Trivalent chromium activated borate broadband near-infrared fluorescent powder and preparation method thereof

Abstract

The invention discloses trivalent chromium activated borate broadband near-infrared fluorescent powder, the chemical general formula of the fluorescent powder is AmY < 1-n > MnGa < 3-x-y > CrxLyB4O15, and the fluorescent powder belongs to a hexagonal crystal system; the space group is P63 / m; wherein A is one or a combination of more of Mg, Ca, Sr and Ba; m is one or a combination of more of Lu, Gd and La; l is one or a combination of Al and In. The value ranges of m, n, x and y are as follows: m = 3, and n is more than or equal to 0 and less than or equal to 1, 0lt; 0 < = y < = 3. The fluorescent powder can be effectively excited by visible light with the wavelength of 200-700 nm, near-infrared broadband emission with the wavelength of 700-850 nm is generated, and the full width at half maximum is 93 nm. The borate broadband near-infrared fluorescent powder disclosed by the invention has the advantages of simple preparation process, no pollution, low sintering temperature, high luminous efficiency, excellent luminous thermal stability and the like, and is beneficial to industrial popularization.

Description

Technical Field

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

[0002] Near-infrared (hereinafter referred to as NIR) has the characteristics of strong penetration, low damage, and low toxicity. It is widely used in food quality testing, medical diagnosis, petroleum energy product analysis, automotive driverless technology, solar cells and other fields. Traditional near-infrared light sources mainly refer to tungsten lamps or halogen tungsten lamps, which have high cost, short life, large size, low luminous efficiency, slow response speed, poor wavelength resolution, and are easily affected by environmental changes. Traditional near-infrared light sources cannot be widely used in portable, intelligent and other fields.

[0003] In recent years, phosphor-converted LED technology, namely pc-LED, has been widely used in lighting and other fields due to its compact structure, fast response speed, low production cost and high efficiency. If broadband near-infrared phosphors are covered on LED chips, that is, the LED light source excites broadband near-infrared phosphors (NIR pc-LEDs) technology solution is adopted, a compact and portable near-infrared light source can be obtained. Therefore, the development of broadband near-infrared phosphors with excellent performance is the key to the commercialization of NIR pc-LEDs devices. Usually rare earth ions, such as Sm 3+ 、Eu 3+ , Yb 3+ and Pr 3+ The activated near-infrared luminescent phosphors have low quantum efficiency and narrow luminescent spectrum range.

[0004] Transition metal chromium ion (Cr 3+ ) has a unique 3d 3 Outermost electron configuration, its characteristic absorption transition 4 A2→ 4 T1( 4 F) can be well matched with commercial blue LED chips, and its luminescence characteristics can also achieve tunable broadband near-infrared emission as the crystal field environment changes. 3+ Activated near-infrared fluorescent materials have obvious advantages in the controllability of luminous efficiency, luminescent wavelength and luminescent band broadening, and have become an important direction for the development of near-infrared luminescent materials.

[0005] At present, some Cr 3+ Activated broadband near-infrared phosphors, for example, Chinese patent CN116769476A discloses a near-infrared phosphor Ba for plant lighting 0.75 Al 2.8 Ga8O 17.25:0.2Cr 3+ , can be effectively excited by blue LED, but this phosphor has a high preparation temperature (≥1500℃). 3+ Doped rare earth-based double perovskite-based phosphor Cs2NaYb 0.91 Cr 0.09 Cl6 has absorption in the ultraviolet, yellow-green and deep red regions, but its emission bandwidth is relatively narrow. Summary of the invention

[0006] To address the above situation, the present invention provides a Cr 3+ The activated broadband near-infrared red phosphor has the advantages of simple preparation process, no pollution, low sintering temperature, high luminous efficiency, excellent thermal stability of luminescence, and is conducive to industrial production. The specific plan is as follows:

[0007] A trivalent chromium activated borate broadband near-infrared phosphor, the general chemical formula of the phosphor is: A m Y 1- n M n Ga 3-x-y Cr x L y B4O 15 , belongs to the hexagonal system; the space group is: P63 / m; A is one or more combinations of Mg, Ca, Sr and Ba; M is one or more combinations of Lu, Gd and La; L is one or two combinations of Al and In. Among them, the value range of m, n, x, and y is: m = 3, 0 ≤ n ≤ 1, 0 <x≤0.3,0≤y≤3。

[0008] Furthermore, the excitation wavelength range of the near-infrared phosphor is 200-700 nm; the wavelength range of the emission spectrum of the near-infrared phosphor is 700-850 nm.

[0009] A method for preparing a trivalent chromium-activated borate broadband near-infrared phosphor comprises the following steps:

[0010] (1) According to A m Y 1-n M n Ga 3-x-y Cr x L y B4O 15 Weigh the raw materials according to the stoichiometric ratio of each element, grind them evenly in an agate mortar to form a mixture;

[0011] (2) sintering the ground product at 800-1150° C. for 2-20 h in a reducing atmosphere;

[0012] (3) After the calcined product is cooled to room temperature, it is ground evenly to obtain a chromium-activated near-infrared phosphor material with borate as the matrix.

