Development of flexible piezoelectric nanogenerator based on PVDF/KNN/ZnO nanocomposite film for energy harvesting application

For solving energy shortages and environmental problems one of the key strategies is renewable energy generation. Among the various techniques available for energy generation and harvesting, piezoelectric energy harvesting has grabbed significant attention owing to the huge demand for self-powered electronic devices. Herein, we report the Potassium Sodium Niobate (KNN) and Zinc Oxide (ZnO) @ Poly (vinylidene fluoride) (PVDF) nanocomposite film-based flexible piezoelectric nanogenerator (PENG) and studied the effect of KNN and ZnO concentration on the piezoelectric performance of the device. In addition, the real-life application of the device was also investigated. The finding showed that PVDF/KNN/0.45%ZnO nanocomposite film possesses the highest electroactive (β) phase (~59.81%), remnant polarization (P_r) (2.87 µC/cm²), maximum polarisation (P_s) (32.83 μC/cm²) and output voltage (39.5 V). The synergistic effect of KNN and ZnO nanoparticles in PVDF polymer matrix considerably improves the resultant piezoelectric performance of the nanogenerator, enabling it to glow four red light-emitting diodes (LEDs) and power a digital wrist watch. Moreover, the developed nanogenerator was also able to generate output voltages of 3.08 V (for pen tapping), 1.72 V (for elbow bending), 1.46 V (for finger moving) and 660 mV (for wrist stretching). Therefore, this fabricated device is a promising candidate for harvesting green and renewable energy and for use in wearable and portable self-powered electronic devices, where a small amount of energy is the basic requirement for their function.