We have studied the quantum efficiency of multilayer organic light emitting diodes (OLEDs). Attention is focused on the recombination efficiency and exciton quenching, controlling the performance of highly efficient OLEDs having Alq(3) (Al(III) 8-hydroxyquinoline) as the emissive layer. The kinetics model is extended to account for the image charge effect on the injection and the narrow bandwidths of carriers. An analytical criterion for maximum recombination efficiency at low voltages is found. The analysis of current voltage dependence and quantum efficiency is performed for Al/LiF/Alq(3)/TPD/ITO devices with or without an ultrathin dielectric layer LiF, taking into account the exciton quenching controlled by the boundary Al-Alq(3). We get a reasonable fit for the experimental data and discuss the optimum modifications required to enhance the device performance.

Date Published: 19 July 1999
PDF: 2 pages
Proc. SPIE 3749, 18th Congress of the International Commission for Optics, (19 July 1999);

Published in SPIE Proceedings Vol. 3749:
18th Congress of the International Commission for Optics
Alexander J. Glass; Joseph W. Goodman; Milton Chang; Arthur H. Guenther; Toshimitsu Asakura, Editor(s)