SnS/Ti₃C₂T_<i>x</i> (MXene) Nanohybrid-Based Wearable Electromechanical Sensors for Sign-to-Text Translation and Sitting Posture Analysis

Abstract

The challenges involved in realizing next-generation applications, like robotics, artificial electronic skin, noninvasive healthcare monitoring, motion detection, and so forth, enabled with wireless human-machine interfaces, present a growing need for high-performance flexible and wearable multifunctional electromechanical sensors. In this regard, emerging classes of two-dimensional nanomaterials and their hybrids show excellent promise as active sensing materials, given their high flexibility and remarkable sensitivity to external pressure and strain. This report is the first demonstration of SnS/Ti3C2Tx nanohybrid-based electromechanical sensors for use in applications like sign-to-text translation and sitting posture analysis. The as-fabricated piezoresistive sensor exhibits a high gauge factor and sensitivity value, that is, 7.41 and 7.49 kPa–1, respectively. Furthermore, the nanohybrid-based sensor displayed a negligible change in performance over ∼3500 and ∼2500 cycles for both pressure and strain characterizations, indicating high robustness and exceptional stability. The underlying intrinsic piezoresistive mechanism in layered nanomaterials and the Ohmic contact formed at the SnS/Ti3C2Tx heterojunction are explained in detail with the help of energy band diagrams wherein the work function and the Ehomo values are extracted experimentally by ultraviolet photoelectron spectroscopy for both SnS and Ti3C2Tx. The successful demonstration of sign-to-text translation and e-cushion applications using SnS/Ti3C2Tx nanohybrid-based piezoresistive sensors will further expand the scope of flexible and wearable electronics research.