Triboelectrics and Tribovoltaics for Energy Harvesting

Energy harvesting systems based on triboelectric nanomaterials are in great demand, as they can provide routes for the development of self-powered devices which are highly flexible, stretchable, mechanically durable, and can be used in a wide range of applications. Ultrasound was used to deliver mechanical energy through skin and liquids and demonstrated that a thin inplantable vibrating triboelectric nanogenerator is able to effectively harvest it. Secondly the presenter is going to introduce a two-dimensional (2D) materials-based tribotronics for possible future application toward tactile sensors, robots, security, human-machine interfaces, etc. The triboelectric charging behaviors of vaious 2D layered materials including graphene, MoS₂, WS₂, etc were investigated in order to decide the triboelectric position of each 2D material using the concept of a triboelectric nanogenerator, which provides new insights to utilize 2D materials in triboelectric devices, allowing thin and flexible device fabrication. Finally I will introduce a novel tribovoltaic effect, which can generate DC power output through the coupling of tribo exciton and drift by built-in electric field to overcome the limitations of conventional AC power-generating triboelectric nanogenerators. It was found that DC power can be generated at dynamic perovskite/CTL heterojunctions by electrical carrier generation from triboelectrification between two layers, which is different from the electric energy generation by photon excitation in solar cells. The tribovoltaic effect enables a paradigm shift in energy harvesting by enhancing battery charging efficiency based on an innovative working mechanism.