Photoluminescent properties of tunable green-emitting oxynitride (Ba3-xSrx)Si6O12N2:Eu2+phosphor and its application in white LEDs

Green emitting Eu2+-doped (Ba3?xSrx)Si6O12N2 solid solutions were synthesized through solid state reaction at 1350 oC for 10 h under a N2/H2 atmosphere. The XRD patterns revealed that the solid solutio...     

High temperature stability of Eu2＋-activated nitride red phosphors

The novel nitride-based luminescent materials have received much attention since the end of the last century. In this paper, the commercial Eu2＋-activated nitride red phosphors, Sr1.95Si5N8：Eu0.05, Sr1.85Si5N8：Eu0.15 and Ca0.99AlSiN3：Eu0.01 phosphors were an-nealed at different temperatures （beyond 300 oC） to investigate the dependence of their luminescence performance and structure vari-ability on the temperature. By photoluminescence spectra, X-ray diffraction （XRD） and thermogravimetry-differential scanning calo-rimetry （TG-DSC） analysis, the high temperature stability of the hosts and activator of the three samples were disclosed. With the an-nealing temperature increasing, the activator Eu2＋ions were firstly oxidized and then host in Sr1.95Si5N8：Eu0.05 and Sr1.85Si5N8：Eu0.15, but for Ca0.99AlSiN3：Eu0.01, only the oxidation of the host could be observed, which would lead to the luminescence degradation and even failure of these phosphors. The activator Eu2＋ions were much more stable in CaAlSiN3：Eu than Sr2Si5N8：Eu due to their crystal surroundings, and its concentration also influenced the temperature stability of Sr2Si5N8：Eu.     

白光LED用硅酸盐系列荧光粉的专利分析

白光LED用硅酸盐荧光粉主要应用在对显色指数不高的暖白光照明领域与中低端液晶背光显示领域,其专利申请量表示了荧光粉的技术发展趋势。以含有M、Si、O、Ce/Eu的白光LED用硅酸盐荧光粉为主要研究对象,对专利文献著录项目数据与核心技术内容进行统计分析,讨论了其全球专利的申请趋势、产出国家或地域分布情况、申请目标国家或地域比例情况,全球主要研究单位专利申请情况,以及其专利在华主要申请单位技术分布情况、在华主要申请单位申请量排名情况等,希望对白光LED用荧光粉的企业及行业发展提供参考与借鉴。     

微波场作用下Gd2O2S：Tb绿色荧光粉的快速合成及其发光特性

首次采用微波法，快速合成了Gd2O2S：Tb绿色荧光粉，用X射线粉末衍射（XgD）、扫描电镜（SEM）、荧光分光光度计等对合成产物的结构、形貌、以及发光特性进行了研究。结果表明，材料的晶体结构为六方晶系，与Gd2O2S的相同,颗粒的形貌为类球形，分散性很好，尺寸在1μm左右,Gd2O2S：Tb的激发光谱呈带状，主峰位于298nm,发射光谱由384、418、439、471、498、547、590、624nm的一系列窄带发射峰组成，归属于Tb^3＋从^5D4、^5D3能级到^7FJ（J=0-6）的跃迁。主发射峰位于547nm，对应于^5D4→^7F5的能级跃迁，导致一种绿光发射,研究发现Tb的掺杂浓度对样品主发射峰的强度有着很重要的影响，在5％（摩尔分数）时达到最大，继续增加Tb的浓度，出现浓度猝灭现象，同时对浓度猝灭的机理进行了探讨。     

糯扎渡水电站500kV GIL的安装与试验

糯扎渡电站500kV气体绝缘金属封闭线路(GIL)是目前国内应用较早,云南省电压等级最高、垂直落差最大(204m)的GIL工程项目。文中就糯扎渡电站500kV GIL结构特性、安装工艺、以及现场交流耐压试验进行了重点论述。糯扎渡水电站500kV GIL已于2012年8月23日投入运行,运行状态良好。     

Preparation and luminescence properties of Eu²⁺-doped CASN-sinoite multiphase system for LED

A series of Eu2+-doped CASN-sinoite multiphase system with a formula of(CaAlSiN3)(1-x)-(Si2N2O)x were successfully synthesized by the high temperature solid-state method.The crystal structure and morphology of the phosphors and their photoluminescence(PL) were investigated.For the Eu2+-doped samples the PL intensity approached its maximum when the molar ratio of Si2N2O in the samples was about 0.15.With increase of the concentration of Si2N2O,the emission peak shifted from 645 to 605 nm.It was because the spectroscopic polarizability(αsp) became smaller with the increase of Si/Al ratio or the adding of O atoms,which caused the change of crystal field strength.In addition,the full width at half maximum(FWHM) widened with the increase of x value,which was favor of the improvement of the color rendering index.     

