Wide-bandwidth piezoelectric energy harvester integrated with parylene-Cbeam structures

摘要

This work presents a wide-bandwidth MEMS energy harvester which converts the energy from ambient vibration into the electrical energy using piezoelectric effect. The proposed device consists of an inertia silicon proof-mass with four parylene-C beam structures, and a piezoelectric PVDF layer. In order to achieve wide-bandwidth harvesting, the design of doubly-clamped beams for inducing tensile stretching strain is adopted. The parylene-C beam structures are fabricated by simple RIE etching method, and the silicon proof-mass is made by isotropic wet etching technique. The piezoelectric film is bonded with the beam structure using parylene-C deposition. The measured frequency responses of the resonance structure show a broad frequency range with relatively large oscillation amplitude. When excited at an acceleration of 0.5 g, the energy harvester achieves to a maximum open-circuit voltage of 368 mV. The maximum output power is 0.288 μW.