Fast microwave-assisted synthesis of AuAg bimetallic nanoclusters with strong yellow emission and their response to mercury(II) ions

A rapid, effective and environmental friendly method was developed for preparing strong yellow fluorescent AuAg bimetallic nanoclusters (BNCs). With microwave irradiation, bovine serum albumin (BSA)-stabilized AuAg BNCs could be synthesized in a one-pot procedure within several minutes. The synthesized BSA-AuAg BNCs were fully characterized by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, infrared spectroscopy, and photoluminescence spectroscopy. The mechanism of the formation of BSA-AuAg BNCs was also discussed in detail. Because the as-prepared BSA-AuAg BNCs display a good response to Hg²⁺, they have been potentially developed for the fabrication of fluorescent Hg²⁺ sensor. More importantly, due to the silver effect of Ag in the AuAg BNCs, the sensitivity of sensor prepared with BSA-AuAg BNCs is 6.3-fold higher than that prepared with BSA-Au NCs. Thus, this work highlights a new approach for the preparation of strongly fluorescent BNCs for the fabrication of highly sensitive fluorescence sensors.