Photoexcitations in Polydiacetylenes

Recent progress in the field of information processing has encouraged the search for new conjugated polymers with low energy gaps and large third order cubic susceptibilitiesl, 2. Among these materials, polydiacetylenes (PDAs) are attracting special attention because their properties can be modified considerably with a proper choice of the side chains attached to the unsaturated backbone. Since the energy gap, Eg, is directly related to the extent of the electronic delocalization, a lowering of Eg could, in principle, be achieved by attaching aromatic groups directly to the backbone. To this end we have undertaken the study of novel unsymmetrical polycarbazolyldiacetylenes with one of the substituents given by the carbazole group (-Cz) and the other by different -CH2R groups.