Charge-Directed Self-Assembly of Carbon Dot-Loaded Cellulose Nanocrystal Chiral Superstructures With Tailorable Circularly Polarized Luminescence.

Abstract

Surface charge critically influences the self-assembly and functional performance of colloidal liquid crystals. However, in circularly polarized luminescence (CPL) systems, the regulatory role of guest surface charge in their self-assembly remains fundamentally unclear, hindering the rational design of adjustable high-performance CPL materials. Herein, we judiciously synthesize a series of positively and negatively charged carbon dots (P-/N-CDs) with satisfactory solid-state emission and incorporate them into colloidal cellulose nanocrystal (CNC) liquid crystal with phase adjustability via evaporation-induced self-assembly (EISA). By precisely modulating the surface charge of CDs, the resulting P-/N-CD-loaded CNC (P-/N-CDCNC) chiral superstructures exhibit tailorable CPL with luminescence dissymmetry factor values from +0.16 to -0.91. The decisive role of surface charge in the EISA process is further elucidated. In situ microscopy demonstrates divergent charge-directed assembly pathways: N-CDs allow CNC tactoid fusion to proceed, whereas P-CDs arrest fusion through electrostatic crosslinking. This triggers unprecedented Janus P-CDCNC superstructures, leading to side-dependent CPL handedness. Such CDCNC superstructures with different polarization states are readily designed to patterns and sophisticated codes, which offer powerful avenues for high-security anticounterfeiting and multilevel information encryption. This work pioneers guest charge modulation as a universal strategy for controlling chiroptical assembly, overcoming limitations to attain handedness-adjustable, high-performance CPL from natural chiral materials.