Effect of ancillary ligands on the properties of heteroleptic green iridium dendrimers functionalized with carbazole dendrons
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- 作者：Junqiao Ding ; Jianhong Lü ; Yanxiang Cheng ; Zhiyuan Xie ; Lixiang Wang ; Xiabin Jing ; Fosong Wang
- 关键词：Iridium ; Homoleptic dendrimer ; Heteroleptic dendrimer ; Non-doped device
- 刊名：Journal of Organometallic Chemistry
- 出版年：2009
- 出版时间：1 August 2009
- 年：2009
- 卷：694
- 期：17
- 页码：2700-2704
- 全文大小：446 K
文摘
A series of heteroleptic green iridium dendrimers functionalized with carbazole dendrons, such as G2(pic) and G2(acac), have been synthesized, in which picolinic acid and acetylacetone are used as the ancillary ligands, respectively. Compared with the corresponding homoleptic iridium dendrimer G2 (8 % ), these heteroleptic ones can be prepared under mild conditions with total yields as high as 55–67 % . Both the dendrimer G2(pic) and G2(acac) display bright green emissions with photoluminescence quantum yields higher than 0.80 in toluene solution. As a result, a maximum external quantum efficiency of 7.1 % (21.0 cd/A) for G2(pic) and 7.7 % (25.8 cd/A) for G2(acac) has been realized based on non-doped device configuration. The state-of-art performance indicates that the heteroleptic dendrimers can be promising candidates used for non-doped electrophosphorescent devices, especially when the ease of synthesis in a large scale is considered.