Triazolotriazine-based thermally activated delayed fluorescence materials for highly efficient fluorescent organic light-emitting diodes (TSF-OLEDs)
Autor: | Feng Yang, Jingbo Lan, Jingsong You, Yuyao Zhao, Rongchuan Su, Zhengyang Bin, Lian Duan |
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Rok vydání: | 2021 |
Předmět: |
chemistry.chemical_classification
Multidisciplinary Materials science Maximum power principle business.industry Band gap Electron acceptor 010502 geochemistry & geophysics 01 natural sciences Fluorescence Acceptor chemistry OLED Optoelectronics Quantum efficiency business 0105 earth and related environmental sciences Diode |
Zdroj: | Science Bulletin. 66:441-448 |
ISSN: | 2095-9273 |
Popis: | Thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light-emitting diodes (TSF-OLEDs) have shown great potential for the realization of high efficiency with low efficiency roll-off and good color purity. However, the superior examples of TSF-OLEDs are still limited up to now. Herein, a trade-off strategy is presented for designing efficient TADF materials and achieving high-performance TSF-OLEDs via the construction of a new type of triazolotriazine (TAZTRZ) acceptor. The enhanced electron-withdrawing ability of TAZTRZ acceptor, fused by triazine (TRZ) and triazole (TAZ) together, enables TADF luminogens with small singlet-triplet energy gap (ΔEST) values. Meanwhile, the increased planarity from the TRZ-phenyl linkage (6:6 system) to the TAZ-phenyl linkage (5:6 system) can compensate the decrease of oscillator strength (f) while lowing ΔEST, thus achieving a trade-off between small ΔEST and high f. As a result, the related TSF-OLED achieved an extremely low turn-on voltage of 2.1 V, an outstanding maximum external quantum efficiency (EQEmax) of 23.7% with small efficiency roll-off (EQE1000 of 23.2%; EQE5000 of 20.6%) and an impressively high maximum power efficiency of 82.1 lm W−1, which represents the state-of-the-art performance for yellow TSF-OLEDs. |
Databáze: | OpenAIRE |
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