Exploring the mechanism of CdTe quantum dots as fluorescent probe to detect Hg(II) ion from the perspectives of fluorescence polarization and light scattering

The mechanism of quantum dots (QDs) as fluorescent nano sensor to detect metal ions remains controversial. Herein, we investigate the mechanism from the perspectives of fluorescence polarization and light scattering, where CdTe QDs are employed as a model fluorescent sensor and Hg2+ion is used as a model quencher. When the QDs react with Hg2+, we observed that the fluorescence is quenched while light scattering is enhanced and the fluorescence anisotropy is increased. This indicates that Hg2+ destabilizes the QDs and drives them to agglomerate, which might be an important contributor to the fluorescence quenching. This work provides novel insights to explain the mechanism of QDs as fluorescent probe to detect metal ions.