Small, but perfectly formed: The microstructure of nanocrystalline oxides

There is considerable interest in nanocrystalline materials due to their unusual properties that offer the possibility of exciting technological applications. This paper concentrates on the microstructure of nanocrystalline binary oxides as revealed by X-ray absorption studies. It will be shown that these experiments yield a picture of the materials in which, even when the particles are only a few nanometres in size, the crystallites are highly ordered and the interfaces are similar to grain boundaries in normal bulk solids. This is in conflict with earlier ideas where it was often assumed the surfaces of nanocrystals and the interfaces between them were very disordered.