Supramolecular rows of discotic liquid crystal on a metal surface

Abstract

Anchoring of discotic liquid crystals on atomically flat surfaces is important in the field of film growth and for a better understanding of charge transport across interfaces. The presented comparative scanning tunneling microscopy study shows that self-organized monolayers of 2,3,6,7,10,11-undecalkoxy-triphenylene (noted T11) reveal a drastically different packing on Au(111) than on highly oriented pyrolitic graphite (HOPG). A hexagonal structure is found on HOPG while on Au(111) T11 molecules form periodic parallel rows of dimers. These rows consist of molecules lying flat on the surface and aligned along specific directions of the underlying substrate. The presented results suggest that the interactions between the alkoxy chains of T11 and the Au(111) substrate drive the formation of the observed supramolecular rows.