Thermal expansion regulation of metal halide perovskites for robust flat-panel X-ray image detectors

Perovskite is a promising candidate for X-ray detection applications, but its high thermal expansion coefficient ( α ) poses a challenge in the fabrication of robust flat-panel X-ray image detectors. We propose a strategy to reduce the α of perovskite to release the residual thermal stress in perovskites, solving the problems of cracking and delamination during the preparation of a large-area perovskite thick film. Using this strategy, we prepared dense and uniform large-area films hundreds of micrometers thick with reduced dark current drift and improved stability. Our X-ray detectors demonstrate a detection limit down to 107 nGy air s −1 . The flat-panel X-ray imaging detector provides imaging results with a spatial resolution of 2.5 lp mm −1 .