W-based double perovskite structure 6+ With rare earth Sm 3+ Doped phosphor and its preparation method and application in white LED

Abstract

The application provides a W 6+ With rare earth Sm 3+ A doping fluorescent powder, a preparation method thereof and application of the fluorescent powder in a white light LED, the fluorescent powder has a chemical general formula of Ca2Sc 0.95 Sb 1‑x W 5x / 6 O6:0.05Sm 3+ , wherein x is a molar fraction of 0.00 to 0.10; the fluorescent powder has an excitation spectrum covering a range of 350-500nm under monitoring of a 600nm emission wavelength, and a main emission peak is located at 600nm; when x=0.02, under excitation of 406nm ultraviolet light, the light emission intensity at 423K temperature is still 88.1% of the light emission intensity at room temperature, the fluorescent powder has wide spectrum excitation and thermal stability, a white light LED prepared by mixing commercial blue light and green light fluorescent powders emits white light under excitation of a 395-400nm chip, and a color rendering index is as high as 94.

Description

Technical Field

[0001] This invention belongs to the field of inorganic luminescent materials technology, and particularly relates to a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphors, their preparation methods, and their applications in white LEDs. Background Technology

[0002] White light-emitting diodes (LEDs) have become the mainstream choice in the lighting field due to their advantages such as high luminous efficiency, long lifespan, environmental friendliness, and energy saving. There are three main methods for generating white light in the industry. One method combines red, green, and blue LED chips to produce white light, but this method faces challenges in terms of cost and technical complexity. Another method uses a blue InGaN chip to excite yellow phosphor (YAG:Ge). 3+ This method, due to the lack of red light components in the phosphor, suffers from high correlated color temperature, low color rendering index, performance degradation after a certain period of operation, and blue light hazard, failing to meet people's demand for high-quality warm white light lighting. Another method is to use near-ultraviolet LED chips to excite red, green, and blue phosphors, but this method suffers from significant light loss, and the red light component exhibits low efficiency and insufficient stability. Based on these reasons, compensating for the red light component in white LEDs has become the preferred strategy for optimizing white LEDs.

[0003] Rare earth ions, due to their abundant 4f-4f electron transitions, have become ideal activators, thus rare earth doping has attracted widespread attention. Eu 3+ While exhibiting excellent performance in deep red light emission, its high cost is the biggest drawback for applications. Rare earth Sm 3+ Ions have abundant 4f-4f electron transitions and high quantum efficiency. Orange-red light emission and low cost can make up for this drawback, showing great application potential in the field of white LEDs.

[0004] Currently, the industry mainly prepares red phosphors through rare-earth doped matrix materials. The choice of matrix material directly determines the phosphor's luminous efficiency, color purity, thermal stability, and compatibility with LED chips. Therefore, selecting a suitable matrix is ​​crucial for preparing excellent phosphors. Existing matrices are mainly classified as follows: ① Simple oxides (Y₂O₃, Gd₂O₃, etc.), disadvantages: high phonon energy, high probability of non-radiative transitions, low luminous efficiency, average color purity, insufficient red component; weak absorption of near-ultraviolet / blue light, low excitation efficiency. ② Aluminate systems (YAG, aluminates, etc.), disadvantages: poor stability under high pressure, insufficient red component. ③ Silicate systems, disadvantages: complex synthesis process, some requiring a reducing atmosphere; poor thermal stability. ④ Phosphate systems, disadvantages: poor stability under high pressure; easily decomposed at high temperatures. ⑤ Nitride and oxynitride systems, disadvantages: harsh synthesis conditions, requiring high temperatures of 1600-1800℃; high preparation cost, high energy consumption; emission wavelengths cover 680-760nm, with a small contribution to the color rendering index. ⑥ Sulfide systems: Disadvantages include poor chemical stability, hygroscopicity, strong temperature resistance, poor thermal stability, production of toxic gases (H2S, etc.) under ultraviolet radiation, and low luminous efficiency. ⑦ Fluoride and halide systems: Disadvantages include low energy transfer efficiency, poor water resistance, hygroscopicity, and moderate thermal stability. ⑧ Perovskite structures, particularly the double perovskite oxide system (A2BB'O6), offer advantages such as high structural tolerance, strong tunability, and mature preparation processes. In recent years, the doping of rare earth ions or transition metal ions into double perovskite antimonate matrices has been extensively studied. However, existing double perovskite phosphors suffer from insufficient thermal stability, resulting in low color rendering indexes for white LEDs. Therefore, it is necessary to provide a red phosphor with better thermal stability, a simpler preparation process, and the ability to improve the color rendering index of LEDs. Summary of the Invention

