Synthesis, structural and transport properties of NaxV2O5⋅nH2O xerogel nanocrystalline thin films

Abstract X-ray diffraction (XRD), scanning electron microscopy (SEM), density thermoelectric power, and transport properties of the as prepared nanocrystalline NaxV2O5⋅nH2O xerogel thin films (0 ⩽ x ⩽ 20 mol%) were investigated. These films have been produced by the sol–gel technique (colloidal route). XRD revealed that the samples are highly orientated nanocrystals and all samples show almost the same X-ray diffraction patterns with different lattice constant. The particle size was found to be about 7.5 nm. In SEM the porosity and microstructure of NaxV2O5⋅nH2O thin films can be tuned effectively by adjusting the concentration of the Na1+ ions in the electrolytic solution. The density of the samples increases with increasing Na-content. The samples are n-type semiconductor according to the thermoelectric power. The thermoelectric power increases with increasing Na-content. The electrical conductivity shows that all samples are semiconductor and it increases with increasing Na-content. The activation energy decreases with increasing Na-content. The conduction was confirmed to obey the non-adiabatic small polaron hopping.