Abstract: Polypyrrole (PPy) nano-fiber array electrodes were fabricated by electrochemical deposition of PPy in the pores of anodic aluminium oxide (AAO) templates. The photocurrent appeared at the potential below －0.1 V (vs Ag/AgCl) was caused by the p-type semiconductor properties of PPy material. Its flat-band potential Efb was determined as －0.217 V (vs Ag/AgCl). The photocurrent of PPy nano-fiber array electrode varied with the length of the PPy nanofibers. For very thin PPy nano-fiber array the photocurrent was small. But if the arrays were too thick the photocurrent was also small because the photo-induced electrons might recombine with photo-induced holes in the film before reaching the back contact. The optimum thickness was 42 nm. The PPy nano-fiber devices might be used as nano photo-electronic device in the future.

Key words: Polypyrrole, Anodic aluminium oxide membrane, Nano-fiber arrays, Photoelectrochemistry