Electronic interactions and excitons in conducting polymers

Conducting polymers can be considered as one-dimensional semiconductors with features of strongly correlated electronic systems. We can distinguish a large distance motion, governed by long range Coulomb interactions, and intra-molecular electronic correlations. We exploit the dielectric screening to go beyond the single chain picture and to compare excitons for polymers in solutions and in films. Our approach allows to connect such different questions as shallow singlet and deep triplet excitons in phenylenes, Ag–Bu exciton levels crossing in polyenes, common 1/N energy dependencies in oligomers. For the fundamental edge structure we describe the suppression of DOS singularity by the long range Coulomb interactions in final state of e–h pair.