▎ 摘　　要

Mildly oxidized graphene has been prepared by O-2 plasma treatments. Compared to pristine graphene, the mildly O-2 plasma treated graphene can significantly enhance the Raman peaks intensities of adsorbed Rhodamine B molecules. This effect is attributed to the strong local electric field on the adsorbed molecules induced by the oxygenated species on graphene after O-2 plasma treatments. The downshift of the Fermi level of graphene has also been demonstrated to be responsible for this chemical enhancement. (C) 2014 Elsevier Ltd. All rights reserved.