Highly sensitive and wide-range iontronic pressure sensors with a wheat awn-like hierarchical structure

Abstract

Flexible pressure sensors with high sensitivity and wide sensing range are highly desired in e-skins and wearable electronics. However, there is always a trade-off between high sensitivity and broad sensing range for most flexible pressure sensors. Herein, an artificial wheat awn-like hierarchical structure is designed onto the dielectric layer of the iontronic pressure sensor, realizing both high sensitivity and broad working range. The sensor is constructed by sandwiching a wheat awn-like polyvinyl alcohol/H₃PO₄ dielectric layer between two transparent electrodes of silver nanowires/thermoplastic polyurethane/ionic liquid. The obtained sensor exhibits a high precision of 1 Pa, a high sensitivity of 47.65 kPa^-1 (1-200 Pa), a wide measurement range from 1 Pa to 238 kPa, short response/recovery time of 13 ms/12 ms, outstanding stability over 6000 cycles, as well as good transparency. Considering these excellent properties, the sensor shows promising potential in health monitoring, human-computer interaction, wearable electronics, etc.

Keywords: Bionic structure; High sensitivity; Pressure sensor; Transparency; Wide sensing range.