Novel core-substituted naphthalene diimide-based conjugated polymers for electrochromic applications

Abstract

A novel core-substituted naphthalene diimide derivative (DPyNDI-TPA) capped with electroactive triphenylamine was employed as an electroactive precursor to prepare p(DPyNDI-TPA) polymer films through in situ electropolymerization on FTO substrates. In contrast to the non-core-substituted NDI-TPA, the introduction of pyrrolidine groups endows the p(DPyNDI-TPA) films with a distinct morphology and a capability of ionization. Under an electric field, the pyrrolidine group could release an electron and combine with counterions in the electrolyte solution. Moreover, compared with the p(NDI-TPA) films, the wrapped counter anions in the p(DPyNDI-TPA) films could serve as balancing charges in electrochromic processes, which provide the film with a much better electrochromic performance (e.g., switching stability, coloring–bleaching speed and coloration efficiency). This meaningful design provides new concepts for the design of organic electrochromic materials and shows great prospects in optoelectrical materials.