Preparation and Study of the Fluorescence Quenching for Different Core/Shell Structures Quantum Dots with Mercury (II) Induction

The probes and sensors of the semiconductor quantum dots are the topic of intense research because they are able to show high-sensitivity fluorescence quenching under different ions conditions. Herein, different multishell structures of CdSe, CdSe-CdS, and CdSe-CdS-ZnS water-soluble quantum dots have been synthesized in aqueous solution. Transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction indicate that these quantum dots have high stability, homogeneous particle size and good monodispersity. More precisely, with different concentrations of mercury (II) induction, the mechanism of the fluorescence quenching for various structures of the quantum dots is discussed based electron transfer and nonradiative recombination patterns. Obtained results indicate that the core-shell structure of the CdSe-CdS quantum dots has the most beautiful performance, which shows high sensitivity in the detection of mercury (II). Moreover, this work provides some guidelines for the rational design of others fluorescence bioprobes and biosensors.