KNN/PDMS/C-based lead-free piezoelectric composite film for flexible nanogenerator

A novel approach to fabricate a high performance flexible piezoelectric nanogenerator (PNG) by employing K0.5Na0.5NbO3 (KNN)/PDMS/C composite thin film has been proposed. The formed 12 wt% C doping KNN/PDMS PNG demonstrates a higher relative permittivity (Ɛr, 173.56) and larger remanent polarization (Pr, 1.84 µC/cm2) than pure KNN/PDMS film, thus serving as the possible origins of their comparative piezoelectric activities, which could generate an maximum output voltage of 10.55 V (3.3 times as much as the PNG without C doping). Besides, the PNG is able to light up a commercial green light-emitting diode (LED) through an energy storage capacitor (47 µF), showing its great potential as power of wearable and mobile devices.