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Synthesis of Highly Fluorescent Silver Clusters on Gold(I) Surface

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journal contribution
posted on 12.02.2013, 00:00 by Mainak Ganguly, Anjali Pal, Yuichi Negishi, Tarasankar Pal
Evolution of fluorescence from a giant core–shell particle is new and synergistic, which requires both gold and silver ions in an appropriate ratio in glutathione (GSH) solution. The formation of highly fluorescent Ag2/Ag3 clusters on the surface of AuI assembly results in giant AuIcore–Ag0shell water-soluble microparticles (∼500 nm). Here, AuI acts as the template for the generation of fluorescent Ag clusters. The presence of gold under the synthetic strategy is selective, and no other metal supports such synergistic evolution. The core–shell particle exhibits stable and static emission (emission maximum, 565 nm; quantum yield, 4.6%; and stroke shift, 179 nm) with an average lifetime of ∼25 ns. The drift of electron density by the AuI core presumably enhances the fluorescence. The positively charged core offers unprecedented long-term stability to the microparticles in aqueous GSH solution.