Enhanced Photoelectrochemical Response of BaTiO3 with Fe Doping: Experiments and First-Principles Analysis

We use a combination of experiments and first principles density functional theory based calculations in a study of the photoelectrocheinical properties of Fe-doped BaTiO3 nanopowder. BaTiO3 with 0.5-4.0 atom % Fe doping is synthesized via a polymeric precursor route and characterized with X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UV-vis spectroscopy, and Mossbauer spectroscopy. We find a red shift of 0.39 eV in the UV-vis spectrum and hence an improved photoelectrochemical activity in the visible range upon Fe doping in BaTiO3. The origin of the observed activity in the visible range is traced through the calculated electronic structure to the electronic states associated with Fe at energies within the band gap. A reasonable agreement between the changes in measured spectra and those in calculated electronic structure augurs well for a judicious use of first-principles calculations in screening of dopants in the design of doped oxide materials with enhanced photoelectrochemical activity, such as that of Fe-doped BaTiO3 demonstrated here.