6:0.20Cr 3+ are shown in Figure 7 Under 460 nm excitation, both samples obtained a wide near-infrared emission band with a peak at ~775 nm in the range of 650 nm-1100 nm. However, due to the high-entropy design, the s2KMF6:0.20Cr3+ Medium Cr 3+ The symmetry of the crystal field environment is reduced, the radiation transition of Cr 3+ is enhanced, and the near-infrared emission of high-entropy-like is increased by 98% compared with single matrix.

[0156] The crystal structure diagram of high-entropy-like is shown in Figure 8 , Cs2KM 0.80 F6:0.20Cr 3+ belongs to the classic cubic double perovskite structure, and the space group is Fm-3m. In this structure, M 3+ and K + are surrounded by 6 F - to form MF 6 and KF 6 octahedron, and Cs + ion is located in the cavity surrounded by 8 GaF6 and KF6 octahedron. At the same time, GaF6 and KF6 octahedron are connected by cross-sharing angle to form a three-dimensional network framework.

[0157] Example 8

[0158] This embodiment provides a blue light excited near-infrared fluorescent material, which has a chemical formula of: LiSr(Al 0.20 ,Ga 0.20 ,In 0.20 ,Gd 0.20 ,Sc 0.20 ) 0.85 F6:0.15Cr 3+ , and the specific preparation method is as follows:

[0159] According to the stoichiometric ratio, 0.0433g of Al2O3, 0.0797g of Ga2O3, 0.1180g of In2O3, 0.0586g of Sc2O3, 0.1541g of Gd2O3, 0.6281g of SrF2, 0.1297g of LiF and 0.0817g of CrF3 were weighed.

[0160] First, Al2O3, Ga2O3, In2O3, Sc2O3 and Gd2O3 were added to the reaction container, then 6mL of HF was added, stirred for 20min, and then CrF3 was added, and the stirring was continued for 5min, then SrF2 and LiF were added to the above solution in turn, and the stirring was continued at room temperature for 20min.

[0161] Then the reaction container was placed in an autoclave and transferred to a reaction device, and incubated at 200℃ for 8h.

[0162] After the reaction is completed and cooled to room temperature, the green product is collected, washed with 30 mL of acetic acid and anhydrous ethanol for 2 times, and finally dried in a 70°C drying oven for 4 h, and finally the high-entropy sample LiSr(Al 0.20 ,Ga 0.20 ,In 0.20 ,Gd 0.20 ,Sc 0.20 ) 0.85 F6:0.15Cr 3+ , abbreviated as LiSrMF6:0.15Cr 3+ .

[0163] Example 9

[0164] This example provides a blue light excited near-infrared fluorescent material, which has a chemical formula: Li3Na3(Al 0.30 ,Ga 0.30 ,In 0.20 ,Sc 0.20 ) 1.91 F6:0.09Cr 3+ , and the specific preparation method is as follows:

[0165] According to the stoichiometric ratio, the corresponding raw materials 0.2406 g of AlF3, 0.2685 g of Ga2O3, 0.2651 g of In2O3, 0.1317 g of Sc2O3, 0.18 g of Cr(NO3)3·9H2O, 1.9454 g of LiF and 0.795 g of Na2CO3 are weighed.

[0166] First, the AlF3, Ga2O3, In2O3 and Sc2O3 raw materials are sequentially added to the reaction container, then 5 mL of HF is added, and mechanical stirring is performed for 15 min, then Cr(NO3)3·9H2O is added, and stirring is continued for 5 min, then LiF and Na2CO3 are added to the above solution, and stirring is continued at room temperature for 35 min.

[0167] Then the reaction container is placed in a high-pressure kettle and transferred to a reaction device, and incubated at 220°C for 14 h.

