The stability to oxygen-based treatments of Au nanocrystals (NCs) coated with different N -heterocyclic carbenes (NHCs) or dodecanethiol (DDT) was investigated. A dominant effect of the ligand type was observed with a significantly greater oxygen resistance of NHC-coated Au NCs compared to the thiol-based analogues. NHC-coated Au NCs are stable to 10 W oxygen plasma etching for up to 180 s whereas the integrity of DDT-coated Au NCs is strongly affected by the same treatment from 60–80 s. In the latter case, the average size of the NCs (from 2.6 to 6.3 nm) and the method of synthesis have no effect on the stability. NHC-coated Au NCs were found to generate of a lower amount of ligand-derived species under molecular oxygen treatment, which could account for the increased stability.
Source : Superior Oxygen Stability of N-Heterocyclic Carbene-coated Au Nanocrystals – Comparison with Dodecanethiol.
X.Ling, N. Schaeffer; S.Roland, M.P. Pileni Langmuir, 2015, 31, 12873-12882