A novel ZnO NRs/PVDF hybrid nanogenerator for wearable energy-harvesting and sensing applications

Abstract

The continuous increase of global economic and industrial status has produced increased demand of new and reneawable energy sources. In addition, the depletion of fossil fuels and its related environmental challenges also forces to find alternative sources of energy. The development of environmental backround energy harvesting nanogenerators can be a solution for this crisis. Miniatured self-powered devices working based hybrid energy harvesting techniques of photovoltaic, piezoelectric, pyroelectric and triboelectrics can reduce the need of energy from other reneawable sources. The miniaturization of electronic devices has attracted significant attention because it enables both implantable and wearable applications. Such flexible electronic miniature devices are typically prepared using polymer-based electrospun nanofibers. However, these polymer-based piezoelectric sensors' poor sensing ability and low power output are major problems. Fortunately, adding zinc-oxide nanorods with conductive polymers such as polyvinylidene fluoride (PVDF) can produce more efficient piezoelectric nanogenerators and mitigate the challenges associated with the commonly used zinc-oxide nanorods or polymers alone. PVDF, a conductive polymer that can be incorporated into zinc oxide (ZnO) nanorod devices, can significantly improve mechanical energy harvesting and pressure-sensor performance. ZnO nanorods are greatly favored for mechanical energy harvesting thanks to their excellent piezoelectric and semiconducting properties, high availability, and low cost. In addition, they are stable in air, easily processable, and biocompatible, which makes them particularly suitable for human implantable devices. In this study, we report a highly efficient and durable piezoelectric nanogenerator that can be fabricated with PVDF-covered ZnO nanorod arrays and investigate its properties. The vertically aligned ZnO nanorods of uniform size are grown on indium tinoxide (ITO)coated polyethylene terephthalate (PET) substrates using a hydrothermal method. This piezoelectric nanogenerator has been explicitly developed to harvest energy from mechanical vibrations and body movements. The power conversion ability of the device is tested under different conditions, such as mechanical bending, pressing, and body motion. It has produced high current compared to existing results on this material.