Low frequency wideband nano generators for energy harvesting from natural environment

A low frequency wideband response cantilever nano generator (NG) was designed for energy harvesting from ambient vibration in natural environment. The textured ZnO nanowires, acting as energy converters, were grown directly on titanium foil to form a composite that can work at resonance mode (around several Hz) after properly modulated. By adding a proper amplitude limiter at one side of the cantilever, the vibration can be modulated from linear mode to piecewise linear mode. As a result, the response bandwidth of single cantilever can be broadened at least 200% compared with that of a simple cantilever device without a limiter. A series of cantilevers with gradient changed resonance frequencies and partially overlapped bandwidth between each other can be integrated to further widen the bandwidth. Such resonance mode NGs can provide efficient energy conversion even at low frequencies. (C) 2014 Elsevier Ltd. All rights reserved.