Aging CsPbBr 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 CsPbBr NCs through isostatic pressing for X-ray detectors, in which the interfacial defects of NCs are remedied by CsPbBr during aging of wafer in ambient humidity. The wafer shows outstanding sensitivity (200 μC Gy cm) and ultralow dark current drift (1.78 × 10 nA cm s V @ 400 V cm). 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.