Sodium-rich titanium-based garnet near-infrared fluorescent powder and preparation method thereof

Abstract

The invention discloses near-infrared light NaGd2InGa2Ti2O12: Cr < 3 + > fluorescent powder and a preparation method thereof. The invention relates to near-infrared light NaGd2InGa2Ti2O12: Cr < 3 + > fluorescent powder, the chemical composition expression formula of the fluorescent powder is NaGd2In1-xGa2-xTi2O12: 2xCr < 3 + >, 2x is the doping amount of Cr < 3 + > ions, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt, 0 lt X is smaller than or equal to 0.05. The near-infrared light NaGd2InGa2Ti2O12: Cr < 3 + > fluorescent powder provided by the invention can be excited by blue light of 425 to 500 nm, red light of 575 to 675 nm, blue light of 425 to 500 nm and red light of 575 to 675 nm, and can emit ultra-wide band near-infrared light of which the main peak is in the range of 740 to 760 nm and the half-peak width reaches 150 nm, and the chromaticity coordinate is (0.7169, 0.2804).

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ Phosphor and preparation method thereof. Background Art

[0002] Today's mainstream LED lighting white light technology uses yellow light YAG:Ce 3+ It is obtained by compounding phosphor and blue light GaN chip. The advantage of this technology is that it can ensure the brightness and efficiency of white light LED devices. However, with the improvement of living standards, people have expectations for higher quality lighting technology - "simulated sunlight lighting". In the spectral composition of sunlight, in addition to visible light, there is also a considerable proportion of near-infrared light. The ideal artificial light source needs to be properly supplemented with near-infrared light to achieve the final effect of simulating sunlight. In order to take into account efficiency, the choice of near-infrared is mainly short-wave infrared light at the edge of the visible light region of 750nm-850nm.

[0003] Transition metal ion Cr 3+ When it occupies a six-coordinated lattice site, it can often obtain luminescence in the red to near-infrared spectral region. 3+ Phosphors as luminescence centers have been widely studied. 3 B 2 X 3 O 12 Garnet-based compounds with a general structural formula naturally become Cr due to their various metal cation sites that are convenient for crystal field regulation. 3+ The hottest matrix for doping. 3+ Garnet-based phosphors have been reported to have Ca 2 LqCy 2 Al 3 O 12 :Cr 3+ , Y 3 Al 5 O 12 :Cr 3+ , NaY 2 Ga 3 Ge 2 O 12 :Cr 3+The main deficiencies are either reflected in the spectral performance - the near-infrared main peak position is not ideal, and the coverage of the 750nm-850nm range is insufficient; or reflected in the synthesis preparation - the phase formation temperature is generally high, the requirements for synthesis equipment are high, and the energy consumption required for production is large; or reflected in the cost - the cost of the raw materials involved is high, the economic benefits are poor, and many other problems that are not conducive to actual industrial application. Therefore, it is of great significance to develop high-efficiency near-infrared phosphors that meet the above requirements. Summary of the invention

[0004] The present invention provides a near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ Phosphor and preparation method thereof, the near infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ The phosphor material can be excited by 425-500nm blue light and 575-675nm red light, emitting ultra-wide-band near-infrared light with a main peak in the range of 740-760nm and a half-peak width of 150nm.

[0005] The purpose of the present invention is to provide a near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ Phosphor, specifically Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared fluorescent material, its chemical composition is expressed as: NaGd 2 In 1-x Ga 2-x Ti 2 O 12 :2xCr 3+ , 2x is Cr 3+ Ion doping amount, where: 0 <x≤0.05。

[0006] Another object of the present invention is to provide the above-mentioned near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+Preparation method of phosphor, comprising the following steps: Weigh raw materials containing sodium, gadolinium, indium, gallium, titanium and chromium metal elements according to their chemical compositions. Among them, the molar ratio of the 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 Ga is additionally added. 2 O 3 and In 2 O 3 are used 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 them in an atmospheric air atmosphere, and then cool them to room temperature. Grind the product to obtain the near-infrared light NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ phosphor.

