Recent Progress in the Development and Applications of Molecular Materials Based on Vibration-Induced Emission (VIE)

Owing to the outstanding optical properties, fluorescent materials have become an important chemical tool for the advancement of modern science and technology. Fluorescence-based probes have also shown promise for a wide variety of biomedical applications. The development of new fluorescent probes relies on the exquisite design of high-performance emissive materials. However, traditional fluorescent dyes suffer from aggregation-caused quenching in aqueous solutions, lead to the production of false-positive and false-negative signals in biological systems. As a consequence, the development of emissive materials with an enhanced performance in aqueous media is a challenging task for both the academic and industrial communities. In particular, the organic fluorescence dyes developed to date generally emit a single fluorescence, which is easily interfered by the complexity of surrounding micro-environment. In the past few years, the development of the so-called ratiometric probes, which can exhibit two spectroscopically differentiated fluorescence emissions, has become a topical research area for the design of optical materials and sensors. Vibration-induced emission (VIE) is a new photophysical phenomenon originally coined by Tian’s group, which describes the unique fluorescence property of 9,14-dihydrodibenzoa,cphenazine derivatives that show a dual-fluorescence emission at ca. 600 nm and 460 nm corresponding to their free and restricted conformational state, respectively. By exquisitely tuning the vibrionic state of VIEgens, the effective development of state-of-the-art organic photoelectric materials, fluorescent probes and supramolecular organic gels has been possible. In this review, the synthesis and photophysical mechanisms of VIE-based compounds will be discussed. The successful use of VIEgens for the development of functional materials will be highlighted. A perspective on the future direction of how VIEgens can be used to construct chemical probes for biological studies and disease diagnosis is given.