Improving processability and efficiency of Resonant TADF emitters: a design strategy

David Hall; Subeesh Madayanad Suresh; Paloma Lays dos Santos; Eimantas Duda; Sergey Bagnich; Anton Pershin; Rajamalli Pachai Gounder; David Bradford Cordes; Alexandra Martha Zoya Slawin; David Belijonne; Anna Köhler; Ifor David William Samuel; Yoann Olivier; Eli Zysman-Colman

doi:10.1002/adom.201901627

Improving processability and efficiency of Resonant TADF emitters: a design strategy

David Hall, Subeesh Madayanad Suresh, Paloma Lays dos Santos, Eimantas Duda, Sergey Bagnich, Anton Pershin, Rajamalli Pachai Gounder, David Bradford Cordes, Alexandra Martha Zoya Slawin, David Belijonne, Anna Köhler, Ifor David William Samuel, Yoann Olivier, Eli Zysman-Colman

Research output: Contribution to journal › Article › peer-review

Abstract

A new design strategy is introduced to address a persistent weakness with resonance thermally activated delayed fluorescence (R-TADF) emitters to reduce aggregation-caused quenching effects, which we identify as one of the key limiting factors. The emitter Mes₃DiKTa shows an improved photoluminescence quantum yield of 80% compared to 75% for the reference DiKTa in 3.5 wt% mCP. Importantly, emission from aggregates, even at high doping concentrations, is eliminated and aggregation-caused quenching is strongly curtailed. For both molecules, triplets are almost quantitatively upconverted into singlets in electroluminescence, despite a significant (~0.21 eV) singlet-triplet energy gap (ΔE_ST), in line with correlated quantum-chemical calculations, and a slow reverse intersystem crossing. We speculate that the lattice stiffness responsible for the narrow fluorescence and phosphorescence emission spectra also protects the triplets against non-radiative decay. An improved EQE_max of 21.1% for Mes₃DIKTa compared to the parent DiKTa (14.7%) and, importantly, reduced efficiency roll- off compared to literature resonance TADF OLEDs, shows the promise of this design strategy for future design of R-TADF emitters for OLED applications.

Original language	English
Article number	1901627
Journal	Advanced Optical Materials
Volume	Early View
Early online date	3 Dec 2019
DOIs	https://doi.org/10.1002/adom.201901627
Publication status	E-pub ahead of print - 3 Dec 2019

Keywords

Blue emission
Multiresonance thermally activated delayed fluorescence
Organic light emitting diodes
SCS-CC2 approach

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10.1002/adom.201901627Licence: CC BY

Hall_2019_AOM_TADF_CC
Copyright © 2019 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 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.
Final published version, 2.64 MBLicence: CC BY

H2020 - ITN ELI ZYSMAN-COLMAN: H2020 MSCA ITN TADFlife
Zysman-Colman, E. (PI)
European Commission
1/10/18 → 30/09/22
Project: Standard
TADF Emitters for OLEDs - Eli Zysman: TADF Emitters for OLEDs
Zysman-Colman, E. (PI)
EPSRC
1/03/17 → 31/03/21
Project: Standard
Blue-Emitting TADF Materials: Blue-Emitting TADF Materials for OLEDs Based on a Lewis Acid-Containing Acceptor
Zysman-Colman, E. (PI)
The Leverhulme Trust
1/08/16 → 30/04/22
Project: Standard

Improving processability and efficiency of Resonant TADF emitters: A design strategy (dataset)
Hall, D. (Creator), Madayanad Suresh, S. (Creator), dos Santos, P. L. (Creator), Duda, E. (Creator), Bagnich, S. (Creator), Pershin, A. (Creator), Pachai Gounder, R. (Creator), Cordes, D. B. (Creator), Slawin, A. M. Z. (Creator), Beljonne, D. (Creator), Köhler, A. (Creator), Samuel, I. D. W. (Creator), Olivier, Y. (Creator) & Zysman-Colman, E. (Creator), University of St Andrews, 4 Dec 2019
DOI: 10.17630/e717a3b6-25b6-4bd8-b1aa-9459da244707
Dataset

