Influence of Color-Center Electronegativity on Circular Dichroism in Single-Walled Carbon Nanotubes.

Covalently functionalized single-walled carbon nanotubes (SWCNTs) have emerged as attractive quantum photonic materials due to their highly tunable optical properties and efficient single-photon emission capabilities. Recent progress in engineering chiral defects has motivated exploration of these systems for tunable circularly polarized photoluminescence. While electronegative defect adducts, such as fluorinated species, induce larger emission redshifts than their electroneutral counterparts, their impact on chiroptical properties remains poorly understood. Here, we theoretically demonstrate that electronegative defects enhance electronic circular dichroism (CD) responses by over 2 times and increase dissymmetry factors (g factors) by more than 2.5 times. Using transition chiral tensor methodology, we identify the atomistic origins of this enhancement, revealing that it arises from substantially increased magnetic transition dipole moment contributions driven by improved electric-magnetic dipole alignment. These results establish atomistic structure-property relationships linking defect chemistry to chiroptical activity and provide design principles for engineering CD responses in functionalized SWCNTs for advanced photonic applications.