The non-covalent functionalisation of graphene is an attractive strategy to alter the surface chemistry of graphene without damaging its superior electrical and mechanical properties. Using the facile method of aqueous-phase functionalisation on larg
e-scale CVD-grown graphene, we investigated the formation of different packing densities in self-assembled monolayers (SAMs) of perylene bisimide derivatives and related this to the amount of substrate contamination. We were able to directly observe wet-chemically deposited SAMs in scanning tunnelling microscopy (STM) on transferred CVD graphene and revealed that the densely packed perylene ad-layers adsorb with the conjugated {pi}-system of the core perpendicular to the graphene substrate. This elucidation of the non-covalent functionalisation of graphene has major implications on controlling its surface chemistry and opens new pathways for adaptable functionalisation in ambient conditions and on the large scale.
We present results of experiments to reproduce the bottom-up formation of covalently bonded molecular nanostructures from single molecular building blocks, previously demonstrated on various coinage metal surfaces, on a technologically more relevant
semiconductor surface: Ge(001). Chlorine was established as the most stable passivation agent for this surface, successfully enabling diffusion of the organic molecular building blocks. Subsequent thermal activation of the intermolecular dehalogenation reactions on this surface resulted in the desired covalently connected molecules, however showing poor network quality when compared to those formed on noble metal substrates.
