Research / 2019 / Article / Fig 4

Review Article

Emerging Devices Based on Two-Dimensional Monolayer Materials for Energy Harvesting

Figure 4

Hydrovoltaic devices for harvesting water kinetic energy on a monolayer graphene surface. (a) Generating electricity by moving a droplet of ionic liquid along the monolayer graphene and a SiO2/Si wafer. (b) DFT results for the distribution of charges at the graphene/solution interface and potential difference induced by moving a droplet. (c) Drawing potential and resistance change with graphene layers. Reproduced with permission from the Nature Publishing Group [79]. (d) Schematic illustration for waving potential by moving graphene across the surface of saltwater. (e) Schematic of the electric double-layer and its boundaries of ion adsorption (A) and desorption (B) on the surface of graphene during the inserting and pulling out processes. Reproduced with permission from the Nature Publishing Group [80]. (f) Sum-frequency vibrational spectroscopy for the mechanism study of electric power generation from ionic droplet motion on polymer-supported graphene. Reproduced with permission from the American Chemical Society [83]. (h) Triboelectrification-induced large electric power generation from a single moving droplet on graphene/PTFE. Reproduced with permission from the American Chemical Society [81]. (i) Measuring the electrical response to a water flow over graphene PVDF heterointerface. Output voltage and resistance change with number of graphene layers. Reproduced with permission from Wiley-VCH [82].