GdAlO_3∶Tb,RE中Tb,RE的能量传递研究

采用柠檬酸盐硝酸盐燃烧法制备了GdAlO3∶Tb,RE荧光粉体.在紫外激发下(254nm),GdAlO3∶Tb发射绿色荧光(5D4→7F5,544nm),Dy共掺杂对绿色发光有增强作用,Ce共掺杂对GdAlO3∶Tb绿色发光有降低作用.激发谱和能谱研究表明:Dy能级嵌入Tb主发射能级5D4(绿色发光能级)、5D3(蓝色发光能级)能级之间,Ce能级嵌入Tb主发射能级5D4、5D3能级上方.这种能级嵌入方式,使得稀土离子之间存在声子支持的共振能量传递,但Tb→Dy→Tb能量传递使Tb绿色发射(5D4→7FJ(J=3,4,5,6))增强,蓝色发射(5D3→7FJ(J=3,4,5,6))减弱;而Ce→Tb能量传递使Tb蓝色发射增强,绿色发射减弱.

Energy Transfer Between Tb and RE in GdAlO3: Tb,RE

GdAlO3∶Tb,RE phosphor powder was prepared by nitric-citric process. Under UV light excitation(254 nm), it gave green emission(5D4→7F5,544 nm). The green luminescence intensity of GdAlO3∶Tb increased when it was co-doped with Dy, and decreased when co-doped with Ce. Excitation spectra and Energy level sketch indicate that Dy energy level is embedded between Tb 5D4 (green emission level) and Tb 5D3 (blue emission level), while Ce energy level is embedded above both 5D4 and 5D3. There are the resonant energy transfers between RE ions by the absorbing or emitting phonons, Tb→Dy→Tb energy transfer increases the green emission (5D4→7FJ(J=3,4,5,6))and decreases the blue emission(5D3→7FJ(J=3,4,5,6)); but Ce→Tb energy transfer increases the blue emission and decreases the green emission.