Correlation between electromechanical, piezo-sensing, and ferroelectric response for energy harvesting applications of PVDF-based polymers

Searching for sustainable power sources suitable for scavenging mechanical energy is an area of intense research. For this purpose, flexible piezoelectric energy harvesters are suitable candidates to cater to the sustainability demand. In this study, devices composed of uniaxially and biaxially stretched polyvinylidene fluoride (PVDF) films were used as pressure sensors. Various mechanical stimuli-based tests were employed to extract and compare the output voltage. A better electro-mechanical response was extracted from the poly(vinylidene fluoride–trifluoroethylene) [P(VDF–TrFE)] films, which were simply prepared by solvent casting without any post-synthesis treatment such as poling or stretching. Detailed characterization revealed that P(VDF–TrFE) exhibited improved crystallinity and ferroelectric response, making it a better energy harvester. A mechanical energy conversion protocol is utilized to generate output voltage from a P(VDF–TrFE) based device. Based on this measurement, response to the external force and the piezoelectric sensitivity values have been quantified.