[0005] In view of the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor, the phosphor having the general chemical formula Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+Where x is a mole fraction of 0.00 to 0.10; the excitation spectrum of the phosphor at a monitored emission wavelength of 600 nm covers the range of 350-500 nm, with the main emission peak located at 600 nm; when x=0.02, under 406 nm ultraviolet light excitation, the luminous intensity at 423 K is still 88.1% of the luminous intensity at room temperature, exhibiting both broad-spectrum excitation and thermal stability. White LEDs prepared by mixing commercial blue and green phosphors emit white light under 395-400 nm chip excitation, with a color rendering index as high as 94.4, effectively solving the problems of low absorption efficiency in the ultraviolet excitation band, easy concentration quenching caused by high concentration doping, and insufficient thermal stability of existing red phosphor materials.

[0006] To achieve the above objectives, the present invention employs the following technical solution: W based on double perovskite structure 6+ With rare earth Sm 3+ Doped phosphor, wherein the phosphor has the general chemical formula Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ , where x is a mole fraction ranging from 0.00 to 0.10.

[0007] As a preferred embodiment of the present invention, the phosphor has a monoclinic biperovskite crystal structure with space group P21 / n; Sm 3+ Occupy Sc 3+ Site, W 6+ Occupy Sb 5+ Site.

[0008] As a further preferred embodiment of the present invention, x is a mole fraction of 0.01 to 0.06.

[0009] As a further preferred embodiment of the present invention, x is a mole fraction of 0.02.

[0010] This invention also provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ A method for preparing doped phosphors, comprising the following steps: (1) Weigh out CaCO3, Sc2O3, Sb2O3 and Sm2O3 and WO3 with a purity ≥99.9% according to the stoichiometric ratio; (2) Place the weighed raw materials in an agate mortar and grind them thoroughly to mix the powder evenly. (3) Place the well-ground powder in a corundum crucible and calcine the corundum crucible in a box-type constant temperature furnace; raise the temperature to 900-1000℃ at 5-10℃ per minute in an air atmosphere, raise the temperature to 1200-1400℃ at 2-5℃ per minute, raise the temperature to 1500-1600℃ at 2-5℃ per minute, hold the temperature for 6-8 hours after raising the temperature to 1500-1600℃, and then cool it with the furnace. (4) The solid obtained after furnace cooling is milled, and the white powder obtained after milling is Ca2Sc. 0.95 Sb 1- x W 5x / 6 O6:0.05Sm 3+ Fluorescent powder.

[0011] The W based on the double perovskite structure provided by this invention 6+ With rare earth Sm 3+ White LEDs with a color rendering index as high as 94.4 can be fabricated by mixing commercial blue and green phosphors with doped phosphors, and therefore can be used in the fabrication of white LED devices.

[0012] The present invention also provides a white LED device. In the preparation of the white LED device, the phosphor described above is first mixed with blue phosphor and green phosphor, and then mixed with ultraviolet curing adhesive and uniformly coated onto the LED chip. The excitation wavelength of the LED chip is 395-400 nm.

[0013] As a preferred embodiment of the present invention, the blue phosphor is BaMgA. 110 O 17 Eu 2+ The green phosphor is (Ba,Sr)₂SiO₄:Eu 2+ .

[0014] As a further preferred embodiment of the present invention, the W based on the double perovskite structure 6+ With rare earth Sm 3+ The doped phosphor is combined with blue phosphor and green phosphor in a mass ratio of 10:2:1.

