Fabrication of nanostructured NiO thick films by facile printing method and their dye-sensitized solar cell performance

Nanostructured NiO thick films were fabricated for use in dye-sensitized solar cells (DSCs) as photocathodes. Pastes were prepared by using nanocrystalline NiO powders, polyethylene glycol (PEG) and water. The pastes were then printed on FTO glass substrates by a facile doctor-blade printing method. The NiO films were obtained by heating at 500°C for 30 min in flowing oxygen. It was shown that the nanostructure of the resultant films was largely dependent on the amount of PEG in the pastes. Coumarin 343 (C343) dye was employed for sensitizing p-type NiO photocathodes. DSCs using our NiO/C343 photocathodes yielded a photocurrent density of 1.26 mA cm^-2, an open-circuit photovoltage of 88 mV, a fill factor of 0.33, and a solar energy conversion efficiency of 0.037 %.