Eu < 3 + >-doped tungstate red luminescent material as well as preparation method and application thereof

Abstract

The invention discloses an Eu < 3 + >-doped tungstate red luminescent material and a preparation method and application thereof, and relates to the technical field of luminescent materials, the chemical general formula of the Eu < 3 + >-doped tungstate red luminescent material is Sr3La2-xW2O12: xEu < 3 + >, 0.001 < = x < = 0.20, and by changing the doping concentration of Eu < 3 + > ions, regulation and control of the luminescent intensity of the luminescent material can be realized; the luminescent material can be effectively excited by ultraviolet-near ultraviolet light of 200-420 nm and blue light of 450-480 nm, has an ultra-wideband excitation spectrum, can be matched with a near ultraviolet LED chip or a blue light LED chip for use, has narrow-band strong red light emission and high color rendering property, has color coordinates located in pure red light regions (0.651, 0.348), has excellent thermal stability, and can be used as a blue light emitting material when the temperature rises to 418 K. The luminescent intensity of the luminescent material is 209.28% under the room temperature condition, the luminescent intensity is still kept at 92.73% under the room temperature when the temperature reaches 558K, the quantum yield reaches up to 89.60%, and the limitation that commercial red luminescent materials in the current market are not high in color rendering property and harsh in synthesis condition is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a Eu 3+ Doped tungstate red luminescent material and preparation method and application thereof. Background Art

[0002] White light-emitting diodes (W-LEDs) have been widely used in the display and lighting fields due to their advantages such as low cost, energy saving, environmental protection, high efficiency and long life. Currently, W-LEDs are mainly composed of InGaN blue chips and yellow phosphor Y3Al5O 12 :Ce 3+ The lack of red light components results in a low color rendering index, which limits the development of W-LED.

[0003] In order to solve this problem, it is necessary to synthesize red phosphors with high color purity that match the blue light chip. However, the red phosphors currently developed are mainly Eu 2+ Activated sulfide and nitride phosphors, and Mn 4+ Activated fluoride phosphors, they all have insurmountable disadvantages:

[0004] (1) Sulfides and fluorides cause environmental pollution during the synthesis process;

[0005] (2) The synthesis reagents of nitride luminescent materials are expensive and the synthesis conditions are harsh;

[0006] (3) Fluoride luminescent materials have poor stability.

[0007] Based on the above shortcomings, the present invention provides a Eu 3+ Doped tungstate red luminescent material and preparation method and application thereof can effectively solve the above problems. Summary of the invention

[0008] The object of the present invention is to provide a Eu 3+ Doped tungstate red luminescent material and its preparation method and application solve the following technical problems:

[0009] How to reduce pollution and cost and improve stability when synthesizing red luminescent materials.

[0010] The purpose of the present invention can be achieved through the following technical solutions:

[0011] Eu 3+ The doped tungstate red luminescent material is characterized in that the chemical formula of the red luminescent material is: Sr3La 2-x W2O 12 :xEu 3+ , where 0.01≤x≤0.2.

[0012] The red luminescent material can be effectively excited by a 200-420nm ultraviolet-near ultraviolet chip and a 450-480nm blue light chip to generate a narrow-band red light emission of 608-630nm, wherein the strongest emission peak is located at 616nm and the half-height width is 3.84nm.

[0013] A Eu as described above 3+ The method for preparing a doped tungstate red luminescent material comprises the following steps:

[0014] Step 1: According to Sr3La 2-x W2O 12 :xEu 3+ Weighing a strontium-containing compound, a lanthanum-containing compound, a tungsten-containing compound, and a europium-containing compound in a molar coefficient ratio, adding a co-solvent to these compounds and mixing them uniformly to obtain a mixed raw material;

[0015] Step 2: The mixed raw materials are heated to 800-1400℃ in an air atmosphere and calcined. After keeping the temperature for 3-5h, they are naturally cooled to room temperature. After grinding into powder, the mixed raw materials are heated to 1000-1400℃ in an air atmosphere and calcined. After keeping the temperature for 4-8h, they are naturally cooled to room temperature. After grinding into powder and particle size classification, Eu can be obtained. 3+ Doped tungstate red luminescent material.

