Thin Films of TiO sub( 2)-MoO sub( 3) Binary Oxides Obtained by an Economically Viable and Simplified Spray Pyrolysis Technique for Gas Sensing Application

Thin films of binary oxides (TiO2-MoO3) of varied molar concentrations of MoO3 (from 0.15 M to 0.30 M insteps of 0.05 M) have been prepared by a simplified and cost effective perfume atomizer technique on quartz substrates at 500 degree C. To investigate the structural, morphological, photoluminescence, optical and gas sensing properties of as-deposited films, the characterization studies using X-ray diffraction(XRD), scanning electron microscope(SEM) and Ultraviolet-Visible-Near infrared (UV-Vis-NIR) and photoluminescence(PL) spectroscopy were utilized. The structural analysis confirmed that the films were polycrystalline with rutile and orthorhombic phase types pertain to TiO2 and MoO3 crystal structures. All the samples exhibited very poor optical transmission in the entire region of UV-vis-NIR and the optical band gap was increased as increase in MoO3 concentration. The variation in intensity of Photoluminescence (PL) emission was also found to occur while varying the concentration. The images of SEM showed structures of spherical grains with minimal distribution and flower like formations for varied concentrations. The gas sensing ability of these films was also demonstrated in 100 ppm of ethanol vapour at room temperature and the enhanced sensitivity was found in Q3 sample.