Collect. Czech. Chem. Commun. 2003, 68, 1395-1406

Self-Assembly of Monolayer-Coated Silver Nanoparticles on Gold Electrodes. An Electrochemical Investigation

Massimo Marcaccio, Massimo Margotti, Marco Montalti, Francesco Paolucci*, Luca Prodi and Nelsi Zaccheroni*

Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2, 40126 Bologna, Italy


Redox behaviour of an array of dodecanethiol-coated silver nanoparticles, self-assembled on the gold electrode surface by dithiol linkers, is dominated in aqueous electrolytes by a reversible faradaic process that has been attributed to the anodic oxidation of silver nanoparticles. The nanoparticle array may be switched between the oxidised and reduced states repeatedly without any significant loss of electroactive material, thus showing a remarkable stability under electrochemical conditions. The mainly capacitive high-frequency electrical response of the nanoparticle array/electrolyte interface is characterised by a low value of capacitance, typical of a self assembled monolayer (SAM) of long-chain alkanethiols on gold; it has been associated with the compact organic layer interposed between the nanoparticles and the gold substrate. At lower frequencies, the interface displays a poorer electrical behaviour with both capacitive and resistive elements, which was associated with the more disordered organic layer located on the outer side of the film.

Keywords: Silver nanoparticles; Electrochemistry; Cyclic voltammetry; Electrochemical impedance spectroscopy; Self assembled monolayers.

References: 62 live references.