| Autor: |
Chenglin Jiang, Jingsheng Miao, Danwen Zhang, Zhenhua Wen, Chuluo Yang, Kai Li |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
Research, Vol 2022 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2639-5274 |
| DOI: |
10.34133/2022/9892802 |
| Popis: |
Organic push-pull systems featuring through-space charge transfer (TSCT) excited states have been disclosed to be capable of exhibiting thermally activated delayed fluorescence (TADF), but to realize high-efficiency long-wavelength emission still remains a challenge. Herein, we report a series of strongly emissive orange-red and red TSCT-TADF emitters having (quasi)planar and rigid donor and acceptor segments which are placed in close proximity and orientated in a cofacial manner. Emission maxima (λem) of 594−599 nm with photoluminescence quantum yields (PLQYs) of up to 91% and delayed fluorescence lifetimes of down to 4.9 μs have been achieved for new acceptor-donor-acceptor (A-D-A) molecules in doped thin films. The presence of multiple acceptors and the strong intramolecular π-stacking interactions have been unveiled to be crucial for the efficient low-energy TSCT-TADF emissions. Organic light-emitting diodes (OLEDs) based on the new A-D-A emitters demonstrated electroluminescence with maximum external quantum efficiencies (EQEs) of up to 23.2% for the red TSCT-TADF emitters. An EQE of 18.9% at the brightness of 1000 cd m-2 represents one of the highest values for red TADF OLEDs. This work demonstrates a modular approach for developing high-performance red TADF emitters through engineering through-space interactions, and it may also provide implications to the design of TADF emitter with other colours. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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