Photoluminescence studies of the light-emitting species in new materials for polymer devices

摘要

Abstract: The photophysics of a soluble, cynao-substituted poly (p- phenylene vinylene) and some related model compounds are compared using steady-state and time-resolved photoluminescence spectroscopy. The nature of the excited states in the model compounds are shown to differ markedly from the polymer as steric hindrance between the cyano group and an alkoxy group disrupts electron delocalization resulting in a twist in the molecular structure. In solution the polymer exhibits emission from both isolated chains, and from aggregates formed when the solution is allowed to equilibrate over a long period of time. The aggregate has its own distinct absorption and emission features and is assigned to a dimer- like species. When spun from the same solvent, thin films of the polymer exhibit the same emission features as the solution aggregates. !29