Effect Of Post-Treatment With Pyridine On The Fluorescence Property Of Water Soluble CdTe Nanocrystals

In this thesis, CdTe nanaocrystals of different sizes were prepared in aqueous solution in the presence of mercaptoacetic acid. By treating with pyridine, the fluorescence properties of CdTe nanocrystals were found to be largely enhanced. Furthermore, various analytic techniques such as UV-Vis, FTIR, XPS and PL etc were used to analyze the structure and physicochemical properties of CdTe NCs with and without post-treatment.(1). Preparation of CdTe NCs: Water soluble CdTe NCs were prepared in aqueous solution in the presence of mercaptoacetic acid, where their diameters were controlled by changing the refluxing time.(2). Characterization of CdTe NCs: UV-Vis, PL, TEM, FTIR etc were used to characterize the surface and physicochemical properties of CdTe NCs.(3). Effect of post-treatment on the fluorescence of CdTe NCs: pyridine was used to treat CdTe NC at room temperature, which leads the large enhancement of the fluorescence of CdTe NCs. Meanwhile, the effects of time, solution pH, and the particle size on the fluorescence of CdTe NCs were systematically investigated. (4). Dynamic behavior of charge carriers in CdTe NCs: time-dependent photoluminescence spectroscopy was used to measure the PL decay kinetics of CdTe NCs before and after pyridine treatment. The result reveals that the luminescence lifetime of CdTe NCs is increased after being treated by pyridine and a possible reason was suggested.