Multi‐Amino Triarylamines for Electrochromic and Electrofluorochromic Applications with Exceptional Stability and Extraordinary Fluorescence Modulation

This study investigates arylamine small molecules functionalized with multiple primary amino groups and various extended π bridges ( TPPA‐2N , TPPA‐4N , and TPB‐4N ) to evaluate their opto‐electrochemical behaviors. TPPA‐4N exhibits polyelectrochromic features and outstanding stability during continuous cyclic voltammetry scans, maintaining 99.0% reversibility after 15 000 cycles and 95.2% reversibility after 10 000 cycles at the first and second oxidation states, respectively. After being fabricated into devices, the TPPA‐4N/HV device retains 96% stability after 1000 switching cycles at the first oxidation state and 500 cycles at the second oxidation state, respectively. In addition, the TPPA‐4N/HV device also exhibits a blue emission at the neutral state with an exceptional intensity contrast ratio (ICR) of up to 950‐fold for electrofluorochromic (EFC) applications, resulting from well‐controlled absorption‐emission modulation that causes the self‐absorption effect. Additionally, the TPB‐4N/HV device reveals a moderate ICR of 393‐fold. By blending TPPA‐4N and TPB‐4N , the resulting EFC device exhibits a highly reversible two‐stage EFC behavior, transitioning from lime to olive green emission and then completely quenching with gratifying ICR values at each emitting color.