Au Nanodisk-Core Multishell Nanoparticles: Synthetic Method for Controlling Number of Shells and Intershell Distance

Au nanodisk-core multishell nanoparticles (NDCMS-NPs) were synthesized using a Au nanodisk core as a seed to deposit a controlled number of surrounding Ag layers, followed by galvanic replacement reactions with Au ions in water. Uniform Au NDCMS-NPs with controllable shell numbers and intershell distances exhibited unique surface plasmon mode shifts, which were found to be dependent on the thickness of the Ag layer. The number of shells was tuned by controlling the multistep reactions from one to five. The Au core played a critical role in terms of holding the multishell structure during the experimental procedures. We systematically followed their shape evolution by monitoring the surface plasmon resonance bands, as well as by viewing these physical changes with electron microscopy.