File

Cite this

Hall, D., Madayanad Suresh, S., dos Santos, P. L., Duda, E., Bagnich, S., Pershin, A., Pachai Gounder, R., Cordes, D. B., Slawin, A. M. Z., Belijonne, D., Köhler, A., Samuel, I. D. W., Olivier, Y., & Zysman-Colman, E. (2019). Improving processability and efficiency of Resonant TADF emitters: a design strategy. Advanced Optical Materials, Early View, Article 1901627. Advance online publication. https://doi.org/10.1002/adom.201901627

@article{871874a1881d4988afb852a1db4196f2,

title = "Improving processability and efficiency of Resonant TADF emitters: a design strategy",

abstract = "A new design strategy is introduced to address a persistent weakness with resonance thermally activated delayed fluorescence (R-TADF) emitters to reduce aggregation-caused quenching effects, which we identify as one of the key limiting factors. The emitter Mes3DiKTa shows an improved photoluminescence quantum yield of 80% compared to 75% for the reference DiKTa in 3.5 wt% mCP. Importantly, emission from aggregates, even at high doping concentrations, is eliminated and aggregation-caused quenching is strongly curtailed. For both molecules, triplets are almost quantitatively upconverted into singlets in electroluminescence, despite a significant (~0.21 eV) singlet-triplet energy gap (ΔEST), in line with correlated quantum-chemical calculations, and a slow reverse intersystem crossing. We speculate that the lattice stiffness responsible for the narrow fluorescence and phosphorescence emission spectra also protects the triplets against non-radiative decay. An improved EQEmax of 21.1% for Mes3DIKTa compared to the parent DiKTa (14.7%) and, importantly, reduced efficiency roll- off compared to literature resonance TADF OLEDs, shows the promise of this design strategy for future design of R-TADF emitters for OLED applications.",

keywords = "Blue emission, Multiresonance thermally activated delayed fluorescence, Organic light emitting diodes, SCS-CC2 approach",

author = "David Hall and {Madayanad Suresh}, Subeesh and {dos Santos}, {Paloma Lays} and Eimantas Duda and Sergey Bagnich and Anton Pershin and {Pachai Gounder}, Rajamalli and Cordes, {David Bradford} and Slawin, {Alexandra Martha Zoya} and David Belijonne and Anna K{\"o}hler and Samuel, {Ifor David William} and Yoann Olivier and Eli Zysman-Colman",

note = "This work is funded by the EC through the Horizon 2020 Marie Sklodowska-Curie ITN project TADFlife. The St Andrews team would also like to thank the Leverhulme Trust (RPG-2016- 047) and EPSRC (EP/P010482/1) for financial support. Computational resources have been provided by the Consortium des {\'E}quipements de Calcul Intensif (C{\'E}CI), 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 F{\'e}d{\'e}ration Wallonie-Bruxelles, infrastructure funded by the Walloon Region under the grant agreement n1117545. AP acknowledges the financial support from the Marie Curie Fellowship (MILORD project, N°. 748042). DB is a FNRS Research Director. We thank Franck-Julian Kahle for support with data analysis.",

year = "2019",

month = dec,

day = "3",

doi = "10.1002/adom.201901627",

language = "English",

volume = "Early View",

journal = "Advanced Optical Materials",

issn = "2195-1071",

publisher = "John Wiley & Sons, Ltd",

}

Hall, D, Madayanad Suresh, S, dos Santos, PL, Duda, E, Bagnich, S, Pershin, A, Pachai Gounder, R, Cordes, DB , Slawin, AMZ, Belijonne, D, Köhler, A, Samuel, IDW, Olivier, Y & Zysman-Colman, E 2019, 'Improving processability and efficiency of Resonant TADF emitters: a design strategy', Advanced Optical Materials, vol. Early View, 1901627. https://doi.org/10.1002/adom.201901627

