Graphene-based flexible NO2 chemical sensors

Abstract We demonstrated graphene-based flexible NO 2 chemical sensors on polyethylene terephthalate substrate where graphene was grown on Cu-foil by chemical vapor deposition technique. Introduction of NO 2 molecules to graphene caused a rapid increase in the currents due to the charge transfer between NO 2 molecules and graphene under both relaxed and strained conditions. However, the recovery was delayed due to slow desorption of NO 2 molecules from defective sites in graphene. Also, strain in graphene increased the resistance of graphene layer where the change in conductance was reversible. Our graphene-based NO 2 chemical sensors showed a great sensitivity and reproducibility under both strained and relaxed conditions.