Tunable Synthesis of Various Hierarchical Structures of In(OH) 3 and In 2 O 3 Assembled by Nanocubes

We show a simple way to synthesize morphology‐controllable In(OH) 3 nanostructures by utilizing an amine‐assisted hydrolysis of In 3+ cations under various reaction temperatures. By annealing as‐prepared In(OH) 3 precursors at 400 °C in air, we obtained In 2 O 3 nanocrystals that inherited the morphologies of their precursors while still slightly distorted due to the dehydration process of In(OH) 3 . This dehydration process that transforms In(OH) 3 into In 2 O 3 was studied by thermogravimetry and differential thermal analysis. X‐ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, and photoluminescence spectra were used to characterize the as‐obtained products. Fourier transform infrared absorption spectra were recorded to investigate the effect of ethylenediamine in In(OH) 3 . It was found that the amines play ternary roles, which include being the alkaline media, the coordinating agent, and the surface‐anchored organic molecules.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)