Porphyrin Functionalized Graphene Sheets in Aqueous Suspensions: From the Preparation of Graphene Sheets to Highly Conductive Graphene Films

作者：Jianxin Geng, Hee‐Tae Jung · 发表于：The Journal of Physical Chemistry C · 年份：2010 · DOI：10.1021/jp1008779 · 被引用次数：326 · 研究领域：Graphene research and applications、Molecular Junctions and Nanostructures、Graphene and Nanomaterials Applications

Graphene has a unique structure and potential applications in nanoelectronics, nanocomposites, conductive and transparent films, etc. Synthesis of graphene is one of the major research efforts in order to make rapid developments in graphene research. In this study, a new method, that makes use of the π−π interactions between porphyrin and graphene to stabilize the chemically converted graphene (CCG), has been developed for preparation of CCG via chemical reduction of exfoliated graphene oxide (GO). Optical absorption spectroscopy measurement shows that π−π interactions take place between GO and porphyrins, 5,10,15,20-tetraphenyl-21 H, 23 H -porphine- p, p ′, p ′′, p ′′′-tetrasulfonic acid tetrasodium hydrate (TPP-SO 3 Na) and 5,10,15,20-tetrakis(4-trimethylammoniophenyl) porphyrin tetra( p -toluenesulfonate). TPP-SO 3 Na functionalized CCG can form a stable aqueous suspension due to the electrostatic repulsion between the CCG sheets, which results from the aggregation of TPP-SO 3 Na molecules on the surfaces of the CCG sheets. Atomic force microscope observation shows that the TPP-SO 3 Na functionalized CCG sheets are single-layer entities, which are sandwiched by TPP-SO 3 Na molecules. Conductive graphene films with various thicknesses have been prepared by using the TPP-SO 3 Na functionalized CCG suspension via a vacuum filtration method. It is found that the change of the sheet resistance of the CCG films follows the percolation mechanism. A sheet resistance as low as ca. ...