Advances of Nonclassical Crystallization toward Self-Purification of Precious Metal Nanoparticle Mixtures

Crystallization is a common procedure used for the purification of compounds. In this work, we use particle-mediated crystallization (i.e., nonclassical crystallization) to separate mixtures of core-shell (Au@Ag) nanocrystals of different size and shape into ordered phases (i.e., crystalline domains) with nanocrystals of similar morphology and size. The self-assembly process of the drying coffee ring effect and of depletion forces and the resulting superstructures are investigated. A depletion based technique efficiently separates nanoparticle mixtures with small differences in size (12-22%) within isolated colloidal crystals, while the coffee ring technique works better for nanoparticles with a bigger difference in size and shape. Besides the development of a successful approach for the self-purification of nanoparticle mixtures, this study additionally deepens our understanding on particle mediated crystallization under various conditions.

Automated summary

The study successfully explores the self-purification of nanoparticle mixtures using particle-mediated crystallization, shedding light on the self-assembly mechanisms involved in the process. The depletion-based technique efficiently separates nanoparticles with small differences in size, while the coffee ring technique is more suitable for nanoparticles with significant differences in size and shape.