Electrochemical properties of gold nanosheets: Investigation of the effect of nanosheet thickness using chemometric methods

Gold nanostructures have been widely studied because of their unique size and shape dependent properties. Two-dimensional (2D) Au nanosheets (AuNSs) attract much attention for their unique features and potential applications. One parameter that should be considered in their potential applications, is their thicknesses. In this study AuNSs were synthesized in three thicknesses (25 nm, 45 nm, and 65 nm), and their electrochemical properties at a glassy carbon electrode were compared. Multivariate curve resolution-alternating least squares (MCR-ALS) was used to resolve the total current to its three main constitutes, which are faradaic, step charging and induced charging currents. The extent of contribution of each current was calculated and related to the parameters affecting the electrochemical systems such as the nature of supporting electrolyte or the composition of the electrode. The results showed that the thickness of AuNSs has a significant effect on the extent of contribution of all currents. For example, the contribution of the faradaic current is higher for 25 nm thickness of AuNSs whereas the contribution of the charging current changes reversely. Our results confirmed that thinner AuNSs are more suitable for using in construction of electrochemical sensors.