Achievement of silver-directed enhanced photophysical properties of gold nanoclusters

Abstract

Herein, we report the modified photophysical properties of luminescent bimetallic gold–silver nanoclusters based on synergism. The syntheses of the nanoclusters were carried out using the dopamine ligand. A blue shift of the emission peak with enhancement in intensity has been observed for bimetallic nanoclusters as compared to the case of gold nanoclusters in an aqueous solution. The increment in the emission intensity was found to be dependent on silver concentration for the bimetallic nanoclusters. A maximum five-fold increment in the fluorescence intensity has been observed at the silver to gold concentration ratio of 0.25 : 0.60. The ‘silver effect’ on the bimetallic nanoclusters is confirmed through the studies of fluorescence and absorption spectra. Physical characterization indicated the presence of Au(0) in monometallic gold nanoclusters and Au(I)/Au(0)–Ag(0) in bimetallic nanoclusters. The activity of dopamine and the stability of the as-synthesized nanoclusters in different organic solvents have been thoroughly discussed.