[0168] After the reaction is completed and cooled to room temperature, the green product is collected, washed with 30 mL of acetic acid and anhydrous ethanol for 2 times, and finally dried in a 70°C drying oven for 4 h, and finally the high-entropy sample LiSr(Al 0.30 ,Ga 0.30 ,In 0.20 ,Sc 0.20 ) 1.91 F6:0.09Cr 3+ , abbreviated as Li3Na3 MF6:0.09Cr 3+

[0169] Example 10

[0170] This example provides a near-infrared pc-LED device, which is prepared by packaging high-entropy fluoride near-infrared fluorescent powder with a commercial InGaN blue LED chip. By testing its photoelectric parameters, its application potential in the near-infrared field is verified.

[0171] Cs2Na(Al 0.25 ,Ga 0.25 ,In 0.25 ,Sc 0.25 ) 0.80 F6:0.20Cr 3+ The high-entropy fluoride near-infrared fluorescent powder and the epoxy resin are mixed uniformly according to a certain mass ratio (near-infrared fluorescent powder: epoxy resin = 1:1). Then, the bubbles in the mixture are removed by a bubble removing machine to ensure the uniformity and stability of the mixture. Subsequently, using professional gluing equipment, it is uniformly coated on the surface of the blue LED chip (3W, ~ 445nm). After coating, the chip is placed in a curing device and cured according to the set temperature and time. Then, it is naturally cooled to room temperature, and a near-infrared pc-LED device is obtained (as shown in Figure 1 ).

[0172] As shown in Figure 1 , the near-infrared pc-LED device packaged by Example 10 and its electroluminescence spectrum are shown. With the gradual increase of the driving current, its near-infrared emission intensity monotonously increases, and no light saturation phenomenon is observed, indicating that it has broad application prospects in the near-infrared field.

[0173] Comparative Example 1

[0174] The near-infrared fluorescent material provided by this comparative example has the chemical formula: K3Al 0.92 F6:0.08Cr 3+ , and the specific preparation method is as follows:

[0175] According to the stoichiometric ratio, 1.7256g of Al(NO3)3·9H2O, 0.0436g of CrF3 and 2.905g of KF are weighed.

[0176] First, Al(NO3)3·9H2O is added to the reaction container; then 4mL of HF is added and stirred for 4min; then CrF3 is added and stirred for another 5min; then KF is added to the above solution and stirred at room temperature for 15min.

[0177] Then, the reaction container is placed in a high-pressure kettle and transferred to a reaction device, and incubated at 160℃ for 12h.

[0178] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 2 times, and finally dried in a 65 °C drying oven for 6 h to obtain the single matrix control sample K3Al 0.92 F6: 0.08Cr 3+ , which is abbreviated as K3AlF6: 0.08Cr 3+ .

[0179] Comparative Example 2

[0180] The near-infrared fluorescent material provided in the present comparative example has a chemical formula of Na3Sc 0.75 F6: 0.25Cr 3+ , and the specific preparation method is as follows:

[0181] According to the stoichiometric ratio, 0.2586 g of Sc2O3, 0.0950 g of Cr2O3 and 3.1493 g of NaF were weighed.

[0182] First, Sc2O3 was added to the reaction container; then 6 mL of HF was added and stirred for 5 min; then Cr2O3 was added and stirred for 15 min; then NaF was added to the above solution and stirred at room temperature for 25 min.

[0183] Then the reaction container was placed in an autoclave and transferred to a reaction device, and incubated at 200 °C for 10 h.

[0184] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 2 times, and finally dried in a 65 °C drying oven for 6 h to obtain the single matrix control sample K3Al 0.75 F6: 0.25Cr 3+ , which is abbreviated as Na3ScF6: 0.25Cr 3+

[0185] Comparative Example 3

[0186] The near-infrared fluorescent material provided in the present comparative example has a chemical formula of K2LiGa 0.90 F6: 0.10Cr 3+ , and the specific preparation method is as follows:

[0187] According to the stoichiometric ratio, 0.4217 g of Ga2O3, 0.038 g of Cr2O3, 4.686 g of KHF2 and 0.1297 g of LiF were weighed.

