Li^＋对Tb^3＋掺杂硅酸盐玻璃闪烁性能的影响

Effects of Li^+ ions on luminescent properties of Tb^(3+)-doped silicate glasses

利用高温熔融法制备了Li+掺杂Tb3+激活硅酸盐闪烁玻璃。通过Li+掺杂Tb3+激活硅酸盐玻璃的紫外可见透射光谱、发射光谱和发光衰减时间谱,研究了Li+的加入对Tb3+掺杂硅酸盐玻璃发光性能的影响。结果表明:适量Li+的加入可有效增强Tb3+激活硅酸盐玻璃的发光强度,且相比于不掺杂Li+的Tb3+掺杂硅酸盐玻璃而言,当掺入质量分数为2.0%的Li+时,Tb3+在玻璃中的最佳掺杂质量分数由12.8%提高至15.3%。其原因是Li+掺杂增加了玻璃体系中非桥氧的数量,从而有利于改善Tb3+在玻璃体中的均匀性,降低Tb3+间因非辐射跃迁而引起的能量损失,以及提高Tb3+的最佳掺杂质量分数。但当掺入Li+的质量分数超过2.0%时,会对Tb3+激活硅酸盐玻璃的闪烁光强产生负面影响,这是因为过多的非桥氧阻碍了X射线激发能达到Tb3+离子的能量传递。

The Tb3＋-doped silicate glasses with and without Li＋ ions were synthesized by high-temperature melting method.The effects of Li＋ ions on the luminescent properties of Tb3＋-doped silicate glasses were studied with ultraviolet-visible transmission,emission and decay time spectra.The results show that the Li＋ ion co-dopant can increase the emission intensity of Tb3＋-doped silicate glasses.Additionally,the optimal Tb3＋ dopant concentration can be raised from 12.8% to 15.3% in the silicate glasses with 2.0% Li＋ ion co-dopant compared to those without Li＋ ions.The reason is tentatively ascribed to nonbridge oxygen.The nonbridge oxygen is propitious to uniform distribution of Tb3＋ ions,thereby its increase reduces the energy loss due to nonradiative transition within Tb3＋ ions and increases the optimal Tb3＋ dopant concentration.However,the emission intensities of Tb3＋ ions will decrease under X-ray excitation when the concentration of Li＋ ions is beyond 2.0% since the Li＋ ion probably result in too much nonbridge oxygen,which is considered as the defect to restrain the energy transfer to Tb3＋ ions.