Electrophosphorescence and delayed electroluminescence from pristine polyfluorene thin-film devices at low temperature -: art. no. 127402

Intrinsic long-lived electrophosphorescence and delayed electroluminescence from a conjugated polymer (polyfluorene) thin film is observed for the first time at low temperature. From bias offset voltage dependent measurements, it is concluded that the delayed fluorescence is generated via triplet-triplet annihilation. A fast and efficient triplet exciton quenching by charge carriers is found to occur in the active polymer layer of the working devices.