Piezoelectric nanofiber/polymer composite membrane for noise harvesting and active acoustic wave detection

Being one of the most common forms of energy existing in the ambient environment, acoustic waves have a great potential to be an energy source. However, the effective energy conversion of an acoustic wave is a great challenge due to its low energy density and broad bandwidth. In this work, we developed a new piezoelectric nanogenerator (PENG), which is mainly composed of a piece of piezoelectric nanofiber/polymer composite membrane. As an energy harvester, the PENG can effectively scavenge a broad low-frequency (from 50 Hz to 400 Hz) acoustic energy from the ambient environment, and it can even scavenge a very weak acoustic energy with a minimum pressure of only 0.18 Pa. When a drum was used as an excitation source, the maximum open-circuit voltage and short-circuit current density of the PENG reached 1.8 V and 1.67 mA m^-2, respectively. In addition, the PENG had a good stability and its output frequency and amplitude were closely related to the driving sound wave, which made the PENG capable of detecting acoustic signals in the living environment and have the potential to be applied as a self-powered active acoustic detector.