Optical properties of gold particle-cluster core–satellite nanoassemblies

Better understanding of core–satellite nanostructures is of great interest to researchers owing to their unusual properties and is key to their promising applications. The well-developed techniques based on protein–nanoparticle interactions were adopted to produce core–satellite nanoassemblies of ∼10 nm core of Au nanoparticles (AuNPs) covered by Au25@BSA or Au10@histidine nanoclusters (NCs). The photoexcited dynamics in the core–satellite nanoassemblies were studied using steady-state and time-resolved spectroscopic measurements. Fluorescence quenching in AuNP–AuNCs core–satellite nanostructures was observed and confirmed as static quenching. The AuNPs alter neither radiative decay nor nonradiative decay in both nanoclusters. This indicates that the electron/energy transfer within the NP–NCs core–satellite nanoassemblies is absent, in contrast to the results involving other larger NP–NPs core–satellite nanoassemblies.