DOPED ORGANIC ELECTROLUMINESCENT DEVICES WITH IMPROVED STABILITY

Remarkable improvement in stability has been demonstrated in an organi c electroluminescent (EL) device using a doped emitter consisting of 8 -hydroxyquinoline aluminum (Alq) as the host and N,N-dimethylquinacrid one (DMQA) as the emissive dopant. A luminance half-life on the order of about 7500 h has been achieved in the DMQA/Alq EL device, operating under a constant current of 20 mA/cm(2) and starting at a high lumina nce of 1400 cd/m(2). The improved stability was attributed to the elim ination of intermolecular hydrogen bonding between the dopant molecule s. (C) 1997 American Institute of Physics.