Aging CsPbBr₃ Nanocrystal Wafer for Ultralow Ionic Migration and Environmental Stability for Direct X-ray Detection

The outstanding photoelectric properties of perovskites demonstrate extreme promise for application in X-ray detection. However, the soft lattice of the perovskite results in severe ionic migration for three-dimensional materials, limiting the operation stability of perovskite X-ray detectors. Although ligand-decorated nanocrystals (NCs) exhibit significantly higher stability than three-dimensional perovskites, defects remaining on the interface of NCs could still trigger halide migration under a high bias due to the incomplete ligand decoration. Furthermore, it is still challenging to realize sufficient thickness of absorption layers based on NCs for X-ray detectors through traditional methods. Herein, we develop a centimeter-size and millimeter-thick wafer based on CsPbBr₃ NCs through isostatic pressing for X-ray detectors, in which the interfacial defects of NCs are remedied by CsPb₂Br₅ during aging of wafer in ambient humidity. The wafer shows outstanding sensitivity (200 μC Gy_air^-1 cm^-2) and ultralow dark current drift (1.78 × 10^-8 nA cm^-1 s^-1 V^-1 @ 400 V cm^-1). Moreover, it shows storage stability with negligible performance degradation for 60 days in ambient humidity. Thus, aging perovskite NC wafers for X-ray detection holds huge potential for next-generation X-ray imaging plates.