Formation of Ordered Self-Assembled Monolayers of Thio-acetyl Alkylthioacetates on Au(111) in Catalytic Tetrabutylammonium Cyanide Solution

Abstract

Surface structures and binding conditions of alkylthioacetate (ATA) self-assembled monolayers (SAMs) on Au(111) formed in catalytic tetrabutylammonium cyanide (TBACN) solution were examined by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) and contact angle (CA). Molecular-scale STM imaging revealed that ATA molecules on Au(111) can form well-ordered SAMs in TBACN catalytic medium compared to in pure solvent or NH4OH solution medium. We found that SAM formation by alkylthioacetates on Au(111) strongly depends on experimental conditions for the deprotection of acetyl group. We study reveal that the adsorption of ATA molecules can form ordered SAMs from vapor deposition. In addition, XPS measurements showed a strong S 2p peak at 162 eV for OTA SAMs on Au(111), implying that the SAMs were formed via chemical reactions between the sulfur atoms and gold surfaces.