Properties of transition metal doped-titania electrodes: Impact on efficiency of amorphous and nanocrystalline dye-sensitized solar cells

In this work, we present the doping by transition metal cations (M: Mn2+, Co2+, Cu2+) effect on TiO2-electrode used in dye sensitized solar cells. The pure and metal transition (Mn, Co, Cu)-doped TiO2 powders, with 0.6% as atomic ratio of M to Ti, were prepared using sol–gel protocol to obtain single phase powders with high chemical purity. The synthesized nanopowders have been systematically characterized as made and after heat treatment at 400 °C. The obtained transition metal cations doped TiO2 powders were characterized by X-ray diffraction, Raman, FT-infrared, UV–vis spectroscopies and I–V measurements. In comparison with undoped and doped TiO2 nanopowders after heat treatment, we demonstrate that the addition of Mn in TiO2 improves considerably the crystallinity, reduces the indirect band gap and increases the power conversion efficiency for the dye sensitized solar cell assembled.