Flexible Pressure Sensors with a Sandwich Structure Based on Vertical Graphene Nanowalls by HFCVD

Recently, flexible pressure sensors have been developed rapidly and used in human–computer interaction, healthcare wearable devices, and electronic skins. Vertical graphene nanowalls (VGNs) have aroused tremendous attention owing to their high electrical conductivity, thermal conductivity, and larger specific surface area, etc. Herein, VGNs were prepared at a low temperature (400°C) by hot filament chemical vapor deposition (HFCVD). A flexible pressure sensor with a sandwich structure was then developed by combining VGN film and polydimethylsiloxane (PDMS) elastomer. The flexible pressure sensors have good sensitivity ( S = 13.0 kPa −1 for the 0–1 kPa region), a fast response speed (142 ms), and a quick recovery speed (96 ms). In addition, the sensitivity can be adjusted by controlling the thickness of the VGNs, while sensors composed of thicker VGNs show higher sensitivity. Furthermore, the flexible pressure sensors show great potential for application in human motion detection and pressure measurement. Graphic Abstract