Synergistic effect between electroactive tetraphenyl-p-phenylenediamine and AIE-active tetraphenylethylene for highly integrated electrochromic/electrofluorochromic performances†
Switchable fluorescent materials have gained great attention due to their promising applications in sensors, memory devices and displays. However, further progress is hindered by the low fluorescence contrast, modest response speed and inferior long-term cycling stability. Based on a rational design strategy by combining a highly conjugated tetraphenyl-p-phenylenediamine (TPPA) unit and an aggregation induced emission (AIE)-active tetraphenylethylene (TPE) unit, we synthesized a novel diamine “N,N′-bis(4-aminophenyl)-N,N′-di(4-(1,2,2-triphenylethenyl)phenyl)-1,4-phenylenediamine” to construct an electro- and AIE-active polymer. In addition to the high efficiency solid-state fluorescence and the extremely stable redox properties, the resulting polymer TPE-TPPA-PA realized highly integrated emission/color dual-switchable properties, including multistage color-changing, high fluorescence on/off contrast up to 252, impressively rapid response rate (1.3/0.5 s for EC and 0.7/2.1 s for EFC processes) and excellent cycling stability over 10 000 s. The demonstrated synergistic effect between stable electroactive TPPA and AIE-active TPE may provide a new pathway for further molecular design to realize high-performance emission/color dual-switchable materials.