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排序方式: 共有1211条查询结果,搜索用时 15 毫秒
1.
2.
YAG:Ce Phosphors for WLED via Nano-Pesudoboehmite Sol-Gel Route 总被引:5,自引:0,他引:5
The sub-micron sized YAG : Ce phosphors were synthesized via a modified sol-gel method by peptizing nano-pesudoboehmite particulate. It is found that YAG phase from the dried gel powders appears at 1000 ℃ then the pure YAG phase exists at a relatively lower sintering temperature of 1400 ℃. The smaller sizes of phosphors in the ranges of 1 - 3 μm are obtained due to the contribution of seeding effects of nano-sized alumina particles to strengthen each step of the processes. Both the excitation and emission spectra of photoluminescence of the phosphor obtained at 1400 ℃ meet well with the spectroscopic requirements of the WLED phosphors. 相似文献
3.
Y1.94-xMgxO2S:0.06Ti (0≤x≤0.10) phosphors with long afterglow were synthesized by solid state reaction route. The photoluminescence spectra, decay curves, thermoluminescent spectra and chromaticity coordinate curves were investigated. The results show that the luminescence intensity of Y1.94-xMgxO2S:0.06Ti (0≤x≤0.10) phosphors decrease gradually with increasing Mg2 ion content, and the shape of luminescence spectra and chromaticity coordinate change as well. Furthermore, two thermoluminescent peaks in single Ti-doped Y2O2S sample are found at 91.8 and 221.5 ℃, respectively. Nevertheless, significant different spectra were found for the Mg, Ti co-doped Y2O2S samples that three thermoluminescence peaks appear at 52.3, 141.7 and 226.8 ℃, respectively. These results indicate that the co-doped Mg ion changes the inherent trap depth of single Ti-doped Y2O2S:Ti phosphor, and induces simultaneously a new trap level in the Y1.94-xMgxO2S:0.06Ti phosphor. Based on the analysis of thermoluminescent spectra, photoluminescent spectra, decay curve and crystal structure defect, it was proposed that the varied structure defect and introduced new trap level by the doped Mg2 ions should be responsible for reducing luminescence intensity and varying color in the Y1.94-xMgxO2S:0.06Ti phosphor. 相似文献
4.
《中国稀土学报(英文版)》2022,40(5):709-716
A series of new oxyapatite red phosphors Ca3Y7(BO4)(SiO4)5O doped with different concentrations of Eu3+ were successfully synthesized by high temperature solid state method. The X-ray diffraction (XRD) Rietveld refinement results show that the structure of the phosphor belongs to space group P63/m and Eu3+ ion replaces Y3+ ion. The emission spectrum consists of the characteristic emission peaks corresponding to Eu3+ under the excitation of 274 nm and the dominant emission peak is at 614 nm (5D0→7F2 of Eu3+). The concentration quenching effect occurs and the optimized Eu3+ concentration is 4.0 mol%. The energy level diagram for luminous mechanism is also given and the non-radiative energy transfer mechanism between Eu3+ is mainly exchange interaction. The CIE coordinate is close to the ideal red light and the color purity is higher than 99.79%. Moreover, the phosphor exhibits moderate thermal stability because the photoluminescence intensity at 423 K is still maintained at higher than 78.97% of that at room temperature. The internal quantum efficiency of Ca3Y7(BO4)(SiO4)5O:4.0 mol%Eu3+ phosphor is 58.2%. A red light emitting diode (LED) device based on it can emit bright red light. The CCT values of the device are basically unchanged when driven by various bias current. The results show that Ca3Y7(BO4)(SiO4)5O:Eu3+ is a new type of oxyapatite red fluorescent material with good comprehensive performances. 相似文献
5.
不同添加剂对SrAl2O4:(Eu,Dy)磷光体发光性能的影响 总被引:1,自引:0,他引:1
在较低的温度下用燃烧合成法快速合成了 Eu2 ,Dy3 掺杂的SrAl2O4长余辉磷光体发光材料.研究了P2O5,CaF2,H3BO3,NaF 几种添加剂对SrAl2O4:(Eu,Dy)粉体发光性能的影响.结果发现:H3BO3和P2O5的添加有利于改善磷光体的发光性能,而在配料中加入CaF2和NaF,磷光体发光效率降低.随着这几种添加剂的加入,SrAl2O4:(Eu,Dy)磷光体材料发射光谱的主发射峰不同程度的出现蓝移.根据实验结果分析了添加剂的作用机理. 相似文献
6.
7.
康明 《武汉理工大学学报(材料科学英文版)》2009,24(1):20-24
Ca(NO3)2·4H2O, Eu(NO3)3 and H2C2O4·2H2O were adopted to synthesize CaO: Eu3+ with the chemical co-precipitation method, and the effects of the calcination temperature and Eu3+ doping concentration on the phosphor structure and its luminescent properties were investigated by TG-SDTA, XRD, and PL-PLE.
