Synthesis and characterization of stable electrochromic polyimides with quinolin-8-yloxy-substituted triphenylamine units

Herein, three kinds of electrochromic aromatic polyimides (PIs) were synthesized from 4,4′-diamino-4″-(quinolin-8-yloxy) triphenylamine (DAQTPA) with different dianhydrides, respectively. These PIs showed good thermostability below 450 °C even in air atmosphere. The maximum UV-vis absorption bands of PIs located at 321-338 nm for solid films. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the PIs were calculated from the cyclic voltammetry (CV) test as − 5.42 to − 5.44 eV and − 3.53 to − 3.85 eV, respectively. These PIs performed stable reversible electrochromic properties with optical transmittance change (ΔT) around 28-43% and coloration efficiency (η) around 74-117 cm2 C− 1.