Enhanced Carrier Transport in X‐Ray Detector Based on Cs ₃ Bi ₂ I ₉ /MXene Composite Wafers

Abstract Intrinsically high attenuation of X‐rays and excellent optoelectronic properties endow Cs 3 Bi 2 I 9 with great promise for high‐performance X‐ray detectors. However, preparation of high quality Cs 3 Bi 2 I 9 single crystal with large area and millimeter‐thick remains challenging and time‐consuming. A size scalable growth technology, a mechanical sintering process, which is applicable for the integration in image detectors is proposed in this work. Compared with the Cs 3 Bi 2 I 9 wafer, the Cs 3 Bi 2 I 9 /MXene composite wafer exhibits higher carrier transfer efficiency and mobility‐lifetime product through incorporation of Ti 3 C 2 T x MXene multilayer nanoflakes (MXene nanoflakes). The Cs 3 Bi 2 I 9 /MXene composite wafer X‐ray detector shows an excellent linearity of X‐ray response, a fast response speed, and a low limit of detection of 231 nGy air s −1 . The sensitivity of 368 µC Gy air −1 cm −2 under 120 V mm −1 is achieved, which is 15.4% enhanced over the Cs 3 Bi 2 I 9 wafer detector. The sensitivity of Cs 3 Bi 2 I 9 /MXene wafer device enhances ≈20–40% at low applied voltage regime. In addition, the Cs 3 Bi 2 I 9 /MXene wafer detector exhibits excellent operational stability after storage for 12 months in ambient air. This work provides an alternative approach for realization of next‐generation high‐performance perovskite X‐ray detectors.