Synthesis and characterization of fluorescent gold nanoclusters

The fluorescent gold nanoclusters (AuNCs) have been synthesized using aqueous reduction of chloroaric acid with mecapto undecanoic acid (MuA) as a thiol protecting agent. These AuNCs exhibited a strong absorption at 370 nm and a fluorescent emission in visible region. The emission spectrum can be tuned from 520 to 560 nm by controlling the NaOH concentrations during the reaction process. The gold nanoclusters exhibit a quantum yield of few percents and a fluorescence lifetime of ~2 ns. These properties of AuNCs provide greatly promising for biological applications.