Fabricating large two-dimensional single colloidal crystals by doping with active particles

TL;DR

This study demonstrates that active particles doped into two-dimensional colloidal crystals can effectively eliminate grain boundaries by promoting defect clustering and boundary mobility, leading to large single-domain crystals after deactivation.

Contribution

It introduces a novel method using active dopants to remove grain boundaries in colloidal crystals, enabling large single-crystal formation.

Findings

Active dopants cluster at grain boundaries.

Dopants increase grain boundary mobility.

Crystals recrystallize into single domains after activity stops.

Abstract

Using simulations we explore the behaviour of two-dimensional colloidal (poly)crystals doped with active particles. We show that these active dopants can provide an elegant new route to removing grain boundaries in polycrystals. Specifically, we show that active dopants both generate and are attracted to defects, such as vacancies and interstitials, which leads to clustering of dopants at grain boundaries. The active particles both broaden and enhance the mobility of the grain boundaries, causing rapid coarsening of the crystal domains. The remaining defects recrystallize upon turning off the activity of the dopants, resulting in a large-scale single-domain crystal.