One-Step Aqueous Solvothermal Synthesis of In₂O₃ Nanocrystals

Abstract

Highly crystalline and nearly monodisperse In2O3 nanocrystals with both cube and flower shapes were successfully synthesized in one step through a facile aqueous solvothermal method for the first time, free of any surfactant or template. X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction (SAED), and high-resolution transmission electron microscopy (HRTEM) were used to characterize the samples. In our work, the use of diethylene glycol (DEG) is a crucial factor for the formation of the In2O3 phase. CO(NH2)2 and a defined amount of water play important roles in the formation of the In2O3 with different nanostructures. Detailed formation mechanisms for the In2O3 phase have been proposed on the hydrolysis of indium alkoxide complexes at elevated temperature in DEG solutions, and the general growth mechanisms for the In2O3 nanostructures have been discussed. Compared with nonaqueous solvothermal synthesis of In2O3, we present a simple aqueous synthesis method by combining a hydrothermal process with a polyol method.