SrAl_2O_4:Eu^(2+),Dy^(3+)发光粉体的长余辉特性研究

Properties of Long Afterglow SrAl_2O_4:Eu^(2+), Dy^(3+) Phosphor

采用高温固相合成法制得了SrAl_2O_4:Eu^（2+）,Dy^（3+）长余辉发光材料.X射线衍射分析(XRD)结果表明:该磷光体为SrAl2O4晶体结构,属单斜晶系.其晶格常数为:a=8.4424A,b=8.822A,c=5.1607A,β=93.415°.SrAl2O4:Eu2+,Dy3+发光材料的激发光谱和发射光谱均为宽带谱,激发谱峰位在300～450nm,发射光谱的峰值波长在518nm处.这一结果表明该材料的发光是由Eu2+的4f65d→4f7(8S7/2)宽带跃迁产生的.其余辉衰减由初始的快衰减和其后的慢衰减所组成.通过热释光谱对材料中的陷阱能级进行了分析,该材料中存在两个较深的陷阱能细。苴深度分别为0.38和1.34eV.

SrAl_2O_4:Eu^（2+）, Dy^（3+） powder phosphors were synthesized by solid-state reaction process. Based on the XRD peaks, the powder phosphors were identified as SrAl2O4 phase, which is monoclinic(a=8.4428A, b=8.822A, c=5.160?A, β=93.415°). These phosphors exhibited broadband peaks in both the excitation and emission spectra. The excitation peaks lied between 300nm and 450nm, and the main emission peaks lied around 518nm. The results indicate that the luminescence of these phosphors are due to 4f65d→4f7(8S7/2) transition of Eu2+. And its luminescence decay consists of the initial fast process and the later extremely slow process. The trap level of phosphors was analyzed through thermoluminescent spectra, which consists two peaks. This means that there are two electron traps in SrAl2O4: Eu2+, Dy3+, which can cause the long afterglow of the phosphors. The trap depths measured are 0.38eV and 1.34eV respectively.