Stability and efficiency improvement of TiO2-based dye-sensitized solar cells by surface modification of MgO

The efficiencies of dye-sensitized solar cells are limited by the recombination of the electrons in the conduction band of the n-type oxide semiconductor with the photogenerated dye cation and acceptors in the electrolyte. Attempts have been made to resolve this problem by inserting ultra-thin barriers of insulating material between the oxide surface and the dye layer. The strategy has been successful in boosting the efficiency of cells based on SnO2. However, according to previous studies, the adoption of this technique to TiO2 has not been successful, because of the constraints of depositing pin hole free ultra-thin films of oxide insulators over TiO2. Here, a simple method is described for deposition of ultra-thin films of MgO on TiO2. Cells prepared by this technique deliver an efficiency of 10.03