In(OH)^sub 3^ and IN2O3 nanorice and microflowers: morphology transformation and optical properties

In this work, In(OH)^sub 3^ and IN2O3 nanostructures with controllable complex morphologies were successfully synthesized through a simple hydrothermal process followed by annealing. The In(OH)^sub 3^ nanostructures were synthesized using urea as the alkaline source at a relatively low temperature without any templates or surfactants. The morphology transformation of In(OH)^sub 3^ from nanorice to microflowers was observed. The In(OH)^sub 3^ nanorice are 180Â nm in diameter and 550Â nm in length, the microflowers are about 3Â [mu]m in diameter and composed of thin nanoflakes with 4-nm thickness. IN2O3 with similar morphology was formed by annealing In(OH)^sub 3^ precursors. The nanostructures were characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Our results suggest that a new nucleation-growth-etching-regrowth mechanism can explain the morphology transformation from nanorice to flower-like frameworks. Raman spectrum and photoluminescence (PL) properties of IN2O3 were also measured, and a 3-nm blue-shift of PL spectrum was observed due to the thinness of the nanostructures.[PUBLICATION ABSTRACT]