Solvent-Specific Controlled Oxidation of Cu Nanospheres to Cu@Cu2O@Cu Nanomatryushkas

A concentric array of Cu@Cu2O core-shell nanostructures and Cu@Cu2O@Cu nanomatryushkas have been synthesized by tailoring the surface oxidation of plasmonic copper nanoparticles through manipulation of binary solvent composition. The concept is based on freezing down the rate of surface oxidation by governing the chemical equilibria directed by Le Chatelier's principle during the evolution of these nanostructures that have been optimized by monitoring their real-time growth in solution. The formation of the nanomatryushkas could be attributed to a reverse Kirkendall mechanism. The observation of plasmon-exciton coupling across the interface as well as confinement of charge at the annular cavity in such periodic heteronanostructures has been elucidated from scattering simulation techniques. It has been revealed that the spectral response is a sensitive function of the dimensions of the core and successive shell layers of these geometrical architectures. The coupling of optical attributes at the same nanostructures could be miniaturized by governing their morphology and compositions to excavate the realm of light-matter interaction.