【作者】 尚卓镔；

【导师】 晋卫军； 王煜；

【作者基本信息】 山西大学 ， 分析化学， 2011， 博士

【摘要】 全文共分六章,列出如下：第一章：绪论。简述了QDs的光学性质,及QDs的合成与表面改性,并对QDs与离子的相互作用作了讨论。第二章：制备并表征了ODE和Ole体系中合成的CdSe QDs。第三章：制备并表征了水溶性的TEA修饰的CdSe QDs。该QDs荧光只有当Hg2+离子和I-离子共存时才被猝灭。这种独特的猝灭行为可用于高选择性和灵敏度测定Hg2+离子和I-离子。实验表明,I-离子是Hg2+离子与QDs之间的桥梁,QDs和Hg2+通过I-离子形成稳定的络合物,有效的电子转移发生在从QDs到Hg2+离子,从而导致QDs的荧光猝灭。第四章：利用一种简便的方法通过在碱性水溶液直接取代Ole配体,制备了水溶性β-CD修饰的CdSe QDs。所制备的QDs具有良好稳定性。多元酸根阴离子,包括磷酸根,亚硫酸根和碳酸根,影响QDs的荧光。其中,磷酸二氢根离子有最大的猝灭效果。对于多元酸根离子,二氢根离子>一氢根离子>>无氢根离子。在碱性pH值时,QDs的荧光被光活化。与阳离子的研究结果表明,Ag+离子,Hg2+离子和Co2+离子对QDs的荧光具有显著的猝灭作用。并探讨了机理。第五章：制备了稳定性极好的MSA修饰的CdSe QDs。Cd2+离子可以被QDs吸附在表面,从而增强QDs的荧光。Ag+和Cu2’离子可以猝灭QDs的荧光,其它离子对QDs的荧光影响较小。最后我们详细的讨论了荧光猝灭和增强的机理。第六章：本章总结了研究结果,并对未来的研究方向进行了推测。更多还原

【Abstract】 The thesis consists of six chapters and is listed as follow:Chapter 1:Introduction. We include a brief discussion on the attractive optical properties of QDs and on the importance of adequate control of the synthesis and surface modification of the luminescent QDs, in order to achieve the desired selectivity and sensitivity for sensing target analytes.Chapter 2:The preparation and Characterization of highly luminescent CdSe QDs with a diameter form 3 to 7nm in a mixture of ODE and Ole.Chapter 3:Water-soluble luminescent CdSe quantum dots surface-modified with triethanolamine (TEA-CdSe-QDs) were prepared with high stability. The fluorescence of the TEA-CdSe-QDs was greatly quenched only when Hg2+ and I- coexisted in the solution, whereas addition of either Hg2+ or I- individually has no noticeable effect on the fluorescence emission. Such a unique quenching effect could be used for reciprocal recognition of mercury (Ⅱ) ions and/or iodide anions in aqueous solution with rather high selectivity and sensitivity. The adequate experiments showed that iodine (Ⅰ) anions could bridge between TEA-CdSe-QDs and Hg2+ to form a stable complex (QDs-I--Hg2+) and the following effective electron transfer from the QDs to the Hg2+ could be responsible for the fluorescence quenching of QDs.Chapter 4:A facile method was developed for the preparation of water soluble P-Cyclodextrin (β-CD)-modified CdSe QDs (β-CD-QDs) by directly replacing the Oleic acid ligands on the QDs surface withβ-CD in an alkaline aqueous solution. The as-prepared QDs show good stability in aqueous solution for several months. Oxoanions, including phosphoric acid ion, sulfite acid ion and carbonic acid ion, affect the fluorescence ofβ-CD-QDs. Among them, H2PO4- exhibited the largest quenching effect. For the polyprotic acids (HO)3AO, the effect of acidic anions on the fluorescence ofβ-CD-QDs was in the order monoanion (HO)2AO2>dianion (HO)AO32->>trianion AO43-. After photo activation for several days in the presence of anions at alkaline pH, theβ-CD-QDs exhibited strong fluorescence emission. The effect of various heavy and transition metal ions on the fluorescence properties of the P-CD-QDs was investigated further. It was found that Ag+, Hg2+ and Co2+ have significant quenching effect on the fluorescence of theβ-CD-QDs. The Stern-Volmer quenching constants increased in the order Hg2+<Co2+<Ag+. The adsorption model of metal ions on P-CD-QDs was explored.Chapter 5:CdSe QDs have been prepared and modified with MSA. They are water-soluble and biocompatible. To improve their fluorescence intensity and stability in water solution, Cd2+ was absorbed onto their surface. Based on the quench of fluorescence signals of the functionalized CdSe QDs by Ag+ ions and Cu2+ ions at pH 7.2, a simple, rapid and specific method for Ag+ and Cu2+ determination was proposed.Chapter 6:This chapter highlights the overlap between QD and analytical chemistry and speculates on future research directions.更多还原