[0007] The near-infrared light NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ phosphor proposed by the present invention utilizes the lattice environment of Cr 3+ in yttrium gallium garnet. The appropriate crystal field strength enables the Cr 3+ ions doped on the Ga 3+ lattice sites to only exhibit 4 T 2 - 4 A 2 transition belonging to a broad-band near-infrared light. The near-infrared light NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ phosphor proposed by the present invention, compared with the traditional garnet isostructural system constructed with aluminum, silicon, and alkaline earth metals, has a significantly reduced solid-phase synthesis reaction temperature, and there are no specific pressure and atmosphere requirements during the synthesis process; compared with the traditional germanium-containing garnet isostructural system, it shows greater economy in terms of the raw material cost of the reactants.

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

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

[0010] Preferably, the raw material containing indium element is selected from gallium indide.

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

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

[0013] Preferably, the raw material containing chromium element is selected from at least one of chromium oxide and chromium nitrate.

[0014] Preferably, the sintering procedure is as follows: heating from room temperature to 1100-1300° C. at a rate of 5° C. / min, and maintaining the temperature constant for 3-5 hours after heating.

[0015] The present invention also protects the above-mentioned near-infrared light NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ Application of phosphor in light-emitting devices. The near-infrared phosphor proposed by the present invention has a wide effective excitation range and a wide emission coverage range, and can be applied in the fields of health lighting, plant lighting, temperature detection, infrared recognition, etc.

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

[0017] (1) Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor can be sintered into a phase in just one step at a temperature as low as 1100-1300℃. It has good crystallinity, high luminous brightness, and short fluorescence lifetime. It can be used as a near-infrared light conversion material for blue LED chip excitation.

[0018] (2) The near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+ Phosphors have the advantages of a wide excitation range, adjustable emission peak, wide emission peak spectrum, cheap raw materials, simple manufacturing process, short synthesis time, low energy consumption, and easy industrialization.

[0019] (3) The near-infrared NaGd 2 InGa 2 Ti 2 O 12 :Cr 3+The phosphor can be excited by 425-500nm blue light and 575-675nm red light, emitting ultra-wideband near-infrared light with a main peak in the range of 740-760nm and a half-peak width of 150nm. Because its emission starts at 650nm and covers a range of more than 860nm, it can be used in many fields such as health lighting, plant lighting, temperature detection, infrared recognition, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The Cr prepared in Example 1 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 X-ray powder diffraction pattern of near-infrared phosphor;

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

[0022] Figure 3 The Cr prepared in Example 1 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Fluorescence excitation spectrum of near-infrared phosphor at 750nm wavelength emission position;

[0023] Figure 4 The Cr prepared in Example 1 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Fluorescence decay curve of near-infrared phosphor.

[0024] Figure 5 The Cr prepared in Example 1 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Chromaticity coordinates of near-infrared phosphors. DETAILED DESCRIPTION

[0025] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention. Unless otherwise specified, the equipment and reagents used in the present invention are conventional commercial products in the art.

[0026] Example 1

[0027] Weigh sodium carbonate (Na 2 CO 3 )0.0265g, gadolinium oxide (Gd 2 O 3 )0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0015g, gallium oxide (Ga 2 O 3 )0.1026g, indium oxide (In 2 O 3 )0.0755g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1250°C at a rate of 5°C / min in a normal pressure air atmosphere environment, and the temperature was kept constant for 4h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0028] Example 2

[0029] Weigh sodium carbonate (Na 2 CO 3 )0.0265g, gadolinium oxide (Gd 2 O 3 )0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0015g, gallium oxide (Ga 2 O 3 )0.1026g, indium oxide (In 2 O 3 )0.0755g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1300°C at a rate of 5°C / min in a normal pressure air atmosphere, and the temperature was kept constant for 3h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0030] Example 3

[0031] Weigh sodium carbonate (Na2 CO 3 )0.0265g, gadolinium oxide (Gd 2 O 3 )0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0015g, gallium oxide (Ga 2 O 3 )0.1026g, indium oxide (In 2 O 3 )0.0755g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1100°C at a rate of 5°C / min in a normal pressure air atmosphere, and the temperature was kept constant for 5h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0032] Example 4

