AAbsorption spectra of TiO2 films doped with cerium

Different kinds of Ce-TiO2 films were fabricated by radio frequency reactive magnetron sputtering. Based on the transmittance spectra measured by UVVis spectrophotometer, it was found that optical absorption band exhibited a red shift with the increase of Ce/Ti doping ratio. Calculation results indicates the band gap energy (Eg) decreases from 3.40eV to 2.73eV with the absorption band shift from 366nm to 455nm, which results in more absorption of visual light. The impurity energy level Ce 4f plays an important role in the absorption of visual light.