Proceedings of nanoGe Spring Meeting 2022 (NSM22)
DOI: https://doi.org/10.29363/nanoge.nsm.2022.271
Publication date: 7th February 2022
Ion migration is a well-known problem in perovskite materials. It causes baseline drift, lowers imaging resolution, accelerated decomposition and device performance degradation. In particular in X-ray detectors, the effect of ion migration is more obvious under working bias. The first principals study reveals that the 0D structure perovskite would show effectively reduced ion migration between neighbouring unit cells compared with the popular 2D and 3D perovskites. A nucleation-controlled strategy is developed to grow superior inch-sized high-quality 0D-structured lead-free (CH3NH3)3Bi2I9 perovskite single crystals (MA3Bi2I9 PSCs) with significantly lower ion migration, much reduced dark current and better environmental stability compared to other perovskite materials, enabling us to design and fabricate a new type of 0D-structured lead-free perovskite X-ray detector. It is found that the X-ray detectors show surprisingly high sensitivity, 15 times more than that of the state-of-the-art commercial α-Se detectors, with very low detection limit that is desired for medical diagnostics, material inspection, etc. Furthermore, their response time is as short as 0.98 ms, the shortest among all X-ray detectors reported in literature, which may allow us to develop an X-ray screening system with reduced X-ray dose and improved resolution.