MXene-enhanced quantum dots ultraviolet photodetector performance towards flexible photoelectric detection

Abstract

The performance of ultraviolet photodetectors (UV PDs) is heavily influenced by the separation and migration of photogenerated charge carriers. However, it is still a tremendous challenge to design a novel semiconductor/metalloid heterostructure to enhance the charge separation and migration efficiency. Herein, we demonstrated a new useful strategy to construct high-performance flexible UV PD through 0D/2D/0D sandwich-like heterostructure composed of ZnMgO (ZMO) quantum dots (QDs) and ultrathin Ti3C2Tx MXene nanosheets (NSs). The ZMO/Ti3C2Tx/ZMO 0D/2D/0D sandwich-like heterostructure can promote efficient charge carrier separation, and improve charge carrier mobility. As a result, the device based on this sandwich-like heterostructure exhibits notably enhanced photocurrent and response sensitivity under UV light illumination. At a 1 V bias and 365 nm UV light, the optimized device demonstrates a photocurrent approximately 40 times higher than that of pristine ZMO QDs. Furthermore, the rise and fall times are significantly reduced, representing 16.6% and 80.4% improvements over the corresponding times for pristine ZMO QDs. Additionally, the device maintains stable photocurrent performance after undergoing large-angle mechanical bending and 1000 bending cycles, demonstrating excellent flexibility and reliability. This work provides a promising strategy for high-performance flexible UV PDs, showing promising application potential in wearable sensing and flexible environmental monitoring.