Wearable rGO-Ag NW@cotton fiber piezoresistive sensor based on the fast charge transport channel provided by Ag nanowire

Wearable sensors with high sensitivity, fast response and recovery are highly desirable for many new application fields. Herein, we synthesized the cotton fiber which coated with reduced graphene oxide doped with silver nanowire (rGO-Ag NW@cotton fiber) via a simple and environmentally friendly hydrothermal method. The flexible and wearable rGO-Ag NW@cotton fiber based piezoresistive sensor was fabricated with the orientation of face-to-face, where the cotton fiber coated with reduced graphene oxide (rGO@cotton fiber) was used as the lower part of the sensor. The addition of silver nanowire (Ag NW) provides a faster and more convenient channel for charge transfer, resulting in the greatly improvement of the performance, showing the high sensitivity, accompanied with the fast response and relaxation properties. With the effectively wrapping and protection of reduced graphene oxide (rGO), Ag NW was well protected and avoid being oxidized by the air, which contributes significantly to the excellent stability of the sensor. Under the synergistic effect of Ag NW and rGO, rGO-Ag NW@cotton fiber based piezoresistive sensor can be well used in detecting human activities such as finger pressing, bending, twisting, walking and pulse waves, showing high sensitivity, fast response, fast recovery and high stability. These results indicate that the rGO-Ag NW@cotton fiber based piezoresistive sensor has an enormous potential for application in the flexible and wearable pressure sensors.