Photoconductive properties of poly(2,3-di(p-tolyl)quinoxaline-5,8-diyl)

Photoconductive properties of poly(2,3-di(p-tolyl)quinoxaline-5,8-diyl), which has a high electron-accepting ability, are reported. The photocurrent spectra were observed using sandwich-type cells fabricated between transparent electrodes (ITO) and metal electrodes (Mg, Al and Au) under irradiation from each side of the electrodes. Two types of photocurrent spectra were observed depending on the experimental conditions, and the results are discussed from a viewpoint of carrier generation mechanisms. We conclude that the dissociation of photogenerated excitons occurs mainly in the depletion layer located near the Mg electrode and plays a major role in the generation of carriers. The dependences on light intensity, temperature and electric field were also measured. These experimental data were inspected based on both Poole-Frenkel theory and Bنsslerʹs model.