▎ 摘　　要

We demonstrated graphene-based flexible NO2 chemical sensors on polyethylene terephthalate substrate where graphene was grown on Cu-foil by chemical vapor deposition technique. Introduction of NO2 molecules to graphene caused a rapid increase in the currents due to the charge transfer between NO2 molecules and graphene under both relaxed and strained conditions. However, the recovery was delayed due to slow desorption of NO2 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 NO2 chemical sensors showed a great sensitivity and reproducibility under both strained and relaxed conditions. (C) 2012 Elsevier B.V. All rights reserved.