排序方式: 共有20条查询结果,搜索用时 15 毫秒
1.
提出了一种绿色、简便的基于Fe2+离子的氧化还原策略来提高锰激活氟化物红色荧光粉的耐湿性。采用共沉淀法合成了K2SiF6:Mn4+(KSFM)荧光材料,并对Fe2+处理前后样品的形貌、晶体成分、元素组成、发光性能、荧光寿命、耐湿性和热稳定性进行了研究。SEM结果表明,经Fe2+离子处理后的K2SiF6:Mn4+(T-KSFM)颗粒的团聚程度得到有效的降低。XPS测试结果表明,T-KSFM样品表面Mn含量减少。光谱测试结果表明,最强激发峰约468 nm处,次强峰位于约360 nm处,而最强窄带发射峰位于632 nm处。经过Fe2+处理后的T-KSFM荧光粉在去离子水浸泡320 min后,其相对发光强度为初始发光强度的80.3%,而KSFM仅还有63.4%。此外,将T-KSFM作为红色组分与黄粉YAG以及蓝光芯片封装制得WLEDs色坐标为(0.4110,0.3963),处于... 相似文献
2.
采用溶胶-凝胶法合成Ca3Al2O6:Eu3+红色荧光粉,通过XRD、SEM、荧光光谱分别对样品的结构、形貌以及发光性能进行表征,讨论煅烧温度、Eu3+掺杂浓度以及电荷补偿剂对样品发光性能的影响.结果表明:实验所得样品的结构与Ca3Al2O6相同,Eu3+掺杂并没有改变其晶体结构.合成的荧光粉在394 nm近紫外光激发下发出615 nm明亮的红光.样品的红光强度随着煅烧温度的升高先增加后减弱,最佳烧结温度为1200℃.同样红光强度也随着Eu3+掺杂浓度的增加先增加后减弱,最佳Eu3+掺杂浓度为4%(摩尔分数).加入电荷补偿剂后样品的发光强度均增强,其中加入K+后发光增强的效果最显著.该铝酸盐红色荧光粉性质稳定,在白光LED近紫外芯片激发中具有潜在的应用. 相似文献
3.
Nanoscale Lu2O3:Eu3+ phosphor was prepared by a modified solution combustion method using urea and acrylamide monomer.The particle sizes and photoluminescent properties of nano-phosphor were closely related to the molar ratio of urea-to-RE nitrates and acrylamide monomer-to-RE nitrates.The as-prepared samples with the sizes of 9.6-11.6 nm were characterized by X-ray diffraction,scanning electron microscopy,transmission electron microscopy and energy dispersive spectrometer.Lu2O3:Eu3+ nano-phosphor that depicted high photoluminescence in the size around 10 nm was reported.Compared with the sample prepared by solid state reaction,the photoluminescence of sample was increased sufficiently to be 45.1%.The emission spectra of the samples presented the typical emission from 5D0 level to 7FJ(J=0,1,2,3,4) level of the Eu3+ ion. 相似文献
4.
The crystal structure of silicate oxyapatite Ca2Y8Si6O26 was indexed as hexagonal,space group P63/m,a=0.93515 nm,c=0.67872 nm,α=β=90°,γ=120°,V=0.5138692 nm3.Three strong peaks located at 32.079o,32.595o,and 50.104o with d=2.7903,2.74649,1.8194 was in accordance with,(112),and(213) planes.The optimum concentration of Tb3+ in Ca2Y8Si6O26 to yield highest photoluminescence intensity was 10 mol.% of Y3+.The corresponding excitation spectrum consisted of an intense broad band from 220 to 260 nm.The photoluminescence measurements showed that the green emission originated from 5D4-7F5 was predominant in the measured range with strong doublet lines at 543 and 549 nm. 相似文献
5.
As well known, molten salt electrolysis was wide ly used for the production of rare earth metals andtheir alloys. And, phase diagrams are the most impor tant data for fused electrolytes. Dealing with the bina ry phase diagrams relating to rar… 相似文献
6.
