Stavrou, K, Madayanad Suresh, S, Hall, D et al. (8 more authors) (2022) Emission and Absorption Tuning in TADF B,N‐Doped Heptacenes: Toward Ideal‐Blue Hyperfluorescent OLEDs. Advanced Optical Materials, 10 (17). 2200688. ISSN 2195-1071
Abstract
Developing high-efficiency purely organic blue organic light-emitting diodes (OLEDs) that meet the stringent industry standards is a major current research challenge. Hyperfluorescent device approaches achieve in large measure the desired high performance by combining the advantages of a high-efficiency thermally activated delayed fluorescence (TADF) assistant dopant with a narrowband deep-blue multi-resonant TADF (MR-TADF) terminal emitter. However, this approach requires suitable spectral overlap to support Förster resonance energy transfer (FRET) between the two. Here, a color tuning of a recently reported MR-TADF B,N-heptacene core through control of the boron substituents is demonstrated. While there is little impact on the intrinsic TADF properties—as both singlet and triplet energies decrease in tandem—this approach improves the emission color coordinate as well as the spectral overlap for blue hyperfluorescence OLEDs (HF OLEDs). Crucially, the red-shifted and more intense absorption allows the new MR-TADF emitter to pair with a high-performance TADF assistant dopant and achieve maximum external quantum efficiency (EQEmax) of 15% at color coordinates of (0.15 and 0.10). The efficiency values recorded for the device at a practical luminance of 100 cd m–2 are among the highest reported for HF TADF OLEDs with CIEy ≤ 0.1.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | hyperfluorescence, MR-TADF, multi-resonant thermally activated delayed fluorescence, OLEDs, organic light-emitting diodes |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemistry (Leeds) > Organic Chemistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Jul 2022 09:53 |
Last Modified: | 25 Jun 2023 23:02 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1002/adom.202200688 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:188629 |