[0015] As a further preferred embodiment of the present invention, when the white LED device is prepared, the mass ratio of UV-curable adhesive to total phosphor is 1:1, and the coating thickness is controlled at 20-300μm.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention are: (1) This invention utilizes a novel design of Ca2ScSbO6 double perovskite as the matrix and Sm 3+ and W 6+ Doping strategy, the prepared Ca2Sc 0.95 Sb1-x W 5x / 6 O6:0.05Sm 3+ The phosphor's excitation spectrum covers the range of 350-500nm at a monitored emission wavelength of 600nm, with the main emission peak located at 600nm. This achieves the spectral excitation characteristics of the phosphor in the 350-500nm band, perfectly matching the ultraviolet LED chip. Furthermore, the synthesized phosphor exhibits strong characteristic emission peaks at 565nm, 600nm, 646nm, and 709nm, showing stable orange-red light emission.

[0017] (2) This invention was made through an unexpected experimental discovery that Ca2Sc 0.95 SbO6:0.05Sm 3+ Phosphor doped with W 6+ This will subsequently improve the material's corresponding luminescent properties (thermal stability, LED color rendering index). The phosphor with the optimal doping concentration (0.02 mol) maintains an emission peak intensity of 88.1% of the room temperature emission intensity under 406 nm UV excitation at 423 K, exhibiting excellent thermal stability, significantly superior to existing Na3Gd phosphors. 0.97 P2O8:0.03Sm 3+ (The luminescence intensity at 423K is 75% of the luminescence intensity at room temperature), Y2MgTiO6:Sm 3+ (The luminescence intensity at 423K is 79.71% of the luminescence intensity at room temperature), SLNO: 0.07Sm 3+ (The luminescence intensity at 423K is 80.7% of the luminescence intensity at room temperature) and other phosphors; and doped with W 6+ The phosphor was mixed with commercial blue and green phosphors and encapsulated into an LED device. The encapsulated LED emitted bright white light and achieved a high color rendering index Ra (94.4), which is significantly better than existing phosphors and undoped W. 6+ Ca2Sc 0.95 SbO6:0.05Sm 3+ Phosphor (color development index Ra is 85.6).

[0018] (3) The phosphor provided by this invention has a monoclinic bis-perovskite crystal structure, and the Sc in the phosphor... 3+ As a B-site ion, its ionic radius (0.75 Å) is similar to that of Sm 3+ The high matching at (0.958 Å) makes Sm 3+ Able to stably occupy Sc 3+ 6-coordination lattice sites; Sb 5+ Ionic radius (0.60 Å) and W 6+ The high degree of matching in ionic radius (0.60 Å) makes W 6+ Able to stably occupy Sb5+ The 6-coordinate crystal lattice sites cause the local coordination environment to change from the original high symmetry to low symmetry, and defects are introduced due to heterovalent substitution. However, experimental results show that W 6+ The introduction of [something] will not cause significant changes to the crystal structure.

[0019] (4) The phosphor provided by the present invention has good chemical stability and is not prone to deliquescence under normal temperature and atmospheric conditions. It is prepared by high temperature solid phase method, which is mature, simple and low cost. Attached Figure Description

[0020] Figure 1 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0-0.10) Phosphor Characterization Figure 1 ; where, (a)Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0-0.10) XRD pattern of phosphor; (b) Schematic diagram of crystal structure; Refined result (c) x=0.00; (d) x=0.02.

[0021] Figure 2 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ Phosphor Characterization Figure 2 Among them, (a) PLE waterfall plot; (b) PLE intensity at 406 nm as a function of x; (c) PLE plot at 600 nm for phosphor monitoring at x=0.02.

[0022] Figure 3 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ Phosphor Characterization Figure 3 Among them, (a) PL spectrum; (b) curve of PL intensity as a function of x at an excitation wavelength of 406 nm and a wavelength of 600 nm.

[0023] Figure 4 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+(x = 0.00, 0.02) Temperature-varying PL plots of phosphors; where (a) x = 0.00; (b) x = 0.02; Temperature-varying PL spectral intensity histograms at 600 nm (c) x = 0.00; (d) x = 0.02.

[0024] Figure 5 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x = 0.02) Emission spectra of LED devices prepared with phosphor; where (a) LED CIE diagram; (b) EL spectrum at 20mA.

