报告题目Title：First-principles study of complex halide scintillators for radiation detection (复杂卤化物闪烁晶体探测辐射的第一原理研究)
报 告 人Speaker：Qingguo Feng (Arkansas State University)
报告时间Time：2017年2月20日 (周一) 14:00
报告地点Venue：校本部E106 Meeting Room 会议室（上海大学量子与分子结构国际中心SHU ICQMS）
摘要：Current demands for cost-effective and high-performance scintillators have led to a discernible shift from simple binary halides (e.g., NaI, CsI) toward host compounds that are structurally and electronically more complex. Eu-doped SrI2 is a prominant example. Despite its advanced properties, improvements are needed for extensive deployment at low cost. Codoping techniques are often useful to improve the electronic response of such insulators. Using first-principles based approach we report on the influence of codoping with aliovalent and isovalent impurities. We find all codopants induce deep levels, show amphoteric character, and may bind with I-vacancy forming charge compensated donor-acceptor pairs. Lack of deep-to-shallow behavior upon codoping and its ramifications will be discussed.
We have studied another set of stable orthorhombic phase of ternary halides containing iodides, e.g. CsCaI3 and KCaI3. One objective is to explore the structure induced difference in scintillation properties. Interestingly, we found distinct behavior in carrier mobility and induced defect levels within these two compounds, which may explain the low light yield in CsCaI3.
