A broadband piezoelectric energy harvester regulated by light activated shape memory polymer

In this paper, a hybrid energy harvesting system is established and studied; the natural frequency of which is regulated by a novel intelligent material named light activated shape memory polymer (LaSMP). LaSMP realizes the shape memory function under the exposure of laser lights with two different wavelengths. During the exposure process, LaSMP exhibits a characteristic of dynamic stiffening effect. A cantilever beam laminated with LaSMP and piezoelectric layers is used as a broadband hybrid energy harvester. Employing this stiffening characteristic of the LaSMP, the natural frequency of the hybrid energy harvester can be manipulated to achieve broadband energy harvesting response. The hybrid energy harvester is designed to adjust its frequency to resonance at the excitation frequency. The results show that the natural frequency of the hybrid energy harvester can be tuned by 5.2%, and the minimum energy harvesting power output increases from 0.001uW to 0.01μW.