High photocurrent conversion efficiency in self-organized porous WO3

Self-organized porous structures of WO3 were grown on tungsten by an anodic oxidation, and their photoelectrochemical properties were characterized. The porous WO3 layers show a regular morphology with average pore sizes of approximately 70nm and a pore wall thickness of approximately 10nm. As formed layers show an amorphous structure but the layers can be altered to a crystalline monoclinic structure by thermal annealing. The annealed porous WO3 layers show a very high specific photocurrent conversion efficiency.