Improving Processability and Efficiency of Resonant TADF Emitters : a Design Strategy

Title data

Hall, David ; Suresh, Subeesh Madayanad ; dos Santos, Paloma L. ; Duda, Eimantas ; Bagnich, Sergey ; Pershin, Anton ; Rajamalli, Pachaiyappan ; Cordes, David B. ; Slawin, Alexandra M. Z. ; Beljonne, David ; Köhler, Anna ; Samuel, Ifor D. W. ; Olivier, Yoann ; Zysman‐Colman, Eli:
Improving Processability and Efficiency of Resonant TADF Emitters : a Design Strategy.
In: Advanced Optical Materials. Vol. 8 (2020) Issue 2 . - No. 1901627.
ISSN 2195-1071
DOI: https://doi.org/10.1002/adom.201901627

Official URL:

Abstract in another language

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 are identified 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% 1,3‐bis(N‐carbazolyl)benzene. 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. It is speculated that the lattice stiffness responsible for the narrow fluorescence and phosphorescence emission spectra also protects the triplets against nonradiative decay. An improved maximum external quantum efficiencies (EQEmax) of 21.1% for Mes3DIKTa compared to the parent DiKTa (14.7%) and, importantly, reduced efficiency roll‐off compared to literature resonance TADF organic light‐emitting diodes (OLEDs), shows the promise of this design strategy for future design of R‐TADF emitters for OLED applications.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Chair Experimental Physics II - Optoelectronics of Soft Matter > Chair Experimental Physics II - Optoelectronics of Soft Matter - Univ.-Prof. Dr. Anna Köhler Faculties Faculties > Faculty of Mathematics, Physics und Computer Science
Result of work at the UBT:	Yes
DDC Subjects:	500 Science > 530 Physics
Date Deposited:	12 Dec 2019 07:47
Last Modified:	08 Feb 2022 13:05
URI:	https://eref.uni-bayreuth.de/id/eprint/53559