Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

• Main Authors: Michael Roos, Benedikt Uhl, Daniela Künzel, Harry E. Hoster, Axel Groß, R. Jürgen Behm
• Format: Article
• Language: English
• Published: Beilstein-Institut 2011-07-01
• Series: Beilstein Journal of Nanotechnology
• Subjects: graphene film; intermolecular interaction; large organic molecules; substrate–adsorbate interaction; supramolecular structure
• Online Access: https://doi.org/10.3762/bjnano.2.42

The competition between intermolecular interactions and long-range lateral variations in the substrate–adsorbate interaction was studied by scanning tunnelling microscopy (STM) and force field based calculations, by comparing the phase formation of (sub-) monolayers of the organic molecules (i) 2-phenyl-4,6-bis(6-(pyridin-3-yl)-4-(pyridin-3-yl)pyridin-2-yl)pyrimidine (3,3'-BTP) and (ii) 3,4,9,10-perylene tetracarboxylic-dianhydride (PTCDA) on graphene/Ru(0001). For PTCDA adsorption, a 2D adlayer phase was formed, which extended over large areas, while for 3,3'-BTP adsorption linear or ring like structures were formed, which exclusively populated the areas between the maxima of the moiré structure of the buckled graphene layer. The consequences for the competing intermolecular interactions and corrugation in the adsorption potential are discussed and compared with the theoretical results.