Skin-Like Near-Infrared II Photodetector with High Performance for Optical Communication, Imaging, and Proximity Sensing

Skin-like second-near-infrared (NIR-II) photodetec-tors are key requirements for a flexible photodetection system that can be seamlessly integrated with three-dimensional geometries to accurately distinguish and acquire real-time various information. However, such devices exhibiting simultaneously high photo-sensitivity, fast photoresponse, and excellent flexibility still remain elusive. Here, we design and fabricate such skin-like NIR-II photodetectors and arrays with a simple bilayer configuration by combining a highly conducting MXene (Ti3C2Tx) and photo-sensitive lead sulfide quantum dots (PbS QDs), where highly promoted photocarrier separation at the interface of bilayers and efficient transport across the spatially separated layers could be achieved. Moreover, the bilayer architecture together with the strong interface bonding between the MXene and PbS QDs ensure a high-quality interface, leading to simultaneously improved optoelectronic performance and mechanical stability. Thus, the resulting device exhibits a high responsivity (1000 mA W-1), a fast photoresponse (30 ms), and excellent mechanical stability (>95% performance retention after 500 cycle bending), which renders this skin-like NIR-II photodetector highly suitable for fabricating various practical and high-performance flexible wireless photodetection systems for optical communication, NIR-II imaging, and proximity sensing in different environments. We anticipate that this simple yet high-performance skin-like MXene/PbS QDs-based photodetector would hold great potential in the applications of next-generation flexible optoelectronics.