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Molecular Design Strategies for Color Tuning of Blue TADF Emitters

Stachelek, Patrycja; Ward, Jonathan S.; dos Santos, Paloma L.; Danos, Andrew; Colella, Marco; Haase, Nils; Raynes, Samuel J.; Batsanov, Andrei S.; Bryce, Martin R.; Monkman, Andrew P.

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Patrycja Stachelek

Jonathan S. Ward

Paloma L. dos Santos

Marco Colella

Nils Haase

Samuel J. Raynes



New thermally activated delayed fluorescence (TADF) blue emitter molecules based on the known donor−acceptor−donor (D−A−D)- type TADF molecule, 2,7-bis(9,9-dimethylacridin-10-yl)-9,9-dimethylthioxanthene- S,S-dioxide (DDMA-TXO2), are reported. The motivation for the present investigation is via the use of rational molecular design, based on DDMA-TXO2, to elevate the organic light emitting diode (OLED) performance and obtain deeper blue color coordinates. To achieve this goal, the strength of the donor (D) unit and acceptor (A) units have been tuned with methyl substituents. The methyl functionality on the acceptor was also expected to modulate the D−A torsion angle in order to obtain a blue shift in the electroluminescence. The effect of regioisomeric structures has also been investigated. Herein, we report the photophysical, electrochemical, and single-crystal X-ray crystallography data to assist with the successful OLED design. The methyl substituents on the DDMA-TXO2 framework have profound effects on the photophysics and color coordinates of the emitters. The weak electron-donating methyl groups alter the redox properties of the D and A units and consequently affect the singlet and triplet levels but not the energy gap (ΔEST). By systematically manipulating all of the aforementioned factors, devices have been obtained with acceptor-substituted III with a maximum external quantum efficiency of 22.6% and Commission Internationale de l’Éclairage coordinates of (0.15, 0.18) at 1000 cd m−2.


Stachelek, P., Ward, J. S., dos Santos, P. L., Danos, A., Colella, M., Haase, N., …Monkman, A. P. (2019). Molecular Design Strategies for Color Tuning of Blue TADF Emitters. ACS Applied Materials and Interfaces, 11(30), 27125-27133.

Journal Article Type Article
Acceptance Date Jul 1, 2019
Online Publication Date Jul 17, 2019
Publication Date Aug 31, 2019
Deposit Date Jul 25, 2019
Publicly Available Date Jul 25, 2019
Journal ACS Applied Materials and Interfaces
Print ISSN 1944-8244
Electronic ISSN 1944-8252
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 11
Issue 30
Pages 27125-27133


Published Journal Article (Advance online version) (3.4 Mb)

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Copyright Statement
Advance online version This is an open access article published under a Creative Commons Attribution (CC-BY)
License, which permits unrestricted use, distribution and reproduction in any medium,
provided the author and source are cited.

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