Routledge, T.J. orcid.org/0000-0003-0890-113X, Lidzey, D.G. orcid.org/0000-0002-8558-1160
and Buckley, A.R.
(2019)
Ultrasonic spray coating as an approach for large-area polymer OLEDs: The influence of thin film processing and surface roughness on electrical performance.
AIP Advances, 9 (1).
015330.
ISSN 2158-3226
Abstract
In this article we present a detailed comparison of ultrasonic spray coating and spin coating for the fabrication of polymer organic light-emitting diodes (OLEDs). Single-carrier devices of hole-transporting polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4’(N-(4-sec-butylphenyl))) diphenylamine] (TFB) were fabricated by ultrasonic spray coating. Uniform reference devices using spin coating were also made. We have shown, across a range of device thicknesses from 37 nm to 138 nm, typical of those used in OLED hole-transport layers, that there is no statistical difference in the hole-injection efficiency between ultrasonic spray coating and spin coating. We have also demonstrated the importance of controlling the roughness of the films and we determine a threshold of 10 nm average roughness below which injection efficiency is not controlled by roughness. However, above 10 nm roughness we find a reduction in injection efficiency up to an 86 % loss in performance for roughnesses of the order of 40 % the thickness of the film. By optimising the deposition parameters, in order to allow the wet films to start to equilibrate, we find a wide processing window for smooth uniform films with excellent injection efficiency. This work reinforces the importance of ultrasonic spray coating as a potential route to high volume manufacturing of OLED based technology.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 28 Feb 2019 12:44 |
Last Modified: | 28 Feb 2019 12:44 |
Published Version: | https://doi.org/10.1063/1.5082791 |
Status: | Published |
Publisher: | AIP Publishing |
Refereed: | Yes |
Identification Number: | 10.1063/1.5082791 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:142461 |