A brighter light on gold integration in silver nanoclusters

Abstract

Bimetallic Ag29-xAuxLA12 clusters were successfully synthesized. A strong preference was seen for the monodoped Ag28Au cluster. The bimetallic clusters showed a two- to threefold increase in luminescence, so that the quantum yield increased from 3.1% to 7.2 %. Based on lifetime measurements at room temperature and at 4 K. it is proposed that this is due to the spin forbidden relaxation transition becoming less spin forbidden due to the gold atom enhancing spin-orbit coupling. Using electron spray ionisation mass spectrometry (ESI-MS) it was found that there is a strong preference for monodoped clusters. Using extended X-ray fine structure (EXAFS) spectroscopy it was determined that gold is preferentially incorporated in the central position of the cluster.