Novel Graphene Electricity Generation Devices

The successful separation of graphene opens the door to the interdisciplinary research of material physics and device.Graphene has extraordinary quantum properties,such as one atomic layer thickness,ultra-high carrier mobility,fine structure constant defined transparency,which shows great prospects in the applications of electronic devices,optoelectronic devices and energy conversion devices.The unique Dirac cone-like energy band and large specific surface area make graphene to be extremely sensitive to external stimuli.As a result,the Fermi level of graphene can easily shift when affected by external environment,which will lead to carrier motion in the two dimensional plane of graphene,resulting in a great potential in the field of high efficient energy conversion.With the global energy crisis and rising energy demand,graphene has been widely used in energy conversion devices.Among the numerous ongoing graphene based research of harvesting energy from the natural environment,the integration of graphene with water is an increasingly popular approach to generate electricity.Although the research on water-enabled electricity generation of graphene is still in its primary stage,the exploration on generating electricity from water flow in graphene has been reported a lot.However,the experimental results in previous studies still have significant discrepancies,and there is no physical mechanism that can explain all these experimental phenomena.In addition,most of the previous researches only used graphene as a common nanomaterial,but ignored its own special quantum properties.Therefore,focusing on the existing various controversies in the research of water flow-induced electricity generation in graphene,a series of experimental research work have been carried out in this dissertation.On this basis,this dissertation proposes unique insights into the mechanism of electricity generation,improves power generation output and expands its application,and preliminary explores the specific expression of graphene quantum properties in the electricity generation process.The main contribution of this dissertation is detailed as follows:1.Considering the two dimensional fermions in graphene,based on Coulomb drag effect,we demonstrate that the flow of charged two dimensional material nanosheets over graphene surface can also induce a voltage in graphene,and propose a moving van der Waals heterostructure mechanism.2.Based on the one atomic layer thickness of the graphene,we propose a graphene/PVDF piezoelectric film heterostructure electricity generator to harvest electricity from the flow of various liquid,we carefully investigate the charge interaction between the three layers of liquid,graphene and the underlying substrate,and analyze the critical role of the substrate in the water flow induced electricity generation process.3.By introducing a PTFE substrate,compared to the previous research results,we realize a 100 times enhanced electricity output from one single droplet moving on monolayer graphene,we suggest the strong negative potential on the surface of the PTFE substrate generated by the triboelectrification effect between PTFE and DI water during the graphene transfer process is the main reason.4.We propose a graphene/Si Schottky heterostructure based two dimensional hybrid electricity generation structue,which can simultaneously harvest solar energy and water flow energy in the two dimensional graphene plane.This dissertation points out the voltage increment induced by water flow originate from the water-flowing enabled continuous doping and dedoping effect of graphene,and this dynamic process can be explained as dynamically adjusting the charge transfer characteristics of graphene/Si Schottky junction by the flow of water droplet.