Abstract
The authors present the results of a study of photoluminescence (PL) in poly (phenylenevinylene) (PPV) and poly (diphenylenediphenylvinylene) (PDPV) and also of photoinduced absorption (PA) in PPV. The contrast between the structured PL seen for PPV and the featureless emission of PDPV is discussed in terms of the effects of disorder. The PA seen in PPV, at 0.6 eV and 1.6 eV suggests that bipolarons are the main product of relaxation following photoexcitation.