Tin oxide based dye-sensitized solid-state solar cells: surface passivation for suppression of recombination

Abstract

Dye-sensitized solid-state solar cells based on SnO2 where the crystallite surface is passivated with ultra-thin structures constituted of MgO, ZnO and CaO are examined using high extinction coefficient indoline dye D149 as the sensitizer. Results clearly demonstrate that surface passivation effectively suppress leakage of electrons from interconnected SnO2 crystallites preventing recombination with the hole transport substrate CuSCN. In the presence of passivating films of any type, the optimum efficiency occurred at nearly same SnO2 film thickness of 12 μm. MgO passivated system at a MgO surface concentration of ~8×10−9 g cm−2 yielded the highest efficiency of 2.82% under standard measurements conditions using cells of active area 0.25 cm2.