Enhanced Carrier Transport in X‐Ray Detector Based on Cs₃Bi₂I₉/MXene Composite Wafers

Abstract Intrinsically high attenuation of X‐rays and excellent optoelectronic properties endow Cs₃Bi₂I₉ with great promise for high‐performance X‐ray detectors. However, preparation of high quality Cs₃Bi₂I₉ 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 Cs₃Bi₂I₉ wafer, the Cs₃Bi₂I₉/MXene composite wafer exhibits higher carrier transfer efficiency and mobility‐lifetime product through incorporation of Ti₃C₂T_x MXene multilayer nanoflakes (MXene nanoflakes). The Cs₃Bi₂I₉/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 Cs₃Bi₂I₉ wafer detector. The sensitivity of Cs₃Bi₂I₉/MXene wafer device enhances ≈20–40% at low applied voltage regime. In addition, the Cs₃Bi₂I₉/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.