High-Performance Flat-Panel Perovskite X-ray Detectors Enabled by Defect Passivation in Ruddlesden-Popper Perovskites

Halide perovskites have emerged as promising candidates in X-ray detection due to their strong X-ray absorption and excellent optoelectronic properties. The development of sensitive and stable flat-panel X-ray detectors with high resolution is crucial for practical applications. In this paper, we introduce a novel flat-panel X-ray detector that integrates quasi-two-dimensional (2D) Ruddlesden-Popper (RP) perovskite with a pixeled thin film transistor (TFT) backplane. We incorporate 2,5-dibromopyrimidine (DBPM) as an additive to passivate the Lewis acid defects in the quasi-2D RP perovskite. This modification results in suppressed ion migration, improved optoelectronic performance, and enhanced operational stability of the device. Impressively, the activation energy of the RP perovskite increases from 0.96 to 1.35 eV with the DBPM additive. As a result, X-ray detectors exhibit a high sensitivity of ∼13,600 μC Gy_air^-1 cm^-2, a low detection limit of 6.56 nGy_air s^-1, and excellent operational stability. Moreover, the flat-panel detectors demonstrate a high spatial resolution of 3.7 line pairs per millimeter and excellent X-ray imaging properties under a remarkably low X-ray dose of ∼50 μGy_air, which is just half of the X-ray dose typically used in commercial equipment. This study opens new avenues for the development of flat-panel perovskite X-ray detectors with significant potential for various applications.