All directional nanogenerators (NGs) with a highly flexible and near field electrospun concentrically aligned nano/micro P(VDF-TrFE) fibers

A self-powered and flexible piezoelectric sensor that are structurally different from previous NFES research were developed in this study. The near-field electrospinning (NFES) is employed to pattern the micro/nano copolymer poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE) fibers (MNFs) arrays on the printed circuit board (PCB). It is expected that these biocompatible, low-cost, flexible, and lightweight nanogenerators (NGs) can become an effective energy source for wearable devices in practical applications. The fibers could only be actuated in a limited direction in previous research because they were mainly patterned in parallel lines. To solve the problem, the parallel alignment is re-arranged into a concentric circle pattern. The apparatus has spectacular performance in capturing mechanical deformation in an arbitrary direction. Therefore, no matter whether the deformation is along the same axis or not, the system can harvest mechanical energy. The device piezoelectric generator with concentrically circular topography (PGCT) can harvest more mechanical energy from arbitrarily directional devices compared to the typical alignment of fiber-based devices. This PGCT has a lot of potential for use as wearable electronics or sensors to improve the output of electronic signals. This research explored the associated conditions related to outdoor experiments, output voltage, and ambient wind energy collection such that the all-directional wind energy generators' capacity and electrical output were systematically assessed. Even at low wind speeds (~ 3.5 m/s), this wind power generator can sustainably generate electricity (~ 2 V) from the ambient and renewable environment, irrespective of the wind direction.