2‐Bromonaphthalene‐Induced Defect Passivation to Suppress Ion Migration in CsPbBr <sub>3</sub> Wafer for X‐Ray Detector with Bias‐Resistant Stability
Xiao Zhao, Ziqing Li, Shimao Wang, Yanan Song, Enliu Hong, Tingting Yan, Gang Meng, Xiaosheng Fang
Abstract
Abstract Featuring exceptional photoelectronic properties and scalability, hot‐pressing processed all‐inorganic (i. e., CsPbBr 3 ) perovskite wafers have emerged as promising candidates for direct X‐ray imaging. Nonetheless, severe ion migration in CsPbBr 3 wafers results in a large and drifting dark current, thereby compromising the bias‐resistant stability of the X‐ray detector. Herein, a solvent‐free interfacial defect passivation strategy is proposed by introducing a passivator molecule, 2‐bromonaphthalene, to passivate interfacial defects and suppress ion migration in CsPbBr 3 wafers. Implementing this strategy effectively inhibits ion migration in CsPbBr 3 wafers, as evidenced by an enhanced ion migration activation energy of 0.56 eV and a negligible dark‐current drift of 4.01 × 10 −8 µA cm −1 s −1 V −1 , representing a 100 fold reduction in dark current drift compared to untreated CsPbBr 3 wafers under a high electric field of 100 V mm −1 , indicating a high bias‐resistant stability. Consequently, the CsPbBr 3 wafer X‐ray detector achieves an impressively high sensitivity of 11090 µC Gy air −1 cm −2 , a low detection limit of 9.41 nGy air s −1 under a 100 V mm −1 electric field, and high‐contrast X‐ray imaging capabilities, with performance comparable to that of CsPbBr 3 single‐crystal‐based X‐ray detector, highlighting the potential of interfacial defect passivation strategy for high‐performance X‐ray detectors.