Research on fluorescent materials is a hot topic in the scientific community because of their huge application potential. Numerous fluorophores have been developed for different applications. These fluorophores are often used as solid films or aggregates in practical applications. However, the emission of most of the conventional fluorophores is severely quenched upon aggregation, and this phenomenon is known as the aggregation-caused quenching (ACQ) effect. Although ACQ luminogens have been widely applied, complete utilization of these luminogens is still impossible because of the detrimental ACQ effect. Recently, a group of propeller-shaped molecules such as siloles and tetraphenylethene with a phenomenon named aggregation-induced emission (AIE) have been reported. These AIE...[ Read more ]

Research on fluorescent materials is a hot topic in the scientific community because of their huge application potential. Numerous fluorophores have been developed for different applications. These fluorophores are often used as solid films or aggregates in practical applications. However, the emission of most of the conventional fluorophores is severely quenched upon aggregation, and this phenomenon is known as the aggregation-caused quenching (ACQ) effect. Although ACQ luminogens have been widely applied, complete utilization of these luminogens is still impossible because of the detrimental ACQ effect. Recently, a group of propeller-shaped molecules such as siloles and tetraphenylethene with a phenomenon named aggregation-induced emission (AIE) have been reported. These AIE luminogens (AIEgens) exhibit weak or no fluorescence in the solution state but their fluorescence intensity is greatly enhanced when they form aggregates. Systematic studies and mechanistic analyses of these molecules suggested that the restriction of intramolecular motion (RIM) is the main reason the AIE effect. Although many works have been done to study its underlying mechanism, the research on AIE materials still have a long way to go. Our group has reported different applications of AIEgens such as optic devices, chemosensors, bio-imaging, theranostic, etc. AIEgens enjoyed the advantages of high brightness, excellent biocompatibility, and good photostability. Making use of these unique advantages, we designed several AIEgens and explored their biological applications. From Chapter II to IV, we developed a series of far-red AIEgens using the same core structure for specific lipid droplet imaging, antibacterial photodynamic therapy (PDT) and anticancer PDT, respectively. In Chapter V, we developed a tetraphenylethene based AIEgen for the quantification of soluble transferrin receptor. Finally, in Chapter VI, we developed a red-emitting AIEgen for lysosomal imaging.