Preparation and Characterization of a Redox Multilayer Film Containing Au Nanoparticles

Gold nanoparticles encapsulated by negatively charged molecules have been stably anchored at a Au substrate through layer-by-layer deposition technique, employing a redox polyviologen derivative as the cationic counterpart. UV−vis spectroscopy, quartz crystal microbalance, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and voltammetric measurements have been performed in order to characterize the systems and to give a rationale to the effect of the deposition conditions on the properties of the resulting multilayers. The behavior of two benchmark electroactive species ([Fe(CN) 6 ] 4− and [Ru(NH 3 ) 6 ] 3+ ) has been studied on nanoparticle-terminated multilayers. The nanoparticles provide charge percolation through the multilayer and charge transfer with redox species in solution. The results imply that the electrochemical behavior of nanoparticle-containing films is partly dependent on the charge compensation mode within polyelectrolyte multilayers.