Investigation of Photoelectrochemical Water Splitting for Mn-Doped In2O3 Film

Undoped and Mn-doped In2O3 films were prepared by radiofrequency magnetron sputtering technique. The effects of Mn doping on the structural and optical properties of as-prepared films were investigated using X-ray diffraction, X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. Mn doping can enhance the intensity of (222) peak in Mn-doped In2O3 thin film, indicating Mn dopant promotes preferred orientation of crystal growth along (222) plane. XPS analyses revealed that the doped Mn ions exist at +2 oxidation states, substituting for the In3+ sites in the In2O3 lattice. UV-Vis measurements show that the optical band gap E-g decreases from 3.33 to 2.87eV with Mn doping in In2O3, implying an increasing sp-d exchange interaction in the film. Our work demonstrates a practical means to manipulate the band gap energy of In2O3 thin film via Mn impurity doping, and significantly improves the photoelectrochemical activity. [GRAPHICS] .