On-skin graphene electrodes for large area electrophysiological monitoring and human-machine interfaces

On-skin sensors capable of capturing human electrophysiological signals are valuable for a variety of areas, such as wearable health monitoring, prosthesis, human machine interfaces (HMI). Extensive research efforts have been devoted to developing on-skin electrodes and they offer potential advantages over conventional rigid electrodes. However, those approaches usually have limitations as they require sophisticated and costly fabrication processes to produce only a small number of electrodes. Here we report the reduced graphene oxide (rGO) electrodes prepared by simultaneous room temperature reduction and patterning process for scalable fabrication of a large number of on-skin electrodes. Due to the low thickness and adhesive substrate adopted, the rGO electrodes can form conformal contact with skin even during deformation, leading to reduced impedance in skin-electrode interface. The rGO electrodes have been successfully adopted for the measurements of electromyography (EMG), electrooculogram (EOG)and electroencephalogram (EEG) signals with high fidelity. And the implementation of a HMI task is demonstrated through the recognition of five typical human hand grasping gestures via a multi-channel rGO electrode array for the control of a dexterous robotic hand to mimic the gestures. The rGO electrodes presented in this study are promising for practical applications in healthcare and HMI.