Wearable RGO/MXene Piezoresistive Pressure Sensors with Hierarchical Microspines for Detecting Human Motion

Abstract

Flexible piezoresistive pressure sensors may exhibit excellent sensing performances to be applied in wearable electronics, medical diagnosis, and electronic skin. Herein, we report a multi-layer and phased-responsive reduced graphene oxide/MXene-based piezoresistive pressure sensor with hierarchical microspines constructed by sandpaper as the template. Thanks to the multi-level and multi-layer structure, the obtained sensor realized phased response and showed wide detection range (up to 70 kPa), fast response (response/recovery time of 40/80 ms), and excellent working stability (1000 fatigue cycles). Furthermore, the sensor was successfully applied for detecting various human motions including pulse beats, cheek bulging, nodding, finger bending, speech recognition, handwriting, and other pressure signals.Besides, a 6 × 6 sensing matrix integrated by the sensors was able to sensitively perceive the distribution of plane pressure. The findings in this work conceivably stand out as a new strategy to fabricate high-performance piezoresistive pressure sensors in the fields of intelligent healthcare and medical diagnosis, wearable electronic devices, electronic skin, and human−machine interaction.

Recent progress in flexible pressure sensors based on multiple microstructures: from design to application

“…Depending on the orientation of the micropatterned structure layers, multilayered micropatterned structures can be subdivided into codirectional stacking structures, 126,128 interlocked structures, 72,103,105,[129][130][131][132][133][134] and multilayer interlocked structures. 135,136 For example, a PS was fabricated by stacking reactive ionic films prepared by the sandpaper template method (Fig. 3a) by Xiao et al 126 The multilayer structure enables the stress to be uniformly distributed to each layer, providing the sensor with a linear operating range from 0.013 to 2063 kPa.…”

MXene‐Based Flexible Sensors: Materials, Preparation, and Applications

“…When airborne VOCs come into contact with a gas sensor, the volatile gas combines with the sensing layer to generate a volatile gas, resulting in a Reproduced with permission. [188] Copyright 2022, American Chemical Society. f) Schematic diagram of the IMN-based pressure sensor array.…”

“…The piezoelectric sensor is a device that converts the signal of deformation under the action of external force into the signal of electric current. Yang et al [188] fabricated a waterproof and highly sensitive piezoelectric flexible sensor HBT using hydrophobic bacterial cellulose and Ti 3 C 2 T x (Figure 11c). The obtained pressure sensor has high sensitivity (65.5 kPa −1 ) (Figure 11d), fast response (50 ms), wide linear monitoring range (0.002-30 kPa), and low detection limit (0.57 Pa), and still has the sensitivity for monitoring after more than 50 000 cycles.…”

“…Reproduced with permission. [ 188 ] Copyright 2022, American Chemical Society. f) Schematic diagram of the IMN‐based pressure sensor array.…”

“…e) HBT pressure sensor monitors the change in resistance of the pressure sensor in real-time when the wrist is bent. Reproduced with permission [188]. Copyright 2022, American Chemical Society.…”