[0013] Furthermore, the value of x in step (1) is in the range of 0.01 to 0.15 mol.

[0014] Furthermore, the reducing gas in step (2) is H2 or CO.

[0015] Furthermore, the Ca-containing 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0016] The Ba 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0017] The Sr 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0018] The Mg 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0019] The Gd-containing 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0020] The Y 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0021] The Lu 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0022] The La 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions;

[0023] The Ga 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions.

[0024] The Cr 3+The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions.

[0025] Furthermore, the above preparation method contains B 5+ The compound is H3BO3.

[0026] The beneficial results of the present invention are: the trivalent chromium activated borate broadband near-infrared phosphor provided by the present invention has a relatively low preparation temperature of only 1000°C; a relatively wide spectral band with a half-width close to 100nm; and is fully compatible with blue light LEDs (~450nm). The preparation method is simple and pollution-free. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the XRD spectrum of the phosphor of Example 10 of the present invention.

[0028] Figure 2 This is the excitation spectrum of the phosphor in Example 10 of the present invention.

[0029] Figure 3 This is the emission spectrum of Example 10 of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0032] Example 1Ba3YGa 2.99 Cr 0.01 B4O 15

[0033] According to the stoichiometric ratio, weigh BaCO3: 0.5920 g, Y2O3: 0.1129 g, Ga2O3: 0.2802 g, Cr2O3: 0.0008 g, and H3BO3: 0.2473 g. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1100°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 10 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ba3YGa 2.99 Cr 0.01 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0034] Example 2 Sr3YGa 2.98 Cr 0.02 B4O 15

[0035] Weigh SrCO3: 0.4429 g, Y2O3: 0.1129 g, Ga2O3: 0.2793 g, Cr2O3: 0.0015 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1000°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 14 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Sr3YGa 2.98 Cr 0.02 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0036] Example 3Ca3YGa 2.94 Cr 0.06 B4O 15

[0037] Weigh CaCO3: 0.3003 g, Y2O3: 0.1129 g, Ga2O3: 0.2755 g, Cr2O3: 0.0046 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1050°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 12 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3YGa 2.94 Cr 0.06 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0038] Example 4Mg3YGa 2.96 Cr 0.04 B4O 15

[0039] Weigh MgO: 0.1209 g, Y2O3: 0.1129 g, Ga2O3: 0.2774 g, Cr2O3: 0.0030 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 900°C in a carbon monoxide CO reducing atmosphere, sinter it for 18 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Mg3YGa 2.96 Cr 0.04 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0040] Example 5Ba 0.5 Sr 2.5 YG 2.99 Cr 0.01 B4O 15

[0041] According to the stoichiometric ratio, weigh BaCO3: 0.0987 g, SrCO3: 0.3691 g, Y2O3: 0.1129 g, Ga2O3: 0.2802 g, Cr2O3: 0.0015 g, H3BO3: 0.2473 g. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 950°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 16 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Mg3YGa 2.96 Cr 0.04 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0042] Example 6Ca3LuGa 2.94 Cr 0.06 B4O 15

[0043] Weigh CaCO3: 0.3003 g, Lu2O3: 0.1990 g, Ga2O3: 0.2755 g, Cr2O3: 0.0046 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1100°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 10 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3LuGa 2.94 Cr 0.06 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0044] Example 7Ca3LuAl2.94 Cr 0.06 B4O 15

[0045] Weigh CaCO3: 0.3003 g, Lu2O3: 0.1990 g, Al2O3: 0.1499 g, Cr2O3: 0.0046 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 900°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 18 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3LuAl 2.94 Cr 0.06 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0046] Example 8 Ca3YGa 2.7 Cr 0.3 B4O 15

[0047] Weigh CaCO3: 0.3003 g, Y2O3: 0.1129 g, Ga2O3: 0.2530 g, Cr2O3: 0.0228 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 950°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 16 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3YGa 2.7 Cr 0.3 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0048] Example 9Ba 0.5 Ca 2.5 YG 2.68 Al 0.3 Cr 0.02 B4O 15

[0049] According to the stoichiometric ratio, weigh BaCO3: 0.0987 g, CaCO3: 0.2502 g, Y2O3: 0.1129 g, Ga2O3: 0.2512 g, Al2O3: 0.0153 g, Cr2O3: 0.0015 g, H3BO3: 0.2473 g. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 800°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 20 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ba. 0.5 Ca 2.5 YG2.68 Al 0.3 Cr 0.02 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0050] Example 10Ca3YGa 2.97 Cr 0.03 B4O 15

[0051] Weigh CaCO3: 0.3003 g, Y2O3: 0.1129 g, Ga2O3: 0.2783 g, Cr2O3: 0.0023 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1100°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 6 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3YGa 2.97 Cr 0.03 B4O 15 Attached Figure 1 Is the XRD pattern of this embodiment; Attached Figure 2 is the excitation spectrum of this embodiment; Figure 3 is the emission spectrum of this example.

