Li^+掺杂对Ca(W,Mo)O_4:Eu^(3+)红色荧光粉结构及发光性能的影响

Effect of Li^+ Doped on the Structure and Luminescence Properties of Ca(W,Mo)O_4:Eu^(3+)Phosphors

采用高温固相反应法制备了一系列Li+掺杂的Ca(W,Mo)O_4∶Eu^(3+)荧光粉。通过X射线衍射仪、扫描电子显微镜及荧光光谱仪对样品的结构、形貌及荧光性能进行了表征。XRD及SEM结果表明,Li^+掺杂没有改变样品原有的四方晶系体心结构,Li+能够以替代和间隙掺杂的方式进入主晶格,适当的Li+掺杂可以改善样品的团聚现象。样品的激发光谱涵盖200~550nm的宽带激发,在395nm激发下,能发射出位于616nm处的窄带红光,归因于Eu^(3+)的~5D_0→~7F_2跃迁,适量Li^+的掺杂明显提升了样品的发光强度。与其他碱金属离子(Na^+、K^+)掺杂相比,Li^+由于半径最小、电负性最强,使得发光强度增强最多。

A series of Li^＋ doped Ca （W, Mo）O4：Eu^3＋ phosphors were synthesized by solid-state reaction method. The structure, morphology and luminescence properties of samples were characterized by XRD, SEM and luminescence spectrometer, respectively. The results show the Li＋doped samples maintain the body-centered tetragonal structure of Ca（W, Mo）O4：Eu^3＋. The Li＋ions could be introduced into the host lattice through the approach of substitutional doping or interstitial doping. By adding appropriate Li^＋ ions to the samples, the agglomeration of samples could be minimized. Li＋doping does not affect the shape and position of the excitation and emission spectrum of samples. The excitation spectrum of samples covers broad band of 200～550 nm. The intense red emission （centered at 616 nm）was observed under the excitation of 395 nm, which should be attributed to the 5D0→7F2 transitions. The introduction of Li^＋ ions to Ca0.93 （W0.1Mo0.9）O4：Eu^3＋0.07 sample significantly enhances the emission intensity. Compared with other alkali metal ions doping, the sample with Li＋doping has the strongest luminous intensity due to the smallest ionic radius and the strongest electronegativity.