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2 Understanding the AIE Mechanism at the Molecular Level
Xiaoyan Zheng1 and Qian Peng2
1 Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
2 School of Chemical Sciences, University of Chinese Academy of Sciences, 100049 Beijing, China
2.1 Introduction
Traditionally, molecular aggregation tends to reduce fluorescence efficiency because of aggregation‐caused quenching (ACQ): the formation of nonemissive excimer, intermolecular charge transfer, or energy transfer to quenching sites through strong π–π stacking, which is a large obstacle to utilize a variety of efficient luminogens in the real world [1]. The opposite phenomenon, where the compounds are non‐ or low‐emissive in dilute solution but highly emissive in the aggregated phase (aggregates in solution, film, or crystalline phase), is termed as aggregation‐induced emission (AIE)