Improving the stability of plasmonic magnesium nanoparticles in aqueous media

This work describes two different core–shell architectures based on Mg nanoparticles (NPs) synthesised in order to improve Mg's stability in aqueous solutions. The shell thickness in Mg–polydopamine NPs can be modulated from 5 to >50 nm by ending the polymerization at different times; the resulting structures stabilize the metallic, plasmonic core in water for well over an hour. Mg–silica NPs with shells ranging from 5 to 30 nm can also be prepared via a modified Stöber procedure and they retain optical properties in 5% water-in-isopropanol solutions. These new architectures allow Mg nanoplasmonics to be investigated as an alternative to Ag and Au in a broader range of experimental conditions for a rich variety of applications.
Plasmonic Mg nanoparticles can be stabilised up to a few hours in aqueous suspensions by protecting them inside core–shell architectures, which are prepared by condensation of either polydopamine or sol–gel silica.