Basilar membrane-inspired self-powered acoustic sensor enabled by highly sensitive multi tunable frequency band

Abstract

Herein, we report a self-powered flexible piezoelectric acoustic sensor (f-PAS) inspired by basilar membrane in human cochlear. The f-PAS covered the voice frequency spectrum via the combination of its low quality (Q) factor and multi-resonant frequency tuning, exhibiting four to eight times higher sensitivity than the conventional condenser sensor. Our piezoelectric acoustic sensor with a thin membrane design produced sufficient output voltages by the distinct resonant movement of the Pb[Zr0.52Ti0.48]O3 (PZT) membrane under the minute acoustic sound stimuli. Multiple sensor channels were integrated in a single f-PAS chip with a size of 1.5 × 3 cm2, which acquire multi-tunable piezoelectric signals without any external power. A linear response of the resonance frequency of the curved piezoelectric membrane was theoretically investigated by a finite element method (FEM) calculation. Low Q factors from corresponding channels were achieved by optimal membrane thickness and channel length.