Transmissive-to-black fast electrochromic switching from a long conjugated pendant group and a highly dispersed polymer/SWNT

Qiang Zhang, Chou-Yi Tsai, Taufik Abidin, Jyh-Chiang Jiang, Wan-Ru Shie, Lain-Jong Li, Der-Jang Liaw

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


In this study, a novel conjugated polymer, denoted as ECPblack, is synthesized. ECPblack demonstrated a unique electrochromic behavior with an ultrahigh contrast ratio (over 80%) in most of the visible regions, boasting an ultrahigh integrated contrast ratio of 71.8% between 380 nm and 880 nm. The long conjugated pendant group (pyrene) in ECPblack enhances the absorption in the blue region in its second oxidized state and results in transmissive-to-black electrochromic switching between the neutral state and the oxidized state. The transmissive-to-black electrochromic switching polymer with an ultrahigh contrast ratio could be especially attractive for applications in electronic displays. In addition, when polytriarylamine/nanotube (SWNT/P2) dispersion is doped in ECPblack, the response time of its electrochemical and electrochromic behaviors is further reduced. The electrochromic switching and bleaching time of SWNT/P2/ECPblack decreased by 73% and 80%, respectively. The improvement is caused by the phase separation of the rigid SWNT and the flexible polymer, which generates a rough surface morphology and provides more pathways for faster diffusion of counterions (ClO4-). The polymer/SWNT doping technique provides a simple way to accelerate ion diffusion in anodically coloring materials.
Original languageEnglish (US)
Pages (from-to)619-626
Number of pages8
JournalPolymer Chemistry
Issue number5
StatePublished - 2018

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We acknowledge the financial support of the Ministry of Science and Technology, Taiwan. We would like to thank Dr Prof. Yap Seong Shan's (Multimedia University, MMU - Cyberjaya Campus: Selangor, Malaysia) help to proofread the manuscript. We also thank Dr Prof. Bing-Joe Hwang's (National Taiwan University of Science and Technology, NTUST) for the electrochemical impedance spectroscopy measurement in this work.


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