Sensitization of mesoscopic NiO films with molecular dyes has attracted a growing scientific interest because these photocathodes represent the key component of tandem dye-sensitized solar cells and tandem dye-sensitized photoelectrosynthetic cells. In this area, quantum dots (QDs) were much less investigated than molecular sensitizers although they proved to be particularly promising light collectors in other photovoltaic technologies such as Schottky type solar cells and conventional TiO₂ based n-QDSSCs. In this presentation, we demonstrate that PbS QDs are promising inorganic sensitizers for NiO based p-DSSCs. Photocurrent is produced until far in the IR (above 950 nm) with a cobalt complex as redox couple supportting thus the real potential of quantum dot sensitized NiO-based photocathodes to exploit the low energy part of the solar spectrum.