Abstract
We use a combination of high-speed video imaging and electrical measurements to study the direct conversion of the impact energy of water drops falling onto an electrically precharged solid surface into electrical energy. Systematic experiments at variable impact conditions (initial height; impact location relative to electrodes) and electrical parameters (surface charge density; external circuit resistance; fluid conductivity) allow us to describe the electrical response quantitatively without any fit parameters based on the evolution of the drop-substrate interfacial area. We derive a scaling law for the energy harvested by such “nanogenerators” and find that optimum efficiency is achieved by matching the timescales of the external electrical energy harvesting circuit and the hydrodynamic spreading process.
- Received 6 March 2020
- Revised 15 May 2020
- Accepted 25 June 2020
DOI:https://doi.org/10.1103/PhysRevLett.125.078301
© 2020 American Physical Society
Physics Subject Headings (PhySH)
Viewpoint
Harvesting Energy from Falling Droplets
Published 12 August 2020
A clever coupling of triboelectric charging and the hydrophobic effect leads to a remarkably efficient electrical nanogenerator.
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