Fang Ming, Wei Wenjuan, Li Ruoxin, Mao Liucheng, Wang Yuanheng, Guan Yan, Chen Qiang, Shuai Zhigang, Wei Yen
Key Lab of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
MOE Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
Polymers (Basel). 2022 Jul 15;14(14):2880. doi: 10.3390/polym14142880.
The study of aggregation-induced emission luminogens (AIEgens) shows promising perspectives explored in lighting, optical sensors, and biological therapies. Due to their unique feature of intense emissions in aggregated solid states, it smoothly circumvents the weaknesses in fluorescent dyes, which include aggregation-caused quenching of emission and poor photobleaching character. However, our present knowledge of the AIE phenomena still cannot comprehensively explain the mechanism behind the substantially enhanced emission in their aggregated solid states. Herein, to systematically study the mechanism, the typical AIEgens tetraphenylethene (TPE) was chosen, to elucidate its photophysical properties, the TPE in THF/HO binary solvents, TPE in THF solvents depending on concentration, and the following direct conversion from a dissolved state to a precipitated solid state were analyzed. Moreover, the TPE derivatives were also investigated to supply more evidence to better decipher the generally optical behaviors of TPE and its derivatives. For instance, the TPE derivative was homogeneously dispersed into tetraethyl orthosilicate to monitor the variance of photophysical properties during sol-gel processing. Consequently, TPE and its derivatives are hypothesized to abide by the anti-Kasha rule in dissolved states. In addition, the factors primarily influencing the nonlinear emission shifting of TPE and its derivatives are also discussed.
聚集诱导发光发光体（AIEgens）的研究在照明、光学传感器和生物治疗等领域展现出了广阔的前景。由于它们在聚集固态中具有强烈发光的独特特性，顺利地规避了荧光染料的缺点，这些缺点包括聚集导致的发光猝灭和较差的光漂白特性。然而，我们目前对AIE现象的认识仍然无法全面解释其聚集固态中发光大幅增强背后的机制。在此，为了系统地研究该机制，选择了典型的AIEgens四苯乙烯（TPE），分析了其在THF/HO二元溶剂中的TPE、不同浓度下THF溶剂中的TPE以及随后从溶解状态直接转变为沉淀固态的光物理性质。此外，还对TPE衍生物进行了研究，以提供更多证据来更好地解读TPE及其衍生物的一般光学行为。例如，将TPE衍生物均匀分散到正硅酸乙酯中，以监测溶胶 - 凝胶过程中光物理性质的变化。因此，推测TPE及其衍生物在溶解状态下遵循反卡莎规则。此外，还讨论了主要影响TPE及其衍生物非线性发射位移的因素。
