Stability and efficiency improvement of TiO 2 -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 SnO 2 . However, according to previous studies, the adoption of this technique to TiO 2 has not been successful, because of the constraints of depositing pin hole free ultra-thin films of oxide insulators over TiO 2 . Here, a simple method is described for deposition of ultra-thin films of MgO on TiO 2 . Cells prepared by this technique deliver an efficiency of 10.03% compared 9.27% those based on bare TiO 2 films. Studies conducted reveal that DSCs based on TiO 2 /MgO films are highly stable than bare TiO 2 films.