Side-by-Side In(OH)3 and In2O3 Nanotubes: Synthesis and Optical Properties

A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D) In(OH)(3) nanostructures. By calcining the 1D In(OH)(3) nanocrystals in air at 250 degrees C, 1D In(2)O(3) nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH)(3) and 1D In(2)O(3) are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH)(3) and 1D In(2)O(3) nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH)(3) and In(2)O(3), respectively. TGA/DTA analyses of the precursor In(OH)(3) and the final product In(2)O(3) confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In(2)O(3) exhibits an evident blueshift with respect to that of the commercial In(2)O(3) powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In(2)O(3) nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies.