Regensburg 2004 – wissenschaftliches Programm
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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.79: Poster
Donnerstag, 11. März 2004, 18:00–21:00, B
Dynamics of Charge Carrier Transport and Electroluminescence in Organic Light-Emitting Diodes — •Anton G. Mückl1 and Wolfgang Brütting2 — 1Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth — 2Experimentalphysik IV, Universität Augsburg, D-86135 Augsburg
When describing the dynamics of charge carrier transport and recombination
processes in organic light-emitting devices not only the dependence of the
drift mobility of the majority charge carriers on temperature and applied
electric field is important but also the dynamics of the minority charge
carriers should be considered. We have investigated the mobility of
electrons and holes in Alq3 at various temperatures and electric fields
using time resolved electroluminescence measurements on a specially
designed multilayer OLED structure. Both, electron and hole mobility show a
Poole-Frenkel-type dependence on temperature and electric field, however in
contrast to
the electron transport the hole transport is found to be non-dispersive
with a temperature independent field enhancement factor. These results
indicate clearly the mechanisms of electron and hole transport in Alq3
to be of
different nature.
We also measured the time-resolved current through unipolar and bipolar
single and double layer OLED structures at various temperatures. The decay
of the current towards the steady-state value will be discussed in terms of
the dynamics of the built-up of space charges and trap filling.