- Synthesis of symmetrical dicarbazole-biphenyls, components of phosphorescentorganic light-emitting diodes (PHOLEDs) using organocuprates
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An effective one-stage method is proposed for obtaining symmetrical dicarbazole-biphenyls, components of phosphorescent organic light-emitting diodes through organocuprates of the corresponding N-(bromophenyl)carbazoles. The reaction products were obtained in moderate to high yields.
- Zyryanov,Kovalev,Egorov,Rusinov,Chupakhin
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- Simple CBP isomers with high triplet energies for highly efficient blue electrophosphorescence
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Two simple CBP isomers, namely m-CBP and o-CBP, were designed and synthesized by finely tuning the linking topology between the carbazole and the central biphenyl units of CBP, and their thermal, photophysical and electrochemical properties were investigated. Such simple modification of the linking topology endows the CBP isomers with high triplet energy and relative high thermal and morphological stability. The high triplet energies of m-CBP and o-CBP ensure efficient energy transfer from the host to the phosphor and triplet exciton confinement on the phosphor, as indicated by the transient photoluminescence decay of 3 wt% FIrpic doped into m-CBP and o-CBP. Blue phosphorescent devices employing FIrpic as guest and the two CBP isomers as hosts exhibit high efficiencies. The best EL performance is achieved for the o-CBP-based device, with a maximum current efficiency of 29.9 cd A-1, and a maximum external quantum efficiency of 14.2%, which are over 2 times higher than those of CBP.
- Gong, Shaolong,He, Xun,Chen, Yonghua,Jiang, Zuoquan,Zhong, Cheng,Ma, Dongge,Qin, Jingui,Yang, Chuluo
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- Synthesis of substituted 4,4′-dihalobiphenyls and their use for the preparation of isomeric bis(carbazolyl)biphenyls
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Model compounds of some polychlorobiphenyl congeners, viz., 4,4′-dihalobiphenyls, were synthesized. These compounds can be successfully utilized by a chemical method for the in situ generation of arynes followed by the reaction with carbazole in order to prepare appropriate bis(carbazolyl)biphenyls as components for molecular electronics and OLED devices.
- Kovalev,Pavlyuk,Zaripov,Zyryanov,Kopchuk,Rusinov,Chupakhin
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p. 1978 - 1981
(2016/05/11)
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- Meta-linked CBP-derivatives as host materials for a blue iridium carbene complex
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We present four derivatives of 4,4′-bis(9-carbazolyl)biphenyl (CBP) for the use as host materials in blue phosphorescent organic light emitting diodes. By replacing the para-linkage by a meta-linkage of the carbazole substituents at the central biphenyl unit materials with improved thermal and optical properties are obtained. The triplet energy of the meta-linked host materials is significantly increased to more than 2.90 eV compared to 2.58 eV for the para-linked CBP. Moreover, selective methyl substitution of the basic meta-CBP structure leads to materials with high glass transition temperatures up to 120 °C and electrochemical stability of the oxidised species against dimerisation. The high triplet energy allows the use of the meta-CBP derivatives as host materials for the carbene emitter mer-tris(N-dibenzofuranyl-N′- methylimidazole)iridium (III) (Ir(dbfmi)) with a pure blue emission at 450 nm.
- Schr?gel, Pamela,Langer, Nicolle,Schildknecht, Christian,Wagenblast, Gerhard,Lennartz, Christian,Strohriegl, Peter
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experimental part
p. 2047 - 2055
(2012/04/05)
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