Modulation of the solid-state luminescent properties of conjugated polymers by changing the connecting points of flexible boron element blocks

Abstract

Flexible molecules are unfavorable for designing luminescent dyes because their excitation states rapidly decay through molecular motions. We recently found that some flexible boron complexes, which potentially show a larger degree of structural relaxation in the excited state, and their polymers exhibit unique optical properties with high environmental sensitivity, such as aggregation-induced emission and luminochromism triggered by external stimuli, upon the addition of structural restrictions. Moreover, these optical properties were drastically changed by modulating the connecting points in the polymers. In this review, recent progress in the development of luminescent polymer films with stimuli responsiveness is illustrated. In particular, the influence of the alteration of connecting points on luminescent behaviors is explained. Polymerization is a versatile strategy not only for transforming a class of nonemissive molecules into luminescent dyes but also for precisely regulating the optical properties of film materials; the resulting materials are promising for application as scaffolds for advanced chemical sensors.