[0188] Ga2O3 was first added into the reaction container; then 5 mL of HF was added and stirred for 5 min; Cr2O3 was then added and stirred for another 10 min; KHF2 and LiF were then added into the above solution and stirred for another 20 min at room temperature.

[0189] The reaction container was then placed into an autoclave and transferred into a reaction device, and kept at 180 °C for 10 h.

[0190] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a drying oven at 65 °C for 8 h, to obtain the single matrix control sample K2LiGaF6. 0.90 F6: 0.10Cr 3+ , which is abbreviated as K2LiGaF6: 0.10Cr 3+ .

[0191] Comparative Example 4

[0192] The near-infrared fluorescent material provided by the present comparative example has a molecular formula of Cs2NaGa 0.80 F6: 0.20Cr 3+ , and the specific preparation method is as follows:

[0193] According to the stoichiometric ratio, 0.1874 g of Ga2O3, 0.20 g of Cr(NO3)3·9H2O, 0.1050 g of NaF and 7.595 g of CsF were weighed.

[0194] Ga2O3 was first added into the reaction container; then 5 mL of HF was added and stirred for 5 min; Cr(NO3)3·9H2O was then added and stirred for another 5 min; NaF and CsF were then added into the above solution and stirred for another 40 min at room temperature.

[0195] The reaction container was then placed into an autoclave and transferred into a reaction device, and kept at 200 °C for 18 h.

[0196] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 30 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a drying oven at 70 °C for 6 h, to obtain the single matrix control sample Cs2NaGaF6. 0.80 F6: 0.20Cr 3+ , which is abbreviated as Cs2NaGaF6: 0.20Cr 3+ .

[0197] Comparative Example 5

[0198] The near-infrared fluorescent material provided by the present comparative example has a molecular formula of LiSrAl 0.85 F6: 0.15Cr3+ The specific preparation method is shown as follows:

[0199] According to the stoichiometric ratio, 0.2167 g of Al2O3, 0.30 g of Cr(NO3)3·9H2O, 0.6281 g of SrF2 and 1.9454 g of LiF were weighed.

[0200] First, Al2O3 was added into the reaction container; then 6 mL of HF was added and stirred for 10 min; then Cr(NO3)3·9H2O was added and stirred for 5 min; then SrF2 and LiF were sequentially added into the above solution and stirred for 20 min at room temperature.

[0201] Then the reaction container was placed into an autoclave and transferred into a reaction device, and incubated at 200°C for 10 h.

[0202] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 20 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a 70°C drying box for 4 h, to obtain a single matrix control sample LiSrAlF6:0.15Cr. 0.85 F6:0.15Cr 3+ , which is abbreviated as LiSrAlF6:0.15Cr. 3+ .

[0203] Comparative Example 6

[0204] The near-infrared fluorescent powder provided by the present comparative example has a chemical formula of Li3Na3Al 1.91 F6:0.09Cr 3+ The specific preparation method is shown as follows:

[0205] According to the stoichiometric ratio, 1.7068 g of Al(NO3)3·9H2O, 0.049 g of CrF3, 0.6299 g of NaF and 1.9454 g of LiF were weighed.

[0206] First, Al(NO3)3·9H2O was added into the reaction container; then 4 mL of HF was added and stirred for 5 min; then CrF3 was added and stirred for 5 min; then NaF and LiF were sequentially added into the above solution and stirred for 20 min at room temperature.

[0207] Then the reaction container was placed into an autoclave and transferred into a reaction device, and incubated at 220°C for 14 h.

[0208] After the reaction was completed and cooled to room temperature, the green product was collected, washed with 25 mL of acetic acid and anhydrous ethanol for 3 times, and finally dried in a 75°C drying box for 4 h, to obtain a single matrix control sample: Li3Na3Al 1.91 F6:0.09Cr3+ , abbreviated as Li3Na3AlF6:0.09Cr 3+ .

[0209] The above only is the preferred embodiment of the present application, and does not use to limit the present application, any modification, equivalent replacement and improvement etc. made within the spirit and principle of the present application, should be included in the protection scope of the present application.

