Energy harvesting from vibration using flexible floroethylenepropylene piezoelectret films with cross-tunnel structure

Flexible fluoroethylenepropylene (FEP) piezoelectret films with a cross-tunnel structure were prepared using a template-based process and contact charging. Energy harvesting from the fabricated FEP films was investigated at various exciting frequencies and load resistances. The results show that the quasi-static piezoelectric d₃₃ coefficients for the FEP piezoelectret samples are of the order of 1000 pCN^-1 at an applied pressure of 3.1 kPa. The output voltage increases with the increase in load resistance, and the output power is dependent on the load resistance and vibration frequency. At a load resistance of 0.9 MΩ and vibration frequency of 650 Hz, the output power of 3.5 μWg^-2 was obtained for the sample with an area of 3.14 cm² and a seismic mass of 44.1 g. Such thin, light and flexible FEP piezoelectret films may be applied in wearable environmental energy harvesting system.