Preparation and electrical characterisation of dodecanethiol monolayer protected silver nanoclusters

Preparation and characterisation of dodecanethiol monolayer protected silver clusters (10-15 nm) (Ag-DDT) is reported here to illustrate its interesting low temperature electrical properties. These monolayer protected silver nanoclusters were found to undergo an insulating to metallic transition around 180 K. in agreement with the theoretical prediction of the disappearance of the Kubo gap at low temperature in these systems, where the interparticle spacing (0.5-1 nm) is less compared to the nanocluster dimensions. The XRD data suggest the formation of multilayered structure, and the equidistant peaks at smaller angle indicates a long-range ordering of nanoclusters. The UV-Vis absorption in solution indicates the presence of a surface plasmon band at 425 nm and cyclic voltammetry studies confirm the accessibility of these passivated clusters for electron transport. (C) 2001 Elsevier Science B.V. All rights reserved.