A flexible nanocomposite film based on PVDF/ZnO-rGO for energy harvesting and self-powered carbon dioxide gas sensing

Abstract

Developing low-cost backup power sources for gas sensors is highly significant in the context of various ambient energy harvesting technologies. Piezoelectric nanogenerators have gained immense attention due to their stable and reliable power generation capabilities. In this work, a self-powered gas sensor based on ZnO was driven by a PVDF/ZnO-rGO composite piezoelectric nanogenerator (PZRNG) for detecting CO2 gas. ZnO nanoparticles were synthesized via a hydrothermal reaction, whereas rGO was prepared using a modified Hummer’s method. An optimal weight ratio of rGO was blended with ZnO nanoparticles to act as a filler, enhancing the conductivity of the composite film. The PVDF/ZnO-rGO composite film served as the active layer of the PZRNG device, achieving a maximum electrical output of 15V and 350 nA, which was superior to the device without the filler. The generated electrical output was validated by charging various commercial capacitors. A self-powered CO2 sensor (SP-CDS) was fabricated using a flexible Kapton substrate and an interdigitated electrode printed with silver via screen printing. The gas sensor integrated with the PZRNG exhibited high sensing performance, with a sensitivity of 0.00457V/ppm and excellent selectivity for CO2. This work provides a cost-effective solution for developing self-powered gas sensors, paving the way for smart functionalities in Industry 4.0 and the Internet of Things.