Synthesis and study of the effects of precursor solution volume, substrate type, and pulsed deposition on the physical properties of titanium dioxide thin films for using as a photoanode

In this research, titanium dioxide (TiO2), as a metal-oxide semiconductor that can be applied in dye-sensitized solar cells as a photoanode, was studied and synthesized. For this reason, thin films of TiO2 were grown using the spray pyrolysis method and their physical properties were studied. To prepare the FTO substrate as the conductive layer, the FTO layer was deposited on the glass substrate. The transmittance above 90% in the visible region and low electrical resistance allows the use of the synthesized FTO as a transparent electrode. Subsequently, TiO2 films were coated using spray pyrolysis at the temperature of 150°C on top of both bare glass and FTO coated glass substrates. The precursor solution for spray was made of TTIP as the main material and isopropanol as solvent. Samples were prepared by two methods of pulsed and non-pulsed spraying in two volumes of precursor solution of 200 and 350 mL. Results showed that the pulsed deposited samples cause the formation of TiO2 films with higher crystal quality. XRD pattern analysis revealed the formation of the anatase crystal phase with preferred growth along the (101) plane on the FTO substrate. Considering its physical characteristics, the TiO2 sample deposited on FTO in a precursor solution volume of 200 mL by the pulsed method was introduced as the most suitable sample for being used as a photoanode.