Self-assembly of π-conjugated discs on heterogeneous surfaces: Effect of the micro- and nano-scale dewetting

We report on the self-assembly from solutions of a large synthetic polycyclic aromatic hydrocarbon (PAH) on a mica surface partially coated by macroscopic gold electrodes. Isotropie structures, continuous monolayers and interconnected networks have been obtained by varying the deposition conditions, including the type of solvent as well as the temperature of the solution and of the substrate. The growth of these organic-inorganic interfaces is governed by the interplay between intermolecular and interfacial interactions. In this frame, the rate of the solvent evaporation plays an important role as the structural arrangement of the PAH ad-layer on the sub-micrometer scale is controlled by the dewetting process. The presence of the gold electrodes influences the film morphology on mica at distances of tens of micrometers from the electrode border, due to the different wettability of gold and mica surfaces.