Boosted UV-SWIR Photoresponse of Full Solution-Processed CdS/PbS Heterojunction via MXene Carrier Collector Strategy

A simple and effective 2D MXene-based carrier collector strategy is developed to improve the photoresponsivity of the CdS/PbS heterojunction photodetector in an ultra-wide band (UWB) from ultraviolet (UV) to short-wavelength infrared (SWIR) range, where all films were sequential hetero-integrated via a facile full-solution-processing route. The optimized devices yield significantly enhanced photoresponse in the whole detection region from 349 to 2000 nm, showing a maximum responsivity of 1.7 and 1.8 A·W ^-1 in the UV (405 nm) and SWIR (1650 nm) region at -2 V bias respectively, as well as a light/dark ratio of 10 ² at 0 V bias under 1650 nm illumination with excellent stability. The performance is far exceeding those of the bare CdS/PbS counterpart and most other congeneric PbS-based photodetectors (PDs) previously reported. This work provides a prospective strategy to fabricate high-performance wide-spectrum photodetector based on 2D-MXene/traditional semiconductor.