[0025] Figure 6 For Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x = 0.00) Emission spectra of LED devices prepared with phosphor; where (a) LED CIE diagram; (b) EL spectrum at 20 mA. Detailed Implementation

[0026] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0027] The specific implementation of the present invention will be described in detail below with reference to specific embodiments. Example

[0028] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor, the phosphor having the general chemical formula Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ , where x is a mole fraction ranging from 0.00 to 0.10; The W based on the double perovskite structure 6+ With rare earth Sm 3+ The preparation method of doped phosphor includes the following steps: (1) Weigh out CaCO3, Sc2O3, Sb2O3 and Sm2O3 and WO3 with a purity ≥99.9% according to the stoichiometric ratio; (2) Place the weighed raw materials in an agate mortar and grind them thoroughly for 20 minutes to achieve uniform mixing of various powders; (3) Place the thoroughly ground powder in a corundum crucible and calcine the corundum crucible in a box-type constant temperature furnace. In an air atmosphere, raise the temperature to 900°C at 10°C / min, raise the temperature to 1400°C at 5°C / min, raise the temperature to 1500°C at 2°C / min, hold the temperature at 1500°C for 6 hours, and then cool it with the furnace. (4) The solid obtained after furnace cooling is milled, and the white powder obtained after milling is Ca2Sc. 0.95 Sb 0.99 W 0.05 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0029] Specifically, this embodiment does not contain W. 6+ For example, x=0.00, the amounts of each raw material are: CaCO3 1.724996 g; Sc2O3 0.564532 g; Sb2O3 1.256046 g; Sm2O3 0.075125 g. Example

[0030] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.994 W 0.03 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1, except that the amount of WO3 weighed is 0.006 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb 0.994 W 0.03 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0031] Specifically, the amounts of each raw material are as follows: CaCO3 1.724005 g; Sc2O3 0.564207 g; Sb2O3 1.247793 g; Sm2O3 0.075082 g; WO3 0.009983 g. Example

[0032] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.99 W 0.05 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1, except that the amount of WO3 weighed is 0.01 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb0.99 W 0.05 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0033] Specifically, the amounts of each raw material are as follows: CaCO3 1.723412 g; Sc2O3 0.564013 g; Sb2O3 1.242344 g; Sm2O3 0.075056 g; WO3 0.016633 g. Example

[0034] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.98 W 0.1 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1 in that the amount of WO3 weighed is 0.02 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb 0.98 W 0.1 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0035] Specifically, the amounts of each raw material are as follows: CaCO3 1.72183g; Sc2O3 0.563496g; Sb2O3 1.228667g; Sm2O3 0.074987g; WO3 0.033236g. Example

[0036] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.96 W 0.2 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1, except that the amount of WO3 weighed is 0.04 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb 0.96 W 0.2 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0037] Specifically, the amounts of each raw material are as follows: CaCO3 1.718726g; Sc2O3 0.56248g; Sb2O3 1.201422g; Sm2O3 0.074852g; WO3 0.066352g. Example

[0038] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.94 W 0.3 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1 in that the amount of WO3 weighed is 0.06 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb 0.94 W 0.3 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0039] Specifically, the amounts of each raw material are as follows: CaCO3 1.715632g; Sc2O3 0.561467g; Sb2O3 1.174275g; Sm2O3 0.074717g; WO3 0.099349g. Example

[0040] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.92 W 0.4 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1, except that the amount of WO3 weighed is 0.08 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc. 0.95 Sb 0.92 W 0.4 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0041] Specifically, the amounts of each raw material are as follows: CaCO3 1.71255g; Sc2O3 0.560459g; Sb2O3 1.147226g; Sm2O3 0.074583g; WO3 0.132227g. Example

[0042] This embodiment provides a W based on a double perovskite structure. 6+ With rare earth Sm 3+ Doped phosphor (Ca2Sc) 0.95 Sb 0.90 W 0.5 / 6 O6:0.05Sm 3+ The preparation method of WO3 in this example differs from that in Example 1, except that the amount of WO3 is 0.10 mol, while the rest is the same as in Example 1, ultimately yielding Ca2Sc.0.95 Sb 0.90 W 0.5 / 6 O6:0.05Sm 3+ Fluorescent powder.

