Study on the preparation and properties of colored iron oxide thin films

Colored iron oxide thin films were prepared using Sol-gel technique. The raw materials were tetraethyl orthosilicate (TEOS), etoh ehanol (EtOH), iron nitrate, and de-ionized water. Various properties were measured and analysed, including the colour of thin films, surface topography, UV-Visible spectra, corrosion resistance and hydrophobicity. To understand how these properties influenced the structural and optical properties of Fe₂O₃ thin films, Scanning Electron Microscope (SEM), UV Spectrophotometer and other facilities were employed. Many parameters influence the performance of thin films, such as film layers, added H₂O content, and the amount of polydimethylsiloxane (PDMS). When the volume ratio of TEOS, EtOH and H ₂O was 15: 13: 1, the quality of Fe(NO₃) ₃·9H₂O was 6g, and pH value was 3, reddish and uniform Fe₂O₃ thin films with excellent properties were produced. Obtained thin films possessed corrosion resistance in hydrochloric acid with pH=l and the absorption edge wavelength was ∼350.2nm. Different H₂O contents could result in different morphologies of Fe ₂O₃ nanoparticles. When 1.5 ml PDMS was added into the Sol, thin films possessed hydrophobiliry without dropping. Coating with different layers, thin films appeared different morphologies. Meanwhile, with the increment of film layers, the absorbance increased gradually.