All-organic flexible ferroelectret nanogenerator for wearable electronics

Piezoelectric nanogenerators used for energy harvesting in wearable electronics require flexibility, durability, and skin compatibility. Previous work has identified expanded polytetrafluoroethylene (ePTFE) as a potential candidate. A ferroelectret film was prepared by laminating ePTFE membranes and two fluorinated ethylene propylene (FEP) films using hot pressing, and injecting charges through corona discharge process. Using conductive fabric containing poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as electrodes, an all-organic nanogenerator was obtained. The open- circuit voltage and short-circuit current were measured to characterize the piezoelectric response. The short-circuit current was found to be approximately 50 nA for one layer of ePTFE membrane (15 × 15 mm2) under light pressure from one finger, and no increase in current and voltage was found from additional ePTFE layers. The polarizability and charges stability of the FEP/ePTFE/FEP film were also evaluated. The flexible ferroelectret nanogenerator can be embedded into clothes or insole and is expected to power continuously future wearable electronics system.