Stabilization and size control of gold nanoparticles during laser ablation in aqueous cyclodextrins

Femtosecond laser radiation has been used to ablate a gold target in aqueous β-cyclodextrin (CD) solutions to produce stable gold nanoparticle colloids with extremely small size (2 to 2.4 nm) and size dispersion (1 to 1.5 nm). On the basis of XPS and ζ-potential measurements, we propose a model involving chemical interactions between the gold and the CDs. The model includes both the hydrophobic interaction of the Au⁰ with the interior cavity of the CD and the hydrogen bonding of O^- groups on the partially oxidized gold surface with -OH groups of the CDs.