Vanadium oxide nanostructured thin films prepared by Aerosol Spray Pyrolysis for gas sensing and thermochromic applications

Vanadium oxide (VxOy) nanostructured films were prepared by Aerosol Spray Pyrolysis technique with different concentrations of precursor solution (0.005 M, 0.01 M, 0.02 M), using ammonium metavanadate (NH4VO3) as precursor. The deposition was carried out onto glass substrates (Corning glass) at two different substrate temperatures (300 degrees C and 400 degrees C). Furthermore, oxalic acid was added to the precursor solution in order to grow the thermochromic VO2(M) monoclinic phase via reduction of the Vanadium oxides in which Vanadium is in a higher oxidizing state. All films were characterized by X-Ray Diffraction technique and UV/Vis/NIR spectroscopy to identify their structural and optical properties, respectively. V2O5 films were tested against ozone, having a sensitivity of 29% in ultra-low concentration of 5ppb ozone, at room temperature. Moreover, nanostructured VO2 films appeared to be thermochromic, having an IR-switching of about 5% at lambda = 2500 nm, upon heating.