posted on 2019-11-10, 17:13authored byTruong-Son Dinh Le, Jianing An, Yi Huang, Quoc Vo, Jeeranan Boonruangkan, Tuan Tran, Seung-Woo Kim, Gengzhi Sun, Young-Jin Kim
Human
voice recognition systems (VRSs) are a prerequisite for voice-controlled
human-machine interfaces (HMIs). In order to avoid interference from
unexpected background noises, skin-attachable VRSs are proposed to
directly detect physiological mechanoacoustic signals based on the
vibrations of vocal cords. However, the sensitivity and response time
of existing VRSs are bottlenecks for efficient HMIs. In addition,
water-based contaminants in our daily lives, such as skin moisture
and raindrops, normally result in performance degradation or even
functional failure of VRSs. Herein, we present a skin-attachable self-cleaning
ultrasensitive and ultrafast acoustic sensor based on a reduced graphene
oxide/polydimethylsiloxane composite film with bioinspired microcracks
and hierarchical surface textures. Benefitting from the synergetic
effect of the spider-slit-organ-like multiscale jagged microcracks
and the lotus-leaf-like hierarchical structures, our superhydrophobic
VRS exhibits an ultrahigh sensitivity (gauge factor, GF = 8699), an
ultralow detection limit (ε = 0.000 064%), an ultrafast
response/recovery behavior, an excellent device durability (>10 000
cycles), and reliable detection of acoustic vibrations over the audible
frequency range (20–20 000 Hz) with high signal-to-noise
ratios. These superb performances endow our skin-attachable VRS with
anti-interference perception of human voices with high precision even
in noisy environments, which will expedite the voice-controlled HMIs.