The results confirm that the Eu3+ ions as luminescent centers substitutes Ca2+ sites without changing the crystal structure of cubic CaO. The optimum calcination temperature and the optimum concentration
of Eu3+ are 1 100 ° and 1 mol%, respectively, under which the best crystallinity and highest PL intensity appeared. The maximum emission
wavelength is 592 nm (5D0→7F1) which is excited by xenon lamp with the wavelength of 200–280 nm, indicating that the Eu3+ ion mainly locates in the symmetric position (Oh) in the crystal lattice of CaO.
Funded by the Science and Technology Bureau of Sichun Province(No. 2006J13-059) and Education Bureau of Sichun Province (No.
2006A094) 相似文献
8.
通过改变氧化钇薄膜中掺杂稀土元素的种类,来控制发光薄膜的荧光发射波长.利用电化学沉积法制备稀土掺杂氧化钇荧光薄膜.电化学沉积法制备的薄膜结晶效果好,掺杂离子分布较均匀,且不需要高温高压或者真空条件,成本很低.所制备的Y2O3:Ln荧光发光薄膜经XRD分析具有立方晶体结构;不同稀土掺杂的氧化钇呈现出不同的表面形貌;掺杂的Ln离子均匀地分布在薄膜中,经测试所有的Y2O3:Ln荧光发光薄膜都显示出较强的发射强度,且发光波长随着掺杂离子的不同而不同:Y2O3:Er3+发绿光,Y2O3:Ce3+发黄绿光,Y2 O3:Sm3+发蓝光,Y2O3:Pr3+发橙光.因此,电化学沉积法可用于制备具有不同发光波长的氧化钇荧光薄膜. 相似文献
9.
Junhang Tian Weidong Zhuang Ronghui Liu Yuanhong Liu Guantong Chen Siwei Chen Ze Jiang 《Journal of the American Ceramic Society》2021,104(8):4014-4023
The Eu2+-activated nitride phosphors have been widely used in solid-state lighting, but the applications in high-power white-light-emitting diodes (wLEDs) field require higher thermal stability of luminescent materials. The oxidation of Eu2+ and the damage of nitride host in the Eu2+-activated nitride phosphors are the two crucial reasons for the luminescence loss while operating. A superficial organic carbon modification is performed on the red-emitting (Sr,Ca)AlSiN3:Eu2+ phosphor via the incorporation of organic carbon by solution mixing and thermal post-treatment under the N2-H2 atmosphere. After the superficial organic carbon modification, the oxidation of Eu2+ and the formation of impurity phases on the phosphor surface are effectively reduced. When the superficial organic carbon modified sample was treated in the 2 wt.% sucrose solutions, the relative brightness is strengthened by 2.15%, the thermal quenching characteristic is improved by 8.9% at 300℃, and the aging test results show an excellent thermal stability. All above indicate that the superficial organic carbon modification is a promising technique to enhance the thermal stability of analogous Eu2+-activated nirtide phosphors. 相似文献
10.
Junpeng Xue Zhongkai Yu Hyeon Mi Noh Jung Hyun Jeong Byung Chun Choi Sung Heum Park Bo Ram Lee Peng Du Mingjun Song 《Journal of the American Ceramic Society》2021,104(10):5086-5098
Ce3+/Tb3+ co-doped NaMgBO3 phosphors were successfully synthesized by solid-state method. Under 381 nm excitation, the cyan emission owing to the 5d → 4f of Ce3+ ions and green emissions arising from the 5D4 → 7FJ (J = 6, 5, 4, and 3) transitions of Tb3+ ions were seen in all the phosphors. Through theoretical analysis, one knows that the energy transfer from Ce3+ to Tb3+ ions with high efficiency of 83.74% was contributed by dipole–dipole transition. Furthermore, the internal quantum efficiency of NaMgBO3:0.01Ce3+,0.03Tb3+ phosphor was 54.28%. Compared with that of at 303 K, the emission intensity of the developed products at 423 K still kept 73%, revealing the splendid thermal stability of the studied phosphors. Through utilizing the resultant phosphors as cyan-green components, the fabricated white-LED device exhibited an excellent correlated color temperature of 2785 K, high color-rendering index of 85.73, suitable luminance efficiency of 25.00 lm/W, and appropriate color coordinate of (0.4279, 0.3617). Aside from the superior photoluminescence, the synthesized phosphors also exhibited excellent cathode-luminescence properties which were sensitive to the current and accelerating voltage. Furthermore, the NaMgBO3:0.01Ce3+,0.03Tb3+ phosphors with multi-mode emissions were promising candidates for optical anti-counterfeiting. All the results indicated that the Ce3+/Tb3+ co-doped NaMgBO3 phosphors were potential multi-platforms toward white-LED, field emission displays, and optical anti-counterfeiting applications. 相似文献