A partially stabilized photoeletrochemical cell using hydrogenated amorphous silicon photoanodes coated with thin films of polypyrrole

Electrochemical Schottky barrier devices with polypyrrole coated hydrogenated amorphous silicon, (a-Si:H), as photoanodes and a variety of aqueous redox solutions have been investigated. The open circuit voltage reaches 0.63 V for most anodic redox couples and exhibits a high degree of surface pinning due to the barrier formed between a-Si:H and the highly conductive polypyrrole. We report a substantial improvement in the stability of the polypyrrole coated electrodes compared with the bare a-Si:H. The efficiency of the present devices is limited by low photocurrent and fill factor.