Structure and optical properties of iron oxide films prepared by a modified wet-chemical method

Iron oxide (α-Fe2O3) films were prepared in isopropyl alcohol with the addition of different concentrations of acetic acid (AcOH). The agglomeration properties of nano-particulated iron oxides and hydroxides precipitated from isopropyl alcohol–water solutions differ from those obtained by precipitation from aqueous solution. Subsequent aging of the precipitated oxides and hydroxides in a weak solution of acetic acid modifies their micro/nanostructure. X-ray diffraction and scanning electron microscopy results demonstrate that use of an isopropyl–water reaction medium produces a material with improved dispersion behavior. The homogeneity of films prepared from the reaction products aged in acetic acid (AcOH) shown to depend on the concentration of acetic acid employed. Increasing concentration of AcOH promotes the coarsening of the nanoparticles and the porosity reduction. Optical spectroscopy analysis indicates that band gap of the materials is ∼2.16 eV, which expected for α-Fe2O3. The crystal structure, morphology and optical absorption studies confirm that it is an efficient method to produce high quality iron oxide films.