Author(s): C Photiphitak, P Rakkwamsuk, P Muthitamongkol
TiO 2 /MgO composite films were prepared by coating the magnesium acetate solution in the pores of meso porous TiO 2 films using a dip coating method. Concentrations of magnesium acetate solution were varied in a range of 1x10 -4 – 1x10 -1 M. The TiO 2 /MgO composite films were characterized by scanning electron microscopy (SEM), transmission electron microscropy (TEM), electrochemical impedance spectroscopy(EIS) , trans ient voltage decay and I-V test. The TiO 2 films and TiO 2 /MgO composite films were immersed in a 0.3 mM N719 dye solution. The Dy e-sensitized solar cells with the TiO 2 /MgO/N719 structure showed an optimal concentration of magnesium acetate solution of 1x10 -3 M resulting in the MgO film estimated thickness of 0.0963 nm and g iving the maximum efficiency of 4.85%. The improved efficienc y of dye- sensitized solar cell was due to the magnesium oxid e film as the wide band gap coating decays the electron back transfer to the triiodide electrolyte and reduce charge recombination.