Highly Resolved X‐Ray Imaging Enabled by In(I) Doped Perovskite‐Like Cs<sub>3</sub>Cu<sub>2</sub>I<sub>5</sub> Single Crystal Scintillator
Qian Wang, Quan Zhou, M. Nikl, Jiawen Xiao, Romana Kučerková, Alena Beitlerová, Vladimír Babin, Petr Průša, V. Linhart, Jingkang Wang, Xuemin Wen, Guangda Niu, Jiang Tang, Guohao Ren, Yuntao Wu
Abstract
Abstract Low‐dimensional perovskite halides have shown a great potential as X‐ray detection materials because of efficient exciton emissions originating from strongly spatially localized charge carriers. Nonetheless, most of them have a scintillation yield far below their theoretical limits. Here, it is found that the harvesting efficiency of produced charge carriers can be significantly enhanced via a small amount of In + doping in these highly localized structures. A bright and sensitive zero‐dimensional Cs 3 Cu 2 I 5 :In + halide with efficient and tunable dual emission is reported. The radioluminescence emission of Cs 3 Cu 2 I 5 :In + crystals under X‐ray excitation consists of a self‐trapped exciton emission at 460 nm and an In + ‐related emission at 620 nm at room temperature. In + doping enhances the photoluminescence quantum efficiency (PLQY) of Cs 3 Cu 2 I 5 from 68.1% to 88.4%. Benefiting from the higher PLQY, Cs 3 Cu 2 I 5 :In + can achieve an excellent X‐ray detection limit of 96.2 nGy air s −1 , and a superior scintillation yield of 53 000 photons per MeV, which is comparable to commercial CsI:Tl single crystals. As a result, a remarkable X‐ray imaging resolution of 18 line pairs mm –1 is demonstrated, which is so far a record resolution for single crystal perovskite‐based flat‐panel detectors. These results highlight the importance of efficient harvesting of carriers (and excitons) in low‐dimensional perovskites for radiation detection applications.