Sr_(1-x)Al_(1+y)Si_(4-y)N_(7-y)O_y:xEu~(2+)橙色荧光粉的合成及发光特性研究

采用常压高温固相法合成一种新型的氮氧化物橙色荧光粉SrAl1+ySi4-yN7-yOy:Eu2+。结合X射线衍射(XRD)、扫描电镜(SEM)和荧光光谱等分析手段,研究了荧光粉的组分配比变化对其物相结构的影响,结果发现当0≤y≤0.225时,该物质属于SrAlSi4N7结构。结合对离子半径及晶格常数变化等的分析,推断晶格中氧是以Al-O键取代了晶格中的Si-N键的方式而存在。通过对该荧光粉的光色特性研究发现,SrAl1+ySi4-yN7-yOy:Eu2+荧光粉可被近紫外到可见光有效激发,产生580~600 nm的橙光发射。对比Sr0.9Al1.225Si3.775N6.775O0.225:Eu0.1荧光粉和Sr0.9AlSi4N7:Eu0.1荧光粉的斯托克斯位移发现,Al-O的引入使得Sr0.9Al1.225Si3.775N6.775O0.225:Eu0.1荧光粉的非辐射弛豫几率相对较小,从而具有相对更高的热稳定性。因此,SrAl1+ySi4-yN7-yOy:Eu系列荧光粉是一款颇具前景的白光LED用橙色荧光粉。     

白光LED用荧光粉的国内外专利分析

发光二极管(Light Emitting Diode,LED)因具有高效节能、绿色环保、超长寿命等优势,被视为最具发展前景的新一代照明技术。此外,因具有功耗低、色彩还原性好、响应快、寿命长等优势,白光LED在液晶显示(Liquid Crystal Display,LCD)用背光源领域的市场份额也在迅速增长。自1962年NickHolony等利用磷砷化镓(GaAsP)制备出第一支红光LED以来,经过50年的发展,LED的发光范围逐渐扩展到绿光、黄光,光效也从早期的0.1lm/W达到的254m/W(2012年4月)。由于白光最     

白光LED荧光粉研究及应用新进展

基于白光发光二极管技术的迅速发展以及荧光粉对白光LED器件的发光效率、显色性和使用寿命等性能的决定性影响,系统阐述了蓝光LED芯片激发用铝酸盐、硅酸盐、氮化物和氮氧化物系列黄色、红色和绿色荧光粉的研究进展和应用现状。探讨了上述荧光粉的研究重点、发展趋势和应用前景,指出需要进一步提高铝酸盐黄粉的发光效率,开发新型高光效氮化物和氮氧化物红粉和绿粉及其低成本制备技术,以满足高光效、高显色、低光衰型白光LED器件制作需要。     

Luminescence properties of Eu2＋ -doped Ba3Si6O12N2 green phosphor： concentration quenching and thermal stability

The efficient Eu2+ -doped Ba3 Si6O12N2 green phosphors were prepared by a traditional solid state reaction method under N2 /H2 atmosphere at a temperature up to 1350 oC for 12h. Photoluminescence (PL) properties showed a broad emission band with a peak of 525 nm and the full width of half-emission maximums (FWHM) of 70 nm under 460 nm light irradiation. The X-ray diffraction patterns (XRD) and scanning electron microscope (SEM) images of the synthesized powder demonstrated its pure phase and excellent crystallization. Quenching concentration in this phosphor was found to be 0.3. The mechanisms of concentration quenching and redshift of emission peak with increasing concentration of Eu2+ were studied. The temperature dependence measurement of this green phosphor revealed excellent thermal quenching property compared to silicate green phosphor. It is believed that Ba3 Si6O12N2 :Eu2+ is an excellent green phosphor for UV or blue chip based white LEDs.