Charge-induced high-performance actuation of borophene

Borophene, a two-dimensional material, has grown fast in the nanomaterials field because of its unique electronic and mechanical properties. In this work, we demonstrate that the unique properties of borophene make this material with a high-performance electromechanical actuator by using first-principles calculations. We find a high Young's modulus about 376.55 N m-1 of a striped borophene, which is larger than that of graphene (∼336 N m-1) in the unit of N m-1. In addition, upon hole injection, maximum actuator strain is up to 1.67% that is over 7 times larger than that of graphene at the same value of hole doping (0.04 e/atom). Therefore, the striped borophene shows a high work-area-density per cycle of 22 MJ m-3•nm, it is approximately 28 and 11 times larger than that of graphene (0.78 MJ m-3•nm) and metallic 1T-MoS2 (2.05 MJ m-3•nm), respectively. Furthermore, the striped borophene still maintains the metal property under charge doping. Thus, an actuator device based on borophene can work under a low applied voltage. Finally, the charge doping effects on the mechanical strength of borophene are investigated. Interestingly, the mechanical strength is increased by 15.8% in the case of electron doping.