Electrochemical stability of self-assembled monolayers on gold

Most applications of functionalized self-assembled monolayers (SAMs) are based on changes in electrochemical properties. Such applications require electrochemical stability. This study reveals that there is only a limited potential window from -0.8 to +0.4 VMSE where self-assembled monolayers of sulfur-containing adsorbates (thiols and alkyl sulfides) on gold are electrochemically stable. A sensitive parameter describes the quality/stability of the monolayers (viz. the charge-transfer resistance). The substitution pattern of the adsorbates influences the window. Highly ordered monolayers, like that of tetrasulfide-based cavitand (10), are more resistant to extreme potentials. The stability window from -0.9 to +0.5 VMSE for this sulfide-based monolayer is comparable to that for a decanethiol monolayer