https://scholars.lib.ntu.edu.tw/handle/123456789/626314
標題: | New bipolar host materials for high power efficiency green thermally activated delayed fluorescence OLEDs | 作者: | Chen C.-H. Lin S.-C. Lin B.-Y. Li C.-Y. Kong Y.-C. Chen Y.-S. Fang S.-C. Chiu C.-H. JIUN-HAW LEE KEN-TSUNG WONG Lin C.-F. Hung W.-Y. Chiu T.-L. |
關鍵字: | Organic light emitting diode (OLED); Power efficiency; Thermally activated delayed fluorescence (TADF) | 公開日期: | 2022 | 卷: | 442 | 來源出版物: | Chemical Engineering Journal | 摘要: | Four bipolar molecules, namely m-CzPym, p-CzPym, m-CzTrz, and p-CzTrz, with carbazole (Cz) donor and a benzonitrile-substituted pyrimidine (Pym) or triazine (Trz) acceptor core were synthesized and characterized. The electron deficiency of heteroaryl cores together with the substitution pattern of benzonitrile were employed to tune the energy levels as well as the thermally activated delayed fluorescence (TADF) characteristics. The four molecules exhibited TADF behavior with inferior photoluminescent quantum yields (PLQYs) that limit their applications as emitters. These bipolar molecules were employed as TADF host materials for the benchmark TADF emitter 4CzIPN to achieve high-performing green TADF organic light-emitting diodes (OLEDs). Among the molecules, m-CzPym-hosted TADF-OLEDs achieved a maximum external quantum efficiency (EQEmax) of 31.5%, maximum power efficiency (PEmax) of 95.6 lm/W, and maximum current efficiency (CEmax) of 100.2 cd/A. Notably, p-CzPym-hosted TADF-OLEDs also achieved a PEmax of 116.5 lm/W, turn-on voltage of 2.5 V, and impressive low efficiency roll-off performance (>89% of EQEmax at 5000 cd/m2), representing one of the highest efficiencies ever reported in 4CzIPN-doped devices. The high device efficiency can be ascribed to the balanced ambipolar carrier-transporting character of the host materials and high PLQY as well as the outstanding light outcoupling efficiency of the emitting layer. © 2022 |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128240169&doi=10.1016%2fj.cej.2022.136292&partnerID=40&md5=aff51d71fcb8369c62a02d02f930fc85 https://scholars.lib.ntu.edu.tw/handle/123456789/626314 |
ISSN: | 13858947 | DOI: | 10.1016/j.cej.2022.136292 | SDG/關鍵字: | Aromatic compounds; Fluorescence; Molecules; Quantum efficiency; Sound insulating materials; Synthesis (chemical); Benzonitriles; Bipolar hosts; Carbazole donors; High power efficiencies; Host materials; Organic light emitting diode; Power-efficiency; Synthesised; Thermally activated delayed fluorescence; Thermally activated delayed fluorescences; Organic light emitting diodes (OLED) |
顯示於: | 化學系 |
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