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
Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 201899, China.
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.
Light Sci Appl. 2024 Aug 14;13(1):190. doi: 10.1038/s41377-024-01532-z.
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) CsCuI: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, and a high scintillation yield of 26 000 photons MeV under 5.49 MeV α-ray are achieved in CsCuI:Tl single crystals, outperforming the commercial ZnS:Ag/PVT composites for charged particle detection applications. Furthermore, a radiation detector prototype based on CsCuI:Tl single crystal demonstrates the capability of identifying radioactive Rn gas for environmental radiation monitoring applications. We believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials.
从基础科学研究到医学诊断、国土安全和环境监测等各个领域，辐射探测材料都至关重要且迫切需要。具有高效自陷激子（STE）发射且光致发光量子产率（PLQY）高的低维卤化物（LDHs）最近显示出作为闪烁体的巨大潜力。然而，在电离辐射下LDHs中激子 - 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。在此，我们通过形成强局域化的Tl束缚激子，证明了零维（0D）CsCuI:Tl卤化物单晶中激子捕获效率的显著提高。由于非辐射激子 - 激子相互作用的抑制，CsCuI:Tl单晶在5.49 MeV α射线照射下实现了2.64的优异α/β脉冲形状鉴别（PSD）品质因数（FoM）、10的卓越拒斥率和26000光子/MeV的高闪烁产率，在带电粒子探测应用方面优于商用ZnS:Ag/PVT复合材料。此外，基于CsCuI:Tl单晶的辐射探测器原型展示了用于环境辐射监测应用中识别放射性Rn气体的能力。我们相信这里提出的激子捕获策略能够极大地推动LDHs材料的应用。
