A Wet‐Fusing Assembly Strategy for Forming Low Dark Current 2D/3D Perovskite X‐Ray Detector on a Thin Film Transistor Backplane

Single‐crystalline metal halide perovskite, due to its large X‐ray attenuation coefficient, high carrier mobility, and facile fabrication properties, is considered as a promising candidate material for direct X‐ray detectors. Despite the rapid development of high‐sensitivity perovskite detectors, their practical application is still hindered by their high dark current levels and the lack of effective approach for assembling the perovskite photodetectors on thin‐film transistor (TFT) backplane. Herein, it is shown that, by using a supersaturated 2D perovskite precursor as a wet‐fusing intermedia, a high‐performance 2D/3D perovskite detector can be fabricated and simultaneously attached to the TFT backplane. The assembled 2D/3D heterostructure perovskite detector shows low dark current density, high sensitivity, and low dose detection limit. This work provides a viable route to realize a low‐dose, high‐resolution direct X‐ray image sensor based on perovskite photodetectors.