Tb^(3+)掺杂ZnO-B_2O_3-SiO_2玻璃长余辉发光机理

Study on long-lasting phosphorescent mechanism of Tb^(3+) doped ZnO-B_2O_3-SiO_2 glass

采用高温熔融法制备了Tb3+掺杂ZnO-B2O3-SiO2玻璃,通过荧光光谱、余辉衰减曲线、热释发光光谱以及紫外-可见吸收光谱等方法的测试分析,系统地研究了该玻璃体系的长余辉发光机理,并建立了其长余辉发光的半程隧穿模型.Tb3+掺杂ZnO-B2O3-SiO2玻璃的长余辉发光只跟能级较浅的电子陷阱有关,不同能级深度的陷阱对应着余辉衰减的不同过程;Tb3+离子是被紫外光直接激发发生光氧化失去电子的,然后电子经由导带被能级深度不同的电子陷阱捕获;电子从陷阱中热致逃逸出来后,通过5d能带隧穿到与陷阱最邻近的激活离子上而复合发光.

Tb^3＋ doped ZnO-B2O3-SiO2 （ZBS） glass was prepared by conventional melt-quenched method. The long-lasting phosphorescent mechanism of this kind of glass was systematically analyzed by fluorescent spectra, afterglow decay curves, glow curves, UV-visible spectra etc. The Half Tunneling model of the long-lasting phosphorescence was also established by related mechanism. This model of mechanism indicated that the long-lasting phosphorescence of Tb^3＋ doped ZBS glass only has a connection with the traps of shallow energy, and that the different traps in energy level depth correspond with different processes of afterglow decay. It also demonstrated that the excited electrons are ultimately captured by traps through conduction band, and that the electrons run away from traps tunnel into luminescent ions through 5d energy band.