Unique domain structure of pi-conjugated tolanethioacetate self-assembled monolayers on Au(111)

Abstract

Surface structures of tolanethioacetate (TTA) self-assembled monolayers (SAMs) on Au(1 1 1), formed in a 0.5 mM N,N'dimethylformamide (DMF) solution, were investigated as a function of solution temperature by scanning tunneling microscopy (STM). The STM study revealed that thioacetyl-terminated TTA molecules on Au(1 1 1) did not form ordered SAMs at room temperature and 80 degrees C, whereas the adsorption of TTA molecules on Au(1 1 1) at a solution temperature of 50 degrees C led to the formation of two mixed phases: a disordered phase and a unique ordered phase, consisting rod-like dom, ains, which can be described as a (/6 x /13)15 degrees superstructure. From this study, it was demonstrated that solution temperature is a key factor controlling the two-dimensional SAM structure of TTA molecules.