A Soft Resistive Acoustic Sensor Based on Suspended Standing Nanowire Membranes with Point Crack Design

An artificial basilar membrane (ABM) is an acoustic transducer that mimics the mechanical frequency selectivity of the real basilar membrane, which has the potential to revolutionize current cochlear implant technology. While such ABMs can be potentially realized using piezoelectric, triboelectric, and capacitive transduction methods, it remains notoriously difficult to achieve resistive ABM due to the poor frequency discrimination of resistive-type materials. Here, a point crack technology on noncracking vertically aligned gold nanowire (V-AuNW) films is reported, which allows for designing soft acoustic sensors with electric signals in good agreement with vibrometer output-a capability not achieved with corresponding bulk cracking system. The strategy can lead to soft microphones for music recognition comparable to the conventional microphone. Moreover, a soft resistive ABM is demonstrated by integrating eight nanowire-based sensor strips on a soft trapezoid frame. The wearable ABM exhibits high-frequency selectivity in the range of 319-1951 Hz and high sensitivity of 0.48-4.26 Pa-1. The simple yet efficient fabrication in conjunction with programmable crack design indicates the promise of the methodology for a wide range of applications in future wearable voice recognition devices, cochlea implants, and human-machine interfaces.