Electric field effect on luminescence efficiency in 8-hydroxyquinoline aluminum (Alq(3)) thin films

Electric field-induced luminescence quenching in thin films made from common organic electroluminescent material of aluminum (III) 8-hydroxyquinoline (Alq(3)) is reported, The dependence of luminescence quenching on excitation wavelength and electric field is attributed to field-assisted hopping separation of charge in localized excited states. The effect extrapolated to high electric fields can reduce the luminescence yield by as much as 60% limiting electroluminescence quantum efficiency in high-field-driven light emitting diodes based on the Alq(3) emitter. (C) 1997 American Institute of Physics.