Cyan fluorescent powder and preparation method thereof

Abstract

The invention provides cyan fluorescent powder, the chemical composition expression formula of which is AxRyBmCnO12: Cez, in which A is at least one of Mg, Ca, Sr and Ba; r is at least one of rare earth elements Lu, Y, Gd and La; b is at least one of Hf and Zr; c is at least one of Al and Ga; x = 2; y = 1; m = 2; n = 3. The preparation method does not need a reducing atmosphere, and has the characteristics of simplicity in preparation, low cost, high safety and suitability for large-scale production. The cyan fluorescent powder can be efficiently excited by near ultraviolet light, and is high in luminous intensity and excellent in thermal stability. The cyan fluorescent powder meets the application requirements of preparation of photoluminescent devices, laser optical devices or nonlinear optical devices on the performance of luminescent materials.

Description

[0001] The present invention belongs to the technical field of luminescent materials, and specifically relates to a cyan phosphor and a preparation method thereof. Background Art

[0002] White light LEDs have attracted widespread attention in the lighting field due to their advantages such as high efficiency, energy saving and environmental friendliness. The mainstream commercial implementation method of white light LEDs is to use LED chips with phosphors. The early way to obtain white light LEDs was to use blue light chips with yellow phosphors. However, the white light obtained by this method had the problem of partial lack of green and red light, resulting in a high color temperature of the obtained white light and poor color rendering. With the maturity of near-ultraviolet chip technology, the use of near-ultraviolet chips with red, green and blue phosphors to obtain white light LEDs has attracted more and more attention. Its color rendering is good, but there is a problem of reabsorption effect, which leads to a decrease in luminous efficiency. In terms of technical means, the development of efficient and stable cyan phosphors can reduce the reabsorption effect while ensuring color rendering and improve luminous efficiency. Therefore, it is of great significance to develop high-performance, low-cost cyan phosphors.

[0003] Phosphors are composed of a matrix and an activator. In the matrix material, the garnet crystal structure has stable physical and chemical properties; in the activator, the Ce based on the 4f-5d transition 3+ Ions have the characteristics of simple configuration, high luminescence efficiency and adjustable performance. 3+ Ion-doped garnet phosphors have excellent luminescence properties. Researchers have reported garnet-structured cyan phosphors Ca2LuZr2(AlO4)3:Ce 3+ and Ca2LuHf2(AlO4)3:Ce 3+ Phosphors such as Ca3Y2Ge3O4 can be excited by near-ultraviolet light and emit cyan light. However, the preparation process requires a reducing atmosphere, which leads to high preparation costs and insufficient safety. 12 :Bi 3+ The preparation process of cyan phosphor does not require a reducing atmosphere, but the luminous intensity is poor, which is not conducive to practical applications.

[0004] The cerium raw material used in phosphors usually exists in the form of CeO2. 3+ The preparation of ion-doped phosphor materials requires a reducing atmosphere, such as H2 or CO. Therefore, a cyan phosphor that does not require a reducing atmosphere is developed and designed. Ce is self-reduced to 4+ Ions are reduced to Ce 3+ Ions can not only greatly reduce the preparation cost, but also improve the safety of the phosphor preparation process, which is of great significance. Summary of the invention

[0005] In view of the problems in the prior art, the present invention provides a method for preparing a cyan phosphor. 3+ Ion-doped garnet phosphors do not require a reducing atmosphere and are simple to prepare, low cost, highly safe, and suitable for large-scale production. The resulting cyan phosphor can be efficiently excited by near-ultraviolet light, has high luminescence intensity, and excellent thermal stability.

[0006] To achieve the above object, the first aspect of the present invention provides a cyan phosphor, the chemical composition of which is expressed as follows: x R y B m C n O 12 :Ce z , wherein A is at least one of Mg, Ca, Sr, and Ba; R is at least one of the rare earth elements Lu, Y, Gd, and La; B is at least one of Hf and Zr; C is at least one of Al and Ga; x=2; y=1; m=2; and n=3.

[0007] Preferably, A is Ca;

[0008] Preferably, 0.02≤z≤0.2;

[0009] A second aspect of the present invention provides a method for preparing a cyan phosphor, characterized by comprising the following steps:

[0010] According to the chemical formula and the stoichiometric ratio, raw materials containing A, R, B, C and Ce elements are weighed into a grinding container, anhydrous ethanol is added, and then the raw materials are manually ground or ball-milled, and then placed in a reaction container, and sintered in a nitrogen atmosphere at a sintering temperature of 1350°C to 1650°C for 3h to 7h. The raw materials are then cooled to room temperature and the product is ground to obtain the cyan phosphor.

[0011] Preferably, the raw material containing element A is at least one of CaCO3, Ca(HCO3)2, and Ca(OH)2;

[0012] Preferably, the raw material containing R element is at least one of Y2O3, Lu2O3, Gd2O3, La2O3

[0013] Preferably, the raw material containing element B is at least one of ZrO2 and HfO2;

[0014] Preferably, the raw material containing the C element is at least one of Al2O3 and Ga2O3.

[0015] Preferably, the raw material containing Ce element is CeO2.

[0016] A third aspect of the present invention provides an application of a cyan phosphor, wherein the cyan phosphor is used to prepare a photoluminescent device, a laser optical device or a nonlinear optical device.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The cyan phosphor described in the present invention can reduce the reabsorption effect of white light LEDs and improve luminous efficiency.

[0019] 2. The preparation method of the cyan phosphor described in the present invention is simple, does not require a reducing atmosphere, is low in cost, highly safe, and is easy to industrialize.

