HIGHLY FLUORESCENT MOLECULAR ORGANIC COMPOSITES FOR LIGHT-EMITTING-DIODES

Organic films of tris-(8-hydroxyquinolinato) aluminum (III) and ,N'-bi s(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine doped with highly fluores cent molecules were prepared by vacuum deposition. Optical absorption and photoluminescence spectra of the composites were measured as a fun ction of dopant concentration. These films were also used as the emitt ing layer in light-emitting diodes, where their electroluminescence sp ectra was studied as a function of dopant concentration. Color tunabil ity from the blue-green to the red-orange based on variation in the fl uorescent molecule and dopant concentration was attained, and quantum efficiencies were found to be enhanced upon doping of the emitter laye r.