期刊
JOURNAL OF LUMINESCENCE
卷 237, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.jlumin.2021.118150
关键词
Garnet scintillators; Ce4+; Excitons; Energy transfer; Synchrotron; XANES
类别
资金
- EU [730872]
- Russian Foundation for Basic Research [20-52-S52001]
The oxidation state of Ce ions in garnets affects their luminescence efficiency, with too high Ce4+ concentration leading to decreased performance. The energy conversion processes between Ce3+ and Ce4+ are crucial in determining the luminescence performance of the garnets.
Scintillators based on Ce-doped garnets are regularly co-doped with Mg2+ or Ca2+ to form Ce ions in 4+ state and reduce undesired afterglow. However overly high Ce4+ concentration leads to poor light yield performance. In order to understand the reason for variation in luminescence efficiency of Ce3+- and Ce4+-doped garnets we investigate the differences in energy conversion processes in complex LuGd2Ga3Al2O12:Ce3+/Ce4+ ceramics by means of VUV synchrotron irradiation. At first we have established via transmission spectroscopy and X-ray absorption spectroscopy that LuGd2Ga3Al2O12:Ce, Mg sample contains cerium in the 4+ state only. Then we show with VUV spectroscopy efficient interaction of excitons with Gd3+ and Ce3+, and lack of exciton absorption edge in LuGd2Ga3Al2O12:Ce4+ excitation spectrum. Instead, Ce4+ exhibits charge-transfer absorption band in the range of exciton emission. We suggest that when Ce4+ concentration becomes too high, the exciton -> Gd3+ -> Ce3+ energy transfer path is hindered. It leads to high intensity of Gd3+ luminescence in Lu1Gd2Ga3Al2O12:Ce, Mg ceramics, but lowered Ce3+ X-ray excited luminescence. Fine balance between 3+ and 4+ Ce concentrations is necessary to achieve the best performance of garnet scintillators.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据