TY - JOUR

T1 - Improving processability and efficiency of Resonant TADF emitters

T2 - a design strategy

AU - Hall, David

AU - Madayanad Suresh, Subeesh

AU - dos Santos, Paloma Lays

AU - Duda, Eimantas

AU - Bagnich, Sergey

AU - Pershin, Anton

AU - Pachai Gounder, Rajamalli

AU - Cordes, David Bradford

AU - Slawin, Alexandra Martha Zoya

AU - Belijonne, David

AU - Köhler, Anna

AU - Samuel, Ifor David William

AU - Olivier, Yoann

AU - Zysman-Colman, Eli

N1 - This work is funded by the EC through the Horizon 2020 Marie Sklodowska-Curie ITN project TADFlife. The St Andrews team would also like to thank the Leverhulme Trust (RPG-2016- 047) and EPSRC (EP/P010482/1) for financial support. 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 n1117545. AP acknowledges the financial support from the Marie Curie Fellowship (MILORD project, N°. 748042). DB is a FNRS Research Director. We thank Franck-Julian Kahle for support with data analysis.

PY - 2019/12/3

Y1 - 2019/12/3

N2 - A new design strategy is introduced to address a persistent weakness with resonance thermally activated delayed fluorescence (R-TADF) emitters to reduce aggregation-caused quenching effects, which we identify as one of the key limiting factors. The emitter Mes3DiKTa shows an improved photoluminescence quantum yield of 80% compared to 75% for the reference DiKTa in 3.5 wt% mCP. Importantly, emission from aggregates, even at high doping concentrations, is eliminated and aggregation-caused quenching is strongly curtailed. For both molecules, triplets are almost quantitatively upconverted into singlets in electroluminescence, despite a significant (~0.21 eV) singlet-triplet energy gap (ΔEST), in line with correlated quantum-chemical calculations, and a slow reverse intersystem crossing. We speculate that the lattice stiffness responsible for the narrow fluorescence and phosphorescence emission spectra also protects the triplets against non-radiative decay. An improved EQEmax of 21.1% for Mes3DIKTa compared to the parent DiKTa (14.7%) and, importantly, reduced efficiency roll- off compared to literature resonance TADF OLEDs, shows the promise of this design strategy for future design of R-TADF emitters for OLED applications.

AB - A new design strategy is introduced to address a persistent weakness with resonance thermally activated delayed fluorescence (R-TADF) emitters to reduce aggregation-caused quenching effects, which we identify as one of the key limiting factors. The emitter Mes3DiKTa shows an improved photoluminescence quantum yield of 80% compared to 75% for the reference DiKTa in 3.5 wt% mCP. Importantly, emission from aggregates, even at high doping concentrations, is eliminated and aggregation-caused quenching is strongly curtailed. For both molecules, triplets are almost quantitatively upconverted into singlets in electroluminescence, despite a significant (~0.21 eV) singlet-triplet energy gap (ΔEST), in line with correlated quantum-chemical calculations, and a slow reverse intersystem crossing. We speculate that the lattice stiffness responsible for the narrow fluorescence and phosphorescence emission spectra also protects the triplets against non-radiative decay. An improved EQEmax of 21.1% for Mes3DIKTa compared to the parent DiKTa (14.7%) and, importantly, reduced efficiency roll- off compared to literature resonance TADF OLEDs, shows the promise of this design strategy for future design of R-TADF emitters for OLED applications.

KW - Blue emission

KW - Multiresonance thermally activated delayed fluorescence

KW - Organic light emitting diodes

KW - SCS-CC2 approach

U2 - 10.1002/adom.201901627

DO - 10.1002/adom.201901627

M3 - Article

SN - 2195-1071

VL - Early View

JO - Advanced Optical Materials

JF - Advanced Optical Materials

M1 - 1901627

ER -

Improving processability and efficiency of Resonant TADF emitters: a design strategy

Abstract

Keywords

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Projects

H2020 - ITN ELI ZYSMAN-COLMAN: H2020 MSCA ITN TADFlife

TADF Emitters for OLEDs - Eli Zysman: TADF Emitters for OLEDs

Blue-Emitting TADF Materials: Blue-Emitting TADF Materials for OLEDs Based on a Lewis Acid-Containing Acceptor

Datasets

Improving processability and efficiency of Resonant TADF emitters: A design strategy (dataset)

Cite this