Pure multistep oriented attachment growth kinetics of surfactant-free SnO2 nanocrystals.

In this work, crystal growth kinetics of surfactant-free nanocrystalline SnO2 in distilled water at 175-250 degrees C were investigated. The growth rate followed the type of asymptotic curve in hundreds of hours, which could be fitted by the multistep oriented attachment (OA) kinetic model. High-resolution transmission electron microscope (HRTEM) data also indicated crystal growth occurring via the multistep OA mechanism. During the growth of SnO2, the concentration of Sn ions in the aqueous solution was examined. It reveals that the unsaturated situation of SnO2 results in crystal growth via the pure OA mechanism. A growth model of self-integration of conjugated nanocrystals was discussed for understanding the OA behavior.