近日，中国科学院上海硅酸盐研究所的吴云涛及其研究小组与西北核技术研究所的欧阳晓平以及中国科学院高能物理研究所的孙希磊等人合作并取得一项新进展。经过不懈努力，他们发现激子收集使零维卤化物中有效的带电粒子检测成为可能。相关研究成果已于2024年8月14日在国际知名学术期刊《光：科学与应用》上发表。

本文中，研究人员展示了通过形成强局域化的Tl束缚激子，在零维（0D）Cs₃Cu₂I₅:Tl卤化物单晶中实现了激子收集效率的显著提升。

由于抑制了非辐射性的激子-激子相互作用，Cs₃Cu₂I₅:Tl单晶在5.49MeV α射线照射下实现了2.64的优异α/β脉冲形状识别（PSD）品质因数（FoM）、10^-9的卓越抑制比以及26 000光子MeV^-1的高闪烁产额，其性能优于商业化的ZnS:Ag/PVT复合材料，适用于带电粒子检测应用。

此外，基于Cs₃Cu₂I₅:Tl单晶的辐射探测器原型展示了识别放射性²²⁰Rn气体的能力，适用于环境辐射监测应用。研究人员相信，本文提出的激子收集策略将极大地推动LDHs材料的应用。

据悉，辐射探测材料在基础科学研究、医疗诊断、国土安全以及环境监测等众多领域都至关重要且需求迫切。近年来，具有高效自陷激子（STE）发射和高光致发光量子产率（PLQY）的低维卤化物（LDHs），作为闪烁体展现出了巨大潜力。然而，LDHs在电离辐射下的激子-激子相互作用这一被忽视的问题，阻碍了其辐射探测应用的拓展。

附：英文原文

Title: Exciton-harvesting enabled efficient charged particle detection in zero-dimensional halides

Author: Wang, Qian, Wang, Chenger, Shi, Hongliang, Chen, Jie, Yang, Junye, Beitlerova, Alena, Kucerkova, Romana, Zhou, Zhengyang, Li, Yunyun, Nikl, Martin, Sun, Xilei, OuYang, Xiaoping, Wu, Yuntao

Issue&Volume: 2024-08-14

Abstract: Materials for radiation detection are critically important and urgently demanded in diverse fields, starting from fundamental scientific research to medical diagnostics, homeland security, and environmental monitoring. Low-dimensional halides (LDHs) exhibiting efficient self-trapped exciton (STE) emission with high photoluminescence quantum yield (PLQY) have recently shown a great potential as scintillators. However, an overlooked issue of exciton-exciton interaction in LDHs under ionizing radiation hinders the broadening of its radiation detection applications. Here, we demonstrate an exceptional enhancement of exciton-harvesting efficiency in zero-dimensional (0D) Cs₃Cu₂I₅:Tl halide single crystals by forming strongly localized Tl-bound excitons. Because of the suppression of non-radiative exciton-exciton interaction, an excellent α/β pulse-shape-discrimination (PSD) figure-of-merit (FoM) factor of 2.64, a superior rejection ratio of 10^-9, and a high scintillation yield of 26 000 photons MeV^-1 under 5.49MeV α-ray are achieved in Cs₃Cu₂I₅:Tl single crystals, outperforming the commercial ZnS:Ag/PVT composites for charged particle detection applications. Furthermore, a radiation detector prototype based on Cs₃Cu₂I₅:Tl single crystal demonstrates the capability of identifying radioactive ²²⁰Rn gas for environmental radiation monitoring applications. We believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials.

DOI: 10.1038/s41377-024-01532-z

Source: https://www.nature.com/articles/s41377-024-01532-z