▎ 摘　　要

A novel approach to leverage the extraordinary properties of graphene for designing thin film strain sensors is demonstrated. Graphene nanosheets (GNS) are produced from graphite by a liquid phase exfoliation (LPE) method using water along with N-methylpyrrolidinone (NMP) as cosolvents. It is found that the water-NMP solvent system enhances the exfoliation yield and the stability of the GNS dispersion, thereby lowering the number of defects in the GNS basal plane. Both LPE-based GNS and reduced graphene oxide (RGO) are synthesized for fabricating thin film strain sensors and for comparison purposes. Detailed micro-Raman, X-ray photoelectron spectroscopy, and transmission electron microscopy studies indicate that the as-produced GNS exhibits lower defects than RGO nanosheets. The strain sensing study reveals that strain sensors fabricated using low-defect GNS exhibit enhanced electrical and electromechanical properties, including higher electrical conductivity, lower noise floor, and more stable electromechanical response as compared to RGO-based sensors.