[0016] In a further embodiment of the present invention, the strontium-containing compound is strontium carbonate, strontium oxide or strontium hydroxide.

[0017] In a further embodiment of the present invention, the lanthanum-containing compound is lanthanum oxide, lanthanum hydroxide or lanthanum carbonate.

[0018] In a further embodiment of the present invention, the tungsten-containing compound is tungsten trioxide.

[0019] In a further embodiment of the present invention, the europium-containing compound is europium oxide or europium nitrate.

[0020] In a further embodiment of the present invention: the co-solvent is one or more of boric acid, ammonium nitrate, fluoride and boron oxide.

[0021] In a further embodiment of the present invention, the amount of the co-solvent added is 1-10% of the total mass of the mixed raw materials.

[0022] An application of the Eu3+-doped tungstate red luminescent material as described above is to apply the luminescent material to white light LED lighting, liquid crystal display, and traffic display excited by ultraviolet chips or blue light chips.

[0023] Beneficial effects of the present invention:

[0024] Eu in the present invention 3+ The chemical formula of the doped tungstate red luminescent material is Sr3La 2-x W2O 12 :xEu 3+ , where 0.001≤x≤0.20, by changing Eu 3+ The doping concentration of ions can realize the regulation of the luminous intensity of the luminescent material; the luminescent material can be effectively excited by 200-420nm ultraviolet-near ultraviolet light and 450-480nm blue light, and can also be excited by 533nm green light, with an ultra-wideband excitation spectrum, and can be matched with near-ultraviolet LED chips or blue light LED chips; the main peak of the emission peak is located at 616nm, and the half-width is only 3.84nm, with narrow-band strong red light emission and high color rendering. The color coordinates of this series of luminescent materials are all in the pure red light area (0.651, 0.348), breaking through the limitations of low color rendering and harsh synthesis conditions of commercial red luminescent materials on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figure 1 Sr3La prepared in Example 1 of the present invention 1.99 W2O 12 :0.01Eu 3+ Excitation spectrum of

[0027] Figure 2 Sr3La prepared in Example 1 of the present invention 1.99 W2O 12 :0.01Eu 3+ Emission spectrum under 394nm light excitation;

[0028] Figure 3 Sr3La prepared in Example 1 of the present invention 1.99 W2O 12 :0.01Eu 3+ Emission spectrum under 465nm light excitation;

[0029] Figure 4 Sr3La prepared in Example 1 of the present invention 1.99 W2O 12 :0.01Eu 3+ Emission spectrum under 533nm light excitation;

[0030] Figure 5 Sr3La prepared in Example 2 of the present invention 1.95 W2O 12 :0.05Eu 3+ Excitation spectrum of

[0031] Figure 6 Sr3La prepared in Example 2 of the present invention 1.95 W2O 12 :0.05Eu 3+ Emission spectrum under 395nm light excitation;

[0032] Figure 7 Sr3La prepared in Example 2 of the present invention 1.95 W2O 12 :0.05Eu 3+ Emission spectrum under 466nm light excitation;

[0033] Figure 8 Sr3La prepared in Example 2 of the present invention 1.95 W2O 12 :0.05Eu 3+ Emission spectrum under 536nm light excitation;

[0034] Fig. 9 It is Sr3La obtained in Example 3 of the present invention. 1.9 W2O 12 :0.1Eu 3+ Excitation spectrum of

[0035] Fig.10 It is Sr3La obtained in Example 3 of the present invention. 1.9 W2O 12 :0.1Eu 3+ Emission spectrum under 395nm light excitation;

[0036] Fig.11 Sr3La prepared in Example 3 of the present invention 1.9 W2O 12 :0.1Eu 3+ Emission spectrum under 466nm light excitation;

[0037] Fig.12 It is Sr3La obtained in Example 3 of the present invention. 1.9 W2O 12 :0.1Eu 3+ Emission spectrum under 534nm light excitation;

