Solvent Effect on Domain Formation of 4-Mercaptopyridine Self-Assembled Monolayers on Au(111) Substrate by Scanning Tunneling Microscopy

We have studied the growth process of 4-mercaptopyridine (4-PySH) self-assembled monolayers (SAMs) on Au(111) substrate, by scanning tunneling microscopy (STM). The three factors which were investigated for the domain formation of 4-PySH were; solvent effect, immersion time dependence and the impurity effect. STM imaging revealed that the solvent effect was very significant in determining the surface morphology of the 4-PySH SAM growth, which was not observed on X-ray photoelectron spectra (XPS). These results indicated that the solvent was an important factor in the domain formation process, especially ethanol which as a typical SAM solvent, assisted the reconstruction of 4-PySH domains on the substrate.