Polyamides containing triazine fused by triphenelamine with D-A block for improving performance of efficient and stable electrochromic/electrofluorochromic bifunctional device in display and camouflage

A highly efficient, stable electrochromic (EC) material with high photoluminiscent (PL) intensity contrast is crucial in EC/electrofluorochromic (EC/EFC) bifunctional devices (EC/EFCD) which play important role in display and camouflage. To solve this issue, we utilized non-planar triphenylamine (TPA) with electron-accepting triphenyltriazine (TPT) to construct novel electron-rich donor-electron-deficient acceptor (D-A) type diamine monomer, which was polymerized with three different diacid monomers to form three non-conjugated polyamides (PAs). TPT-TPA-CA film exhibits strong solid-state emission (φ^PL = 74 %), suitable for highly integrated EC/EFCD, maintaining not only high optical transmittance change (ΔT = 46 %) after cycling for 3000 s but also high PL intensity contrast (ΔPL = 70 %). Furthermore, these PAs are yellow in the neutral (bleached) state and green in the oxidized (colored) state during the EC process, demonstrating their potential for display and military camouflage. Especially, TPT-TPA-OA film exhibits good cycle stability (more than 15000 s), high ΔT (72 %), and fast response times (3.5 s/4.1 s for t_c/t_b). Moreover, due to strong emission, TPT-TPA-CA exhibits promising in the application of chemical sensors which has low limit of detection (LOD) for the explosive 2,4,6-Trinitrophenol (TNP) (LOD = 76 nM in solution and LOD = 304 nM in film). In summary, this research provides a novel approach for the field of EC/EFC displays and chemical sensors.