Ce^(3+)和Tb^(3+)掺杂钆-钡-硅酸盐闪烁玻璃的发光性能

Luminescence Properties of Ce^(3+) and Tb^(3+) Doped Gd-Ba-silicate Scintillating Glass

采用高温熔融法制备Ce^(3+)或Tb^(3+)单掺和Ce^(3+)/Tb^(3+)共掺钆-钡-硅酸盐闪烁玻璃。通过透射光谱、光致激发和发射光谱、X射线激发发射光谱及荧光衰减曲线等手段对其发光性能进行研究。实验结果表明:在紫外光的激发下,Tb^(3+)掺杂闪烁玻璃发出明亮的绿光(544 nm),而Ce^(3+)掺杂闪烁玻璃发出蓝紫光。对于Ce^(3+)/Tb^(3+)共掺闪烁玻璃,在紫外光和X射线激发下均观察到Ce^(3+)离子敏化Tb^(3+)离子发光的现象,这是由于存在Ce^(3+)→Tb^(3+)的能量转移。Ce^(3+)/Tb^(3+)共掺闪烁玻璃的最佳Ce2O3掺杂摩尔分数为0.2%,此时Ce^(3+)离子向Tb^(3+)离子的能量传递效率为45.7%。在X射线激发下,Ce_2O_3摩尔分数为0.2%的Ce^(3+)/Tb^(3+)共掺闪烁玻璃在544 nm处的发光强度是Bi_4Ge_3O_(12)(BGO)闪烁晶体在500 nm处发光强度的4.2倍,积分闪烁效率达到BGO晶体的55.6%,这有利于在高分辨率医学成像中降低辐射剂量。

Novel Tb3＋or Ce3＋doped and Tb3＋/ Ce3＋codoped Gd-Ba-silicate scintillating glasses were synthesized by melt-quenching method. The luminescence properties were studied by transmission spectra,photoluminescence excitation and emission spectra,X-ray excited luminescence spectra and luminescence decay curves. The results show that Tb3＋doped scintillating glasses exhibit bright green emission at about 544 nm and Ce3＋doped scintillating glasses have a strong purplishblue light under ultraviolet excitation. For Tb3＋/ Ce3＋codoped scintillating glasses,Ce3＋ions can strongly sensitize the luminescence of Tb3＋ions under both UV and X-ray excitation,which is caused by the energy transfer process from Ce3＋to Tb3＋ions. The optimal doping mole fraction of Ce2O3 in Tb3＋/ Ce3＋codoped scintillating glasses was 0. 2%. In this case,the evaluated energy transfer efficiency from Ce3＋to Tb3＋is about 45. 7%. Under X-ray excitation,not only the intensity of 544 nm emission in Tb3＋/ Ce3＋codoped scintillating glasses with 0. 2% of Ce2O3 was 4. 2 times than that of 500 nm emission in the commercial Bi4Ge3O（12）（ BGO） crystals,but also the integral scintillation efficiency was about 55. 6% of the BGO crystals. It is beneficial for reducing radiative dose to obtain high-resolution medical X-ray imaging.