Highly red-emitting gold nanoclusters rapidly synthesized in aqueous phase: Effects of precursor quality and detection of Hg2+

Key Words:FLUORESCENT-PROBES; AU; NANOCOMPOSITES; CU2+; SIZE

Abstract:Metal nanoclusters have attracted considerable interest due to their unique fluorescence properties in the fields of environmental monitoring, chemical detection and biosensing. In this study, we developed a rapid synthesis method for highly red-emitting gold nanoclusters (AuNCs) via direct reduction of precursor HAuCl4 by sodium borohydride in presence of glutathione (GSH) at 0 degrees C. Our results demonstrated that the precursor quality had an important effect on the luminescence properties of the AuNCs, only the samples derived from high-purity precursors (99.9 % and 99.99 %) emitted strong red fluorescence. The obtained AuNCs can be excited in a broad range of 250-600 nm and can emit fluorescence of 560-730 nm. The maximum fluorescence quantum yield of the AuNCs derived from 99.99 % precursor achieved a high value of 9.98 %. Additionally, these fluorescent nanoclusters exhibited high selectivity toward Hg2+ by quenching. A linear calibration range of 10-100 mu M Hg2+ was demonstrated with a limit of detection (LOD) of 1.45 mu M using the as-obtained AuNCs as fluorescence probes, and in a narrowed range of 1-25 mu M Hg2+, a LOD of 0.13 mu M was determined using the diluted nanoclusters as probes. These results offer a significant reference for the synthesis and application of the AuNCs as fluorescence nanoprobes.

Volume:718

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Translation or Not:no