Ultrasound-Assisted Crystallization Enables Large-Area Perovskite Quasi-Monocrystalline Film for High-Sensitive X-ray Detection and Imaging.

Abstract

In recent years, halide perovskites have shown great application potential in X-ray detection due to their superior optoelectronic properties and high X-ray attenuation coefficient. However, large-area perovskite fabrication for high performance X-ray detectors remains extremely challenging. Herein, ultrasound-assisted crystallization combined with the hot-pressing method is proposed to prepare large-area (10 cm × 10 cm) and high-quality quasi-monocrystalline thick film of a mixed-cation perovskite MA_0.42 FA_0.58 PbI₃ . The rapid ultrasound-assisted crystallization provides more homogeneous nucleation, which is essential to the fabrication of large-area and uniform perovskite microcrystalline film. Furthermore, the post hot-pressing treatment is implemented to fuse the crystal boundaries, rearrange the crystal grains, and eliminate the voids between crystals, resulting in a quasi-monocrystalline film. After the hot-pressing treatment, the carrier mobility and the carrier mobility-lifetime product increased about 13-fold (from 1.8 to 23.5 cm² s^-1 V^-1 ) and 18 times (from 8.4 × 10^-6 to 1.5 × 10^-4 cm² V^-1 ), respectively. As a result, a high-performance MA_0.42 FA_0.58 PbI₃ quasi-monocrystalline X-ray detector is achieved with an impressively high sensitivity (1.16 × 10⁶ µC Gy_air ^-1 cm^-2 ) and low detection limit (37.4 nGy_air s^-1 ), demonstrating the potential of the ultrasound-assisted crystallization and hot-pressing strategy from an industrial perspective.