Synthesis and Properties of Donor-Acceptor Type Electrochromic Materials Based on Triphenylamine and Quinoxaline

Recently, electrochromic devices based on donor-acceptor (D-A) type conjugated polymers have received great attention, owing to their fast response rate, tunable color, good cycle stability, and so on. Two novel donor-acceptor-donor (D-A-D) type monomers N-(4-(5-(4-(diphenylamino)phenyl)-2,3-dimethylquinoxalin-8-yl)phenyl)-N-phenylbenzenamine (Q1) and N-(4-(6-(4-(diphenylamino)phenyl)-1,2,3,4-tetrahydrophenazin-9-yl)phenyl)-N-phenylbenzenamine (Q2) using triphenylamine as electron donor and quinoxaline-based moiety as electron acceptors were designed, which were further electrochemical polymerized to prepare D-A type electrochromic polymers poly(N-(4-(5-(4-(diphenylamino)phenyl)-2,3-dimethylquinoxalin-8-yl)phenyl)-N- phenylbenzenamine) (PQ1) and poly(N-(4-(6-(4-(diphenylamino)phenyl)-1,2,3,4-tetrahydrophenazin-9-yl)phenyl)-N-phenylbenzenamine) (PQ2), respectively. The as-prepared D-A type polymers exhibited pale yellow in the neutral state, and multicolor change with the increase of the applied potentials. These novel electrochromic materials showed fast switch rate, good cycle stability as well as good coloration efficiency. Moreover, the highest contrast ratio of both exceeded 70% around 780 nm, which guaranteed their potential practical applications.