Literature by the same author
plus at Google Scholar

Bibliografische Daten exportieren
 

Unveiling the TADF Emitters with Apparent Negative Singlet-Triplet Gaps : Implications for Exciton Harvesting and OLED Performance

Title data

Chen, Xinrui ; Bagnich, Sergey ; Pollice, Robert ; Li, Bing ; Zhu, Yuanyuan ; Saxena, Rishabh ; Yin, Yixiao ; Zhu, Weiguo ; Aspuru-Guzik, Alan ; Zysman-Colman, Eli ; Köhler, Anna ; Wang, Yafei:
Unveiling the TADF Emitters with Apparent Negative Singlet-Triplet Gaps : Implications for Exciton Harvesting and OLED Performance.
In: Advanced Optical Materials. Vol. 12 (2024) Issue 6 . - 2301784.
ISSN 2195-1071
DOI: https://doi.org/10.1002/adom.202301784

Official URL: Volltext

Abstract in another language

Abstract Intramolecular through-space charge transfer thermally activated delayed fluorescence (TSCT-TADF) has attracted much attention recently as it can achieve both small energy splitting and high emission efficiency. However, the relationship of excited states between TSCT and through-bond charge transfer (TBCT) remains a challenge in the TSCT-TADF molecules. Herein, three compounds DPS-m-bAc, DPS-p-bAc, and DPS-OAc that possess emissive TSCT and/or TBCT states are prepared. Interestingly, a so-called inverted energy gap is found for both DPS-m-bAc and DPS-p-bAc in toluene solution, which results from the different charge transfer states of ICThigh and ICTlow, as proved by the detailed transient photoluminescence and calculated results. Intense emission from blue to yellow associated with high photoluminescence quantum yields of 70–100% are measured in doped polymethyl(methacrylate) (PMMA) films. Notably, compound DPS-m-bAc achieves the highest reverse intersystem crossing rate constant (kRISC) of over 107 s−1 in a PMMA film, benefiting from close-lying TSCT and TBCT states. The solution-processed device with DPS-m-bAc displays a maximum external quantum efficiency of 21.7% and a relatively small efficiency roll-off (EQE of 20.2% @ 100 cd m−2). Overall, this work demonstrates how with judicious emitter engineering, a synergy between different charge transfer excited states, can be achieved, providing an avenue to achieve highly efficient solution-processed OLEDs.

Further data

Item Type: Article in a journal
Refereed: Yes
Keywords: charge transfer; delayed fluorescence; fast reverse intersystem crossing; solution-processed OLED; thermally activated delayed fluorescence
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: 26 Oct 2023 06:49
Last Modified: 14 Mar 2024 09:16
URI: https://eref.uni-bayreuth.de/id/eprint/87394