Jiahong Wang

Abstract Black phosphorus (BP), a burgeoning elemental 2D semiconductor, has aroused increasing scientific and technological interest, especially as a channel material in field‐effect transistors (FETs). However, the intrinsic instability of BP causes practical concern and the transistor performance must also be improved. Here, the use of metal‐ion modification to enhance both the stability and transistor performance of BP sheets is described. Ag + spontaneously adsorbed on the BP surface via cation–π interactions passivates the lone‐pair electrons of P thereby rendering BP more stable in air. Consequently, the Ag + ‐modified BP FET shows greatly enhanced hole mobility from 796 to 1666 cm 2 V −1 s −1 and ON/OFF ratio from 5.9 × 10 4 to 2.6 × 10 6 . The mechanisms pertaining to the enhanced stability and transistor performance are discussed and the strategy can be extended to other metal ions such as Fe 3+ , Mg 2+ , and Hg 2+ . Such stable and high‐performance BP transistors are crucial to electronic and optoelectronic devices. The stability and semiconducting properties of BP sheets can be enhanced tremendously by this novel strategy.

Abstract Heterostructures composed of two‐dimensional black phosphorus (2D BP) with unique physical/chemical properties are of great interest. Herein, we report a simple solvothermal method to synthesize in‐plane BP/Co 2 P heterostructures for electrocatalysis. By using the reactive edge defects of the BP nanosheets as the initial sites, Co 2 P nanocrystals are selectively grown on the BP edges to form the in‐plane BP/Co 2 P heterostructures. Owing to disposition on the original defects of BP, Co 2 P improves the conductivity and offers more active electrocatalytic sites, so that the BP/Co 2 P nanosheets exhibit better and more stable electrocatalytic activities in the hydrogen evolution and oxygen evolution reactions. Our work not only extends the application of BP to electrochemistry, but also provides a new idea to improve the performance of BP by utilization of defects. Furthermore, this strategy can be extended to produce other BP heterostructures to expand the corresponding applications.