Designing ligand-enhanced optical absorption of thiolated gold nanoclusters

The optical spectra of thiolated Au-25(SR)(18)/Au-23(SR)(16) clusters with different R residues are investigated via TDDFT simulations. Significant enhancements in the optical region and effective electron delocalization are simultaneously achieved by tuning the ligands' steric hindrance and electronic conjugating features, producing a resonance phenomenon between the Au-S core motif and the ligand fragments.