STM investigations of physisorbed monolayers of dialkoxy-​substituted aromatics

The molecular adhesion layers studied in this work are comprised of symmetrical dialkoxy-substituted aromatics of the anthracene and biphenyl type, selected for their chemical and structural properties, i.e. 2,6-bis(octyloxy)anthracene, 2,6-bis(dodecyloxy)anthracene, 4,4′-bis(decyloxy)biphenyl and 4,4′-bis(hexadecyloxy)biphenyl. The characterization of these physisorbed monolayers is presented, and we propose plane-filling packing structure models for the 2D crystals. The models are based on sub Å calibrated images of the reproducibly scanned adhesion layers. The molecular 2D crystals formed yield domains of varying sizes