A sodium-rich titanium-based garnet near-infrared phosphor and its preparation method

Abstract

The present invention discloses a near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor and its preparation method. A near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor, the chemical composition expression formula of which is: NaGd2In 1‑x Ga 2‑x Ti2O 12 :2xCr 3+ , 2x is the doping amount of Cr 3+ ions, wherein: 0 < x ≤ 0.05. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor proposed by the present invention can be excited by 425-500 nm blue light and 575-675 nm red light, and emits a super-wideband near-infrared light with a main peak in the range of 740-760 nm and a full width at half maximum of 150 nm, and the chromaticity coordinates are located at (0.7169, 0.2804).

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, and more particularly to a near-infrared NaGd2InGa2Ti2O 12 :Cr 3+ Phosphors and their preparation methods. Background Technology

[0002] The mainstream white light technology used in LED lighting today utilizes yellow light YAG:Ce. 3+ This technology combines phosphors with blue GaN chips to achieve the desired brightness and efficiency of white LED devices. However, with rising living standards, people are increasingly expecting higher-quality lighting technologies—"simulated sunlight lighting." In addition to visible light, sunlight contains a significant proportion of near-infrared light. Ideal artificial light sources require appropriate supplementation with near-infrared light to achieve the desired simulated sunlight effect. To balance efficiency, the near-infrared light selected primarily consists of short-wavelength infrared light in the 750nm-850nm range at the edge of the visible light spectrum.

[0003] Transition metal ions Cr 3+ When occupying six-coordinate lattice sites, luminescence in the red to near-infrared spectral region is often obtained. Therefore, Cr... 3+ Phosphors, serving as luminescent centers, have been extensively studied. Among them, A3B2X3O... 12 Garnet-based compounds of the general structural formula naturally become Cr due to the presence of multiple metal cation lattice sites that facilitate crystal field modulation. 3+ Popular doping matrices. Existing technologies involving Cr... 3+ Garnet-based phosphors have been reported in the form of Ca2LuZr2Al3O 12 :Cr 3+ Y3Al5O 12 :Cr 3+ NaY2Ga3Ge2O 12 :Cr 3+ The main shortcomings of current near-infrared phosphors are either in their spectral performance—the position of the near-infrared main peak is not ideal, and the coverage of the 750nm-850nm range is insufficient; or in their synthesis and preparation—the phase formation temperature is generally too high, requiring sophisticated synthesis equipment and consuming a large amount of energy during production; or in their cost—the raw material costs of the elements involved are high, resulting in poor economic benefits and other problems that hinder practical industrial applications. Therefore, the development of high-efficiency near-infrared phosphors that meet the above requirements is of great significance. Summary of the Invention

[0004] This invention provides a near-infrared NaGd2InGa2Ti2O 12 :Cr 3+Phosphor and preparation method thereof, near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ The phosphor material can be excited by blue light at 425 - 500 nm and red light at 575 - 675 nm, and emits near-infrared light with an ultra-wide spectral band having a main peak in the range of 740 - 760 nm and a full width at half maximum of 150 nm.

[0005] The object of the present invention is to provide a near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor, specifically Cr 3+ doped NaGd2InGa2Ti2O 12 near-infrared light fluorescent material, the chemical composition expression formula of which is: NaGd2In 1-x Ga 2-x Ti2O 12 :2xCr 3+ , 2x is the doping amount of Cr 3+ ions, where: 0 < x ≤ 0.05.

[0006] Another object of the present invention is to provide a preparation method of the above-mentioned near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor, including the following steps: Weigh raw materials containing sodium, gadolinium, indium, gallium, titanium and chromium metal elements according to the chemical composition. Among them, the molar ratio of metal elements is Na:Gd:In:Ga:Ti:Cr = 1:2:1 - x:2 - x:2:2x, where: 0 < x ≤ 0.05. Then, according to the high or low experimental temperature, an appropriate amount of Ga2O3 and In2O3 is additionally added to compensate for the loss of Ga and In during the high-temperature reaction process. Grind them thoroughly to make them evenly mixed, and put them into a reaction vessel. Sinter in an atmospheric air atmosphere, and then cool to room temperature. Grind the product to obtain the above-mentioned near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor.

