Synthesis and study of the quantum-confinement effect of gold-nanoclusters via optical properties protected by 2-phenylethanethiol ligand

Herein, gold-nanoclusters Au 6 (SR) 6 are synthesized in the argon atmosphere, using 2-phenylethanethiol and tetraoctylammonium bromide, as ligands and surfactants, respectively. Au 6 (SR) 6 possesses ca. 1.95 eV HOMO-LUMO gap, which is comparatively high and is also a dominant factor for quantum confinement effect. Moreover, the X-ray Photoelectron Spectroscopy (XPS) study shows the peak of Au 4f 7/2 appears at 86.89 eV, which describes the consistency regarding the size of clusters with XPS peak shift for Au 4f 7/2 value. In addition, the full width half maximum (FWHM) increases accordingly by decreasing the size of clusters.