Poly(9,9-dioctylfluorene)-based light-emitting diodes with pure β-phase emission

The authors report on poly(9,9-dioctylfluorene) (PFO)-based light-emitting diodes exhibiting an emission spectrum which was previously attributed to the so-called beta phase. These devices were prepared by drop cast from dilute toluene solutions. Photoluminescence and electroluminescence spectra, recorded at room temperature, show no evidence of the usual amorphous phase emission. Devices with pure beta-phase emission exhibit a higher color stability, upon increase of the driving voltage, than those based on amorphous PFO. (C) 2007 American Institute of Physics.