▎ 摘　　要

Generation of electric potential by the flow of an electrolyte droplet on a graphene surface is investigated to develop a liquid motion energy harvester. Most of the research efforts to date have been focused on unveiling the interaction between graphene and an electrolyte droplet. However, other factors that significantly affect the output potential have not been paid much attention. Here, we report the electrostatic charging of graphene during a layer-transfer process and its influence on the enhancement of the performance of graphene-based liquid motion energy harvesting devices. In particular, we investigated the dependence of the output voltage on the triboelectric properties of the substrate. Our finding indicates that the triboelectric surface charging of graphene is significantly influenced by physisorption between graphene and the underlying substrate. Therefore, it directly affects the output power generation and the concentration of electrolyte solution at which the maximum power generation can be achieved. The method presented here is a simple route to further improve the output performance of graphene-based liquid motion energy harvesting devices and this study extends the physical understanding of charge interaction between graphene and an electrolyte solution.