Coexistence of Closely Packed c(4 × 2) and Striped Phases in Self-Assembled Monolayers of Decylthiocyanates on Au(111)

Abstract

Decylthiocyanate (DTC) self-assembled monolayers (SAMs) on Au(111) were prepared by solution and vapor phase deposition methods at 50 o C for 24 h. The formation and surface structure of DTC SAMs were examined using scanning tunneling microscopy (STM). STM imaging revealed that DTC SAMs formed in 1 mM ethanol solution at 50 o C were composed of small ordered domains with lateral dimensions of a few nanometers and disordered phases, whereas DTC SAMs formed in the vapor phase at 50 o C contained two ordered phases: a closely packed c(4 × 2) superlattice and a striped phase with an interstripe spacing of 2.6 -2.8 nm. It was also found that the ordered domain and vacancy island formation for DTC SAMs on Au(111) differs significantly from that of decanethiol SAMs, suggesting that adsorption mechanism is different from each other. From this study, it was confirmed that DTC SAMs with a high degree of structural order can be obtained by vapor phase deposition.

Effects of Solvent on the Structure of Octanethiol Self-Assembled Monolayers on Au(111) at a High Solution Temperature

“…[1][2][3][4][5] In particular, the formation and structure of alkanethiol SAMs on gold surfaces have been extensively studied using various surface characterization techniques. [6][7][8][9] Experimental conditions, such as solvent, temperature, concentration, immersion time, and substrate cleanliness significantly affect the formation and structure of alkanethiol SAMs.…”

Direct Adsorption and Molecular Self-Assembly of Octylthioacetates on Au(111) in the Vapor Phase

“…[1][2][3][4][5][6] Alkanethiol SAMs on gold surfaces have been thoroughly studied by a number of research groups, and their structural properties have been well characterized. Organic thiols are prone to easily oxidize to disulfides or other oxidized species that can affect the formation and structure of SAMs.…”