Dependence of ultrafast dynamics in gold–silver alloy nanoclusters on the proportion of the metal content

Abstract

Bimetallic nanoclusters (NCs) have attracted extensive attention in present research due to the synergic effect of the two kinds of metal atoms and their valuable applications. The broad range of applications of these noble metal NCs and their molecular nature instigated understanding their property of luminescence and the underlying ultrafast dynamics. With a view to enlighten the weakly known changes in excited state dynamics of luminescent noble metal alloy NCs, protein protected bimetallic alloy gold–silver NCs (Au–Ag NCs) with different molar ratios were synthesized and characterized. The results show that a particular optimum molar ratio of the two metal atoms gives maximum luminescence to the NCs. The findings from transient absorption spectroscopy and excited state decay analysis consolidated the results and provided detailed description in this direction. Various applications, such as optical energy harvesting, bio-medical imaging and photocatalysis, would find ample flexibility on knowing the characteristics of the alloy metal NCs that might lead to relevant modulations in their properties. The present study is intended to develop the concept of ultrafast dynamics in noble metal alloy NCs. Fluorescence intensity of gold–silver alloy nanoclusters is decided by an optimum molar ratio of the metals. One can synthetically impose maximum luminescence to the alloy nanoclusters knowing the underlying dynamics.