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Single Au Atom Doping of Silver Nanoclusters
摘要： Ag29 nanoclusters capped with lipoic acid (LA) can be doped with Au. The doped clusters show enhanced stability and increased luminescence efficiency. We attribute the higher quantum yield to an increase in the rate of radiative decay. With mass spectrometry, the Au-doped clusters were found to consist predominantly of Au1Ag28(LA)12 3 – . The clusters were characterized using X-ray absorption spectroscopy at the Au L3-edge. Both the extended absorption fine structure (EXAFS) and the near edge structure (XANES) in combination with electronic structure calculations confirm that the Au dopant is preferentially located in the center of the cluster. A useful XANES spectrum can be recorded for lower concentrations, or in shorter time, than the more commonly used EXAFS. This makes XANES a valuable tool for structural characterization.
关键词： x-ray spectroscopy,structure elucidation,doping,Au1Ag28,Ag29,luminescence,bimetallic nanocluster
更新于2025-09-23 15:21:01
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Insights into the Synthesis Mechanism of Ag <sub/>29</sub> Nanoclusters
摘要： The current understanding of the synthesis mechanisms of noble metal clusters is limited, in particular for Ag clusters. Here, we present a detailed investigation into the synthesis process of atomically monodisperse Ag29 clusters, prepared via reduction of AgNO3 in the presence of dithiolate ligands. Using optical spectroscopy, mass spectrometry and X-ray spectroscopy, it was determined that the synthesis involves a rapid nucleation and growth to species with up to a few hundred Ag atoms. From these larger species, Ag29 clusters are formed and their concentration increases steadily over time. Oxygen plays an important role in the etching of large particles to Ag29. No other stable Ag cluster species are observed at any point during the synthesis.
关键词： synthesis mechanism,Ag29 nanoclusters,optical spectroscopy,X-ray spectroscopy,mass spectrometry
更新于2025-09-23 15:21:01