Luminescent behavior of soluble poly(para-phenylene vinylene) copolymers

Soluble diblocks with well-defined lengths of poly(phenylene vinylene), PPV, and an inert polymer, polynorbornene, PNBE, have been made by a new type of synthesis. For dilute solutions and relatively short lengths of PPV the quantum efficiency of luminescence is over 70% and the radiative lifetimes are 3 ns. We find that with increasing concentration of PPV in solution the luminescence efficiency decreases, which we propose is due to formation of polaron pairs.