Photoelectrochemical cells have been constructed with SnO2/ZnO, SnO2, ZnO and TiO2 films sensitized with eosin Y (sodium salt and triethyl ammonium salt). SnO2/ZnO composite system gives a significantly high shea-circuit photocurrent and an efficiency compared to the cells made from SnO2, ZnO or TiO2. It is suggested that the recombination is better suppressed in the composite system and a possible mechanism involved is discussed.