Direct Exfoliation of Graphite to Graphene in Aqueous Media with Diazaperopyrenium Dications

In recent times, the materials properties of graphene have generated ever-increasing interest across multiple scientifi c disciplines including physics, [ 1 ] material science [ 2 ] and chemistry. [ 3 ] The quantity and quality of graphene produced directly impacts the performance and development of applications related to organic fi eld-effect transistors (OFETs), [ 4 ] conductive materials, [ 2b , 5 ] and photovoltaics, [ 6 ] not forgetting biological applications. [ 7 ] Generally, the techniques used to prepare graphene are based on either physical processes, [ 8 ] chemical methodologies [ 3a , 9 ] or a blend of the two. Although physical methods are able to produce high-quality graphene consistently, the amount of processable graphene produced is always limited, as well as being quite costly. [ 10 ] Conversely, although chemical oxidation of graphite to graphene oxide [ 11 ] (GO), followed by reduction, results in reduced graphene oxide (RGO) in large quantities, this method generates defect-laden RGO to the extent that the resultant graphene is generally of lower quality than that produced by physical methods. [ 12 ] Despite the fact that there are some reports [ 13–16 ] relating to the use of wet chemistry to exfoliate graphene from graphite, the exfoliation of graphite to graphene employing noncovalent π – π interactions with π -conjugated molecules in water is relatively unexplored. Herein, we describe the preparation of graphene by direct exfoliation of graphite through the exploitation of π – π