Origin and stabilization of photoexcitations in conjugated polymers

We report studies on the nature of photoexcitations in onedimensional organic semiconductors using photoluminescence, absorption and photoinduced absorption techniques. The polymers of interest —ladder-type poly(para-phenylenes) (LPPPs) —show high intrachain order and a small distribution of effective conjugation lengths, which makes them a perfect model system for conjugated polymers. The influence of the effective conjugation length on the energetic position and the stabilization of photoexcited charged and neutral states is investigated. Interchain interactions are discussed on the base of optical spectroscopy under hydrostatic pressure.