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

Abstract 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, PbI 2 ‐DMSO powders are introduced into the MAPbI 3 wafer to facilitate crystal growth. The PbI 2 powders absorb a certain amount of DMSO to form the PbI 2 ‐DMSO powders and PbI 2 ‐DMSO is converted back into PbI 2 under heating while releasing DMSO vapor. During isostatic pressing of the MAPbI 3 wafer with the PbI 2 ‐DMSO solid additive, the released DMSO vapor facilitates in situ growth in the MAPbI 3 wafer with enhanced crystallinity and reduced defect density. A dense and compact MAPbI 3 wafer with a high mobility‐lifetime (µ τ ) product of 8.70 × 10 −4 cm 2 V −1 is produced. The MAPbI 3 ‐based direct X‐ray detector fabricated for demonstration shows a high sensitivity of 1.58 × 10 4 µC Gyair −1 cm −2 and a low detection limit of 410 nGy air s −1 .