Pressure-sensitive electronic skin applications generally require high sensitivity for applied pressures of up to ≈ 10 kPa, which corresponds to a gentle touch, most of previously reported pressure sensors did not sustain their high sensitivity to this upper pressure value. Because of the narrow sensing range, these sensors could not discriminate a subtle change in the relatively high-pressure regime. Furthermore, most of these sensors did not exhibit a wide range of linear sensitivity. In this study, we present a high-performance piezo-resistive pressure-sensor device with a linear relationship between applied pressure and output and with a high sensitivity of 8.5 kPa −1 for a wide range of pressures, specifically between 0 and 12 kPa, by using a bioinspired hierarchical structure consisting of PDMS covered with monolayer graphene. Our pressure sensor was shown to exhibit a high durability of 10,000 cycles and a low limit of detection of 1 Pa. In addition, the highly transparent and conductive monolayer graphene resulted in a transparent sensor with a low operating voltage of only 1 V.

 1.2. Pressure/Temperature Sensing Bimodal Electronic Skin with Stimulus Discriminability