PbI₂‐DMSO Assisted In Situ Growth of Perovskite Wafers for Sensitive Direct X‐Ray Detection

Although perovskite wafers with a scalable size and thickness are suitable for direct X-ray detection, polycrystalline perovskite wafers have drawbacks such as the high defect density, defective grain boundaries, and low crystallinity. Herein, PbI₂ -DMSO powders are introduced into the MAPbI₃ wafer to facilitate crystal growth. The PbI₂ powders absorb a certain amount of DMSO to form the PbI₂ -DMSO powders and PbI₂ -DMSO is converted back into PbI₂ under heating while releasing DMSO vapor. During isostatic pressing of the MAPbI₃ wafer with the PbI₂ -DMSO solid additive, the released DMSO vapor facilitates in situ growth in the MAPbI₃ wafer with enhanced crystallinity and reduced defect density. A dense and compact MAPbI₃ wafer with a high mobility-lifetime (µτ) product of 8.70 × 10^-4 cm² V^-1 is produced. The MAPbI₃ -based direct X-ray detector fabricated for demonstration shows a high sensitivity of 1.58 × 10⁴ µC Gyair^-1 cm^-2 and a low detection limit of 410 nGy_air s^-1 .