Annealing time and temperature dependent morphological and optical properties of dip coated TiO2 thin films

Abstract

Anatase TiO2 thin films were deposited on ITO coated glass substrates via hydrothermal assisted sol gel dip coating method and the change in their morphological and optical properties were observed as a function of annealing time and temperature. All the samples showed densely packed spherical or almost spherical nanoparticles that tended to become more irregular and agglomerated as annealing time and temperature were increased. This also led to decreased values of transmittance with increasing annealing time and temperature. Both refractive indices and extinction coefficient increased with increasing annealing time and temperature. Annealing at higher temperature and for longer time decreases non-stoichiometric lattice sites leading to less non-radiative recombination and higher PL intensity.