The Reseach Of CdSe Quantum Dots And Its Application

The concept of quantum dots was first proposed in1990s, which wasoriginally developed to solve the global energy crisis. Now it has playeda very important role in the field of light-emitting devices, solar cells,optical biomarkers. These years, with the big improvement of quantum dottechnology, the scientists have developed a variety of methods tosynthesize the quantum dots. Due to the unique optical properties ofquantum dots, it has wide application prospects in the study ofbiochemistry, molecular biology, cell biology, genomics, proteomics, drugscreening, biological molecules interaction and etc.In this thesis, we introduced the original concept and some importantproperties of the quantum dots. Based on these theories and also combinedwith the research result of many experts and predecessor scholars, wediscussed the advantage and disadvantage of different synthesis methodsof semiconductor quantum dots and successfully synthesize themonodisperse and high-quantum yield CdSe nanoparticles in thenon-coordinated reaction system by thermal decomposition of the organicprecursors. Meanwhile, based on the synthesis reaction kinetics, wediscussed the influence of different experimental conditions onsynthesizing CdSe QDs, and summarized the best solvent ratio, reactiontemperature, reaction time and other related experimental conditions tosynthesize the high-quality CdSe QDs. And found out that the growthrate of quantum dots will be decremented with the reaction time’s increase.While also found out that the number of nucleation and particle sizedistribution are able to be controlled by adjusting the ODA concentration of the reaction system. Subsequently, in order to increase the chemicalstability and fluorescence quantum yield of the quantum dot, we use thehigh-band gap shell material to wrap the CdSe QDs by using an excessiveion layer adsorption reaction technique to get different core-shellnanoparticles.Then, we use Mercaptopropionic Acid (MPA) to modify the surfaceof quantum dots again to transfer them from oil phase to water phase sothat it can be applied in biomedicine. The result of the experiment showsthat after transferred to the water phase, the most stable and with thehighest fluorescence quantum yield is the core-shell CdSe/ZnS QDs. Buton the other side the quantum yield of CdSe/CdS QDs will be reducedrapidly in the water phase.Finally, we successfully achieved the bio-conjugation of quantumdots and bovine serum albumin by covalent coupling connection methodso that it can be used in multiplexed biological detection, labeling andimaging.