中文摘要：

采用高温固相反应法在还原气氛下制备了Li2Sr0．995-xSiO4：OQ005Eu^2＋，xLa^3＋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Li2SrSi04晶体结构化合物。Li2Sr0．995-xSiO4：OQ005Eu^2＋，xLa^3＋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408nm左右。在此波长激发下可得到峰值位于570nm左右的宽波段单峰发射光谱，其对应于Eu^2＋离子4f65d1→4f7，电子跃迁。La^3＋掺杂Li2SrSi04：Eu^2＋荧光粉基质产生了晶格缺陷2LaSr·VSr，其可以吸收光能并将能量传递给发光中心离子Eu^2＋，进而增强Li2Sr0．995-xSiO4：OQ005Eu^2＋，xLa^3＋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La^3＋掺杂能够增加Eu^2＋的激发态吸收能量，延长发光中心Eu^2＋离子荧光衰减寿命。

英文摘要：

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.