Electrofluorochromism has attracted great attention due to the intelligence optoelectronic and sensing applications. The intrinsically switchable fluorophores with high solid-state fluorescence are regarded as key for ideal electrofluorochromic materials. Here, we reported an AIE-active polyamide with diphenylamine and tetraphenylethylene units, showing high fluorescence quantum yield up to 69.1% for the solid polymer film and stable electrochemical cycling stability. The polyamide exhibited reversible color and emission switching even in hundreds of cycles, and the fluorescence on/off contrast ratio was determined up to 417, which is the highest value to our knowledge. Furthermore, as the response time is vital for the real-life applications, to speed up the response of electrofluorochromism, a porous polymer film was readily prepared through a facile method, notably exhibiting high fluorescence contrast, long-term stability and obviously improved response, due to the sharply increased surface area. Therefore, the AIE-functionalization combining the porous structure strategy will synergistically and dramatically improve the electrofluorochromic performance, which will also promote their practical applications in the near future.

A novel semi-aromatic polyamide with bis(diphenylamino)-fluorene moieties was designed and synthesized, which exhibited highly stable electrochromic/electrofluorescent dual-switching properties.

Multiple stimuli-responsive fluorescent materials have gained increasing attention for their fundamental investigation and intelligent applications. In this work, we report design and synthesis of a novel polyamic acid bearing oligoaniline, triphenylamine, and fluorene groups, which served as sensitive units and fluorescence emission unit, respectively. The resulting polymer exhibits multiple stimuli-responsive fluorescence switching behavior triggered by redox species, pH, electrochemical, and pressure stimuli. Every fluorescence switching mechanism upon each stimulus was studied in detail. The interactions and energy transfer between sensitive units and emission unit are largely responsible for this fascinating fluorescent switching behavior. This work provides a deep understanding of the optical switching essence upon these stimuli, opening the way for the development of new fluorescent sensing applications.

Electrofluorochromic (EFC) materials have aroused great interest owing to their interesting ability of tuning fluorescence in response to the applied potential. However, some crucial characteristics, such as response speed, fluorescence contrast, and switching stability, are still not well realized to meet the requirements of practical applications. Herein, we designed and synthesized a novel polyamide-bearing aggregation-induced emission (AIE)-active tetraphenylethylene (TPE) and a highly conjugated triphenylamine (TPA) pendant group. The rational combination of the highly conjugated TPA and TPE caused the resultant polymer to exhibit highly integrated electrochromic (EC) and EFC performances including multiple color-changing (colorless to green to blue), fast response speed (1.8/1.1 s for EC and 0.4/2.9 s for EFC process), high fluorescence contrast (82 at the duration time of 20 s), and excellent long-term stability over 300 cycles. The strategy of AIE functionality by combing a highly conjugated redox unit demonstrates a synergistic effect to prepare high-performance emission/color dual-switchable materials, greatly promoting their applications in sensors, smart windows, and displays.