Regensburg 2002 – wissenschaftliches Programm
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SYOH: Organische Halbleiter
SYOH 7: Poster
SYOH 7.38: Poster
Montag, 11. März 2002, 18:00–21:00, C
Organic thin film morphology and triplet electroluminescence in OLEDs with doped charge transport layers — •Dashan Qin1, Donghang Yan2, Lixiang Wang2, Martin Pfeiffer1, Jan Blochwitz-Nimoth1, and Karl Leo1 — 1Institut fuer Angewandte Photophysik, TU Dresden, D- 01062 Dresden, Germany — 2State Key Lab of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun 130023, P.R. China
Three kinds of typical organic materials for OLEDs, i.e., Alq3 (a light-emitting material), NPB (a hole transporting material) and PBD (an electron transporting material), have been chosen, and the effects of substrate temperature and substrate type on the morphologies of these thin films have been studied in detail.
The growth modes of all three materials depends strongly on substrate temperature. Effects like molecular configuration, wettability of the substrate and diffusion ability play important roles. We observed amorphous NPB-films at high substrate temperature and investigated the influence of the film-structure on OLED performance. For the PBD-films, a glassy phase transition could be observed for the first time. Additionally, we report about the effect of the morphology of Alq3 thin-films on the device performance, which indicates that Alq3 thin-films prepared at high substrate temperature shows higher quantum efficiencies than films prepared at room temperature.
Furthermore, we will present recent results about organic light emitting diodes with triplet emitters and doped charge transport layers to lower the operating voltage of such devices.