Nanorods of ZnO made by flame spray pyrolysis

Inorganic nanorods with closely controlled aspect ratio were made by flame spray pyrolysis - a single-step, continuous, and scaleable process. Indium and tin dopants selectively affect a specific ZnO crystal plane and are incorporated into its lattice. Nanorod formation is attributed to the higher valency and coordination of indium and tin dopants relative to zinc and the associated disruption of crystal growth within the Zn plane. In contrast, lithium, with an equivalent ionic radius to these dopants but lower valency than zinc, has no effect on the ZnO texture. The formation of the nanorods within the flame occurs by annealing crystallization during flame cooling.