Defect Mitigation in Lead-Free Cs3Bi2I9 Single Crystals for High Performance X-Ray Detection and Imaging

Cs3Bi2I9 single crystals has attracted increasing attention in perovskite X-ray detectors due to its low cost, nontoxicity, high stability and low detection limit. With the gradual improvement of device performance, the growth of high-quality, low-defect single crystals becomes increasingly crucial. In this work, we developed a polypropylene glycol nucleation control strategy for the effective growth of Cs3Bi2I9 single crystals with fewer defects. The X-ray detectors prepared by this strategy exhibit excellent detection and imaging performance, reaching a sensitivity of $173.9~\mu $ C $\cdot $ Gy $_{\text {air}}^{-{1}}\cdot $ cm $^{-{2}}$ at 40 V $\cdot $ mm $^{-{1}}$ and a detection limit of $1.57~\mu $ Gy $_{\text {air}}\cdot $ s $^{-{1}}$ , and showcasing sharp imaging ability. This research contributes to the advancement of next-generation X-ray detection.