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

Abstract

We use a combination of experiments and first-principles density functional theory based calculations in a study of the photoelectrochemical properties of Fe-doped BaTiO 3 nanopowder. BaTiO 3 with 0.5À4.0 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), UVÀvis spectroscopy, and M€ ossbauer spectroscopy. We find a red shift of 0.39 eV in the UVÀvis spectrum and hence an improved photoelectrochemical activity in the visible range upon Fe doping in BaTiO 3 . 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 BaTiO 3 demonstrated here.

Surface composition of BaTiO3/SrTiO3(001) films grown by atomic oxygen plasma assisted molecular beam epitaxy

“…12 This last system has also recently shown interesting photochemical activity making promise in the field of hydrogen production. 13 Most novel applications including BaTiO 3 are now based on thin films of nanometer thickness. Chemistry based methods to produce BaTiO 3 thin films using nanopowders synthesized by the polymeric precursor route 13 are efficient but not well suited for the thin films dedicated to nanoferronics applications.…”

Adsorption of small molecules at the cobalt-doped SrTiO3(001) surface: A first-principles investigation

“…properties [25,27,28], they have received little attention in comparison to the bulk case. We are aware of only two theoretical studies regarding substitutional metal impurities at the SrTiO 3 (001) surface, where surface segregation of iron atoms was predicted [29].…”

Spray pyrolytically deposited Fe-doped Cu2O thin films for solar hydrogen generation: Experiments & first-principles analysis

“…Maximum value of the open -circuit photovoltage (V oc ) value for this sample also supports the higher photocurrent density value as compared to undoped and higher dopant concentration samples. On the other hand, higher concentration of dopant would provide more defect-scattering/ recombination centers inhibiting the increased charge separation efficiency [15]. Fig.…”

“…Semiconductor, used as working electrode, is the heart of any PEC cell and it must be chemically stable with an optimum band gap of~2 eV, enabling it to absorb bulk of the solar radiations [7e9]. Research work, since then has been mainly focused on n-type semiconductors such as TiO 2 [10,11], Fe 2 O 3 [12], ZnO [13], WO 3 [14], BaTiO 3 [15] etc as photoanode, whereas studies on p-type metal oxide semiconductor as photocathode have been relatively limited [16e20].…”