Spectroelectrochemistry of silver deposition on single gold nanocrystals

Abstract

We report the electrodeposition of metallic silver onto gold nanostars adsorbed to ITO electrodes. The electrochemical process was studied at the single particle level by correlated in situ dark field spectroscopy and scanning electron microscopy (SEM). Underpotential deposition avoids bulk silver formation on the ITO substrates. SEM proves that deposition occurs on all surfaces of the gold nanostars when polyvinylpyrrolidone (PVP) is stabilizing the nanostars or preferentially at the nanostar tips when the ligand is removed. The surface plasmon resonance blue-shifts by more than 100 nm following the formation of a 5 nm Ag film on PVP stabilized gold nanostars, moving the scattered color fro..