Catalytic Effect of Metal Ions on the In: SnO2/Aqueous Polysulfide Interface: Application for Polysulfide Based Photoelectrochemical Cells

Large surface area photoelectrochemical cells exhibit low fill factors mainly due to mass transport polarizations in the electrolyte. To avoid that problem transparent (and conductive) materials must be used either as substrate to the photoelectrode or as a counter electrode. — It is shown here that cobalt(II), can reduce the overpotential at the interface between the transparent electrode and polysulfide electrolyte, without loss in transmittivity, rendering those materials good counter electrode. Surface analyses reveal that the metal ions form some kind of a sulfide superstructure with typical grain size of few tens of angstroms. The binding to the oxide layer is briefly discussed.