Long‐Lasting, Steady and Enhanced Energy Harvesting by Inserting a Conductive Layer into the Piezoelectric Polymer

Abstract Flexibility, higher piezoelectric performance, and long‐lasting stability of devices have a great demand in next generation energy technologies. Polyvinylidene fluoride (PVDF) polymer has a greater mechanical flexibility, but it suffers from low piezoelectric performance. Herein, sandwich‐structured piezoelectric film (SS‐PF) is designed by inserting the conductive poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) layer between two PVDF layers. The SS‐PF based flexible piezoelectric energy harvester (f‐PEH) generates higher voltage and current of 3.73 times and 4.64 times than the pristine PVDF film type f‐PEH. Moreover, the SS‐PF based f‐PEH shows no degradation in the output voltage confirming the excellent long‐lasting stability over 6 months. DFT simulation shows the occurrence of intermolecular forces between the PVDF/PEDOT:PSS interface. The electric field‐dependent charges alignment in PEDOT:PSS may induce the charge accumulation at the PSS‐PVDF interface and charge depletion at the PEDOT‐PVDF interface leading to the change in orientation of molecular structure in PVDF. Next, the SS‐PF based f‐PEH is tested for a vibration sensor to monitor the vibrations of curvy pipes and machines, and its output voltages are comparable with the commercial PVDF vibration sensor to confirm the real‐time use. The results present a novel design strategy, indicating a new direction for investigating piezo‐polymer‐based f‐PEH.