[0033] Weigh sodium carbonate (Na 2 CO 3 )0.0265g, gadolinium oxide (Gd 2 O 3 )0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0075g, gallium oxide (Ga 2 O 3 )0.1005g, indium oxide (In 2 O 3 )0.0725g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1200°C at a rate of 5°C / min in a normal pressure air atmosphere, and the temperature was kept constant for 4h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0034] Example 5

[0035] Weigh sodium bicarbonate (NaHCO 3 )0.0420g, gadolinium oxide (Gd 2 O 3)0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0015g, gallium oxide (Ga 2 O 3 )0.1026g, indium oxide (In 2 O 3 )0.0755g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1200°C at a rate of 5°C / min in a normal pressure air atmosphere environment, and the temperature was kept constant for 4h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0036] Example 6

[0037] Weigh sodium bicarbonate (NaHCO 3 )0.0420g, gadolinium oxide (Gd 2 O 3 )0.1813g, titanium oxide (TiO 2 )0.0799g, chromium oxide (Cr 2 O 3 )0.0075g, gallium oxide (Ga 2 O 3 )0.1005g, indium oxide (In 2 O 3 )0.0725g of the above raw materials were ground in an agate mortar, and after grinding evenly, solid phase reaction was carried out. The temperature was raised from room temperature to 1200°C at a rate of 5°C / min in a normal pressure air atmosphere, and the temperature was kept constant for 4h. After the reaction, it was allowed to cool naturally and ground evenly to obtain Cr 3+ Doped NaGd 2 InGa 2 Ti 2 O 12 Near-infrared phosphor.

[0038] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, 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 regarded as the protection scope of the present invention.

Claims

1. A near-infrared NaGd2InGa2Ti2O 12 :Cr 3+ Phosphor, its chemical composition is expressed as: NaGd2In 1-x Ga 2- x TiO 12 :2xCr 3+ , 2x is Cr 3+ Ion doping amount, where: 0<x≤0.05。 2. The near-infrared NaGd2InGa2Ti2O according to claim 1 12 :Cr 3+ The method for preparing phosphor is characterized in that: It includes the following steps: Weigh the raw materials containing each metal element of sodium, gadolinium, indium, gallium, titanium and chromium according to their chemical compositions respectively. Among them, the molar ratio of the 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 are additionally added to compensate for the loss of Ga and In during the high-temperature reaction. Grind them充分研磨使其混合均匀, and put them into a reaction vessel. Sinter them in an atmospheric air atmosphere, and then cool them to room temperature. Grind the product to obtain the near-infrared light NaGd2InGa2Ti2O 12 :Cr 3+ phosphor. It should be noted that there is an unclear expression "充分研磨使其混合均匀" in the original text. I have translated it as "Grind them充分研磨使其混合均匀" for the time being. You may need to clarify this part for a more accurate translation.

3. The near infrared light NaGd2InGa2Ti2O according to claim 2 12 :Cr 3+ The method for preparing phosphor is 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 according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: 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 according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: The raw material containing indium element is selected from indium oxide.

6. The near infrared light NaGd2InGa2Ti2O according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: The raw material containing gallium element is selected from gallium oxide.

7. The near infrared light NaGd2InGa2Ti2O according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: The raw material containing titanium element is selected from titanium oxide.

8. The near infrared light NaGd2InGa2Ti2O according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: The raw material containing chromium element is selected from one or more of chromium oxide and chromium nitrate.

9. The near infrared light NaGd2InGa2Ti2O according to claim 2 12 :Cr 3+ The method for preparing phosphor is characterized in that: The specific sintering steps are: only one-step sintering, the temperature is 1100-1300°C, the time is 3-5h, the heating rate is 5°C / min, and the use of Ga2O3 and In2O3 in the reaction process requires a superstoichiometric ratio to compensate for the loss of Ga and In during the high-temperature reaction.

10. The near-infrared NaGd2InGa2Ti2O according to claim 1 12 :Cr 3+ The application of phosphors in health lighting, plant lighting, temperature detection, infrared recognition and other devices.

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