Silver particles with rhombicuboctahedral shape and effectively isotropic interactions with light

TL;DR

This paper reports the synthesis of silver rhombicuboctahedral nanoparticles with isotropic plasmonic responses, elucidating the growth mechanism and demonstrating the stability and characterization of these shapes.

Contribution

It introduces a preferential growth pathway towards thermodynamically stable silver rhombicuboctahedra using copper-based etching, expanding understanding of nanoparticle shape control.

Findings

Silver rhombicuboctahedra are the thermodynamically favored shape.

Comprehensive characterization confirms the morphology.

Reaction mechanism is elucidated and applicable to similar etching processes.

Abstract

Truly spherical silver nanoparticles are of great importance for fundamental studies including plasmonic applications, but the direct synthesis in aqueous media is not feasible. Using the commonly employed copper-based etching processes, isotropicplasmonic response can be achieved by etching well-defined silver nanocubes. Whilst spherical like shape is typically prevailing in such processes, we established that there is a preferential growth towards silver rhombicuboctahedra (AgRCOs), which is thethermodynamically most stable product of this synthesis. The rhombicuboctahedral morphology is further evidenced by comprehensive characterization with small-angle X-ray scattering in combination with TEM tomographyand high resolution TEM. Wealso elucidate the complete reaction mechanism based on UV-Vis kinetic studies, and the postulated mechanism can also be extended to all copper-based etching processes.