Ultra-wide-spectrum garnet-based near-infrared fluorescent powder and preparation method thereof

Abstract

The invention discloses ultra-wide-spectrum garnet-based near-infrared fluorescent powder and a preparation method thereof. The chemical composition expression formula of the ultra-wide-spectrum garnet-based near-infrared light fluorescent powder is Y3Mg < 1-x > CrxGa < 2 + x > AlGe < 1-x > O12, and x is more than or equal to 0.01 and less than or equal to 0.05. The near-infrared light Y < 3 > Mg < 1-x > Cr < x > Ga < 2 + x > Al < Ge < 1-x > O < 12 > fluorescent powder provided by the invention can be excited by ultraviolet light with the wavelength of 260-300 nm, blue light with the wavelength of 400-500 nm and red light with the wavelength of 575-675 nm, and can emit ultra-wide-band near-infrared light with the main peak at 765 nm and the half-peak width not less than 150 nm.

Description

Technical fields:

[0001] This invention relates to the field of luminescent materials technology, and in particular to an ultra-wideband garnet-based near-infrared phosphor and its preparation method. Background technology:

[0002] Light source technology has continuously upgraded with scientific development, from primitive firelight to incandescent lamps, halogen lamps, and mercury lamps in the industrial era, and now to LEDs, always pursuing portability, economy, energy saving, and environmental protection. Improved living standards have further fueled people's desire for high-quality lighting. While mainstream white LED technology, based on blue GaN chips exciting single-color yellow YAG phosphors, boasts high efficiency, brightness, and lumens, it is insufficient to meet higher requirements such as full-spectrum lighting (pursuing broad spectrum and ultra-high color rendering) and simulated sunlight lighting (requiring a spectrum closely approximating sunlight, including visible light and sufficient near-infrared light). The key to achieving simulated sunlight lies in finding new luminescent materials that can be excited by blue light to effectively supplement the deep red to near-infrared region (660-880nm).

[0003] Cr 3+ It is one of the popular near-infrared light-activated ions, often achieving efficient luminescence in the deep red or near-infrared regions within a six-coordinate lattice environment. Garnet structures naturally contain elements suitable for Cr... 3+ The six-coordinate lattice environment, therefore, Cr 3+ Activated garnet-based luminescent materials have become a key focus in the research and development of novel near-infrared phosphors. However, existing garnet-based Cr... 3+ Phosphors (such as Y3Sc2Ga3O) 12 :Cr 3+ ,Ca2LuZr2Al3O 12 :Cr 3+ Phosphors often suffer from problems such as an unfavorable position of the main spectral peak and an excessively narrow half-width at half-maximum (HWHM) of the main emission peak, making it unable to fully and adequately cover the entire spectrum and the 660-880 nm region essential for simulating sunlight illumination. Therefore, the development of novel ultrawideband garnet-based near-infrared phosphors has become an urgent need for the iterative upgrading of light source technology. Summary of the Invention:

[0004] This invention solves the problems existing in the prior art and provides an ultra-wideband garnet-based near-infrared phosphor and its preparation method. The near-infrared phosphor material can be excited by 260-300nm ultraviolet light, 400-500nm blue light and 575-675nm red light, emitting ultra-wideband near-infrared light with a main peak at 765nm and a half-maximum width of not less than 150nm.

[0005] The first objective of this invention is to provide an ultra-broadband garnet-based near-infrared phosphor, the chemical composition of which is expressed as: Y3Mg1-x Cr x Ga 2+x AlGe 1-x O 12 Where: 0.01≤x≤0.05.

[0006] The ultra-broadband near-infrared Y3Mg light proposed in this invention 1-x Cr x Ga 2+x AlGe 1-x O 12 Using Cr 3+ The unique non-equivalent six-coordinate lattice site environment in yttrium magnesium gallium aluminum germanium garnet makes Cr 3+ When Cr occupies a six-coordinate lattice site in yttrium magnesium gallium aluminum germanium garnet, 3+ The significant increase in environmental disorder is equivalent to an increase in Cr. 3+ The type of microenvironment at the six-coordinate lattice site. Cr 3+ ion 4 T2- 4 The fluorescence emission peak associated with the A2 transition exhibits an ultra-wide spectral coverage due to the increased crystal field microenvironment.

[0007] The second objective of this invention is to provide a method for preparing the aforementioned ultra-wideband garnet-based near-infrared phosphor, comprising the following steps: weighing raw materials containing yttrium, magnesium, gallium, aluminum, germanium, and chromium according to their chemical composition, wherein the molar ratio of the metal elements is Y:Mg:Ga:Al:Ge:Cr=3:1-x:2+x:1:1-x:x, where 0.01≤x≤0.05; adding an additional amount of Ga2O3 to compensate for Ga loss during the high-temperature reaction, depending on the experimental temperature; thoroughly grinding to ensure uniform mixing; and then performing a first-step sintering in atmospheric air at normal pressure at a sintering temperature of 1325±50℃ for 8-12 hours; after sintering, naturally cooling to room temperature and re-grinding for a second-step sintering at a sintering temperature of 1500±25℃ for 4-8 hours; and finally, naturally cooling to room temperature and grinding the product to obtain the aforementioned near-infrared phosphor Y3Mg. 1-x Cr x Ga 2+ x AlGe 1-x O 12 Fluorescent powder.

