Relationship between water droplet motion and output characteristics in droplet-based electricity generator

Recently water droplet-based electricity generators (DEGs), which utilize triboelectricity between a droplet and a dielectric material, has a great attention. DEG generates an instantaneous high-power density despite its simple metal/dielectric/metal stack structure. In the DEG, the contact area between a droplet and a dielectric surface affects the output characteristics. We fabricated a DEG using a PTFE film as a dielectric material, measured the output voltage and evaluated the contact area in various dropping heights and positions. We demonstrated that the output peak voltage increased as the contact area increased related to spreading and rebounding of a droplet.