title: Engineering the Interconnecting Position of Star-Shaped Donor-π-Acceptor Molecules Based on Triazine, Spirofluorene, and Triphenylamine Moieties for Color Tuning from Deep Blue to Green.
abstract: Pi-conjugated organic molecules featuring the donor-bridge-acceptor (D-π-A) structure have been widely used in semiconducting materials owing to their rigid structure, good thermal stability, excellent charge transfer, and high emission efficiency. To investigate the effect of the D-π-A molecular structure on the photophysical properties, in this contribution, three star-shaped D-π-A isomers based on the 2,4,6-triphenyl-1,3,5-triazine, spirofluorene, and triphenylamine moieties, that is, p-TFTPA, mp-TFTPA, and m-TFTPA, were synthesized by elaborately engineering the interconnecting position in the building-block units. The optophysical properties of these compounds were systematically explored by experiments and theory calculations. Definitively, changing the interconnecting position in these molecules played a significant role in the degree of π conjugation, which resulted in tunable emission colors from deep blue to green. Moreover, these isomers were employed as emissive dopants in organic light-emitting diodes. The highest external quantum efficiency of 2.3 % and current efficiency of 6.2 cd A(-1) were achieved by using the p-TFTPA based device. This research demonstrates a feasible way to realize blue emitters by engineering D-π-A conjugation.
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China. qiji830404@hotmail.com.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Wanhui
authors.initials: W
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Hunan Institute of Engineering, Xiangtan, 411104, P.R. China.
authors.forename: Jiyong
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan, Hubei, 430072, P.R. China. guohua.xie@whu.edu.cn.
authors.forename: Guohua
authors.initials: G
authors.lastname: Xie
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Yuanwei
authors.initials: Y
authors.lastname: Liao
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Zuoming
authors.initials: Z
authors.lastname: Qu
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Tan
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: College of Chemistry, Xiangtan University, Xiangtan City, Hunan, 411105, P.R. China.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Zhu
keywords: conjugation; donor-acceptor systems; interconnecting position; photophysics; solvatochromism