Effect of solid polymer electrolyte on the sensitization of photocurrents in solid-state electrochemical cells using conducting polypyrrole

The effect of small concentration of methylene blue dye on photocurrents was studied in the solid-state photoelectrochemical cells fabricated using conducting polypyrrole-coated electrodes sandwiched with solid-polymer electrolyte, namely, polyvinylpyrrolidone with phosphoric acid. A maximum photosensitivity factor (S=I_l/I_d, where I_l is the photocurrent and I_d is the dark current) of the order of 5 is observed. The current–voltage (I–V) characteristics in such cells reveal that charge transport is mainly governed by the space charge effect. Comparison of the results presented in this paper with the ones we reported earlier [23] indicates that the matrix in which dye has been incorporated plays an important role in such sensitization processes. A matrix that can efficiently transport the photogenerated charge carriers is observed to be more suitable for such dye-sensitized devices.