title: Modulation of aggregation-induced emission and electroluminescence of silole derivatives by a covalent bonding pattern.
abstract: The deciphering of structure-property relationships is of high importance to rational design of functional molecules and to explore their potential applications. In this work, a series of silole derivatives substituted with benzo[b]thiophene (BT) at the 2,5-positions of the silole ring are synthesized and characterized. The experimental investigation reveals that the covalent bonding through the 2-position of BT (2-BT) with silole ring allows a better conjugation of the backbone than that achieved though the 5-position of BT (5-BT), and results in totally different emission behaviors. The silole derivatives with 5-BT groups are weakly fluorescent in solutions, but are induced to emit intensely in aggregates, presenting excellent aggregation-induced emission (AIE) characteristics. Those with 2-BT groups can fluoresce more strongly in solutions, but no obvious emission enhancements are found in aggregates, suggesting they are not AIE-active. Theoretical calculations disclose that the good conjugation lowers the rotational motions of BT groups, which enables the molecules to emit more efficiently in solutions. But the well-conjugated planar backbone is prone to form strong intermoelcular interactions in aggregates, which decreases the emission efficiency. Non-doped organic light-emitting diodes (OLEDs) are fabricated by using these siloles as emitters. AIE-active silole derivatives show much better elecroluminescence properties than those without the AIE characterisic, demonstrating the advantage of AIE-active emitters in OLED applications.
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China).
authors.forename: Han
authors.initials: H
authors.lastname: Nie
authors.affiliation: College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (P.R. China).
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China).
authors.forename: Changyun
authors.initials: C
authors.lastname: Quan
authors.affiliation: College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (P.R. China).
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (P.R. China).
authors.forename: Huayu
authors.initials: H
authors.lastname: Qiu
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China).
authors.forename: Rongrong
authors.initials: R
authors.lastname: Hu
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China).
authors.forename: Shi-Jian
authors.initials: SJ
authors.lastname: Su
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China).
authors.forename: Anjun
authors.initials: A
authors.lastname: Qin
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China). mszjzhao@scut.edu.cn.|College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (P.R. China). mszjzhao@scut.edu.cn.
authors.forename: Zujin
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (P.R. China). tangbenz@ust.hk.|Department of Chemistry, Division of Biomedical Engineering, Division of Life Science, The Hong Kong University of Science & Technology, Kowloon, Hong Kong (P.R. China). tangbenz@ust.hk.
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
keywords: aggregation; conjugation; density functional calculations; luminescence; structure-property relationships