Conversion of double layer charge-stabilized Ag@citrate colloids to thiol passivated luminescent quantum clusters.

A red luminescent silver cluster was synthesized in milligram quantities by the direct core reduction of the most widely studied class of large silver nanoparticles, namely silver@citrate of tens of nanometres diameter. No byproducts such as thiolates were detected, unlike in the case of typical methods of making such clusters. The route provides nearly pure clusters. The possibility to make diverse clusters from large nanoparticles expands the scope of cluster research.