Fabrication and characterization of miniature nonlinear piezoelectric harvester applied for low frequency and weak vibration

In order to collect energy from human activities, piezoelectric energy harvesters should have a flexible structure, low resonant frequency and wide frequency bandwidth. In this paper, the fabrication and characterization of a metal-based Pb(Zr,Ti)O3 (PZT) bimorph thick film energy harvester. PZT thick films were deposited on cantilever-shaped titanium (Ti) substrate via a dip-coating process. The electrical properties of the PZT films sintered at different temperatures were investigated. The nonlinear piezoelectric energy harvester has the following advantages: it is suitable for low frequency, weak vibration, and wide frequency bandwidth. The maximum open-circuit voltage of the piezoelectric energy harvester is 1.6 V and the output power is 0.85 μW with 150 kΩ load resistance at low resonant frequency of 17.6 Hz when the input vibration acceleration was 0.12 g. In addition, the frequency bandwidth is broadened from 0 to 8.4 Hz as the input acceleration increases from 0.05 g to 0.12 g.