A-Site Cation Engineering of Ruddlesden-Popper Perovskites for Stable, Sensitive, and Portable Direct Conversion X-ray Imaging Detectors.

Perovskite flat-panel X-ray detectors are promising products for realizing low-dose medical imaging, a nondestructive test, and security inspection. However, the perovskite X-ray imager still faces intractable problems such as severe baseline drift, a low signal-to-noise ratio, and rapid performance degradation, which were involved by the notorious intrinsic ion migration of the perovskite functional layer. In this work, sensitive, stable, and portable pixel quasi-two-dimensional (2D) Ruddlesden-Popper (RP) perovskite X-ray imagers were obtained by an advanced solvent-free laminated fabrication approach. A-Site cation engineering of RP perovskites provides a hint for solving the trade-off between stability and detection performance, resulting in a stable pixel X-ray imager that shows a sensitivity of ∼7000 μC Gy air -1 cm -2 , a detection limit of 7.8 nGy air s -1 , and good 2D multipixel X-ray imaging. This work demonstrates both a high-performance, stable X-ray imager and its robust fabrication, paving the way for adopting a RP perovskite imager as novel flat-panel X-ray detectors.