Highly Sensitive and Wearable ZnO–Graphene Nanocomposite-Based Strain Sensors for Human Motion Detection

Flexible electronic sensors have garnered considerable interest in wearable health-monitoring devices and electronic skin. In this work, a simple method for the fabrication of flexible zinc oxide–graphene nanoplatelet (ZnO–GNP) nanocomposite-based strain sensors has been proposed. The sensing element was deposited on the polydimethylsiloxane (PDMS) substrate by a facile spin and peel strategy to yield flexible sandwiched sensors. The effect of varying the blending ratio of the constituents on the electromechanical responses of the sensors was studied. The sensors exhibited high stretchability, good sensitivity, high reversibility, and superior stability under tensile and bending loads. The flexible nanocomposite sensors were able to detect extensive human movements such as bending of the elbow, wrist, and finger and also subtle motions such as eye blinking, wrist pulse, and phonation. Owing to the facile and economical fabrication method, high sensitivity, and good reversibility, the ZnO–GNP sensors have a high prospect of application in wearable health-monitoring devices, robotics, and various forms of human–machine interface.