Transient electroluminescence measurements on organic heterolayer light emitting diodes

We have investigated the field dependence of the electron and hole drift mo bility in tris-(8-hydroxyquinoline) aluminium (Alq(3)) in organic multi lay er light emitting diodes (LEDs) using transient electroluminescence measure ments. The electron transport in thin films of Alq(3) can be understood in terms of hopping processes. We obtain a full set of parameters for a modifi ed Poob-Frenkel equation describing the temperature and field dependence of the electron drift mobility. For the measurement of the hole drift mobilit y, a special device structure was designed. We were able to determine the h ole drift mobility in Alq(3) and found good agreement with the data obtaine d from previous time-of-flight (TOF) measurements. (C) 2000 Elsevier Scienc e S.A. All rights reserved.