Circularly Polarized Luminescence Chirality Inversion and Dual Anticounterfeiting Labels Based on Fluorescent Cholesteric Liquid Crystal Particles

The development of materials with circularly polarized luminescence (CPL) properties is a promising but challenging frontier in advanced materials science. Modulating the chiral properties of chiral polymers has also been a focus of research. Studies have been conducted to control the ground-state chirality of chiral polymers by adjusting the concentration of the chiral dopant. However, the chirality inversion of CPL of fluorescent liquid crystal particles by chiral dopant concentration has not been reported. Here, we report the preparation of fluorescent cholesteric liquid crystal (FCLC) particles that display polarizable structural color and CPL, demonstrating how varying the chiral dopant amount can reverse the CPL direction, leading to systems where the rotation directions of polarizable structural color and CPL either align or differ. This study confirmed the critical role played by the formation of the twist grain boundary phase in inducing the inversion of the ground-state chirality of FCLC particles and, subsequently, triggering the inversion process of CPL chirality. Furthermore, it leverages chiral structural color and fluorescence of FCLC particles to develop a sophisticated dual verification system. This system, utilizing both circularly polarized light and fluorescence, offers enhanced anticounterfeiting protection for high-value items.