Self-alignment of nanoparticles is a key process in the formation of single crystals through aggregation-based crystal growth. In their Communication on
page 12836 ff., R. Tang and co-workers demonstrate by using high-resolution transmission electron microscopy random aggregation of nanoparticles on the surface of a bulk single crystal. Subsequently, surface stress drives the grain boundary to migrate from the crystal bulk to the random surface layer to induce realignment of the randomly attached nanoparticles, which are then integrated into the single crystal.