Electrochromic materials based on novel polymers containing triphenylamine units and benzo[c][1,2,5]thiadiazole units

Six novel electrochromic (EC) polymers containing triphenylamine units and benzo[ c ][1,2,5]thiadiazole (BTD) units, coded as TPABTA, TPABTD, TPABTD-a, TPABTD-b, TPABTD-c and TPABTD-d, were successfully synthesized through polymer condensation reaction and their electrochromic properties were characterized in detail. The films of these polymers exhibited reversible color changes, high optical transparency, good solubility in many organic solvents and good coloration efficiency. Among them, the TPABTD-b film showed a set of reasonable electrochromic features, including high coloration efficiency (270 cm 2 ·C -1 ), appropriate transmittance change (23 % at 849 nm) and a relatively longer response time in bleaching process (t b  = 3.7 s).