Au-adatoms in Self-assembly of Benzenethiol on the Au(111) Surface

Abstract

Self-assembly of benzenethiol at low coverage on Au(111) was studied using low-temperature scanning tunneling microscopy. Phenylthiolate species (PhS), formed by thermal dehydrogenation of the parent PhSH molecule, was found to self-assemble into surface- bonded complexes with gold adatoms. Each such complex involves two PhS species and one gold adatom. The PhS-species form either cis- or trans-geometry relative to each other. At a higher coverage the complexes coalesce, most likely due to the formation of weak C- H..S hydrogen bonds facilitated by the spatial arrangement of the PhS-groups. Our findings thus establish that the self-assembly of arenethiols on Au(111) surface is driven by gold adatom chemistry, which has recently been found to be the key ingredient in the self- assembly of alkanethiols on gold.