Efficient Mn-doped CdS quantum dot sensitized solar cells based on SnO₂ microsphere photoelectrodes

Mn-doped CdS quantum dot sensitized solar cells based on SnO₂ microsphere photoelectrodes are prepared with successive ionic layer adsorption and reaction method. It is found that with Mn-doped CdS quantum dot sensitizers, the photovoltaic performance of the cells based on SnO₂ microsphere photoelectrodes can obviously be enhanced. The reasons are owing to the improved light absorption and the expanded light absorption edge by doping Mn in CdS quantum dots. The electrochemical impedance spectroscopy analysis found that the cells with Mn-doped CdS quantum dot sensitized SnO₂ microsphere photoelectrodes can efficiently suppress dark reaction, owing to the increased related resistance. Moreover, it is also found that the Mn-doped CdS quantum dot sensitized SnO₂ microsphere photoelectrode can increase the electron diffusion lifetime in the cell. The power conversion efficiency of the cell with 4 wt% Mn-doped CdS quantum dot sensitizers can attain to 2.80 %, with 53 % enhancement compared with that of the CdS quantum dot sensitized cell (1.83 %).