Hot‐Pressed CsPbBr3 Quasi‐Monocrystalline Film for Sensitive Direct X‐ray Detection

Abstract An X‐ray detector with high sensitivity would be able to increase the generated signal and reduce the dose rate; thus, this type of detector is beneficial for applications such as medical imaging and product inspection. The inorganic lead halide perovskite CsPbBr 3 possesses relatively larger density and a higher atomic number in contrast to its hybrid counterpart. Therefore, it is expected to provide high detection sensitivity for X‐rays; however, it has rarely been studied as a direct X‐ray detector. Here, a hot‐pressing method is employed to fabricate thick quasi‐monocrystalline CsPbBr 3 films, and a record sensitivity of 55 684 µC Gy air −1 cm −2 is achieved, surpassing all other X‐ray detectors (direct and indirect). The hot‐pressing method is simple and produces thick quasi‐monocrystalline CsPbBr 3 films with uniform orientations. The high crystalline quality of the CsPbBr 3 films and the formation of self‐formed shallow bromide vacancy defects during the high‐temperature process result in a large µτ product and, therefore, a high photoconductivity gain factor and high detection sensitivity. The detectors also exhibit relatively fast response speed, negligible baseline drift, and good stability, making a CsPbBr 3 X‐ray detector extremely competitive for high‐contrast X‐ray detections.