Dual functional electrochromic/electrofluorochromic conjugated D-A polymer based on thieno[3,4-c]pyrrole-4,6-dione

Dual functional electrochromic (EC)/electrofluorochromic (EFC) materials play a pivotal role in wearable and smart electronic equipments. Developing new materials with high performance of EC/EFC properties is still a big challenge. Here a new D-A structure polymer PPDOTTPD based on thieno(3,4-c)pyrrole-(4,6)dione (TPD) was synthesized by Stille coupling, and the EC/EFC properties were investigated for the first time. PPDOTTPD film exhibits reversible color changes from purple neutral state to transparent colored state in the process of reversible redox. Photophysical and electrochemical studies revealed that the polymer has outstanding EC properties, including high optical contrast (52%), fast response time (0.5 s/0.7 s), high coloring efficiency (427.1 cm2 C-1) and good stability. What's more, PPDOTTPD exhibited EFC phenomenon. PPDOTTPD film showed an intense red near-infrared fluorescence with a peak of 672 nm, which gradually doped with the increase of applied potential with a maximum contrast ratio of 12.9. The EC/EFC dual-functional device based on PPDOTTPD was also successfully fabricated, which exhibited high optical and fluorescence contrast. The fine dual-functional performance indicates TPD can be further explored as potential acceptors for synthesizing high performance D-A molecules for intelligent optical devices.