Characterization of sprayed TiO2 on ITO substrates for solar cell applications

Titanium dioxide (TiO2) thin films had been deposited with various substrate temperatures by spray pyrolysis technique onto ITO substrates. All films exhibited polycrystalline nature with the preferred orientation along (101) plane. At the substrate temperature 450 degrees C, the film favored the formation of anatase phase. The higher substrate temperature (475 degrees C) favored the appearance of rutile structure. The SEM image of the film at substrate temperature (Ts = 450 degrees C) showed high structural quality with the porous nature. The typical AFM image of TiO2 film deposited at the substrate temperature, 450 degrees C depicted the regular arrangement of fine closely packed tetragonal structured grains. The transmittance of the spectra exhibited above 85% with energy band gap of 3.6 eV. From the study of photoluminescence, the emission at 417 nm, 437 nm and with weak emission at 551 nm was observed, which confirmed the lesser defects in the samples. The electrical resistivity was found to be 6.856 x 10(1) Omega cm for the substrate temperature 450 degrees C. The efficiency of anatase TiO2 photoelectrode deposited at the substrate temperature 450 degrees C based cell was much higher than the efficiency of TiO2 photoelectrode deposited at the substrate temperature 475 degrees C based cell. (C) 2015 Elsevier B.V. All rights reserved.