Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence

doi:10.1002/adfm.200901615

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	Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence
	Tao, Youtian 1; Wang, Qiang 2; Yang, Chuluo 1; Zhong, Cheng 1; Zhang, Kai 1; Qin, Jingui 1; Ma, Dongge 2
刊名	ADVANCED FUNCTIONAL MATERIALS
	2010-01-22
卷号	20 期号:2 页码:304-311
ISSN号	1616-301X
DOI	10.1002/adfm.200901615
英文摘要	A series of bipolar transport host materials: 2,5-bis(2-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (o-CzOXD) (1), 2,5-bis(4-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (p-CzOXD) (2), 2,5-bis(3-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (m-CzOXD) (3) and 2-(2-(9H-carbazol-9-yl)phenyl)-5-(4-(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (op-CzOXD) (4) are synthesized through simple aromatic nucleophilic substitution reactions. The incorporation of the oxadiazole moiety greatly improves their morphological stability, with T(d) and T(g) in the range of 428-464 degrees C and 97-133 degrees C, respectively. The ortho and meta positions of the 2,5-diphenyl-1,3,4-oxadiazole linked hybrids (1 and 3) show less intramolecular charge transfer and a higher triplet energy compared to the para-position linked analogue (2). The four compounds exhibit similar LUMO levels (2.55-2.59 eV) to other oxadiazole derivatives, whereas the HOMO levels vary in a range from 5.55 eV to 5.69 eV, depending on the linkage modes. DFT-calculation results indicate that 1, 3, and 4 have almost complete separation of their HOMO and LUMO levels at the hole- and electron-transporting moieties, while 2 exhibits only partial separation of the HOMO and LUMO levels possibly due to intramolecular charge transfer. Phosphorescent organic light-emitting devices fabricated using 1-4 as hosts and a green emitter, Ir(ppy)(3) or (ppy)(2)Ir(acac), as the guest exhibit good to excellent performance. Devices hosted by o-CzOXD (1) achieve maximum current efficiencies (eta(c)) as high as 77.9 cd A(-1) for Ir(ppy)(3) and 64.2 cd A(-1) for (ppy)(2)Ir(acac). The excellent device performance may be attributed to the well-matched energy levels between the host and hole-transport layers, the high triplet energy of the host and the complete spatial separation of HOMO and LUMO energy levels.
语种	英语
出版者	WILEY-V C H VERLAG GMBH
WOS记录号	WOS:000274269300016
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/69449]
专题	中国科学院化学研究所
通讯作者	Tao, Youtian
作者单位	1.Wuhan Univ, Dept Chem, Hubei Key Lab Organ & Polymer Optoelect Mat, Wuhan 430072, Peoples R China 2.Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
推荐引用方式 GB/T 7714	Tao, Youtian,Wang, Qiang,Yang, Chuluo,et al. Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence[J]. ADVANCED FUNCTIONAL MATERIALS,2010,20(2):304-311.
APA	Tao, Youtian.,Wang, Qiang.,Yang, Chuluo.,Zhong, Cheng.,Zhang, Kai.,...&Ma, Dongge.(2010).Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence.ADVANCED FUNCTIONAL MATERIALS,20(2),304-311.
MLA	Tao, Youtian,et al."Tuning the Optoelectronic Properties of Carbazole/Oxadiazole Hybrids through Linkage Modes: Hosts for Highly Efficient Green Electrophosphorescence".ADVANCED FUNCTIONAL MATERIALS 20.2(2010):304-311.