Synthesis of oleophilic chiral chalcogenide quantum dots via ligand engineering

Chiral chalcogenide quantum dots (QDs) are typically prepared by coupling chiral ligands to the QD surface via aqueous-phase synthesis, water/oil interface-mediated synthesis, or post-synthetic ligand exchange. However, the hydrophilic nature of conventional chiral ligands restricts the chiral QDs to polar solvents, limiting their processability. The synthesis of oleophilic chiral chalcogenide QDs remains an unmet challenge. Here, we present a ligand design strategy that grafts chiral amino acids with long alkyl chains, preserving their chiral integrity and coordination capacity while conferring oleophilic solubility. Using this approach, we successfully prepared various chiral chalcogenide QDs that can be stably dispersed in nonpolar solvent. Quantum-confinement-tunable (size-dependent) circular dichroism (CD) spectra were achieved in chiral CdS and CdSe QDs. Notably, the thioether-containing chiral ligands (L/D-Cys-2C₁₂) can concurrently act as sulfur sources, permitting direct synthesis of oleophilic chiral sulfide QDs. It opens a new avenue for the synthesis of oleophilic chiral chalcogenide QDs and therefore expands their application prospects.