Low Bandgap Conjugated Polymers Based on a Nature-Inspired Bay-Annulated Indigo (BAI) Acceptor as Stable Electrochromic Materials

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• 作者：Bo He ; Wei Teng Neo ; Teresa L. Chen ; Liana M. Klivansky ; Hongxia Wang ; Tianwei Tan ; Simon J. Teat ; Jianwei Xu ; Yi Liu
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2016
• 出版时间：May 2, 2016
• 年：2016
• 卷：4
• 期：5
• 页码：2797-2805
• 全文大小：607K
• 年卷期：0
• ISSN：2168-0485

文摘

The donor–acceptor (D–A) approach, which is to incorporate alternating electron-rich (donor) and electron-deficient (acceptor) units along the conjugated polymer mainchain, has become an effective method to provide an informed search for high performance electrochromic low bandgap polymers. Herein a potent electron acceptor, namely, a much more soluble version of the nature-inspired bay-annulated indigo (BAI), was employed in the synthesis of two solution-processable donor–acceptor polymers for efficient electrochromic devices (ECDs). The devices fabricated from spin-coated polymer thin films can switch reversibly between deep blue and transmissive light green hues, with high optical contrasts in the visible and near-infrared (NIR) regions, good coloration efficiency and promising ambient stability. In particular, electrochromic devices based on the copolymer containing a carbazole donor unit exhibit optical contrasts of 41% and 59% in the visible and NIR regions, respectively, and a long-term stability of more than 7500 cycles under ambient conditions with limited reduction in optical contrasts. Such longer term ambient stability underlines the great potential of BAI-derived electron acceptors for the development of practical EC materials.