[0043] Specifically, the amounts of each raw material are as follows: CaCO3 1.709528g; Sc2O3 0.560459g; Sb2O3 1.120305g; Sm2O3 0.074451g; WO3 0.164992g. Example

[0044] This embodiment provides a white LED device, comprising the phosphor described in Embodiment 4 above, and commercial blue light powder (BAM (BaMgA)). 110 O 17 Eu 2+ (main peak 450-460nm) and commercial green phosphor ((Ba,Sr)2SiO4:Eu) 2+ The process involves a phosphor with a main peak of 530-540 nm and an ultraviolet semiconductor chip with an excitation wavelength of 395-400 nm; wherein the phosphor is combined with commercial blue phosphor and commercial green phosphor in a mass ratio of 10:2:1; and a high-performance white LED device is constructed by encapsulating it in silicone.

[0045] Specifically, LED packaging parameters: 1. Add the phosphor material described in Example 4 above; silicate green powder; BAM blue powder; 2. Use UV-curable adhesive, Leaftop 9300, mix the powder and adhesive evenly, apply it to the LED chip, cure, and then test. 3. The powder-to-resin mass ratio is 1:1 (this refers to the total mass of all powders mixed together). The coating thickness is controlled at 20-300μm (after curing) according to the industry standard coating process parameters for conventional silicone / epoxy resin encapsulation. 4. LED chip: 1 W, 395-400 nm, Sanan Optoelectronics.

[0046] Example 10: This embodiment provides a white LED device, which differs from Embodiment 9 in that it uses the phosphor described in Embodiment 1.

[0047] The present invention tests the phosphor prepared above, as follows: XRD testing was performed using a Shimadzu XRD-7000 powder diffractometer equipped with a Cu Kα source (λ = 0.15418 nm). Intensity data of the prepared samples were collected within the range of 10–90° at the 2θ angle under operating conditions of 45 kV and 40 mA to obtain the crystal structure and phase purity of the prepared samples.

[0048] XRD refinement: The XRD data of the prepared samples were refined using GSAS software.

[0049] Using an Edinburgh FLS-1000 fluorescence spectrometer, the sample was placed in the instrument's detection area, and the room-temperature fluorescence emission spectrum (PL spectrum) and fluorescence excitation spectrum (PLE spectrum) of the sample were collected by controlling the xenon lamp and the built-in sensor.

[0050] The high-temperature variable-temperature fluorescence emission spectra of the phosphor were collected using a Horiba Jobin Yvon Fluorologo-3 fluorescence spectrometer with continuous irradiation from a 450 W xenon lamp as the fluorescence excitation source.

[0051] result: Figure 1 (a) Demonstrates the present invention Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ The XRD pattern of the phosphor was shown and compared with the standard card PDF#ICSD 262995 (Ca2ScSbO6). The figure shows that different W... 6+ Ca2Sc with doping levels (x ranges from 0.00 to 0.10) 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ The sample's XRD pattern perfectly matched the standard card, and no impurity phases were observed in any of the diffraction peaks, indicating that Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ The sample is a pure phase; moreover, magnification at 32° revealed that the main diffraction peak did not shift significantly with increasing x-value, indicating that the unit cell did not undergo significant distortion, suggesting that W... 6+ (0.60Å) has the potential to replace Sb 5+ (0.60 Å) lattice site. (b) Schematic diagram of the synthesized phosphor crystal structure. From the structural diagram, it can be seen that Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ The sample exhibits a double perovskite structure, where Sm, W, and Sb are coordinated with six O atoms to form octahedra, with W potentially substituting for Sb lattice sites. Ca is coordinated with seven O atoms to form a decahedral structure, with space group P21 / n. (c) and (d) are Ca2Sc, respectively. 0.95 Sb 1-x W 5x / 6 O6:0.05Sm3+ The XRD refined structures of the phosphor at x=0.00 and x=0.02 are shown in the figure. All fitted parameters meet the requirements (R²). wp <10%,x 2 <3). Where x=0.00, the phosphor lattice parameters are a=5.507, b=5.638, c=7.866, v=244.268; and x=0.02, the phosphor lattice parameters are a=5.503, b=5.633, c=7.859, v=243.600. The refined data shows that the volume of the W-doped phosphor crystal structure is slightly reduced, possibly due to the W... 6+ Ion doping to replace Sb 5+ Ionic lattice sites cause changes in the coordination environment of the crystal structure.

