Characterization of Tribo/Piezoelectric Transducers for Application in Botanical Energy Harvesting From Low-Amplitude and Low-Frequency Motion

We investigate and characterize the extraction of energy from induced vibrations in plants via kinetic-electric conversion. The proposed transduction mechanism is based on a triboelectric/piezoelectric converter that underpins the energy harvester, which can be used to power sensing and measurement systems. The pair of transducers is based on an electret as a generating layer between two cylindrical structures, which act as linear converters for harvesting energy from the large displacements of the plant, while polyvinylidene difluoride (PVDF) foils are used to collect energy from the vibrations of leaves. The largest PVDF sheet tested generated a maximum power of approximately 5.59 nW across a 100 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> resistor, while the triboelectric system achieved a peak power of 0.50 nW with a 200 k<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> resistive load, power levels in line with the limited energy usually obtainable from the movement of leaves and branches swaying in the wind. The results and system characterization demonstrate the potential viability of the studied energy harvester in various applications involving distributed measurement systems that require environmentally friendly and unobtrusive energy harvesters, such as smart agriculture and the monitoring of cultural heritage sites and historical gardens.