Flexible Self-Powered Ti3C2T x MXene Nanosheet/CdS Nanobelt Photodetector with Enhanced Responsivity and Photosensitivity

Can the semimetallic 2D Ti3C2T x MXene function as an active photosensitive material rather than merely an electrode? Can a flexible, self-powered photodetector based entirely on 2D and 1D photoactive materials overcome the persistent challenge of high dark current that often limits low-light detection? Addressing these questions, we report a flexible self-driven photodetector constructed from a 2D Ti3C2T x MXene and a 1D CdS nanobelt heterojunction, where both constituents actively contribute to low-light detection. Unlike conventional approaches where MXene serves as a passive electrode, Ti3C2T x here plays an active role in photogeneration and charge separation. The 2D-1D architecture facilitates the formation of a strong built-in electric field across the interface, promoting efficient photocarrier extraction while significantly suppressing dark current. The device achieves an exceptional light-to-dark current ratio exceeding approximate to 105, a high responsivity of approximate to 34.42 A/W, and detectivity up to approximate to 5.68 x 1014 Jones, along with a rapid response time of approximate to 7.2/120 mu s under zero bias. These results highlight the potential of MXene-based heterostructures in advancing high-performance, low-light, self-powered optoelectronic platforms.