Growth of tin oxide nanorods induced by nanocube-oriented coalescence mechanism

SnO 2 nanocrystals (NCs) with spherical, cubic, and cuboid nanorod morphologies are obtained at different stages in hydrothermal synthesis using a SnCl4⋅5H2O to CO(NH2)2 ratio of 1 to 10. Microstructural examination and theoretical derivation reveal that small spherical NCs are formed initially and some of them morph into cylindrical NCs because of the low surface free energy. These NCs transform into bigger cubic NCs with time finally evolving into cuboid nanorods due to Brownian motion. The cuboid nanorods have a lower surface free energy than the cubic NCs and constitute a stable nanostructure.