Conformation pre-organization in fluorene-based conjugated polymer for simultaneous enhancement of luminescence and charge mobility

Abstract

Generally in organic electronics, high-mobility organic materials require strong intermolecular interaction for delocalized electrons, while high luminescent efficiency needs localization of excitons. Thus, simultaneous enhancement of luminescent efficiency and charge mobility are theoretically difficult. In this work the simultaneous enhancement was realized by aggregation induced complanation in conformation pre-organization of a fluorene-based copolymer. Polymer chain conformation has been tesitifed as tending to be more planar in a poor solvent induced aggregate than in a good solvent, which is the same as that in an excited and charged state. This complanation effectively decreases conformation relaxation during excitation and charge transfer, which simultaneously enhances emission efficiency and charge mobility, and eventually improves electroluminescent efficiency in the PLED. This result will inspire new ideas for conjugated polymers, especially in processing film fabrication for high efficiency devices.