Author/Authors :
Sun، نويسنده , , R.G. and Wang، نويسنده , , Y.Z. and Wang، نويسنده , , D.K and Zheng، نويسنده , , Q.B and Kyllo، نويسنده , , E.M and Gustafson، نويسنده , , T.L. and Wang، نويسنده , , Fosong and Epstein، نويسنده , , A.J، نويسنده ,
Abstract :
Photoluminescence (PL) quantum efficiency is a key issue in designing successful light-emitting polymer systems. Exciton relaxation is strongly affected by exciton quenching at nonradiative trapping centers and the formation of excimers. These factors reduce the PL quantum yield of light-emitting polymers. In this work, we have systematically investigated the effects of exciton confinement on the PL quantum yield of an oligomer, polymer, and alternating block copolymer (ABC) PPV system. Time-resolved and temperature-dependent luminescence studies have been performed. The ABC design effectively confine photoexcitations within the chromophores, preventing exciton migration and excimer formation. An unusually high (PL) quantum yield (above 90%) in the solid state is reported for the alternating block copolymer PPV, as compared to that of ∼30% of the polymer and oligomer model compounds.
