Preparation and characterisation of silver quantum dot superlattice using self-assembled monolayers of pentanedithiol

Abstract

A superlattice of silver nanoclusters was prepared using sequential self-assembly of 1,5-pentanedithiol on an Au(111) substrate. The formation of highly ordered silver nanocluster arrays was confirmed using AFM and also by the longitudinal periodicity observed in the low angle X-ray diffraction pattern. In contrast to the behaviour of dithiol self-assembled monolayers (SAM) on gold substrates, which give only blocking behaviour, the superlattice exhibits interesting electrochemical properties in terms of redox accessibility of silver nanoclusters with respect to potential cycling. The room temperature emission spectrum suggests the formation of minibands in the superlattice structure as evidenced by three distinct peaks at 320, 400 and 620 nm.