Graphene based two dimensional hybrid nanogenerator for concurrently harvesting energy from sunlight and water flow

Harvesting energy from multiple sources in our living environment is highly demanded, not only to cope with the increasing energy crises, but also to realize the self-powered electronics. Here we propose a graphene based two dimensional (2D) hybrid nanogenerator which can generate electricity through capturing sunlight as well as water flow. This 2D nanogenerator is mainly based on a graphene/silicon van der Waals Schottky diode. Two different metal electrodes are employed to build an asymmetric internal potential profile in the graphene channel, allowing for harvesting energy from sunlight in the 2D graphene plane with a maximum output power of 49.3 μW. When water flows over the graphene surface under illumination, an additional voltage can be generated simultaneously. This flow-induced voltage arises from an additional charge transfer in the graphene channel induced by a continuous doping and dedoping of the graphene, owing to a reversible wetting and dewetting effect of water during the water flowing process. The results show a physical picture of dynamic adjusting the charge transfer characteristic of graphene/silicon Schottky diode through water flow when under illumination, which may open prospects for practical applications for graphene nanogenerator.