Effect of Self-Assembled Monolayers on the Locally Electrodeposited Silver Thin Layers

Abstract

The localized electrodeposition of silver on gold coated with self-assembled monolayers (SAMs) by scanning electrochemical microscopy (SECM) is reported. The SAMs were ω-functionalized alkanethiols of the form X–(CH2)2SH, X = OH, NH2, CO2H, SO3H, as well as 4-mercaptobenzoic acid. The SAMs were characterized by X-ray photoelectron spectroscopy (XPS) and cycling voltammetry (CV). The anodic dissolution of a Ag microelectrode, which was held within a few microns from the Au surface, formed a well-controlled flux of Ag+. Deposition of silver nanostructures was driven by the electrochemical reduction of the Ag+ on the Au surface. The effect of the functional group on the Ag local deposition was studied and compared with bulk deposition on the same SAMs. For bulk deposition, we found that the interaction between Ag+ ions and the functional group of the alkanethiols slowed the kinetics of Ag deposition, shifting the deposition to potential that is more negative and caused the formation of large, well-faceted Ag...