[0038] Fig.13 Sr3La prepared in Example 4 of the present invention 1.85 W2O 12 :0.15Eu 3+ Excitation spectrum of

[0039] Fig.14Sr3La prepared in Example 4 of the present invention 1.85 W2O 12 :0.15Eu 3+ Emission spectrum under 395nm light excitation;

[0040] Fig.15 Sr3La prepared in Example 4 of the present invention 1.85 W2O 12 :0.15Eu 3+ Emission spectrum under 466nm light excitation;

[0041] Fig.16 Sr3La prepared in Example 4 of the present invention 1.85 W2O 12 :0.15Eu 3+ Emission spectrum under 534nm light excitation;

[0042] Fig.17 Sr3La prepared in Example 5 of the present invention 1.8 W2O 12 :0.2Eu 3+ Excitation spectrum of

[0043] Fig.18 Sr3La prepared in Example 5 of the present invention 1.8 W2O 12 :0.2Eu 3+ Emission spectrum under 395nm light excitation;

[0044] Fig.19 It is Sr3La obtained in Example 5 of the present invention. 1.8 W2O 12 :0.2Eu 3+ Emission spectrum under 466nm light excitation;

[0045] Fig. 20 It is Sr3La obtained in Example 5 of the present invention. 1.8 W2O 12 :0.2Eu 3+ Emission spectrum under 533nm light excitation;

[0046] Fig.21 It is Sr3La 2-x W2O 12 :xEu 3+ CIE color coordinate diagram of red luminescent materials and Sr3La in Example 3 1.9 W2O 12 :0.1Eu 3+ Photos under different lighting conditions;

[0047] Fig. 22 is Sr3La in Example 3 of the present invention 1.9 W2O 12 :0.1Eu 3+ XRD pattern of

[0048] Fig.23 is Sr3La in Example 3 of the present invention 1.9 W2O 12 :0.1Eu 3+ Emission spectrum stereogram in the test temperature range of 298-558K;

[0049] Fig.24 is Sr3La in Example 3 of the present invention 1.9 W2O 12 :0.1Eu 3+ Emission spectrum plane diagram in the test temperature range of 298-558K;

[0050] Fig.25 is Sr3La in Example 3 of the present invention 1.9 W2O 12 :0.1Eu 3+ Data and graphs related to quantum yield calculations. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] Example 1

[0053] According to the target product chemical formula Sr3La 1.99 W2O 12 :0.01Eu 3+The composition of the target product is 0.005 mol; 2.2143 g of strontium carbonate, 1.6211 g of lanthanum oxide, 2.3184 g of tungsten trioxide, 0.0088 g of europium oxide and 0.3698 g of boric acid are accurately weighed as raw materials, and these raw materials are placed together in an agate mortar, and a small amount of anhydrous ethanol is added to make the raw materials into a paste, and the raw material mixture is ground until the anhydrous ethanol is completely volatilized to obtain a raw material mixture, and the raw material mixture is transferred to an alumina crucible, placed in a box-type high-temperature furnace, heated to 1000°C in an air environment, and calcined for 4 hours, cooled to room temperature as the furnace, taken out and ground into powder, and then placed in a box-type high-temperature furnace, heated to 1200°C in an air environment, and calcined for 5 hours, cooled to room temperature as the furnace, taken out and ground again to obtain a white powder, which is the final product Sr3La 1.99 W2O 12 :0.01Eu 3+ Its excitation spectrum is shown in Figure 1 As shown, its emission spectra under near-ultraviolet 394nm, blue light 465nm and green light 533nm excitation are respectively as shown in Figure 2-4 shown.

