Exciton-harvesting enabled efficient charged particle detection in zero-dimensional halides
Qian Wang, C. Wang, Hongliang Shi, Jie Chen, Junye Yang, Alena Beitlerová, Romana Kučerková, Zhengyang Zhou, Yunyun Li, M. Nikl, Xilei Sun, Xiaoping Ouyang, Yuntao Wu
Abstract
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) Cs 3 Cu 2 I 5 :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 5.49 MeV α-ray are achieved in Cs 3 Cu 2 I 5 :Tl single crystals, outperforming the commercial ZnS:Ag/PVT composites for charged particle detection applications. Furthermore, a radiation detector prototype based on Cs 3 Cu 2 I 5 :Tl single crystal demonstrates the capability of identifying radioactive 220 Rn gas for environmental radiation monitoring applications. We believe that the exciton-harvesting strategy proposed here can greatly boost the applications of LDHs materials.