Electropolymerized thiophene-based polymer with pure donor system enable magenta-to-transmissive electrochromic-supercapacitor bifunctional material.

• New strategy to disrupt planarity and obtain available color. • pQ3TQ exhibited magenta-to-transmissive with excellent EC performances. • Novel ECS bifunctional materials were prepared. • pQ3TQ has large area capacitance for 2.47 mF·cm−2. • Completing the CMY palette through electropolymerization. Developing electropolymerized magenta-to-transmissive electrochromic polymers is crucial in completing the CMY color palette. In this paper, three pure donor-type monomers (E3TE, Q3TQ and pro3Tpro) with various degrees of twisting blocks as peripheral electropolymerization units (EDOT/Prodot-Me 2 /proDot) and terthiophene (3T) as the central nucleus have been synthesized. Moreover, the corresponding polymers (pE3TE, pQ3TQ) were prepared via electropolymerization successfully. The electrochemical and electrochromic properties of both polymers were systematically investigated. Introducing the 3, 4-propylenedioxythiophene into 3T yields pQ3TQ with heightened degrees of twisting along the polymer backbone, slightly increasing the onsets of oxidation and blue-shifting the absorption precisely. The neutral polymer colors were fine-tunable from purple to magenta while maintaining transmissive oxidized states from pE3TE to pQ3TQ. The pQ3TQ has low oxidation potential (less than 1 V (E vs Ag/AgCl)), fast-switching time (0.63 s/0.29 s at 531 nm), reasonable optical contrast (31.9 % at 531 nm), good optical memory, excellent coloring efficiency (479.9 cm2/C), robust cycle stability (600 cycles) and large area specific capacitance (2.47 mF/cm2). This work provides a novel strategy to precisely disrupt planarity to obtain available color adjustment of electropolymerized polymer films and also provides an electrochromic-supercapacitor bifunctional material. [ABSTRACT FROM AUTHOR]