Effect of variation of precursor concentration on structural, microstructural, optical and gas sensing properties of nanocrystalline TiO2 thin films prepared by spray pyrolysis techniques

The objective of the present paper is to investigate the effect of variation of precursor concentration (0·01, 0·02 and 0·03 M) on the structural, microstructural, optical and gas sensing properties of TiO $₂$ thin films. Titanium dioxide (TiO $₂$ ) films were prepared from aqueous solution of titanium chloride (TiCl $₃\cdot $ 6H $₂$ O, 99·9% pure, Merck made, Germany) onto the glass substrates heated at a temperature of 350 °C by the spray pyrolysis technique. Bandgap energy of the films vary from 3.28 to 3.29 eV. X-ray diffraction shows that films to be nanocrystalline with anatase phase having tetragonal crystal structure. The d values calculated from electron diffraction patterns (TEM) were observed to be matching with d values calculated from XRD. Transmission electron microscopy (TEM) reveled that grain sizes were observed to increase (10–29 nm) with an increase in the concentration of precursor solution. The gas sensing performance of the films was tested.