采用高温固相法制备了LiGd(W_(0.4)Mo_(0.6)O_4)_2:Eu~(3+)白光LED用红色荧光粉。通过扫描电子显微镜、X射线衍射仪、荧光光谱仪考察了不同助熔剂对荧光粉的形貌、结构、光学性能的影响,探讨了不同助熔剂的作用机理。结果表明,不同种类助熔剂未改变LiGd(W_(0.4)Mo_(0.6)O_4)_2的四方晶系白钨矿结构;396nm激发下,添加质量分数为2%的H_3BO_3,LiF或NH_4F使样品的发光强度分别提高了21%,17%,9.6%;而添加2%的Na_2CO_3样品发光强度下降了10.9%。同时,H_3BO_3可有效地减少样品颗粒的团聚,其最佳用量为3%;由于F-声子能量低,可减少能量的无辐射跃迁概率的原因,当以1%H_3BO_3与2%LiF同时作为助熔剂制备荧光粉时,相比未添加助熔剂的样品发光强度提高40%。 相似文献
7.
相图计算 (Calculation of Phase Diagram, CALPHAD)是冶金 、化工 、材料设计等各个领域的重要研究工具,随着传统材料体系的研究深入和新材料体系的不断被发现,相关的相图和热力学实验数据愈显匮乏.基于电子层面的第一性原理计算(First-principles Calculations),可以从体系基态性质出发,研究亚稳相、金属间化合物的结构、合金的稳定性,促进 CALPHAD 的发展.文中关注了近年来第一性原理计算在 CALPHAD 技术当中的应用研究进展,从计算化合物的能量性质,相图,动力学性质等方面进行系统阐述. 相似文献
8.
we developed a new silicate-based full-color phosphor Ba3Lu2(SiO4)3:Eu2+ through solid state reaction.The host crystal structure was isostructural with Ca3Y2(SiO4)3 instead of garnet-type.The phosphor absorbed near-ultraviolet light from 250 to 400 nm,which was very suitable for a color converter of white LED that used UV-LED as the primary light source.The photoluminescence peak wavelength of Ba3Lu2(SiO4)3:Eu2+ was about 461 nm and a shoulder peak was around 522 nm,which resulted from the 5d-4f transition ... 相似文献
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稀土氧化物可作为稳定剂、烧结助剂、掺杂改性剂加入到ZrO2陶瓷材料中,能极大地提高和改善陶瓷材料的强度、韧性,降低其烧结温度,减少生产成本.文中简要综述了稀土氧化物ZrO2陶瓷材料的制备及应用研究状况,包括Y2O3复合ZrO2陶瓷粉体、富铈稀土氧化物复合ZrO2陶瓷粉末、Nd2O3复合ZrO2陶瓷材料、Pr2O3\Pr6O11复合ZrO2陶瓷、La2O3复合ZrO2陶瓷、Yb2O3复合ZrO2陶瓷、Sm2O3复合ZrO2陶瓷材料及氧化锆中掺杂多种稀土氧化物陶瓷粉体的制备和应用,分析讨论了一些需要解决的问题,并展望了稀土复合ZrO2陶瓷制备技术及未来研究发展趋势. 相似文献
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对P507-N235双溶剂无皂化萃取体系的直接沉淀工艺进行研究,将传统先反萃后沉淀工艺合二为一,从酸度、流比、草酸用量及搅拌时间等方面,考察盐酸-草酸水溶液作为P507-N235-磺化煤油体系沉淀剂直接沉淀的效果.实验以稀土钕直收率来表征实验效果的差异性.研究结果表明:通过加入盐酸调节酸度并控制一定的流比、草酸用量和搅拌时间,可大大提高沉淀的效果.最优草酸沉淀条件为:酸度0.40 mol/L、流比1:1、草酸理论用量的120 %,搅拌时间5 min,其单级钕直收率可达97 %以上.反萃后有机相结构未发生改变,萃取能力可达到新有机相的90 %. 相似文献