Polyoxometalate Complexes as Precursors to Vanadium-Doped Molybdenum or Tungsten Oxide Thin Films by Means of Aerosol-Assisted Chemical Vapour Deposition

Aerosol-assisted chemical vapour deposition of substituted polyoxometalates H4[PMo11VO40], H7[PMo8V4O40], [nBu4N]4[PVW11O40] and [nBu4N]5[PV2W10O40] resulted in the formation of vanadium-doped metal oxide thin films. Depositions were carried out at 550 °C in methanol or acetonitrile for the POMs that contained molybdenum or tungsten, respectively. The as-deposited films were X-ray amorphous and relatively non-adherent. However, on annealing in air at 600 °C, decolourised translucent films that were more mechanically robust were obtained. Films deposited from H4[PMo11VO40] and H7[PMo8V4O40] consisted of V-doped MoO3 in the orthorhombic phase and films from [nBu4N]4[PVW11O40] and [nBu4N]5[PV2W10O40] comprised of monoclinic V-doped WO3. All films were fully characterised by using X-ray photoelectron spectroscopy, energy-dispersive X-ray diffraction, scanning electron microscopy and UV/Vis spectroscopy.