https://scholars.lib.ntu.edu.tw/handle/123456789/607218
標題: | Tetraphenyl ornamented carbazolyl disubstituted diphenyl sulfone as bipolar TADF host for highly efficient OLEDs with low efficiency roll-offs | 作者: | Gudeika D Bezvikonnyi O Masimukku N Volyniuk D Chen C.-H Ding W.-C Lee J.-H Chiu T.-L Grazulevicius J.V. JIUN-HAW LEE |
關鍵字: | 9H-carbazole;Diphenylsulfone;TADF OLED;Tetraphenyl;Thermally activated delayed fluorescence;Electroluminescence;Electron affinity;Energy transfer;Fluorescence;Glass transition;Ionization potential;Organic light emitting diodes (OLED);9h-carbazole;Carbazolyl;Diphenylsulphone;Lightemitting diode;Low efficiency roll offs;Organic light-emitting;Property;Thermally activated delayed fluorescences;Polycyclic aromatic hydrocarbons;Efficiency;Energy Transfer;Glass Transition Temperature;Rolls;Spectra;Thermal Stability | 公開日期: | 2021 | 卷: | 194 | 來源出版物: | Dyes and Pigments | 摘要: | Highly efficient organic light emitting diodes based on thermally activated delayed fluorescence were fabricated using 9,9'-(sulfonylbis([1,1':3′,1?-terphenyl]-5′,2′-diyl))bis(9H-carbazole) as a host. The best device demonstrated high maximum external quantum efficiency of 23.3%, maximum current efficiency of 67.7 cd/A, maximum power efficiency of 60.9 lm/W with low efficiency roll-off. These characteristics were achieved due to the utilization of bipolar TADF host with tetraphenyl ornamenting. The molecular design strategy used allowed to obtain OLED host with the required combination of properties, i.e. triplet harvesting ability, perfect host→guest energy transfer, emission not affected by intermolecular interaction (no excimer/exciplex formation), high triplet level (2.98 eV), bipolar charge transporting properties, thermal stability up to sublimation temperature of 467 °C, amorphous forming properties with high glass transition temperature of 153 °C, good charge injecting properties (ionization potential of 5.9 eV and electron affinity of 2.8 eV). When the compound was used as TADF emitter, practically the same electroluminescent spectra peaked at 430 nm were obtained for deep-blue OLEDs with both non-doped and doped emitting layers. Such untypical electroluminescent behaviour of TADF OLEDs is attributed to the restricted by phenyl substituents changes of dihedral angels between donor and acceptor moieties and to reduced posibilities of the formation of the different conformers and aggregates in solid state. ? 2021 Elsevier Ltd |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85110552562&doi=10.1016%2fj.dyepig.2021.109573&partnerID=40&md5=79742daba2ea9c07a4696ad53f8a1547 https://scholars.lib.ntu.edu.tw/handle/123456789/607218 |
ISSN: | 01437208 | DOI: | 10.1016/j.dyepig.2021.109573 |
顯示於: | 電機工程學系 |
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