Effect of the electrolyte composition on the response of a TIO2|CDS-Based Photoanode

Sulfide solutions are the most widely selected electrolyte for the photoelectrochemical characterization of metal chalcogenide (like CdS and CdSe) based solar cells because its good hole scavenging properties and improved stabilization of the semiconductor sensitizer. However, the photocurrent values of CdS sensitized TiO2 photoanodes depend on the sodium sulfide analytical concentration and pH values in the electrolyte solution. In this report, we show that the mass transport of the sulfide hole scavenger is the main limiting process and if its concentration is lower than the HO− concentration there is a competition for adsorption sites onto TiO2 surface, decreasing the photocurrent value. A careful optimization of these two variables it is necessary in order to attaining high overall photoelectrochemical cell efficiency.