Journal ArticleDOI
The role of fluorine-substitution on the π-bridge in constructing effective thermally activated delayed fluorescence molecules
Yun Li,Jiao Jiao Liang,Hong Cheng Li,Lin-Song Cui,Man-Keung Fung,Stephen Barlow,Seth R. Marder,Chihaya Adachi,Zuo-Quan Jiang,Liang-Sheng Liao +9 more
TLDR
In this paper, two thermally activated delayed fluorescence (TADF) emitters were synthesized and compared to the previously reported molecule 9′-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9′H-9,3′:6′, 9′,9′-tercarbazole (TCTZ-F), which led to the highest photoluminescence quantum yield (PLQY).Abstract:
Two thermally activated delayed fluorescence (TADF) emitters 9′-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-fluorophenyl)-9′H-9,3′:6′,9′′-tercarbazole (TCTZ-F) and 9′-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2,6-difluorophenyl)-9′H-9,3′:6′,9′′-tercarbazole (TCTZ-2F) were synthesized and compared to the previously reported molecule 9′-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9′H-9,3′:6′,9′′-tercarbazole (TCTZ) to explore the possible effects of the fluorine atom(s) on the molecular conformation, electronic coupling between the donor and acceptor groups, and consequently the photophysical behavior of the emitters. Specifically, the TCTZ-F molecule was calculated to have a smaller dihedral angle than TCTZ-2F and a smaller S1–T1 gap than TCTZ, which led it to have the highest photoluminescence quantum yield (PLQY) among this series of compounds. An OLED fabricated with TCTZ-F as the emitter achieved the highest external quantum efficiencies (22.5%) of this series, indicating that fluorination can play a useful role in TADF emitters.read more
Citations
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Journal ArticleDOI
The role of host–guest interactions in organic emitters employing MR-TADF
Xiugang Wu,Bo Kang Su,Deng-Gao Chen,Denghui Liu,Chi Chi Wu,Zhi Xuan Huang,Ta Chun Lin,Cheng Ham Wu,Mengbing Zhu,Elise Y. Li,Wen-Yi Hung,Weiguo Zhu,Pi-Tai Chou +12 more
TL;DR: In this article, an investigation into a well-known thermally activated delayed fluorescence (TADF) material, DABNA-1, together with other new MR materials (9H-quinolino[3,2,1-kl]phenothiazin-9-one (QPO)) yields new insights regarding the origin of TADF.
Journal ArticleDOI
Rational Molecular Design of Highly Efficient Yellow-Red Thermally Activated Delayed Fluorescent Emitters: A Combined Effect of Auxiliary Fluorine and Rigidified Acceptor Unit
TL;DR: Organic light emitting device fabricated with the FDQCNAc and FBPCNAc emitters demonstrated high external quantum efficiency (EQE) of 27.6 and 25.4 % in the yellow-red TADF OLEDs, respectively.
Journal ArticleDOI
Blue TADF Emitters Based on Indenocarbazole Derivatives with High Photoluminescence and Electroluminescence Efficiencies.
Xialei Lv,Rongjuan Huang,Shuaiqiang Sun,Qing Zhang,Songpo Xiang,Shaofeng Ye,Panpan Leng,Fernando B. Dias,Lei Wang +8 more
TL;DR: It is demonstrated that the substituted position on the carbazole and different substituents in the same position have clear influence on the donor character of indenocarbazole derivatives, and thus excellent blue emitters can be obtained.
Journal ArticleDOI
Incorporating a tercarbazole donor in a spiro-type host material for efficient RGB phosphorescent organic light-emitting diodes
Xiang-Dong Zhu,Yuan-Lan Zhang,Yi Yuan,Qi Zheng,You-Jun Yu,Yun Li,Zuo-Quan Jiang,Liang-Sheng Liao +7 more
TL;DR: In this paper, a spiro-configured host 3,6-di(9H-carbazol-9-yl)spiro[indolo[3,2,1-de]acridine-8,9′-thioxanthene]10′,10′-dioxide (TCZSO2) incorporating 9′H-9,3′:6′, 9′′-tercarbazole and 9H-thoxanthene 10,10-dimioxide moieties is designed and synthesized.
Journal ArticleDOI
Electron spin resonance resolves intermediate triplet states in delayed fluorescence.
Bluebell H. Drummond,Bluebell H. Drummond,Naoya Aizawa,Yadong Zhang,William K. Myers,Yao Xiong,Matthew W. Cooper,Stephen Barlow,Qinying Gu,Leah R. Weiss,Leah R. Weiss,Alexander J. Gillett,Dan Credgington,Yong-Jin Pu,Seth R. Marder,Emrys W. Evans,Emrys W. Evans +16 more
TL;DR: In this article, the role of spin-vibronic coupling in TADF organic emitters using transient electron spin resonance spectroscopy was investigated, and it was shown that as the energy separation between local excitation and charge-transfer triplet states decreases, spin interconversion changes from a direct, singlet-triplet mechanism to an indirect mechanism involving intermediate states.
References
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TL;DR: In this article, a blue organic light-emitting diodes that harness thermally activated delayed fluorescence was realized with an external quantum efficiency of 19.5% and reduced roll-off at high luminance.
Journal ArticleDOI
Design of Efficient Thermally Activated Delayed Fluorescence Materials for Pure Blue Organic Light Emitting Diodes
Qisheng Zhang,Jie Li,Katsuyuki Shizu,Shuping Huang,Shuzo Hirata,Hiroshi Miyazaki,Chihaya Adachi +6 more
TL;DR: TADF has been characterized for a carbazole/sulfone derivative in both solutions and doped films and a pure blue organic light emitting diode (OLED) based on this compound demonstrates a very high external quantum efficiency (EQE) of nearly 10% at low current density.
Journal ArticleDOI
Highly efficient blue electroluminescence based on thermally activated delayed fluorescence.
Shuzo Hirata,Sakai Yumi,Kensuke Masui,Hiroyuki Tanaka,Sae Youn Lee,Hiroko Nomura,Nozomi Nakamura,Mao Yasumatsu,Hajime Nakanotani,Qisheng Zhang,Katsuyuki Shizu,Hiroshi Miyazaki,Chihaya Adachi +12 more
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Journal ArticleDOI
Anthraquinone-Based Intramolecular Charge-Transfer Compounds: Computational Molecular Design, Thermally Activated Delayed Fluorescence, and Highly Efficient Red Electroluminescence
Qisheng Zhang,H. Kuwabara,William J. Potscavage,Shuping Huang,Yasuhiro Hatae,Takumi Shibata,Chihaya Adachi +6 more
TL;DR: It is demonstrated that increasing the distance between donor (D) and acceptor (A) in intramolecular-charge-transfer molecules is a promising strategy for simultaneously achieving small ΔE(ST) and large k(F), which is in good agreement with those predicted by corrected time-dependent density functional theory.