Phase-modulation measurements of photoinduced infrared absorptions from poly(p-phenylene) and poly(2,5-dioctyloxy-p-phenylenevinylene)

Photoinduced infrared absorption spectra of poly(p-phenylene) and poly(2,5-dioctyloxy-p-phenylenevinylene) have been measured by the phase- modulation technique. The modulation-frequency dependencies of the intensity and the phase delay of the photoinduced infrared absorptions have been obtained. The observed modulation-frequency dependencies have been numerically simulated on the basis of a model consisting of a bimolecular recombination of the positive and negative polarons that are formed from a photogenerated polaron pair (interchain charge-transfer exciton). The rate constant of the bimolecular recombination process has been obtained. (C) 2000 Elsevier Science B.V.