Nanocluster reaction-driven in-situ transformation of colloidal nanoparticles to mesostructures

Abstract

Atomically precise noble metal nanoclusters (NCs) are molecular materials known for their precise composition, electronic structure, and unique optical properties, exhibiting molecular reactivity. Herein, we demonstrated a simple one-pot method of fabricating self-assembled Ag-Au bimetallic mesostructures using a reaction between atomically precise gold NCs and colloidal silver nanoparticles (Ag NPs) under a tunable reaction microenvironment. The reaction carried out in toluene at 45 °C with a constant stirring at 250 RPM yielded a thermally stable, micron-sized cuboidal mesocrystal of self-assembled AgAu@PET nanocrystals. However, a reaction in dichloromethane at room temperature with a constant stirring at 250 RPM resulted in a self-assembled mesostructure of randomly close-packed AgAu@PET NPs. We used a host of experimental techniques, including optical and electron microscopy, optical absorption spectroscopy, and light scattering, to study the nucleation and growth process. Our findings highlight a strategy to utilize precision and plasmonic NP chemistry in tailored microenvironments, leading to customizable bimetallic hybrid 3D nanomaterials with potential applications.