[0008] Preferably, the yttrium-containing raw material is selected from one or more of yttrium oxide, yttrium oxalate, yttrium carbonate, and yttrium nitrate.

[0009] Preferably, the magnesium-containing raw material is selected from magnesium hydroxide.

[0010] Preferably, the gallium-containing raw material is selected from gallium oxide.

[0011] Preferably, the aluminum-containing raw material is selected from aluminum hydroxide.

[0012] Preferably, the germanium-containing raw material is selected from germanium oxide.

[0013] Preferably, the chromium-containing raw material is selected from one or more of chromium oxide and chromium nitrate.

[0014] Preferably, to compensate for the loss of Ga during the high-temperature reaction, an additional 10% of Ga2O3 needs to be added on top of the stoichiometric ratio.

[0015] This invention also protects the application of the aforementioned ultra-wideband garnet-based near-infrared phosphor in light-emitting devices. The near-infrared phosphor proposed in this invention has a large effective excitation range and a wide emission coverage, and can be applied in optical light source devices and equipment such as health lighting, plant lighting, temperature detection, and infrared recognition.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The near-infrared Y3Mg proposed in this invention 1-x Cr x Ga 2+x AlGe 1-x O 12 Phosphors can be sintered in two steps at room temperature and pressure to form a phase with good crystallinity, high luminous brightness, and short fluorescence lifetime. They can be used as near-infrared light conversion materials excited by blue LED chips.

[0018] (2) The near-infrared Y3Mg proposed in this invention 1-x Cr x Ga 2+x AlGe 1-x O 12 Phosphors have advantages such as a wide excitation range, broad emission peak spectrum, readily available raw materials, simple manufacturing process, short synthesis time, and ease of industrialization.

[0019] (3) The near-infrared Y3Mg proposed in this invention 1-x Cr x Ga 2+x AlGe 1-x O 12Phosphors can be excited by 260-300nm ultraviolet light, 400-500nm blue light, and 575-675nm red light, emitting ultra-broad-band near-infrared light with a main peak at 765nm and a full width at half maximum (FWHM) of no less than 150nm. Because its near-infrared light ranges from 660nm to over 880nm, this broad-band emission region is suitable for applications in optical light source devices and equipment such as full-spectrum simulation of sunlight, plant lighting, temperature detection, and infrared recognition. Attached image description:

[0020] Figure 1 The ultra-broadband near-infrared Y3Mg light obtained in Example 1 1-x Cr x Ga 2+x AlGe 1-x O 12 X-ray powder diffraction pattern of phosphor;

[0021] Figure 2 The ultra-broadband near-infrared Y3Mg light obtained in Example 1 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescence emission spectrum of phosphor excited at 445 nm wavelength;

[0022] Figure 3 The ultra-broadband near-infrared Y3Mg light obtained in Example 1 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescence excitation spectrum of phosphor at 765 nm emission;

[0023] Figure 4 The ultra-broadband near-infrared Y3Mg light obtained in Example 1 1-x Cr x Ga 2+x AlGe 1-x O 12 Chromaticity coordinate diagram of phosphor;

[0024] Figure 5 The ultra-broadband near-infrared Y3Mg light obtained in Example 1 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescence decay curve of phosphor. Detailed implementation method:

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof.

[0026] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental materials and reagents used herein are commercially available products conventionally available in this technical field.

[0027] Example 1

[0028] 0.3387 g of yttrium oxide (Y₂O₃), 0.0571 g of magnesium hydroxide (Mg(OH)₂), 0.2082 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), 0.1025 g of germanium oxide (GeO₂), and 0.0015 g of chromium oxide (Cr₂O₃) were weighed separately and ground in an agate mortar. After uniform grinding, a solid-state reaction was carried out. The temperature was increased from room temperature to 1325°C at a rate of 5°C / min under normal atmospheric pressure and held at this temperature for 10 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the mixture was re-ground for the second sintering step at 1500°C for 6 hours. After the sintering, the product was allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y₃Mg₂. 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescent powder.

[0029] X-ray powder diffraction pattern, fluorescence emission spectrum, fluorescence excitation spectrum, chromaticity diagram, and fluorescence decay curve of near-infrared phosphor are shown below. Figure 1-5 As shown, near-infrared phosphors can be excited by 260-300nm ultraviolet light, 400-500nm blue light and 575-675nm red light, emitting ultra-wideband near-infrared light with a main peak at 765nm and a half-maximum width of not less than 150nm.

