The general occurrence of fluorescence emission quenching in molecular aggregates is circumvented in select classes of molecules. This has largely been attributed to the rigidification of the molecule and its environment, which hinders non‐radiative excited state energy loss through structural relaxation; since such an effect should in principle apply to most aggregates and crystals, there must clearly be other critical factors that make the select molecules exceptional. Discovery of three crystalline structures of a new push–pull molecule in its enantiomorphic and racemic forms, exhibiting not only very high, but distinctly different solid state fluorescence enhancements, has now allowed a systematic investigation of the role of intramolecular and intermolecular excited state energy loss pathways. Crystallographic, spectroscopic and computational investigations provide a detailed appraisal of the assembly patterns in the crystals, and rigorous establishment of an inverse correlation between intermolecular energy transfer and solid state fluorescence. The study provides a clear visualization of the critical role of oriented molecular aggregation in solid state fluorescence efficiency enhancement.

中文翻译：

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建立定向聚集在分子固态荧光增强中的关键作用

在分子聚集体中避免了分子聚集体中荧光发射猝灭的普遍发生。这在很大程度上归因于分子及其环境的刚性化，这阻碍了通过结构弛豫产生的非辐射激发态能量损失。由于这种作用原则上应适用于大多数聚集体和晶体，因此显然必须存在其他使选择分子异常的关键因素。发现新的推挽分子的三种晶体结构，其对映体和外消旋体不仅表现出非常高的固态荧光增强，而且表现出明显不同的固态荧光增强，现在已经可以系统地研究分子内和分子间激发态能量损失的作用途径。晶体学 光谱和计算研究提供了晶体中组装模式的详细评估，并严格建立了分子间能量转移与固态荧光之间的反相关关系。该研究清楚地显示了定向分子聚集在固态荧光效率增强中的关键作用。