Dye-sensitized photoelectrochemical cells based on porous SnO2/ZnO composite and TiO2 films with a polymer electrolyte

Polyacrylonitrile polymer electrolyte based photoelectrochemical cells have been fabricated with ruthenium bipyridyl complex as the sensitizer using p orous films of SnO2/ZnO composite and also TiO2 films. The redox component of the electrolyte is XI + I-2, where X+ = Cs+, K+, Na+, Li+, or tetrabutyl ammonium ion. For both types of cells (SnO2/ZnO and TiO2) highest short-cir cuit photocurrents and efficiencies are obtained when X = Cs and in all cas es these parameters were higher for the cells made from SnOz/ZnO. Results a re explained as originating from the dependence of the mobility of I- in th e polymer electrolyte on nature of the cation X+ and the necessity of wide separation of photogenerated electron and the resulting dye cation to overc ome the diffusion-controlled kinetics of I- transport.