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Investigating the root causes of the stability-gap between solution-coated and vacuum-deposited small-molecule organic light-emitting devices (Conference Presentation)
Author(s): Yong Joo Cho; Hyeonghwa Yu; Elizabeth Salsberg; Hany Aziz
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Paper Abstract

Although the promise of realizing lower cost fabrication by means of solution-based processing techniques, such as spin coating, web coating or inkjet printing, has been one key driver behind the interest in OLEDs for the last two decades, the lower stability of devices made by these techniques has been a long-standing issue. With recent advances in developing solution-processable small molecule materials, it is now possible to make OLEDs of the same small molecule materials by either solution coating or vacuum deposition. Despite this, there continues to be an intriguing stability gap. In this work, we investigate this phenomenon with the purpose of identifying its root causes. Photoluminescence, electroluminescence and delayed electroluminescence measurements are used to study and compare between the aging behaviour in OLEDs made by spin-coating versus vacuum-deposition. Hole-only devices are also utilized, and employed to study the effects of charges and excitons, separately and combined. The results reveal that solution-coated materials are more susceptible to degradation by excitons in comparison to their vacuum-deposited counterparts. Results also show that they are more susceptible to aggregation under electrical stress, and that interactions between excitons and polarons play a role in this phenomenon. Results from these investigations will be presented and discussed.

Paper Details

Date Published: 8 March 2019
Proc. SPIE 10942, Advances in Display Technologies IX, 109420B (8 March 2019); doi: 10.1117/12.2511531
Show Author Affiliations
Yong Joo Cho, Univ. of Waterloo (Canada)
Hyeonghwa Yu, Univ. of Waterloo (Canada)
Elizabeth Salsberg, Univ. of Waterloo (Canada)
Hany Aziz, Univ. of Waterloo (Canada)

Published in SPIE Proceedings Vol. 10942:
Advances in Display Technologies IX
Jiun-Haw Lee; Qiong-Hua Wang; Tae-Hoon Yoon, Editor(s)

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