Simple and Reproducible Procedure to Prepare Self-Nanostructured NiO Films for the Fabrication of P-Type Dye-Sensitized Solar Cells

Porous and nanostructured thin films of NiO (3.5 μm thick) were prepared on FTO coated glass by annealing nickel acetate films obtained by recrystallization under hydrothermal conditions in the presence of hexamethylenetetramine. The photovoltaic performances of the NiO films were optimized with coumarin C343 as sensitizer and iodide/triodide as redox mediator and led to the following values of V OC, J SC, ff, and η: 117 mV, 0.88 mA/cm2, 0.28, and 0.036% respectively, under AM 1.5. With the improved PMI-NDI dyad as sensitizer and the tris(4,4′-bis(tertbutyl)bipyridine) cobaltII/III couple as redox mediator, the overall photoconversion efficiency reached 0.16%. An essential advantage of this procedure lies in its good reproducibility offering a reliable strategy to test new dyes and other parameters to improve the photoconversion efficiency of this new type of DSSC.