Ion Migration Suppression via Doping Multivalent Cations in Perovskite for High Thermal Stability X-ray Detectors
Xiaolong Feng, Lu Zhang, Xiaofeng Feng, Jiaxue You, Jiacheng Pi, Hanqing Zeng, Depeng Chu, Chengzhi Xue, Ke Zhao, Shilong Jia, P Tong, Zhiwen Jin, Yucheng Liu, Alex K.‐Y. Jen, Shengzhong Liu
Abstract
CsPb 2 Br 5 single crystals (SCs) are promising for X-ray detection due to their high absorption, excellent photoelectric properties, and stability. However, thermal stress in high-temperature environments accelerates ion migration within perovskite structures, leading to degraded performance. In this study, we investigate the effects of Cr 3+ doping, which induces lattice contraction and distortion due to its small ionic radius and strong electrophilic properties. This increases the formation energy of Br vacancies and activation energy for ion migration, enhancing the crystal’s resistance to thermal stress. As a result, Cr-doped CsPb 2 Br 5 exhibits a high μτ value of 5.46 × 10 –3 cm 2 V –1, a lower temperature coefficient of resistance (−1.58 × 10 – 2 °C – 1 ), and excellent ion migration resistance at 70 °C. These improvements lead to a high sensitivity of 7183.5 μC Gy air – 1 cm – 2 and a low detection dose rate of 11.5 nGy air s – 1, with stable performance in X-ray imaging at elevated temperatures, making it suitable for complex environments.