PHOTOELECTROCHEMICAL RESPONSE IN CONDUCTING POLYMER-FILMS

The photoelectrochemical responses of electrochemically prepared polya niline, polypyrrole and poly(3-methylthiophene) polymer films were stu died. For polyaniline, the behavior of the photocurrent was analyzed w ith respect to the nature and concentration of the electrolyte solutio n, wavelength of the incident light and type of working electrode. Pol yaninile shows a cathodic photocurrent in the reduced state and an ano dic photocurrent in the oxidized state, indicating a transition from p -type to n-type semiconductor behavior. Chemically prepared polyanilin e deposited by solution evaporation onto a gold substrate and covered with an aluminum layer shows a photocurrent comparable to a commercial photodiode. Polypyrrole and poly(3-methylthiophene) show characterist ic cathodic photocurrent responses in the reduced state when irradiate d with pulsed light, indicating a p-type semiconductor behavior.