THE ELECTROCHEMISTRY OF POLY(3-OCTYLTHIOPHENE) BASED LIGHT-EMITTING ELECTROCHEMICAL-CELLS

Cyclic voltammetry (CV) has been performed on light-emitting electroch emical cells (LECs) using poly(3-octylthiophene) (P3OT) as the active luminescent polymer. Above the threshold voltage, current in an LEC co nsists of ionic and electronic components. A purely ionic (negative) c omponent is clearly discernible in the return scan of the CV below thr eshold when, as a result of the relaxation of the p-n junction, the el ectronic current becomes negligible. Analysis of the peak negative cur rent reveals that LECs exhibit a mixture of thin film and diffusion co ntrolled current behavior. Weak orange light emission is observed with an onset above 2 V.