Preparation and characterization of oil-soluble In₂O₃ nanoparticles and In₂O₃-SnO₂ nanocomposites and their calcined thin films

Oil-soluble In₂O₃ nanoparticles and In₂O₃-SnO₂ nanocomposites were prepared in oleylamine via decomposition of metal acetylacetonate precursors. Thin films of In₂O₃ and In₂O₃-SnO₂ were obtained by spin-coating solutions of the oil-soluble In₂O₃ nanoparticles and In₂O₃-SnO₂ nanocomposites onto substrates and then calcining them. Transmission electron microspectroscopy, scanning electron microspectroscopy, atomic force microspectroscopy, X-ray diffraction, ultraviolet-visible absorption, and photoluminescence spectroscopy were used to investigate the properties of the nanoparticles and thin films. The In₂O₃ nanoparticles were cubic-phased spheres with a diameter of ~8 nm; their spectra exhibited a broad emission peak centered at 348 nm. The In₂O₃-SnO₂ nanocomposites were co-particles composed of smaller In₂O₃ particles and larger SnO₂ particles; their spectra exhibited a broad emission peak at 355 nm. After the In₂O₃-SnO₂ nanocomposites were calcined at 400℃, the obtained thin films were highly transparent and conductive, with a thickness of 30-40 nm; the surfaces of the thin films were smooth and crack-free.