Structural, optical and electrical characterization of nanostructured titania thick films.

Thick films of pure and Nb-doped nanostructured TiO2 have been fabricated by screen-printing, starting from nanometric powders. Structural and morphol. studies show that addn. of niobium inhibits grain growth at high annealing temp. and hinders conversion of anatase to rutile. Absorption and photoluminescence measurements prove that the optical properties of these polycryst. films vary with thermal treatment. The behavior is due to the anatase-to-rutile phase transition as obsd. in structural anal. Elec. characterization shows that firing temp. and dopant content strongly influence the gas response of the films. It is also possible to infer that the elec. performance of these samples is directly bound up to the layer morphol.