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.