TY - JOUR
T1 - Emission and Absorption Tuning in TADF B,N-Doped Heptacenes
T2 - Toward Ideal-Blue Hyperfluorescent OLEDs
AU - Stavrou, Kleitos
AU - Madayanad Suresh, Subeesh
AU - Hall, David
AU - Danos, Andrew
AU - Kukhta, Nadzeya A.
AU - Slawin, Alexandra M.Z.
AU - Warriner, Stuart
AU - Beljonne, David
AU - Olivier, Yoann
AU - Monkman, Andrew
AU - Zysman-Colman, Eli
N1 - Funding Information:
K.S. and S.M.S. contributed equally to this work. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement No 838885 (NarrowbandSSL) and under the Marie Skłodowska Curie grant agreement No 812872 (TADFlife). S.M.S. acknowledges support from the Marie Skłodowska-Curie Individual Fellowship (grant agreement No 838885 NarrowbandSSL). The St. Andrews team would like to thank the Leverhulme Trust (RPG-2016-047) for financial support. E. Z.-C. is a Royal Society Leverhulme Trust Senior Research fellow (SRF\R1\201089). Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifiques de Belgique (F. R. S.-FNRS) under Grant No. 2.5020.11, as well as the Tier-1 supercomputer of the Fédération Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n 1117545. The authors thank F. Rodella and Prof. P. Strohriegl from Bayreuth University for help with the thermogravimetric analysis.
Funding Information:
K.S. and S.M.S. contributed equally to this work. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement No 838885 (NarrowbandSSL) and under the Marie Skłodowska Curie grant agreement No 812872 (TADFlife). S.M.S. acknowledges support from the Marie Skłodowska‐Curie Individual Fellowship (grant agreement No 838885 NarrowbandSSL). The St. Andrews team would like to thank the Leverhulme Trust (RPG‐2016‐047) for financial support. E. Z.‐C. is a Royal Society Leverhulme Trust Senior Research fellow (SRF\R1\201089). Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI), funded by the Fonds de la Recherche Scientifiques de Belgique (F. R. S.‐FNRS) under Grant No. 2.5020.11, as well as the Tier‐1 supercomputer of the Fédération Wallonie‐Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n 1117545. The authors thank F. Rodella and Prof. P. Strohriegl from Bayreuth University for help with the thermogravimetric analysis.
Publisher Copyright:
© 2022 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH.
PY - 2022/9/5
Y1 - 2022/9/5
N2 - 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.
AB - 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.
KW - hyperfluorescence
KW - MR-TADF
KW - multi-resonant thermally activated delayed fluorescence
KW - OLEDs
KW - organic light-emitting diodes
UR - http://www.scopus.com/inward/record.url?scp=85131782811&partnerID=8YFLogxK
U2 - 10.1002/adom.202200688
DO - 10.1002/adom.202200688
M3 - Article
AN - SCOPUS:85131782811
SN - 2195-1071
VL - 10
JO - Advanced Optical Materials
JF - Advanced Optical Materials
IS - 17
M1 - 2200688
ER -