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

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.