Luminous efficiency in polar environment and aggregated state, as well as high-contrast luminescence on/off switching under external stimuli are significant issues to be addressed in developing functional fluorescent materials. Combining the advantages of solvatochromic effect in intramolecular charge transfer (ICT) compounds with their nanostructured morphological effects, we herein report a series of A–π–D–π–A fluorene derivatives, which simultaneously exhibit negative solvatochromism, aggregation-induced emission (AIE) and mechanoresponsive luminescence (MRL) turn-on. These molecules contain the same fluorene donor (D) and 1,3-indandione acceptor (A) but differ in alkyl substituents in the 9-position of the fluorene segment, including 9,9-dibutyl (b-DIPF), 9,9-dioctyl (o-DIPF) and 9,9-didodecyl (d-DIPF). The emission colors of these compounds were changed from blue to orange-red, and the fluorescence quantum yields increased upon increasing the solvent polarity from nonpolar hexane to polar dimethyl sulfoxide. Due to the formed random nanostructured aggregates, the compounds exhibited AIE characteristics in THF/H₂O mixtures. Oppositely, their emission quenched 0D particles which were afforded by quick evaporation of their dichloromethane solvents under vacuum displayed remarkable mechanoresponsive luminescence turn-on behavior. Our results suggest that rationally design ICT molecules and control their nanostructures would be promising way for realizing multifunctional fluorescent materials.

极性环境和聚集状态下的发光效率，以及在外部刺激下的高对比度发光开/关切换是开发功能性荧光材料时要解决的重要问题。结合分子内电荷转移（ICT）化合物中溶剂致变色效应的优势及其纳米结构形态效应，我们在此报告了一系列A–π–D–π–A芴衍生物，它们同时表现出负溶剂致变色，聚集诱导发射（AIE ）和机械响应发光（MRL）开启。这些分子包含相同的芴供体（D）和1,3-茚满二酮受体（A），但在芴链段的9位烷基取代基不同，包括9,9-二丁基（b -DIPF），9,9 -二辛基（o-DIPF）和9,9-二十二烷基（d -DIPF）。这些化合物的发射颜色从蓝色变为橘红色，并且随着溶剂极性从非极性己烷增加到极性二甲基亚砜，荧光量子产率增加。由于形成了无规纳米结构的聚集体，因此该化合物在THF / H ₂ O混合物中显示出AIE特性。相反，通过在真空下快速蒸发二氯甲烷溶剂而获得的发射淬灭0D粒子表现出了显着的机械响应性发光开启行为。我们的结果表明，合理设计ICT分子并控制其纳米结构将是实现多功能荧光材料的有前途的方法。