Furan, Selenophene, and Thiophene‐Bridged Triphenylamine Polymer Films: A Systematic Chalcogen Study of Bifunctional Electrochromic Supercapacitor Electrodes

ABSTRACT

Bifunctional electrochromic supercapacitor devices (ESD), which integrate electrochromic and pseudocapacitive functionalities within a single electrode material, have emerged as a promising platform for intelligent energy management systems. However, the rational molecular design principles governing the simultaneous optimization of both functions remain insufficiently understood. Herein, we report a systematic chalcogen engineering strategy in which triphenylamine (TPA) is coupled with furan ( M1 ), selenophene ( M2 ), and thiophene ( M3 ) to yield three structurally analogous monomers electropolymerized on indium tin oxide (ITO) electrodes to afford the corresponding polymer films P1 , P2 , and P3 . By isolating the chalcogen heteroatom as the sole structural variable within an otherwise identical molecular framework, we establish comprehensive chalcogen‐dependent structure‐property relationships governing optical bandgap, charge transfer resistance, pseudocapacitive storage mechanism, electrochromic optical contrast, and polaron band position simultaneously. The thiophene‐bridged polymer P3 delivers the most favorable bifunctional performance, achieving a maximum areal specific capacitance of 10.63 mF/cm ² , energy density of 1.71 µWh/cm ² , and optical contrast of 66% (1100 nm), outperforming its furan and selenophene analogues. Asymmetric ESDs (AESDs) fabricated with PEDOT as the counter electrode further validates the practical device applicability of the optimized material. These results provide clear and transferable molecular design guidelines for next‐generation bifunctional electrochromic supercapacitor materials.