Conformation-induced self-assembly of rubrene on Au(111) surface

Large -area well-ordered monolayer of rubrene has been fabricated on Au(111) surface by gradually annealing a multilayer of rubrene in vacuum. Scanning tunneling microscopy clearly demonstrates that the rubrene monolayer experiences a disorder-order transition with increase of the annealing temperature and the molecules form dimer rows with opposite directions for two neighbored rows. The π-π and π-H interactions between the molecules induced by conformation of the molecules in monolayer account for the main driving forces to form this kind of ordered layer.