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 porous films of SnO 2 /ZnO composite and also TiO 2 films. The redox component of the electrolyte is XI + I 2, where X + = Cs +, K +, Na +, Li +, or tetrabutylammonium ion. For both types of cells (SnO 2 /ZnO and TiO 2 ) highest short-circuit photocurrents and efficiencies are obtained when X = Cs and in all cases these parameters were higher for the cells made from SnO 2 /ZnO. Results are explained as originating from the dependence of the mobility of I - in the polymer electrolyte on nature of the cation X + and the necessity of wide separation of photogenerated electron and the resulting dye cation to overcome the diffusion-controlled kinetics of I - transport.