[0052] Figure 2 This invention, Ca2Sc, demonstrates... 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ Excitation spectrum of phosphor (λex = 406 nm, λem = 600 nm). Figure (a) shows the excitation spectrum of Ca2Sc under the condition of a monitoring peak at 600 nm. 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ The excitation spectrum of the phosphor was observed to vary with x. The peak position and shape remained consistent with x, indicating that the samples exhibited the same luminescence mechanism. Figure (b) shows the excitation peak intensity as a function of x at the optimal excitation wavelength. The figure shows that the excitation peak intensity first increases and then decreases with increasing x, reaching a maximum at x=0.02. Figure (c) shows the excitation spectrum of the prepared sample Ca2Sc at a monitoring wavelength of 600 nm. 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0.02) Excitation spectrum. The figure shows a distinct excitation peak before 300 nm, which is the charge transfer band (CTB), corresponding to O. 2- 2p orbital Sm 3+ Charge transfer transitions in 3d orbitals. Sharp peaks at 347, 364, 377, 406, 419, 439, 468, 479, and 494 nm correspond to Sm in the phosphor, respectively. 3+ ion 6 H 5 / 2 → 4 D 5 / 2 , 6 H 5 / 2 → 4 D 3 / 2 , 6 H5 / 2 → 6 P 7 / 2 , 6 H 5 / 2 → 4 F 7 / 2 , 6 H 5 / 2 → 6 P 5 / 2 , 6 H 5 / 2 → 4 G 9 / 2 , 6 H 5 / 2 → 4 I 13 / 2 , 6 H 5 / 2 → 4 I 11 / 2 , 6 H 5 / 2 → 4 I 9 / 2 The excitation peak at 406 nm is the most prominent, indicating that the ff transition requires higher energy. Therefore, 406 nm is the optimal excitation wavelength for obtaining the phosphor emission spectrum.

[0053] Figure 3 (a) Shows the prepared Ca2Sc 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x = 0.00-0.10) Emission spectrum of phosphor at excitation wavelength of 406 nm. The peak position and shape of the emission spectrum remain consistent under different doping concentrations, with the highest emission peak intensity at 600 nm. Four relatively strong emission peaks are observed in the figure, including one at 565 nm (x = 0.00-0.10). 4 G 5 / 2 - 6 H 5 / 2 ), 600nm ( 4 G 5 / 2 - 6 H 7 / 2 ), 646nm 4 G 5 / 2 - 6 H 9 / 2 ), 709nm ( 4 G 5 / 2 - 6 H 11 / 2 Figure (b) shows the emission intensity as a function of x at the 600 nm emission peak. It was observed that the phosphor emission intensity first increased and then decreased with increasing x, reaching its highest value at x = 0.02. This indicates that the concentration is Ca2Sc. 0.95 Sb1-x W 5x / 6 O6:0.05Sm 3+ Optimal doping concentration of phosphor.

[0054] Figure 4 This invention, Ca2Sc, demonstrates... 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0.00, 0.02) Emission spectra of the phosphor were collected at varying temperatures from 298 to 498 K under steady-state excitation at 406 nm. Figures 4(a) and (b) show that the spectral shape remained highly consistent throughout the temperature range, indicating that no significant thermally induced distortion occurred in the crystal field environment. Figure 4 As shown in (c) and (d), the emission peak intensity gradually decreases with increasing temperature. At 423 K (150 °C), the emission peak intensity still remains at 84.5% and 88.1% of the peak intensity at 298 K, respectively, indicating that W... 6+ The introduction significantly enhances the thermal stability of the phosphor.

[0055] Figure 5 The Ca2Sc described in this invention is shown 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0.02) Phosphor and commercial blue phosphor BaMgA 110 O 17 Eu 2+ (BAM) and commercial green phosphor (Ba,Sr)2SiO4:Eu 2+ The mixture was prepared in a specific ratio and uniformly coated onto a 395-400 nm ultraviolet light chip. A simple LED device was fabricated and its luminous performance was tested. Figure 5 (a) shows the color coordinates calculated by CIE1931 software. The inset image is a digital photograph of the LED device under current-only and current-free conditions. When a 20mA current is applied to the LED device, it will display a bright white color. Figure 5 (b) shows the luminescence spectrum of the LED under a forward current of 20mA. The WLEDs emit white light with a color rendering index (Ra) of 94.4.

