Regensburg 2007 – wissenschaftliches Programm

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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.68: Poster

Dienstag, 27. März 2007, 18:00–20:00, Poster B

Degradation of PVK-based electrophosphorescent devices — •Andriy Kuksov, Xiaohui Yang, and Dieter Neher — University of Potsdam, Institute of Physics, Am Neuen Palais 10, 14469 Potsdam, Germany

Organic light-emitting diodes based on the hole-conducting polymer PVK blended with electron-transporting molecules and phosphorescent Iridium-complexes have recently been shown to exhibit high external quantum efficiencies and very good color stability [1]. Unfortunately, these diodes based on polymer blends degrade quite rapidly. Therefore, understanding the mechanisms of degradation is of high importance in the view of the commercialization of polymer-based OLEDs. It has been proposed that phase-separation of the individual components in the blend layers is the main origin of device degradation. By comparing the photoluminescence (PL) and electroluminescence (EL) of as-prepared and aged devices, we conclude that phase separation is not the determining factor. In contrast, the effect of ageing is clearly revealed in transient electroluminescence (TEL) experiments. This suggests that the rapid degradation of these blend devices is due to chemical rather than physical ageing.