One-step synthesis of Fe-Au core-shell magnetic-plasmonic nanoparticles driven by interface energy minimization

Directing the assembly of atoms into core-shell particles generally requires elegant but sophisticated procedures. Here we show how the thermodynamic driving force to minimization of surface and interface energy can be exploited to produce colloidal Fe-Au core-shell nanoparticles in one step and with a yield approaching 99.7% in mass. This is obtained by laser ablation with nanosecond pulses of thin bimetallic films immersed in acetone. The Fe-Au core-shell nanoparticles show magnetic and plasmonic properties, and a surface available to bioconjugation and analytical assays. This laser assisted synthetic method represents a step forward in the facile preparation of core-shell nanospheres with multiple appealing functionalities.