Claims

1. A blue light-excited near-infrared fluorescent material, characterized in that, Including those with the general chemical formula A2BM 1-x F6:xCr 3+ ACM 1-x F6:xCr 3+ A compound having at least one of the following chemical formulas: A2BM 1-x F6:xCr 3+ The compound satisfies the following conditions: The A and B sites are both K, and the M site is a combination of four elements: Al, Ga, In, and Sc; or, the A and B sites are both Na, and the M site is a combination of five elements: Zn, Al, Ga, Sc, and Ti; or, the A site is K, the B site is Li, and the M site is a combination of five elements: Al, Ga, In, Sc, and Lu; or, the A site is Cs, the B site is Na, and the M site is a combination of four elements: Al, Ga, In, and Sc; or, the A site is Rb, the B site is K, and the M site is a combination of seven elements: Al, Ga, In, Y, Gd, Sc, and Lu; or, the A site is Cs, the B site is Na, and the M site is a combination of four elements: Al, Ga, In, and Sc; the general chemical formula is ACM. 1-x F6:xCr 3+ Compounds that satisfy the following conditions: Li at the A site, Sr at the B site, and a combination of five elements: Al, Ga, In, Gd, and Sc at the M site; The molar percentage of each element contained in the M position is in the range of 5% to 35%; the difference in molar percentage of each element contained in the M position is within 10%. 0.01≤x≤0.35。 2. The blue light-excited near-infrared fluorescent material as described in claim 1, characterized in that, The excitation wavelength of the blue light-excited near-infrared fluorescent material is 420 nm to 470 nm; and / or, the emission wavelength is 700 nm to 1000 nm.

3. A method for preparing a blue light-excited near-infrared fluorescent material, characterized in that, Includes the following steps: The raw material components are obtained according to the stoichiometric ratio of the chemical formula in the blue light-excited near-infrared fluorescent material according to any one of claims 1 to 2; the raw material components include Cr element raw material components, M-site raw material components and A-site raw material components, and also include B-site raw material components and / or C-site raw material components. The raw material components are subjected to hydrothermal treatment to prepare a blue light-excited near-infrared fluorescent material; the solvent used in the hydrothermal treatment includes an acidic aqueous solution containing fluorine.

4. The method for preparing blue light-excited near-infrared fluorescent materials as described in claim 3, characterized in that, The raw material components satisfy at least one of the following (1) to (5): (1) The Cr element raw material components include at least one of chromium chloride, chromium nitrate, chromium hydroxide, chromium fluoride and chromium oxide; (2) The raw material components at the M site include at least one of oxides, fluorides and metal salts; (3) The raw material component at site A includes at least one of fluoride and carbonate; (4) The raw material component at site B includes at least one of fluoride and carbonate; (5) The C-position raw material component includes at least one of fluoride and carbonate.

5. The method for preparing blue light-excited near-infrared fluorescent materials as described in claim 3, characterized in that, The control parameters in the hydrothermal treatment step include: The hydrothermal treatment temperature is 160 ℃~240 ℃, and / or the hydrothermal treatment time is 6 h~24 h.

6. The method for preparing the blue light-excited near-infrared fluorescent material according to any one of claims 3 to 5, characterized in that, The step of hydrothermal treatment of the raw material components includes: First, the M-site raw material component and the solvent used in the hydrothermal treatment are mixed; then the Cr element raw material component is added and mixed; then the A-site raw material component, and at least one of the B-site raw material component and the C-site raw material component are added and mixed to obtain a mixture. The mixture is subjected to hydrothermal treatment.

7. A light-emitting device, characterized in that, It includes a light source and a luminescent material excited by the light source, wherein the luminescent material includes a blue light-excited near-infrared fluorescent material as described in any one of claims 1 to 2, or a blue light-excited near-infrared fluorescent material obtained by the preparation method described in any one of claims 3 to 6.

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