摘要
采用高温固相反应法在还原气氛下制备了Li2Sr0.995-x SiO4:0.005Eu2+,xLa3+荧光粉。利用X射线衍射仪、荧光光谱仪和紫外可见分光光度计对样品的晶体结构、激发光谱、发射光谱与荧光衰减寿命以及漫反射光谱进行测试分析。实验结果表明:所制得的样品为单一相的Li2SrSiO4晶体结构化合物。Li2Sr0.995-x SiO4:0.005Eu2+,xLa3+荧光粉的激发光谱均呈现出宽激发带,其中最强的激发峰位于408 nm左右。在此波长激发下可得到峰值位于570 nm左右的宽波段单峰发射光谱,其对应于Eu2+离子4f65d1→4f7电子跃迁。La3+掺杂Li2SrSiO4:Eu2+荧光粉基质产生了晶格缺陷[2La·Sr·V″Sr],其可以吸收光能并将能量传递给发光中心离子Eu2+,进而增强Li2Sr0.995SiO4:0.005Eu2+荧光粉的发光强度。漫反射光谱和荧光衰减寿命测试结果也证实La3+掺杂能够增加Eu2+的激发态吸收能量,延长发光中心Eu2+离子荧光衰减寿命。
La3＋ doping Li2Sr0.995-x SiO4 ： 0. 005Eu2＋ was prepared through high temperature solid state re- action under reducing atmosphere. The crystal struc- tures, luminescence properties and fluorescent lifetimes as well as diffuse reflection spectra were charac- terized by X-ray diffraction, fluorescence spectropho- tometer and UV-visible light spectrophotometer. XRD patterns revealed that the samples were single phase ofLizSrSiO4 compounds. The excitation spectrum of all samples showed wide excitation band with the strongest peak at 408 nm. Under the excitation of 408 nm, the typical band emission spectrum with single peak at a- bout 570 nm can be achieved, which was attribute to the energy level transition of Eu2＋ （4fC5d1→f7）. The complex defects in the host lattice caused by doping La3＋ can absorb some energy and then transfer them toEu2 ＋, which is considered to be the mechanism that significantly enhances the luminous intensity of Li2Sr0.995 SiO4 ： 0. 005Eu2＋ phosphor. The diffuse re- flection spectra and fluorescent lifetime test results showed that the doped La3＋ could increase the excited state energy and prolong the lifetime of Eu2＋ lumines- cent centers.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2013年第5期540-546,共7页
Journal of the Chinese Society of Rare Earths
基金
国家自然科学基金(51202051)
浙江省自然科学基金(LQ12E02001,Y1101252,Y1110992)
浙江省重点科技创新团队项目(2011R09006-05)资助
关键词
硅酸盐荧光粉
掺杂
发光强度
稀土
silicates phosphors
doping
luminous intensity
rare earths
