A growth model of single crystalline hollow spheres:: Oriented attachment of Cu2O nanoparticles to the single crystalline shell wall

A growth mechanism for single crystalline hollow spheres was proposed based on the study of the formation process of single crystalline Cu2O multishelled hollow spheres. On the basis of transmission electron microscopy, high resolution transmission electron microscopy, selected area electron diffraction analysis of the product collected at different formation stages, it is found that the nanoparticles with a size of 2-5 nm first formed well-crystallized porous shelled hollow spheres via oriented attachment, and then the porous shells were further crystallized and became compact by Ostwald ripening to form well-crystallized hollow spheres.