The Research Of CdTe Quautum Dots As Smart Fluorescent Probes

Recent years, luminescent semiconductor nanocrystals have attracted great interesting. Comparing with the traditional organic dyes, semiconductor quantum dots (QDs) have unique optical properties, such as wide excitation spectrum, narrow and symmetry emission spectrum. In the past twenty years, semiconductor QDs displayed their unique charm of the nature and had a broad and far-reaching application of foreground, which have attracted many scientists actively involved in the research. As important semiconductor nanocrystal, CdTe QDs were chosen for the study. In this paper, we have researched the preparation, assembly, composition and application of the CdTe QDs, and got some innovative results. The specific contents are as follows:Firstly, the high luminescent CdTe QDs were synthesized and modified by mercaptoacetic acid in water, which were composited with SiO₂. So we got SiO₂/CdTe nanoparticles. Then, using the sol - gel method, we modified calixarene on the surface of SiO₂/CdTe and got the core-shell structure of C[n]/ SiO₂/CdTe nanoparticles, which were characterized by transmission electron microscopy (TEM), fluorescence spectroscopy, UV vis-spectroscopy, and FT-IR spectroscopy. We also researched the properties of them.Secondly, the applications of the core-shell C[n]/SiO₂/CdTe nanoparticles were studied as fluorescence probes to determinate neutral molecules (pesticides and polycyclic aromatic hydrocarbons), the possible mechanisms were also discussed.Thirdly, a sensitive identification method of pesticides was developed using supramolecular nano-sensitizers combining of CdTe QDs and p-sulfonatocalix[4]arene as additive by fluorescent spectroscopic technique, which made the adjustment analysis between fenamithion and acetamiprid come true.Fourthly, using CdTe QDs as the fluorescent brightening agent and cyclodextrins (CD) as sensitizers, we constructed a selective recognition system to detect polycyclic aromatic hydrocarbons (PAHs) via changing the numbers of CDs. And we can use it to detect PAHs in the qualitative and quantitative analysis.