Inversely Induced Circularly Polarized Luminescence of Achiral Luminophores in the Inner and Outer Surface Helical Nanotube

Co-assembling nanostructures with achiral luminescent moieties represents a significant approach for developing circularly polarized luminescence (CPL) materials. However, for chiral nanotube structures, it remains unclear whether their inner and outer surfaces exhibit equivalent induction effects. Here, enantiomeric C3-symmetric chiral methylphenylalanine derivatives were designed, and uniform supramolecular helical nanotubes were successfully fabricated. These helical nanotubes serve as host materials for the selective loading of achiral luminescent organic dye or inorganic quantum dots (QDs) into their inner channels or onto their outer surfaces via co-assembly. It was revealed that through chiral transfer, the achiral luminescent units acquired CPL activity upon integration with the chiral nanotubes, achieving dissymmetry factors (g_lum) on the order of 10^-2 to 10^-3, respectively. Interestingly, the CPL signals induced by the inner and outer surfaces exhibited opposite signs, with the signal from the inner surface being ten times stronger than that from the outer surface. Further structural analysis indicated that the concave geometry and nanoconfinement effects of the inner surface contributed to the CPL sign inversion and the enhanced luminescence dissymmetry. This work provides a novel and versatile platform for customizing the fluorescence and CPL properties of achiral luminescent units.