Enhanced Carrier Transport in X-Ray Detector Based on Cs_3Bi_2I_9/MXene Composite Wafers

摘要

Intrinsically high attenuation of X-rays and excellent optoelectronic properties endow Cs_3Bi_2I_9 with great promise for high-performance X-ray detectors. However, preparation of high quality Cs_3Bi_2I_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_3Bi_2I_9 wafer, the Cs_3Bi_2I_9/MXene composite wafer exhibits higher carrier transfer efficiency and mobility-lifetime product through incorporation of Ti3C2Tx MXene multilayer nanoflakes (MXene nanoflakes). The Cs_3Bi_2I_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 nGyair s~(?1). The sensitivity of 368 μC Gyair~(?1) cm~(?2) under 120 V mm~(?1) is achieved, which is 15.4 enhanced over the Cs_3Bi_2I_9 wafer detector. The sensitivity of Cs_3Bi_2I_9/MXene wafer device enhances ≈20–40 at low applied voltage regime. In addition, the Cs_3Bi_2I_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.