Multi-colored electrochromic polymers based on BEDOT-pyridines

The poly{2,5-bis[2-(3,4-ethylenedioxythienyl)]pyridine} (PBEDOT-Pyr) family, which includes PBEDOT-Pyr, PBTh-PyrPyr (poly{5,8-bis(2-thienyl)-2,3-diphenylpyrido[3,4-b]pyrazine}), and PBEDOT-PyrPyr (poly{5,8-bis(3,4-ethylenedioxy-2-thienyl)-2,3-diphenylpyrido[3,4-b]pyrazine}), are presented as a new family of low band gap donor acceptor (D-A) polymers which exhibit multi-color electrochromism. Bandgaps for the polymers range from 1.9 eV for PBED()T-Pyr to 1.2 eV for PBEDOT-PyrPyr. BEDOT-Pyr has three color states: sky blue reduced, dark red neutral, and purple oxidized. PBEDOT-PyrPyr switches between a bright green neutral form and gray oxidized form.