Mechanochromic fluorescence (MCF) materials are a sort of smart material whose photophysical properties are sensitive to mechanical stimulation, such as photoluminescence color, fluorescence quantum yield and emission lifetime. Recently, an increasing number of studies have shown that these photophysical properties can be affected greatly by the molecular packing and conformation, enabling the rapid development of functional materials with mechanochromic fluorescence properties. In this review, we focus on MCF materials with distinct emission properties and various molecular arrangements, especially the inherent correlation between molecular packing modes and emissive behaviors. Many of the selected representative examples possess polymorphism, offering the possibility of exploring different emissions from the exact molecular packing in single crystals. Correspondingly, some remarks are made on the outlook for the next developments in MCF materials and the required thinking about the structure–packing–performance relationship.

中文翻译：

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分子构象和堆积：它们在机械变色荧光材料发射性能中的关键作用

机械变色荧光（MCF）材料是一种智能材料，其光物理特性对机械刺激敏感，例如光致发光颜色，荧光量子产率和发射寿命。最近，越来越多的研究表明，这些光物理性质会受到分子堆积和构象的极大影响，从而使具有机械致变色荧光性质的功能材料得以快速发展。在这篇综述中，我们重点研究具有独特发射特性和各种分子排列的MCF材料，尤其是分子堆积模式与发射行为之间的内在联系。所选的许多代表性示例都具有多态性，提供了探索单晶中确切分子堆积产生的不同发射的可能性。相应地，对于MCF材料的下一步发展前景以及有关结构，包装和性能关系的必要思考，有一些评论。