▎ 摘　　要

Chemical modification of the graphene is emerging as a promising approach in producing graphene devices for electronics and nano/biotechnology applications. The electronic and chemical properties of graphene can be modified by Diels-Alder chemistry via formation of sp(3) centers on the graphene lattice. Here we develop an approach of creating -COOH functional groups on CVD graphene using Diels-Alder reaction with hydrolysis. Conventionally, -COOH functional groups on graphene was often created using graphene oxide. In our approach, we functionalized a CVD graphene sheet and -COOH groups can be conjugated to fluorophores and proteins. This allows visualization of a graphene layer and estimation of functional group density using XPS with efficiency and convenience. (C)2016 Optical Society of America