Characterization and Modeling of Meshed Electrodes on Free Standing Polyvilylidene Difluoride (pvdf) Films for Enhanced Pyroelectric Energy Harvesting

Flexible pyroelectric energy generators provide unique features for harvesting temperature fluctuations, which can be effectively enhanced using meshed electrodes that improve thermal conduction, convection, and radiation into the pyroelectric material. In this paper, thermal radiation energy is continuously harvested with pyroelectric free standing polyvilylidene difluoride (PVDF) films over a large number of heat cycles using a novel microsized symmetrical patterned meshed electrode. It is shown that, for the meshed electrode geometries considered in this paper, the polarization-field and current-field characteristics and device capacitance are unaffected since the fringing fields were generally small; this is verified using numerical simulations and comparison with experimental measurements. The use of meshed electrodes has been shown to significantly improve both the open-circuit voltage (from 16 to 50 V) and closed-circuit current (9 to 32 nA). The pyroelectric alternating current is rectified for direct current storage, and 30% reduction in capacitor charging time is achieved using the optimum meshed electrode coverage. The use of meshed electrodes on ferroelectric materials provides an innovative route to improve their performance in applications such as wearable devices, novel flexible sensors, and large-scale pyroelectric energy harvesters.