Enhanced OLED performance upon photolithographic patterning by using an atomic-layer-deposited buffer layer
Resource
Organic Electronics, Volume 9, Issue 5, October 2008, Pages 667-672
Journal
Organic Electronics
Journal Volume
Volume 9
Journal Issue
Issue 5
Pages
-
Date Issued
2008
Date
2008
Author(s)
Abstract
This study addresses the problem of patterning-induced degradations to organic light-emitting diodes (OLEDs) by using a thin (10 Å) atomic-layer-deposited (ALD) Al2O3 film as both an electron-injection layer and a protecting layer for the electroluminescent material, poly[1-methoxy-4-(2′-ethyl-hexyloxy)-2,5-phenylene vinylene] (MEH-PPV). With the ALD Al2O3 film, the OLEDs not only withstood an aggressive photolithographic patterning process without any degradation but unprecedentedly showed increased luminous efficiency (by 100%) and lowered turn-on voltage (by 19%) afterward. Although the ALD precursor, trimethylaluminum (TMA), was found to damage the MEH-PPV layer through electrophilic addition to the vinylene groups of MEH-PPV during the deposition of the Al2O3 film, its damaging effect was eliminated by pre-treating the MEH-PPV surface with isopropyl alcohol (IPA), whose hydroxyl groups scavenged TMA throughout the ALD process. The performance of the photo-patterned OLEDs was further improved by using a high-conductivity hole-injection layer, which increased accumulation of holes at the EL-buffer interface to enhance electron injection. The method reported herein improves the applicability of photolithography to OLED fabrication, promising to resolve the issue of patterning that has in part impeded OLED's commercialization. © 2008 Elsevier B.V. All rights reserved.
Subjects
Atomic layer deposition; Conjugated polymer; Electroluminescence; Photolithography
Other Subjects
Alumina; Aluminum oxide; Atoms; Charge injection; Conjugated polymers; Electroluminescence; Electron injection; Image enhancement; Organic light emitting diodes (OLED); Photolithography; Atomic layer deposited; Electroluminescent materials; Electron injection layers; Electrophilic additions; Hole injection layers; Induced degradation; Organic light emitting diodes(OLEDs); Photolithographic patterning; Atomic layer deposition
Type
journal article
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