Solvent and Temperature Effects on Formation of Thioacetyl-terminated Tolane Self-Assembled Monolayers on Au(111)

Abstract

Self-assembled monolayers (SAMs) of conjugated molecules on metal surfaces have drawn much attention for the fabrication of molecular devices such as logic gate, transistor, and resonant tunneling diode. Especially, thioacetyl-terminated conjugated molecules were often used for SAM fabrication because aromatic thiols can easily undergo oxidation to form disulfide or other oxidized products in the presence of a small amount of oxygen. In this study, tolane thioacetate SAMs were characterized by scanning tunneling microscopy and x-ray photoelectron spectroscopy. It was revealed that the property of solvent and the temperature of solution play a very important role in determining two-dimensional (2D) SAM structures. It was found that 2D ordered SAMs with high molecular density were obtained in base condition at high temperature of solution.