Sr^2＋的掺入对CaAl2O4：Eu^2＋，Nd^3＋，La^3＋陷阱分布和余辉性能的影响

用固相反应法制备了发射峰为446 nm的蓝紫色长余辉材料CaAl2O4：Eu^2 ，Nd^3 ，La^3 ，它有两个激发峰276 nm和335 nm。Sr^2 的加入使材料的激发和发射主峰向短波方向发生了移动。不同Sr^2 含量样品的X射线衍射分析表明：随着Sr^2 含量的增加，材料中的杂相CaAl4O7逐渐消失，变为纯的CaAl2O4；从测得的相应的热释光曲线分析，热释峰由强度较弱、分布分散的5个峰(峰值温度分别为：153，180，327，355K和399K)，逐渐变为分布集中、强度较大的2个峰(峰值温度分别为175K和346K)，这说明材料中的陷阱能级分布趋于集中。用一般阶动力学模型对热释光曲线进行拟合，得出了它们的陷阱参数。在Sr^2 添加量为0．20 moll时，材料的余辉性能最好，它的两个热释峰所对应的陷阱深度分别为0．17 eV和0．37 eV。陷阱分布趋于集中的状况和合适的深度使材料的余辉性能得到了很大的提高。

EFFECT OF Sr~2+ DOPING ON DISTRIBUTION OF TRAPS AND CHARACTERISTIC OF AFTERGLOW FOR CaAl_2O_4: Eu~2+ , Nd~3+ , La~3+

Blue - purple long afterglow materials CaAl2O4 : Eu2+ , Nd3+ , La3+ with emission peak of 446 nm and two excitation peaks at 276 nm and 335 nm were synthesized by the conventional solid phase reaction method. With the increase of Sr2+ doped concentration, positions of main emission and excitation peak shift to the side of short waves. X-ray powder diffraction results show that the crystal structure is changed from multiphase (CaAl2O4and CaAl4O7) to single phase (CaAl2O4) with the increase of adding quantity of Sr2+. At the same time the thermoluminescence glow curves display that a centralized distribution of ther-moluminescence peaks is gradually appearing, and five small thermoluminecence peaks at 153, 180, 327, 355 K and 399 K turn to two strong peaks at 175 K and 346 K. At the same time the long afterglow characteristic of materials is improved extremely. The trapped depths are acquired by fitting experimental results with general order kinetic model. Experiment results indicate that the fine long afterglow characteristic of materials is due to the formation of two traps with trap depths of 0. 17 eV and 0. 37 eV respectively and a centralized distribution of thermoluminescence peaks.