标题：Branched triphenylamine luminophores: Aggregation-induced fluorescence emission, and tunable near-infrared solid-state fluorescence characteristics via external mechanical stimuli
作者：Zhu, Huichao; Huang, Jianyan; Kong, Lin; Tian, Yupeng; Yang, Jiaxiang
作者机构：[Zhu, Huichao; Huang, Jianyan; Kong, Lin; Tian, Yupeng; Yang, Jiaxiang] Anhui Univ, Coll Chem & Chem Engn, Anhui Prov Key Lab Chem Inorgan Organ Hybri 更多
通讯作者地址：[Kong, L; Yang, JX]Anhui Univ, Coll Chem & Chem Engn, Anhui Prov Key Lab Chem Inorgan Organ Hybrid Func, Hefei 230601, Anhui, Peoples R China;[Yang, J 更多
来源：DYES AND PIGMENTS
关键词：Branched luminophores; Aggregation-induced fluorescence emission;; Tunable near-infrared solid-state fluorescence behavior;; Crystallization-induced fluorescence enhanced
摘要：Three AIE-active branched luminophores (defined as 4a, 4b and 4c) containing triphenylamine and carbazole units forming intramolecular charge transfer (ICT) states have been developed. The studies of the mechanical stimuli effect on solid state showed that the branch number can affect effectively the performance of the tunable fluorescence in the solid state. Interestingly, only compound 4a displayed a distinct bathochromic shift of its fluorescence emission from the visible (lambda(em) = 598 nm) to the near-infrared section (lambda(em) = 643 nm) by mechanical stimuli. Moreover, 4a exhibited an obvious crystallization-induced emission enhancement (CIEE) effect. The crystal samples of 4a emit strong orange light with 49.8% solid-state fluorescence quantum yield (Phi(F)) and the amorphous showed decreased red emission with 7.6% (Phi(F)). Mechanical grinding and organic solvent stimuli can reversibly change the phase transition between crystalline and amorphous states. However, compounds 4b and 4c are not sensitive to the mechanical stimuli, because it is difficult for them to form crystalline structure due to bigger steric hindrance effect. The mechanism for their solid-state fluorescence behavior was investigated in detail by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) analysis.