Preparation of fluorescent sensors based on metal nanoclusters and their composites for mercury ion and temperature monitoring in aqueous environment

In the last decade, nanoclusters and carbon dots have been a promising class of nanomaterials with a wide range of potential applications in different industrial fields, through their favorable fluorescence properties for a variety of applications, especially in temperature detection and metal ion detection. In this study, sensitive detection of Hg 2+ and temperature was achieved by metal nanoclusters and carbon dots. Well-stabilized red fluorescent gold nanoclusters (AuNCs) were successfully prepared using a one-pot hydrothermal method, and Hg 2+ ions strongly quenched the fluorescence emission of AuNCs. Subsequently, we used this finding to develop a fluorescent nanoprobe for Hg 2+ detection, in which the fluorescence color of AuNCs transitions from red to blue as the concentration of Hg 2+ increases, thus providing a promising avenue for the detection of Hg 2+ in real environmental water samples. Simultaneously, CDs/AuNCs fluorescent nanocomposites are synthesized using a dehydration condensation process between CDs and AuNCs. It is noteworthy that the red fluorescence emission is significantly sensitive to temperature changes. With the gradual increase in temperature, the fluorescence color of CDs/AuNCs nanocomposites gradually changes from pink-purple to blue, making it a promising nanothermometer. In summary, we prepared a novel fluorescent probe for Hg 2+ and temperature detection.