[0052] Example 11Ca3YGa 2.82 Cr 0.08 In 0.1 B4O 15

[0053] Weigh CaCO3: 0.3003 g, Y2O3: 0.1129 g, Ga2O3: 0.2643 g, Cr2O3: 0.0061 g, In2O3: 0.0139 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1000°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 14 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca3YGa 2.82 Cr 0.08 In 0.1 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0054] Example 12 Sr3LuGa 2.72 Cr 0.08 Al 0.1 In 0.1 B4O 15

[0055] Weigh SrCO3: 0.4429 g, Lu2O3: 0.1990 g, Ga2O3: 0.2549 g, Cr2O3: 0.0061 g, Al2O3: 0.0051 g, In2O3: 0.0139 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix evenly in an agate mortar, put into a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 900°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 16 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Sr3LuGa 2.72 Cr 0.08 Al 0.1 In 0.1 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10.

[0056] Example 13Ca 2.5 Y 0.5 G 0.5 Ga 2.85 Cr 0.15 B4O 15

[0057] Weigh CaCO3: 0.2502 g, Y2O3: 0.0565 g, Gd2O3: 0.0906 g, Ga2O3: 0.2671 g, Cr2O3: 0.0114 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 1150°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 8 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Ca 2.5 Y 0.5 G 0.5 Ga 2.98 Cr 0.02 B4O 15 Its crystal structure, excitation and emission spectra are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0058] Example 14Sr 2.5 G 0.5 La 0.5 Ga 2.98 Cr 0.02 B4O 15

[0059] Weigh SrCO3: 0.3691 g, Gd2O3: 0.0906 g, La2O3: 0.0815 g, Ga2O3: 0.2793 g, Cr2O3: 0.0015 g, H3BO3: 0.2473 g according to the stoichiometric ratio. Grind and mix them evenly in an agate mortar, put them in a corundum crucible, cover it, place it in a high-temperature furnace, heat it to 950°C in a carbon monoxide (CO) reducing atmosphere, sinter it for 18 hours, cool it naturally, and grind it for 5 minutes to obtain the phosphor Sr 2.5 G 0.5 La 0.5 Ga 2.98 Cr 0.02 B4O 15 Its crystal structure and excitation spectrum are similar to those of Example 10, but the luminescence intensity is slightly weaker.

[0060] Obviously, the above embodiments are only examples for clear explanation, and are not limitations on the implementation methods. Other different forms of changes or modifications can be made based on the above description. The inventor cannot list all the implementation methods. However, the obvious changes or modifications derived from them are still within the protection scope of the invention.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. A trivalent chromium activated borate broadband near-infrared phosphor, characterized in that: The general chemical formula of the phosphor is: m Y 1-n M n Ga 3-x-y Cr x L y B4O 15 , belongs to the hexagonal crystal system; the space group is: P63 / m; A is one or more combinations of Mg, Ca, Sr and Ba; M is one or more combinations of Lu, Gd and La; L is one or two combinations of Al and In.

2. The trivalent chromium activated borate broadband near-infrared phosphor according to claim 1, characterized in that: The value range of m, n, x and y is: m = 3, 0 ≤ n ≤ 1.0, 0 <x≤0.3,0≤y≤3。 3. A method for preparing a trivalent chromium activated borate broadband near-infrared phosphor, characterized in that: The following steps are involved: (1) According to A m Y 1-n M n Ga 3-x-y Cr x L y B4O 15 , weigh the raw materials according to the stoichiometric ratio of each element, grind them evenly in an agate mortar to form a mixture; (2) sintering the ground product at 800-1150° C. for 2-20 h in a reducing atmosphere; (3) After the calcined product is cooled to room temperature, it is ground evenly to obtain a trivalent chromium-activated borate broadband near-infrared luminescent material.

4. The method for preparing a trivalent chromium activated borate broadband near-infrared phosphor according to claim 2, characterized in that: The value range of x in step (1) can be further optimized to 0.01 to 0.15 mol.

5. The method for preparing a trivalent chromium activated borate broadband near-infrared phosphor according to claim 3, characterized in that The reducing gas is H2 or CO.

6. The method for preparing a trivalent chromium activated borate broadband near-infrared phosphor according to claim 3, characterized in that : The Ca 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Ba 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Sr 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Mg 2+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Gd-containing 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Y 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Lu 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The La 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Ga 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions; The Cr 3+ The compound is one or more of oxides, carbonates, nitrates and halides containing corresponding ions.

7. The method for preparing a trivalent chromium activated borate broadband near-infrared phosphor according to claim 3, characterized in that: The B 5+ The compound is H3BO3.

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