Recrystallization of deformed metal nanoparticles

Abstract

Despite great advances in the fabrication methods of metal nanoparticles with various sizes and shapes, the available tools for manipulating their microstructure and morphology still remain limited. In the present work we introduce the age-old metallurgical technique of recrystallization to the synthesis of metallic nanoparticles. We uniaxially compressed a large number of single crystalline and defect free Pt nanoparticles obtained by solid-state dewetting and annealed them at the temperature of 1000 °C. Our findings reveal that, while the as-dewetted particles exhibited similar shapes and crystallographic orientations, the plastic deformation and annealing led to a diverse range of shapes, microstructures, and orientations among the particles. We categorized the particles into four distinct types based on their appearance: slanted, terraced, “Danish pastry”, and broken particles. Finally, we propose a differentiation mechanism responsible for this diversification, which relies on a combination of recrystallization, surface step formation, and solid-state dewetting processes.