Steady State Photoconductivity in Conjugated Polymers

Abstract

Visible and ultraviolet photoconductivity (PC) measurements have been performed on thick (7µm) and thin (170nm) films of poly[2-methoxy, 5 ethyl (2' hexyloxy) paraphenylenevinylene] (MEH-PPV) sandwiched between indium tin oxide (ITO) and semitransparent gold (Au) electrodes. PC spectra were obtained for samples under different bias polarities and for illumination through the ITO electrode and through the Au electrode. The results obtained indicate that the absorbed photons form excitons that dissociate extrinsically at or near the electrodes to form hole polarons or intrinsically at higher photon energies in the bulk polymer.