[0056] Figure 6 The Ca2Sc described in this invention is shown 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ (x=0.00) Phosphor and commercial blue phosphor BaMgA 110 O 17 Eu 2+(BAM) and commercial green phosphor (Ba,Sr)2SiO4:Eu 2+ The mixture was prepared in a specific ratio and uniformly coated onto a 395-400 nm ultraviolet light chip. A simple LED device was fabricated and its luminous performance was tested. Figure 6 (a) shows the color coordinates calculated by CIE1931 software. The inset image is a digital photograph of the LED device under current-only and current-free conditions. When a 20mA current is applied to the LED device, it will display white. Figure 6 (b) shows the luminescence spectrum of the LED under a forward current of 20mA. The WLEDs emit white light with a color rendering index (Ra) of 85.6.

[0057] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. W based on double perovskite structure 6+ With rare earth Sm 3+ Doped phosphor, characterized in that, The general chemical formula of the phosphor is Ca2Sc. 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ , where x is a mole fraction ranging from 0.00 to 0.

10.

2. The W based on a double perovskite structure according to claim 1 6+ With rare earth Sm 3+ Doped phosphor, characterized in that, The phosphor has a monoclinic biperovskite crystal structure with space group P21 / n; Sm 3+ Occupy Sc 3+ Site, W 6+ Occupy Sb 5+ Site.

3. The W based on a double perovskite structure according to claim 1 6+ With rare earth Sm 3+ Doped phosphor, characterized in that, The value of x is a mole fraction ranging from 0.01 to 0.

06.

4. The W based on a double perovskite structure according to claim 3 6+ With rare earth Sm 3+ Doped phosphor, characterized in that, The value of x is 0.02 moles.

5. The W based on the double perovskite structure according to any one of claims 1 to 4 6+ With rare earth Sm 3+ A method for preparing doped phosphors, characterized in that, The method includes the following steps: (1) Weigh out CaCO3, Sc2O3, Sb2O3 and Sm2O3 and WO3 with a purity ≥99.9% according to the stoichiometric ratio; (2) Place the weighed raw materials in an agate mortar and grind them thoroughly to mix the powder evenly. (3) Place the well-ground powder in a corundum crucible and calcine the corundum crucible in a box-type constant temperature furnace; raise the temperature to 900-1000℃ at 5-10℃ per minute in an air atmosphere, raise the temperature to 1200-1400℃ at 2-5℃ per minute, raise the temperature to 1500-1600℃ at 2-5℃ per minute, hold the temperature for 6-8 hours after raising the temperature to 1500-1600℃, and then cool it with the furnace. (4) The solid obtained after furnace cooling is milled, and the white powder obtained after milling is Ca2Sc. 0.95 Sb 1-x W 5x / 6 O6:0.05Sm 3+ Fluorescent powder.

6. The W based on the double perovskite structure according to any one of claims 1 to 4 6+ With rare earth Sm 3+ Application of doped phosphors in the fabrication of white LED devices.

7. A white LED device, characterized in that, During the fabrication of the white LED device, the W based on the double perovskite structure described in any one of claims 1 to 4 is first... 6+ With rare earth Sm 3+ The doped phosphor is mixed with blue phosphor and green phosphor, then mixed with UV-curable adhesive and uniformly coated onto the LED chip. The excitation wavelength of the LED chip is 395-400 nm.

8. A white LED device according to claim 7, characterized in that, The blue phosphor is BaMgA 110 O 17 Eu 2+ The green phosphor is (Ba,Sr)₂SiO₄:Eu 2+ .

9. A white LED device according to claim 8, characterized in that, The W based on the double perovskite structure 6+ With rare earth Sm 3+ The doped phosphor is combined with blue phosphor and green phosphor in a mass ratio of 10:2:

1.

10. A white LED device according to claim 9, characterized in that, When fabricating the white LED device, the mass ratio of UV-curable adhesive to total phosphor is 1:1, and the coating thickness is controlled between 20-300 μm.

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