Dimeric phenanthroimidazole for blue electroluminescent materials: the effect of substituted position attached to biphenyl center.
Two isomers of 4,40-bis(1-phenyl-phenanthro[9,10-d]-imidazol-2-yl)biphenyl (BPPI), L-BPPI and Z-BPPI were prepared by tuning the substituted position on the biphenyl from para- to meta-coupling. Because of the conjugated degree change at the C2-position in the phenanthroimidazole block, the fluorescent color of L-BPPI (433 nm) and Z-BPPI (402 nm) showed an obvious blue-shift compared with that of BPPI (468 nm) in the films. Meanwhile, their non-doped devices exhibited more valuable and stable deep-blue emissions with a CIE coordinate of (0.16, 0.10) and (0.16, 0.11), respectively. Furthermore, some valuable information on structure–properties was obtained by density functional theory calculations, and photophysical and electrochemical characterization.
School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang, 111003, P. R. China. wangzhm1983@163.com.
Zhiming
Z
Wang
Ying
Y
Feng
Hui
H
Li
Zhao
Z
Gao
Xiaojuan
X
Zhang
Ping
P
Lu
Ping
P
Chen
Yuguang
Y
Ma
Shiyong
S
Liu