From gas separation to ion transport in the cavity of hyperbranched polyamides based on triptycene aimed for electrochromic and memory devices

Abstract

With the aim to obtain robust electrochemical cycling stability which is crucial for the application of smart electrochromic devices (ECDs), we propose an effective strategy by introducing three-dimensional (3D) star-shaped triptycene as a core binding with methoxy-diphenylamine. This design allows fast ion transport, reduces the respiration effect and prevents the electroactive polymer film from peeling off. A series of hyperbranched polyamides (HBPAs) (denoted as T3TPA-CA, T3TPA-6F and T3TPA-OA) containing triptycene with excellent electrochemical stability of up to 10 000 s continuous cycles without degradation were synthesized and characterized. The soluble T3TPA-OA shows a high contrast of 65% at 780 nm with a colouring efficiency of 206 cm² C⁻¹ which is distinguished from conventional HBPAs. In addition, the HBPAs have incredible memory characteristics with a current switching ratio of 1.5 × 10⁴. It is expected to be used in smart display devices and storage devices.