Photoelectrochemical characteristics of cells with dyed and undyed nanoporous p-type semiconductor CuO electrodes

We prepared nanoporous p-type CuO semiconductor electrodes adsorbing various dyes with different HOMO levels and anchoring groups. Solar cells were fabricated by coupling each of the dyed electrodes with a platinum counter electrode and filled with electrolytes containing I−/I3− redox couple. Cathodic photocurrent due to hole injection from the adsorbed dye to the semiconductor was observed. Only the dyes with HOMO and LUMO potentials more positive than valence and conduction band edges, respectively, functioned as sensitizers for p-type dye-sensitized solar cells. Effects of annealing temperature and thickness of the CuO nanoporous membrane on cell performance were investigated as well.