Chemical functionalization of graphene with aromatic molecule

We investigated the doping effects of chemical functionalization on graphene field-effect transistors (G-FETs). A pyrene backbone with an electron-withdrawing group (1-pyrenebutanoic acid succinimidyl ester, PBASE) and DMF acting as a solvent were used. The pyrene derivative was stably immobilized onto the graphene surface via π-π stacking between the two highly conjugated systems, confirmed by electric measurements with different incubation times and linker molecule concentrations. Dimethyl formamide (DMF) can decrease the conductivity of the FET devices and showed an n-doping effect while the pyrene derivative showed a p-doping effect. Because of this, the functionalization with PBASE in DMF could be regarded as a competitive process. This study provides a new insight into chemical functionalization with aromatic molecule, and understanding of doping effects about electron donor and electron acceptor on graphene during the functionalization process.