Effects of Sonication and Hydrothermal Treatments on the Optical and Chemical Properties of Carbon Dots

In our study, we have tested the effects of sonication and hydrothermal treatments on the properties of carbon dots synthesized from a microwave-assisted method (C-dots(MW)). When the carbon dots are sonicated in an aerobic environment, the fluorescence quantum yield decreases drastically because the molecular fluorophores attached to the surface of the carbon dots are oxidized during the sonication process. Meanwhile, the sonicated C-dotsMW also lose their Hg2+ ion sensing and photoreduction activity due to the oxidization of surface functional groups. After the hydrothermal treatment, the fluorescence quantum yield of C-dots(MW) increases due to the formation of new fluorophores; however, the Hg2+ ion sensitivity and photoreduction activity of C-dots(MW) decrease significantly due to the oxidization of surface functional groups. By autoclaving the C-dots(MW) at 100 degrees C, we have demonstrated that we can enhance the fluorescence quantum yield of C-dotsMW without losing their Hg2+ ion sensitivity. This finding can be used to improve the fluorescence quantum yield of the fluorescent ion sensor based on C-dots.

Automated summary

In our study, we found that sonication and hydrothermal treatments can alter the properties of carbon dots synthesized from a microwave-assisted method, affecting their fluorescence quantum yield and activities involving Hg2+ ion sensing and photoreduction. Autoclaving the carbon dots at 100 degrees Celsius can enhance their fluorescence quantum yield without compromising their sensitivity to Hg2+ ions.