[0030] Example 2

[0031] 0.3387 g of yttrium oxide (Y₂O₃), 0.0577 g of magnesium hydroxide (Mg(OH)₂), 0.2072 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), 0.1036 g of germanium oxide (GeO₂), and 0.0008 g of chromium oxide (Cr₂O₃) were weighed separately and ground in an agate mortar. After uniform grinding, a solid-state reaction was carried out. The temperature was increased from room temperature to 1325 °C at a rate of 5 °C / min under normal atmospheric pressure and air atmosphere, and then held at this temperature for 10 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the mixture was re-ground for the second sintering step at 1500 °C for 6 hours. After the sintering, the mixture was allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y₃Mg₂. 1-x Crx Ga 2+x AlGe 1-x O 12 Fluorescent powder.

[0032] Example 3

[0033] 0.3387 g of yttrium oxide (Y₂O₃), 0.0554 g of magnesium hydroxide (Mg(OH)₂), 0.2113 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), 0.0994 g of germanium oxide (GeO₂), and 0.0038 g of chromium oxide (Cr₂O₃) were weighed separately and ground in an agate mortar. After uniform grinding, a solid-state reaction was carried out. The temperature was increased from room temperature to 1325 °C at a rate of 5 °C / min under normal atmospheric pressure and air atmosphere, and then held at this temperature for 10 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the mixture was ground again for the second sintering step at 1500 °C for 6 hours. After the sintering, the product was allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y₃Mg₂. 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescent powder.

[0034] Example 4

[0035] 0.3387 g of yttrium oxide (Y₂O₃), 0.0571 g of magnesium hydroxide (Mg(OH)₂), 0.2082 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), 0.1025 g of germanium oxide (GeO₂), and 0.0015 g of chromium oxide (Cr₂O₃) were weighed out and ground in an agate mortar. After uniform grinding, a solid-state reaction was carried out. The temperature was increased from room temperature to 1275°C at a rate of 5°C / min under normal atmospheric pressure and air, and then held at this temperature for 12 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the mixture was ground again for the second sintering step at 1525°C for 4 hours. After the sintering, the product was allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y₃Mg₂. 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescent powder.

[0036] Example 5

[0037] 0.3387 g of yttrium oxide (Y₂O₃), 0.0571 g of magnesium hydroxide (Mg(OH)₂), 0.2082 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), 0.1025 g of germanium oxide (GeO₂), and 0.0015 g of chromium oxide (Cr₂O₃) were weighed separately and ground in an agate mortar. After uniform grinding, a solid-state reaction was carried out. Under normal atmospheric pressure, the temperature was increased from room temperature to 1375°C at a rate of 5°C / min and held at this temperature for 8 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the mixture was re-ground for the second sintering step at 1475°C for 8 hours. After the sintering, the product was allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y₃Mg₂. 1- x Cr x Ga 2+x AlGe 1-x O 12 Fluorescent powder.

[0038] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of ​​the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A broadband garnet-based near-infrared phosphor, characterized in that, Its chemical composition is represented as: Y3Mg 1- x Cr x Ga 2+x AlGe 1-x O 12 Where: 0.01≤x≤0.

05.

2. The method for preparing the ultra-broadband garnet-based near-infrared phosphor according to claim 1, characterized in that, The process includes the following steps: Raw materials containing yttrium, magnesium, gallium, aluminum, germanium, and chromium are weighed according to their chemical composition. The molar ratio of the metal elements is Y:Mg:Ga:Al:Ge:Cr = 3:1-x:2+x:1:1-x:x, where 0.01≤x≤0.

05. Depending on the experimental temperature, a certain amount of Ga2O3 is added to compensate for Ga loss during the high-temperature reaction. After thorough grinding to ensure uniform mixing, the mixture is sintered in atmospheric air at normal pressure at a temperature of 1325±50℃ for 8-12 hours. After sintering, the mixture is allowed to cool naturally to room temperature, and then ground again for a second sintering process at a temperature of 1500±25℃ for 4-8 hours. After sintering, the mixture is allowed to cool naturally to room temperature and then ground to obtain the near-infrared Y3Mg. 1-x Cr x Ga 2+x AlGe 1-x O 12 Fluorescent powder.

3. The preparation method according to claim 2, characterized in that, The raw materials containing yttrium are selected from one or more of yttrium oxide, yttrium oxalate, yttrium carbonate, and yttrium nitrate.

4. The preparation method according to claim 2, characterized in that, The magnesium-containing raw material is selected from magnesium hydroxide.

5. The preparation method according to claim 2, characterized in that, The gallium-containing raw material is selected from gallium oxide.

6. The preparation method according to claim 2, characterized in that, The aluminum-containing raw material is selected from aluminum hydroxide.

7. The preparation method according to claim 2, characterized in that, The germanium-containing raw material is selected from germanium oxide.

8. The preparation method according to claim 2, characterized in that, The chromium-containing raw materials are selected from one or more of chromium oxide and chromium nitrate.

9. The preparation method according to claim 2, characterized in that, To compensate for the loss of Ga during the high-temperature reaction, an additional 10% of Ga2O3 needs to be added on top of the stoichiometric ratio.

10. The application of the ultra-wideband garnet-based near-infrared phosphor according to claim 1 in light-emitting devices.

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