[0054] Example 2

[0055] According to the target product chemical formula Sr3La 1.95 W2O 12 :0.05Eu 3+ The composition of the target product is 0.005 mol; accurately weigh 2.2143 g of strontium carbonate, 1.5885 g of lanthanum oxide, 2.3184 g of tungsten trioxide, 0.0440 g of europium oxide and 0.3699 g of boric acid, put these raw materials together in an agate mortar, add a small amount of anhydrous ethanol to make the raw materials into a paste, grind until the anhydrous ethanol is completely volatilized to obtain a raw material mixture, transfer the raw material mixture to an alumina crucible, place it in a box-type high-temperature furnace, heat it to 1000°C in an air environment, and calcine for 4 hours, cool it to room temperature as the furnace, take it out and grind it into powder, then place it in a box-type high-temperature furnace, heat it to 1200°C in an air environment and calcine for 5 hours, cool it to room temperature as the furnace, take it out and grind it again to obtain a white powder, which is the final product Sr3La 1.95 W2O 12 :0.05Eu 3+ Its excitation spectrum is shown in Figure 5 As shown, its emission spectra under near-ultraviolet 394nm, blue light 465nm and green light 533nm excitation are respectively as shown in Figure 6-8 shown.

[0056] Example 3

[0057] According to the target product chemical formula Sr3La 1.9 W2O 12 :0.1Eu3+ The composition of the target product is 0.005 mol; 2.2143 g strontium carbonate, 1.5477 g lanthanum oxide, 2.3184 g tungsten trioxide, 0.0880 g europium oxide and 0.3701 g boric acid are accurately weighed as raw materials, and these raw materials are placed together in an agate mortar, and a small amount of anhydrous ethanol is added to make the raw materials into a paste, and the raw material mixture is ground until the anhydrous ethanol is completely volatilized to obtain a raw material mixture, and the raw material mixture is transferred to an alumina crucible, placed in a box-type high-temperature furnace, heated to 1000°C in an air environment, and calcined for 4 hours, and then cooled to room temperature in the furnace, taken out and ground into powder, and then placed in a box-type high-temperature furnace, heated to 1200°C in an air environment, and calcined for 5 hours, and then cooled to room temperature in the furnace, taken out and ground again to obtain a white powder, which is the final product Sr3La 1.9 W2O 12 :0.1Eu 3+ Its excitation spectrum is shown in Fig. 9 As shown, its emission spectra under near-ultraviolet 394nm, blue light 465nm and green light 533nm excitation are respectively as shown in Figure 10-12 Its XRD pattern is shown in Fig. 22 As shown in the figure, the emission spectrum of the test temperature is in the range of 298-558K. Figure 23-24 The relevant data and spectra for the quantum yield calculation are shown in Fig.25 shown.

[0058] Example 4

[0059] According to the target product chemical formula Sr3La 1.85 W2O 12 :0.15Eu 3+ The composition of the target product is 0.005 mol; accurately weigh 2.2143 g of strontium carbonate, 1.5070 g of lanthanum oxide, 2.3184 g of tungsten trioxide, 0.1320 g of europium oxide and 0.3703 g of boric acid, put these raw materials together in an agate mortar, add a small amount of anhydrous ethanol to make the raw materials into a paste, grind until the anhydrous ethanol is completely volatilized to obtain a raw material mixture, transfer the raw material mixture to an alumina crucible, place it in a box-type high-temperature furnace, heat it to 1000°C in an air environment, and calcine for 4 hours, cool it to room temperature as the furnace, take it out and grind it into powder, then place it in a box-type high-temperature furnace, heat it to 1200°C in an air environment and calcine for 5 hours, cool it to room temperature as the furnace, take it out and grind it again to obtain a white powder, which is the final product Sr3La 1.85 W2O 12 :0.15Eu 3+ Its excitation spectrum is shown in Fig.13 As shown, its emission spectra under near-ultraviolet 394nm, blue light 465nm and green light 533nm excitation are respectively as shown in Figure 14-16 shown.

