Melt‐Processable Perovskite Semiconductors for Sensitive x‐ray Detection

Metal halide perovskite x‐ray detectors are currently garnering significant research attention due to their ability to effectively detect x‐ray radiation with a low threshold. However, their practical development is impeded by challenges in fabricating high‐quality crystalline perovskite films with several hundred micrometers thick over a large area. Herein, we report a novel meltable 2D Ruddlesden‐Popper perovskite that features a low melting point of 122°C and a decomposition temperature of 240°C, offering an ideal process window for melt‐casting. Then, ∼500‐µm‐thick, dense, and uniform perovskite films with high electronic quality over large areas were fabricated by a low‐temperature melt‐casting approach. This enabled us to fabricate direct‐conversion x‐ray detectors with a sensitivity of ∼1500 µC Gy air −1 cm −2 and a detection limit of ∼40 nGy air s −1 . The strong interfacial adhesion between perovskite and substrate can withstand a tensile stress of 6.24 × 10 5 Pa without detachment, endowing a superior mechanical reliability. Finally, imaging devices integrated with thin‐film transistor (TFT) demonstrated excellent imaging capability, highlighting the practical applicability of this material system.