Electrochemical stability of self-assembled monolayers on gold

Most applications of functionalized self-assembled monolayers (SAMs) are ba sed on changes in electrochemical properties. Such applications require ele ctrochemical stability. This study reveals that there is only a limited pot ential window from -0.8 to +0.4 V-MSE where self-assembled monolayers of su lfur-containing adsorbates (thiols and alkyl sulfides) on gold are electroc hemically stable. A sensitive parameter describes the quality/stability of the monolayers (viz. the charge-transfer resistance). The substitution patt ern of the adsorbates influences the window. Highly ordered monolayers, lik e that of tetrasulfide-based cavitand (10), are more resistant to extreme p otentials. The stability window from -0.9 to +0.5 V-MSE for this sulfide-ba sed monolayer is comparable to that for a decanethiol monolayer.