Small-angle X-ray scattering studies of nanophase TiO2 thin films

Nanosized TiO2 thin films on glass substrate of thickness ranging from 1 to 7 μm were prepared using sol–gel and P25 paste procedure [1–6]. SAXS measurements at the ELETTRA synchrotron (Italy, Trieste) revealed that TiO2 crystallite size increased in `average particle radiiʹ values 〈R〉 from 2.5 to 10.0 nm with annealing temperature from room temperature to 900°C. Thermal annealing was performed in atmospheres of H2, O2 and N2 for sol–gel and in O2 and H2 for P25 prepared samples. The `average particle radiiʹ values 〈R〉 varied differently between the two different types of preparation. The specific surface area of these films was also determined and generally varied from 106 to 108 cm−1.