Boosting electrochromic properties of polyamides through altering the structure bonded to triarylamine groups by xanthene

To obtain a high-performance material with large optical contrast, fast response, stable redox reversibility and easy processability simultaneously, a novel amine monomer, N1, N1'-(spiro(fluorene-9,9 & PRIME;-xanthene)-2,7-diyl)-bis (N1-(4-methoxyphenyl) benzene-1,4-diamine) (SFXMOPb-NH2) was designed and prepared by inserting xanthene group core into two electron-rich triarylamine (TAA) systems. Then, SFXMOPb-NH2 was polycondensed with various carboxylic acids to obtain three high-performance polyamides (PAs), namely SFXMOPb-OA, SFXMOPb-CA, and SFXMOPb-6F, respectively, in which the SFXMOPb-OA possesses excellent properties with good solubility and thermal stability, long cycle stability (cycle times up to 20,000 s and 2000 switching cycles), high coloring efficiency (CE, up to 463 cm2 C-1), and large optical contrast (& UDelta;T, up to 62%). Obvious color transformation from red to blue is obtained in an electrochromic device (ECD). These PAs also reveal memristors properties. It demonstrates that introducing twisted structure and ringlike ether into PAs could pave the way for design and preparation of molecules for fabrication of high-performance EC devices and memristors.