Dye-sensitized nanostructured p-type nickel oxide film as a photocathode for a solar cell

Nanostructured NiO film was prepared by depositing nickel hydroxide slurry on conducting glass and sintering at 500 degrees C to a thickness of about 1 mu m. The photocurrent-voltage (IV) characteristics of the plain nanostructured NiO electrode recorded potentiostatically in a standard three-electrode setup upon UV illumination demonstrate p-type behavior, while the IV characteristics of a dye-sensitized nanostructured NiO electrode coated with erythrosin B show cathodic photocurrent under visible Light illumination. The highest incident photon-to-current conversion efficiencies of tetrakis(4-carboxyphenyl) porphyrin (TPPC) and erythrosin B-coated NiO films were 0.24% and 3.44%, respectively. In sandwich solar cells with a platinized conducting glass as counter electrode exposed to Light from a sun simulator (light intensity: 68 mW/cm(2)), a short-circuit cathodic photocurrent density I-SC) of 0.079 mA/cm(2) and an open-circuit voltage (V-OC) of 98.5 mV for TPPC-coated NiO electrode were achieved. Similarly, I-SC = 0.232 mA/cm(2) and V-OC = 82.8 mV were registered when the NiO electrode was coated with erythrosin B. The cathodic photocurrent is explained by hole injection from dye molecule to the valence band of the p-NiO electrode.