P(TT-TPA) featuring a conjugated extended structure: enabling high-performance flexible electrochromic-supercapacitors

Electrochromic-supercapacitors (EC-SCs) based on conducting polymers hold broad application prospects in fields such as smart electronic devices, wearable devices, and the Internet of Things. However, complex structures generated by their large molecular weights severely deteriorate the disorder of chain arrangements, which significantly hinders the migration of charge carriers within the chains and exerts an adverse impact on the opto/electric performance. In this work, triphenylamine (TPA) is adopted as the scaffold, and thieno[3,2-<i>b</i>]thiophene (TT) groups are introduced to successfully construct TT-TPA (HTPA) with a conjugated extended structure. Leveraging the intermolecular π-π stacking effect effectively restricted the rotation of single bonds, significantly enhancing the molecular planarity. Concurrently, the introduction of multiple active sites opened up more channels for charge storage. The obtained P(TT-TPA) (PHTPA) films exhibit remarkable optical contrast (51% at 1050 nm) and outstanding energy storage capacity (177 F g^-1 at 1 A g^-1). The flexible devices based on PHTPA show significant color changes, excellent capacitive performance (46 F g^-1 at 1 A g^-1), and good bending resistance. In summary, the molecular design strategy of expanding the conjugated structure furnishes a certain theoretical foundation and referential significance for the development of EC-SC electrode materials that balance comprehensive performances.