钇掺杂量对Lu_xY_(1-x)AlO_3:Ce晶体结构和发光性能的影响

Influence of Amount of Yttrium Dopant on Structure and Scintillation Properties of Lu_xY_(1-x)AlO_3:Ce Single Crystals

研究了Y掺杂量对LuxY1-xAlO3:Ce晶体结构和发光性能的影响,结果表明:固溶体晶体LuxY1-xAlO3:Ce(x=0～0.3)仍为正交晶系赝钙钛矿型结构。随着Y掺杂量的减少,晶胞体积减小、晶体密度增大、本征吸收降低、光输出增大,衰减时间由YAlO3:Ce的29.7ns降低至Lu0.3Y0.7AlO3:Ce的24.2ns。随着Y掺杂量的减少,发射谱的峰位由YAlO3:Ce的390nm逐步紫移至Lu0.3Y0.7AlO3:Ce的384nm,这表明尽管LuxY1-xAlO3:Ce晶体的光激发-发射机制并未发生明显的变化,但掺杂还是引起了稀土格位晶体场的变化,激活离子Ce3+的激发态与基态能级之间的能级差随Y掺杂量的减少逐步加大。Y掺杂含量的降低在改善晶体闪烁性能的同时也降低了晶体的热稳定性,增强了晶体的放射性本底。

A systematic investigation and an in-depth discussion were carried out on the influence of the amount of Y dopant on the structure and scintillation properties of LuxY1-xAlO3：Ce single crystals. The results showed that LuxY1-xAlO3：Ce （x = 0 - 0.3） single crystals still possessed a perovskite structure, their cell volume decreased and density increased as the amount of Y dopant decreased. With such a decrease, the intrinsic absorption of the solid solution crystals decreased, the light output increased and the decay time decreased from 29.7 ns of YAlO3 ： Ce to 24.2 ns of Lu0.3Y0.7AlO3：Ce. As the amount of Y dopant decreased, the emission peak position shifted from 390 nm （YAlO3：Ce） to 384 nm （Lu0.3Y0.TAlO3：Ce）. That indicated that the crystal field at the rare earth lattice site changed, and as a result, the energy gap between the excited state and the ground state of Ce^3＋ in- creased, while there was no obvious change in the mechanism of UV-excited emission. However, the thermal stability of the solid solution crystals decreased and the radioactivity background increased with the decrease of the amount of Y dopant.