[0007] The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor proposed by the present invention utilizes the lattice environment of Cr 3+ in sodium yttrium gallium germanium garnet. The appropriate crystal field strength enables the Cr 3+ ions doped at the Ga 3+ lattice sites to only exhibit 4 T2- 4 A2 transition belonging to the wide spectral band near-infrared light. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+The phosphor, using a novel garnet matrix constructed from sodium, titanium, gallium, and indium, exhibits a significantly lower reaction temperature for solid-phase synthesis compared to traditional garnet isomorphic systems constructed from aluminum, silicon, and alkaline earth metals. The synthesis process does not require specific pressure or atmosphere. Compared to traditional germanium-containing garnet isomorphic systems, it demonstrates greater economic efficiency in terms of reactant raw material costs.

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

[0009] Preferably, the raw material containing gadolinium is selected from one or more of gadolinium oxide, gadolinium oxalate, gadolinium carbonate, and gadolinium nitrate.

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

[0011] Preferably, the gallium-containing raw material is selected from gallium oxide.

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

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

[0014] Preferably, the sintering procedure is as follows: the temperature is increased from room temperature to 1100-1300℃ at a rate of 5℃ / min, and then held at a constant temperature for 3-5 hours after the temperature increase is completed.

[0015] This invention also protects the above-mentioned near-infrared NaGd2InGa2Ti2O 12 :Cr 3+ Applications of phosphors in light-emitting devices. The near-infrared phosphor proposed in this invention has a wide effective excitation range and a wide emission coverage range, and can be applied in fields such as health lighting, plant lighting, temperature detection, and infrared recognition.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] (1) The Cr proposed in this invention 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphors can be sintered in a single step at temperatures as low as 1100-1300℃, exhibiting excellent crystallinity, high luminescence 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 light NaGd2InGa2Ti2O 12 :Cr 3+Phosphors have advantages such as a wide excitation range, tunable emission peak, broad emission peak spectrum, inexpensive raw materials, simple manufacturing process, short synthesis time, low energy consumption, and easy industrialization.

[0019] (3) The near-infrared NaGd2InGa2Ti2O proposed in this invention 12 :Cr 3+ Phosphors can be excited by blue light (425-500nm) and red light (575-675nm), emitting ultra-broadband near-infrared light with a main peak in the 740-760nm range and a half-maximum width (WHM) of up to 150nm. Because its emission starts from 650nm and covers a range exceeding 860nm, this broad-band emission region can be used in many fields such as health lighting, plant lighting, temperature detection, and infrared identification. Attached Figure Description

[0020] Figure 1 The Cr prepared in Example 1 3+ Doped NaGd2InGa2Ti2O 12 X-ray powder diffraction pattern of near-infrared phosphor;

[0021] Figure 2 The Cr prepared in Example 1 3+ Doped NaGd2InGa2Ti2O 12 Fluorescence emission spectrum of near-infrared phosphor under excitation at 460 nm wavelength;

[0022] Figure 3 The Cr prepared in Example 1 3+ Doped NaGd2InGa2Ti2O 12 Fluorescence excitation spectrum of near-infrared phosphor at emission position of 750 nm wavelength;

[0023] Figure 4 The Cr prepared in Example 1 3+ Doped NaGd2InGa2Ti2O 12 Fluorescence decay curve of near-infrared phosphor.

[0024] Figure 5 The Cr prepared in Example 1 3+ Doped NaGd2InGa2Ti2O 12 Chromaticity coordinates of near-infrared phosphors. Detailed Implementation

[0025] The following embodiments are further illustrations of the present invention, but not limitations thereof. Unless otherwise specified, the equipment and reagents used in the present invention are commercially available products conventional in this technical field.

[0026] Example 1

[0027] Weigh out 0.0265g of sodium carbonate (Na₂CO₃), 0.1813g of gadolinium oxide (Gd₂O₃), 0.0799g of titanium oxide (TiO₂), 0.0015g of chromium oxide (Cr₂O₃), 0.1026g of gallium oxide (Ga₂O₃), and 0.0755g of indium oxide (In₂O₃). Grind the above raw materials in an agate mortar until uniform. Then, carry out a solid-state reaction. Under normal pressure and air atmosphere, raise the temperature from room temperature to 1250℃ at a rate of 5℃ / min, and hold the temperature for 4 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0028] Example 2

[0029] Weigh out 0.0265g of sodium carbonate (Na₂CO₃), 0.1813g of gadolinium oxide (Gd₂O₃), 0.0799g of titanium oxide (TiO₂), 0.0015g of chromium oxide (Cr₂O₃), 0.1026g of gallium oxide (Ga₂O₃), and 0.0755g of indium oxide (In₂O₃). Grind the above raw materials in an agate mortar until uniform. After grinding, carry out a solid-state reaction. In an atmospheric pressure environment, heat the mixture from room temperature to 1300℃ at a rate of 5℃ / min, and hold it at this temperature for 3 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0030] Example 3