[0060] Example 5

[0061] According to the target product chemical formula Sr3La 1.8 W2O 12 :0.2Eu 3+ The composition of the target product is 0.005 mol; 2.2143 g of strontium carbonate, 1.4663 g of lanthanum oxide, 2.3184 g of tungsten trioxide, 0.1760 g of europium oxide and 0.3705 g of boric acid are accurately weighed, and these raw materials are placed together in an agate mortar, and a small amount of anhydrous ethanol is added to make the raw materials into a paste, and the raw material mixture is ground until the anhydrous ethanol is completely volatilized to obtain a raw material mixture, and the raw material mixture is transferred to an alumina crucible, placed in a box-type high-temperature furnace, heated to 1000°C in an air environment, and calcined for 4 hours, cooled to room temperature with the furnace, taken out and ground into powder, and then placed in a box-type high-temperature furnace, heated to 1200°C in an air environment, and calcined for 5 hours, cooled to room temperature with the furnace, taken out and ground again to obtain a white powder, which is the final product Sr3La 1.8 W2O 12 :0.2Eu 3+ Its excitation spectrum is shown in Fig.17 As shown, its emission spectra under near-ultraviolet 394nm, blue light 465nm and green light 533nm excitation are respectively as shown in Figure 18-20 shown.

[0062] See also Fig.21 , Fig.21 Sr3La 2-x W2O 12 :xEu 3+ CIE color coordinate diagram of red luminescent materials and Sr3La in Example 3 1.9 W2O 12 :0.1Eu 3+ Photos under different lighting conditions.

[0063] Combined sample Sr3La 2-x W2O 12 :xEu 3+ The CIE color coordinate value is used to calculate the color purity by the following formula:

[0064]

[0065] Among them, (x, y) is the color purity of the sample, with a value of (0.651, 0.348), (xi, yi) is the color coordinate of standard white light, with a corresponding value of (0.333, 0.333), and (xd, yd) is the color coordinate of the 615nm main wavelength, with a value of (0.673, 0.327). The calculation results show that the color purity of this series of fluorescent materials is as high as 93.62%.

[0066] According to Sr3La 1.9 W2O 12 :0.1Eu 3+ It can be seen from the photos under different wavelengths of light excitation that the Eu 3+ Doped tungstate red luminescent materials can all emit bright red light.

[0067] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, and a specific direction structure and operation, and therefore, cannot be understood as a limitation on the present invention. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0068] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A Eu3+ doped tungstate red luminescent material, characterized in that: The chemical formula of the red luminescent material is: Sr3La 2-x W2O 12 :xEu 3+ , where 0.01≤x≤0.

2. The red luminescent material can be effectively excited by a 200-420nm ultraviolet-near ultraviolet chip and a 450-480nm blue light chip to generate a narrow-band red light emission of 608-630nm, wherein the strongest emission peak is located at 616nm and the half-height width is 3.84nm.

2. Eu according to claim 1 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The following steps are involved: Step 1: According to Sr3La 2-x W2O 12 :xEu 3+ Weighing a strontium-containing compound, a lanthanum-containing compound, a tungsten-containing compound, and a europium-containing compound in a molar coefficient ratio, adding a co-solvent to these compounds and mixing them uniformly to obtain a mixed raw material; Step 2: The mixed raw materials are heated to 800-1400℃ in an air atmosphere and calcined. After keeping the temperature for 3-5h, they are naturally cooled to room temperature. After grinding into powder, the mixed raw materials are heated to 1000-1400℃ in an air atmosphere and calcined. After keeping the temperature for 4-8h, they are naturally cooled to room temperature. After grinding into powder and particle size classification, Eu can be obtained. 3+ Doped tungstate red luminescent material.

3. Eu according to claim 2 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The strontium-containing compound is strontium carbonate, strontium oxide or strontium hydroxide.

4. Eu according to claim 2 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The lanthanum-containing compound is lanthanum oxide, lanthanum hydroxide or lanthanum carbonate.

5. Eu according to claim 2 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The tungsten-containing compound is tungsten trioxide.

6. Eu according to claim 2 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The europium-containing compound is europium oxide or europium nitrate.

7. Eu according to claim 2 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The co-solvent is one or more of boric acid, ammonium nitrate, fluoride and boron oxide.

8. Eu according to claim 7 3+ The method for preparing a doped tungstate red luminescent material is characterized in that: The amount of the co-solvent added is 1-10% of the total mass of the mixed raw materials.

9. Eu according to claim 1 3+ Application of doped tungstate red luminescent material, characterized in that: The luminescent material is applied to white light LED lighting, liquid crystal display and traffic display excited by ultraviolet chips or blue light chips.

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