- Tetraphenylsilane group containing carbazoles as high triplet energy host materials for solution-processable PhOLEDs
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A series of solution processable, wide band-gap host materials composed of carbazole and tetraphenylsilane groups were designed and synthesized. Their thermal, electrochemical, and photophysical properties were fully investi- gated. The introduction of bulky tetraphenylsilane and tert-butyl groups around the carbazole led to high glass transition temperatures (Tg) between 120 and 204 ° C. The triplet energies (ET ) of the synthesized materials were examined by low temperature (77 K) photoluminescence studies and determined as ET > 2.6 for all compounds. Phosphorescent organic light-emitting devices with the ITO/PEDOT:PSS/EML/TPBi/Cs2CO3 /Al device structure were fabricated by using synthesized materials as the host and two kinds of phosphorescent emitters, FIrpic and Ir(ppy)3 , as the guests. The highest luminous and power efficiency values obtained by using FIrpic were 3.6 cd A -1 and 1.48 lm W -1 , respectively, with commission International de I'Eclairage (CIE) coordinates of (0.17, 0.36), whereas these values were 7.8 cd A -1 and 2.9 lm W -1 for the device structure when Ir(ppy)3 was used as the guest [CIE (0.28, 0.62)].
- ?ner, Saliha,?ner, Ilker,Akdag, Haydar,Varlikli, Canan
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p. 917 - 929
(2015/10/29)
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- Durene-decorated CBP derivatives as phosphorescent hosts and exciton-blocking materials for efficient blue OLEDs
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Two novel durene-containing molecules, 1,4-bis-[4-(9-carbazolyl)-phenyl]- durene (CPD) and 1,4-bis-{4-[9-(3,6-(di-tert-butyl)carbazoyl)]-phenyl}-durene (t-BuCPD), which are derived from 4,4′-bis(9-carbazolyl)biphenyl (CBP) by inserting durene in its biphenyl core, are designed and synthesized for use as host materials for blue phosphors in organic light-emitting diodes (OLEDs). Inserting durene in biphenyl causes a right-angle torsion between the durene and the adjacent phenyl groups due to the strong steric hindrance effect of the durene group, confining the effective π-conjugation on only one carbazole and one phenyl and increasing the triplet energies of CPD and t-BuCPD to over 3.0 eV. These durene-decorated molecules show higher thermal stabilities than many other CBP derivatives. Blue phosphorescent OLEDs were fabricated using CPD and t-BuCPD as triplet hosts and traditional iridium(iii)bis(4,6-(difluorophenyl) pyridinato-N,C2′)picolinate (Firpic) as a dopant and excellent performances were achieved. In particular, peak efficiencies of 26.2 cd A -1 and 14.8 lm W-1 were realized when CPD was used as both a host and exciton-blocking material. This is the first report using durene to tune the triplet energy levels of phosphorescent host materials.
- Deng, Lijun,Li, Jiuyan,Wang, Xinzeng,Zhang, Zhengchuan
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p. 19700 - 19708,9
(2020/08/31)
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- High triplet energy polymer as host for electrophosphorescence with high efficiency
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We report the conjugated polymer P(tBu-CBP) as a host with high triplet energy (ET 2.53 eV) and suitable HOMO (5.3 eV) and LUMO (2.04 eV) energy levels. Upon doping with green and red emission Ir-complexes, it gives devices with high luminous a
- Chen, Yen-Chun,Huang, Guo-Sheng,Hsiao, Chung-Chin,Chen, Show-An
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p. 8549 - 8558
(2007/10/03)
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