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: Mn 2+, Co 2+, Cu 2+ ) effect on TiO 2 -electrode used in dye sensitized solar cells. The pure and metal transition (Mn, Co, Cu)-doped TiO 2 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 TiO 2 powders were characterized by X-ray diffraction, Raman, FT-infrared, UV–vis spectroscopies and I – V measurements. In comparison with undoped and doped TiO 2 nanopowders after heat treatment, we demonstrate that the addition of Mn in TiO 2 improves considerably the crystallinity, reduces the indirect band gap and increases the power conversion efficiency for the dye sensitized solar cell assembled.