Role of molar concentration in structural, optical and gas sensing performance of anatase phase TiO2 nanofilms: automated nebulizer spray pyrolysis (ANSP) technique

TiO 2 nanofilms were deposited on a glass substrate at 500 °C using automated nebulizer spray pyrolysis. The anatase polycrystalline structure with increased grain size and variations of surfactant planes ( T c ) were influenced by molar concentration on XRD study. AFM study shows the average roughness values were increased with increase in molar concentration. A granular domain like microstructure with crack and void-free particle was examined by FESEM. The maximum transmittance ~95.5% (529.6 nm) for x = 0.05 M/L, further increment of molar concentration showed the decremented transmittance with red shift absorption edge and the calculated band gap values ( E g = 3.53–3.20 eV) also noted. The gas sensing performances of films were studied with respect to various gas sensing parameters and the ammonia (NH 3 ) gas showed better sensing response ( S max = 89%) at 150 °C for 300 ppm gas concentration against other gases (C 2 H 6 O, CH 4 O, C 3 H 8 O and C 3 H 6 O).