The development of an efficient dye-sensitized photoelectrochemical (DSPEC) cell can contribute to mitigating energy and environmental challenges via converting and storing solar energy into chemical bonds. However, the overall efficiency of the DSPEC cell is limited by severe charge recombination at the photocathode, which has a substantially lower performance than the photoanode. In a dye-sensitized photocathode, a monolayer of a molecular dye is anchored onto the surface of a p-type semiconductor and functions as the light absorber. A catalyst for proton or CO2 reduction can be linked to the dye, co-adsorbed on the semiconductor or even dissolved into the electrolyte. Light-induced charge separation by hole injection from the dye into the valence band of the semiconductor should be followed by electron transfer to the catalyst. This working principle differs from conventional photoelectrodes, based on e.g.