Ligand-induced chirality and vacancy-rich Cu_xS nanoflowers enabling strong electromagnetic attenuation with ultrathin...

Developing ultrathin electromagnetic wave (EMW) absorbers with strong attenuation capability remains a critical challenge due to the difficulty in simultaneously optimizing impedance matching, dielectric dissipation, and structural polarization. Herein, ligand-induced chirality and vacancy-rich Cu_xS nanoflowers were constructed through a chiral amino acid-regulated self-assembly strategy using L/D-histidine and L/D-arginine as molecular inducers. The chiral ligands not only directed the asymmetric assembly of Cu_xS nanosheets into three-dimensional nanoflower architectures with distinct chiroptical activity, but also modulated the phase composition, surface electronic states, and sulfur vacancy concentration. Among the designed absorbers, D-arginine-modified Cu_xS nanoflowers exhibited the most favorable electromagnetic response, achieving a minimum reflection loss of approximately -66 dB at an ultrathin matching thickness of 1.52 mm. The superior absorption performance is attributed to the synergistic contribution of hierarchical conductive pathways, abundant sulfur-vacancy-induced dipole polarization, interfacial/space-charge polarization among interconnected nanosheets, and chirality-regulated asymmetric polarization pathways. Density functional theory calculations further reveal that sulfur vacancies promote charge redistribution and electronic delocalization, thereby strengthening carrier transport and polarization loss. This work demonstrates that chiral ligand engineering offers an effective route to manipulate defect chemistry and electromagnetic coupling in transition metal sulfides, providing a new strategy for designing lightweight, ultrathin, and high-efficiency EMW absorbers.