Effect of annealing temperature on photoelectrochemical properties of WO3/Fe2O3 Photoelectrodes

WO₃ thin film was prepared by simple electrodeposition while Fe₂O₃ was deposited onto the WO₃ layer by chemical bath deposition. Post-annealing temperature was found to have drastic effect on the photoelectrochemical performance of these films. The light absorption range of the bilayer photoelectrodes was improved from 450 nm to 525 nm. Flat band potentials of the bilayer photoelectrodes were obtained from Mott-Schottky plot and they were shifted to higher potential. Photocurrent density produced by bilayer photoelectrode annealed at 450 °C was 1.89 times greater than monolayer WO₃ photoelectrode under standard illumination conditions (AM 1.5, 100 mW/cm²).