[0020] 3. The cyan phosphor prepared by the method of the present invention can be excited by 400-420nm near-ultraviolet light, and the emission spectrum covers the range of 450-600nm, with high luminous intensity, which can meet the application requirements of optoelectronic devices for the photochromic properties of luminescent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The XRD pattern of the phosphor prepared in Example 1 of the present invention;

[0022] Figure 2 The emission spectrum and excitation spectrum of the phosphor prepared in Example 1 of the present invention;

[0023] Figure 3 The XRD pattern of the phosphor prepared in Example 2 of the present invention;

[0024] Figure 4 The emission spectrum and excitation spectrum of the phosphor prepared in Example 2 of the present invention;

[0025] Figure 5 The XRD pattern of the phosphor prepared in Example 3 of the present invention;

[0026] Figure 6 The emission spectrum and excitation spectrum of the phosphor prepared in Example 3 of the present invention;

[0027] Figure 7 The XRD pattern of the phosphor prepared in Example 4 of the present invention;

[0028] Figure 8 The emission spectrum and excitation spectrum of the phosphor prepared in Example 4 of the present invention; DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below by specific implementation methods. The embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0030] Example 1

[0031] A method for preparing cyan phosphor

[0032] Weigh 0.1601 g of calcium carbonate (CaCO3), 0.0867 g of yttrium oxide (Y2O3), 0.1224 g of aluminum oxide (Al2O3), 0.2694 g of hafnium oxide (HfO2), and 0.0055 g of cerium oxide (CeO2) respectively, add anhydrous ethanol to the above raw materials in an agate mortar and grind them manually. After grinding evenly, put them into a corundum crucible and sinter them in a nitrogen atmosphere at a sintering temperature of 1550°C and a sintering time of 4 hours. Then cool them to room temperature and grind the products to obtain the cyan phosphor.

[0033] Example 2

[0034] A method for preparing cyan phosphor

[0035] Weigh 0.1601g of calcium carbonate (CaCO3), 0.0867g of yttrium oxide (Y2O3), 0.1224g of aluminum oxide (Al2O3), 0.1578g of zirconium oxide (ZrO2), and 0.0055g of cerium oxide (CeO2) respectively, add anhydrous ethanol to the above raw materials in an agate mortar and grind them manually. After grinding evenly, put them into a corundum crucible and sinter them in a nitrogen atmosphere at a sintering temperature of 1550°C and a sintering time of 4h. Then cool them to room temperature and grind the products to obtain the cyan phosphor.

[0036] Example 3

[0037] A method for preparing cyan phosphor

[0038] Weigh 0.1601 g of calcium carbonate (CaCO3), 0.0867 g of yttrium oxide (Y2O3), 0.1224 g of aluminum oxide (Al2O3), 0.1347 g of hafnium oxide (HfO2), 0.0789 g of zirconium oxide (ZrO2), and 0.0055 g of cerium oxide (CeO2) respectively, add anhydrous ethanol to the above raw materials in an agate mortar and grind them manually. After grinding evenly, put them into a corundum crucible and sinter them in a nitrogen atmosphere at a sintering temperature of 1525°C and a sintering time of 4 hours. Then cool them to room temperature and grind the products to obtain the cyan phosphor.

[0039] Example 4

[0040] A method for preparing cyan phosphor

[0041] Weigh 0.1201 g of calcium carbonate (CaCO3), 0.1086 g of lutetium oxide (Lu2O3), 0.0918 g of aluminum oxide (Al2O3), 0.2021 g of hafnium oxide (HfO2), and 0.0093 g of cerium oxide (CeO2) respectively, add anhydrous ethanol to the above raw materials in an agate mortar and grind them manually. After grinding evenly, put them into a corundum crucible and sinter them in a nitrogen atmosphere at a sintering temperature of 1500°C and a sintering time of 4 hours. Then cool them to room temperature and grind the products to obtain the cyan phosphor.

[0042] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A cyan phosphor, characterized in that: Its chemical composition is expressed as: A x R y B m C n O 12 :Ce z , wherein A is at least one of Mg, Ca, Sr, and Ba; R is at least one of the rare earth elements Lu, Y, Gd, and La; B is at least one of Hf and Zr; C is at least one of Al and Ga; x=2; y=1; m=2; and n=3.

2. The cyan phosphor according to claim 1, characterized in that: A is Ca.

3. The cyan phosphor according to claim 1, characterized in that: 0.02≤z≤0.2。 4. A method for preparing a cyan phosphor, characterized in that: The method comprises the following steps: According to the chemical formula and the stoichiometric ratio, raw materials containing A, R, B, C and Ce elements are weighed into a grinding container, anhydrous ethanol is added, and then the raw materials are manually ground or ball-milled, and then placed in a reaction container, and sintered in a nitrogen atmosphere at a sintering temperature of 1350°C to 1650°C for 3h to 7h. The raw materials are then cooled to room temperature and the product is ground to obtain the cyan phosphor.

5. The preparation method according to claim 4, characterized in that: The raw material containing element A in the steps is at least one of CaCO3, Ca(HCO3)2, and Ca(OH)2; the raw material containing element R is at least one of Y2O3, Lu2O3, Gd2O3, and La2O3; the raw material containing element B is at least one of ZrO2 and HfO2; the raw material containing element C is at least one of Al2O3 and Ga2O3; and the raw material containing element Ce is CeO2.

6. The cyan phosphor according to claim 1 is used in photoluminescent devices, laser optical devices or nonlinear optical devices.

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