A general method for precise chain assembly of noble metal nanoparticles

Abstract

Salt-induced aggregation is a convenient method for obtaining chains of Au nanoparticles, but it only applies to small nanoparticles (<15 nm) and often with branched and globular aggregates as the by-products. By mechanistic investigation and rational design of reaction conditions, we show that the modulation of ligand concentration and solvent polarity are more effective for chain aggregation, which is also consistent with the DLVO theory. Our method gives precise chain aggregates (error ratio ∼ 4%), which were verified via silica encapsulation. It can be broadly applied to noble metal nanoparticles of various sizes and a wide variety of ligands, including surface-enhanced Raman scattering (SERS)-active ones.