[0031] Weigh out 0.0265g of sodium carbonate (Na₂CO₃), 0.1813g of gadolinium oxide (Gd₂O₃), 0.0799g of titanium oxide (TiO₂), 0.0015g of chromium oxide (Cr₂O₃), 0.1026g of gallium oxide (Ga₂O₃), and 0.0755g of indium oxide (In₂O₃). Grind the above raw materials in an agate mortar until uniform. After grinding, carry out a solid-state reaction. In an atmospheric pressure environment, heat the mixture from room temperature to 1100℃ at a rate of 5℃ / min, and hold it at that temperature for 5 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0032] Example 4

[0033] Weigh out 0.0265g of sodium carbonate (Na₂CO₃), 0.1813g of gadolinium oxide (Gd₂O₃), 0.0799g of titanium oxide (TiO₂), 0.0075g of chromium oxide (Cr₂O₃), 0.1005g of gallium oxide (Ga₂O₃), and 0.0725g of indium oxide (In₂O₃). Grind the above raw materials in an agate mortar until uniform. Then, carry out a solid-state reaction. Under normal pressure and air atmosphere, raise the temperature from room temperature to 1200℃ at a rate of 5℃ / min, and hold the temperature for 4 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0034] Example 5

[0035] Weigh out 0.0420g of sodium bicarbonate (NaHCO3), 0.1813g of gadolinium oxide (Gd2O3), 0.0799g of titanium oxide (TiO2), 0.0015g of chromium oxide (Cr2O3), 0.1026g of gallium oxide (Ga2O3), and 0.0755g of indium oxide (In2O3). Grind the above raw materials in an agate mortar until uniform. Then, carry out a solid-state reaction. Under normal pressure and air atmosphere, raise the temperature from room temperature to 1200℃ at a rate of 5℃ / min, and hold the temperature for 4 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0036] Example 6

[0037] Weigh out 0.0420g of sodium bicarbonate (NaHCO3), 0.1813g of gadolinium oxide (Gd2O3), 0.0799g of titanium oxide (TiO2), 0.0075g of chromium oxide (Cr2O3), 0.1005g of gallium oxide (Ga2O3), and 0.0725g of indium oxide (In2O3). Grind the above raw materials in an agate mortar until uniform. Then, carry out a solid-state reaction. Under normal pressure and air atmosphere, raise the temperature from room temperature to 1200℃ at a rate of 5℃ / min, and hold the temperature for 4 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Cr. 3+ Doped NaGd2InGa2Ti2O 12 Near-infrared phosphor.

[0038] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor, whose chemical composition is expressed as: NaGd2In 1-x Ga 2- x Ti2O 12 :2xCr 3+ , 2x is the doping amount of Cr 3+ ions, wherein: 0<x≤0.05。 2. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized in that The method comprises the following steps: respectively weighing raw materials containing sodium, gadolinium, indium, gallium, titanium and chromium according to chemical composition, wherein the molar ratio of the metal elements is Na:Gd:In:Ga:Ti:Cr=1:2:1-x:2-x:2:2x, wherein 0 12 :Cr 3+ fluorescent powder.

3. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized in that The raw material containing sodium element is selected from one or more of sodium carbonate, sodium bicarbonate and sodium oxalate.

4. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized by, The raw material containing gadolinium element is selected from one or more of gadolinium oxide, gadolinium oxalate, gadolinium carbonate and gadolinium nitrate.

5. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized by, The raw material containing indium element is selected from indium oxide.

6. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ A method for preparing a fluorescent powder, characterized by, The raw material containing gallium element is selected from gallium oxide.

7. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized by, The raw material containing titanium element is selected from titanium oxide.

8. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized by, The raw material containing chromium element is selected from one or more of chromium oxide and chromium nitrate.

9. The near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ Method for producing a phosphor, characterized by, The sintering step is specifically as follows: one-step sintering, temperature is 1100-1300℃, time is 3-5h, the heating rate is 5℃ / min, and the use of Ga2O3 and In2O3 needs to be in excess of stoichiometric ratio to compensate for the loss of Ga and In in the high-temperature reaction process.

10. The near-infrared light NaGd2InGa2Ti2O of claim 1 12 : Cr 3+ Application of the phosphor in healthy lighting, plant lighting, temperature detection, infrared identification device equipment.

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