可溶性零维和一维纳米材料的制备及其分析应用-CdHgTe、Au

【作者】 杨菲；

【导师】 唐波；

【作者基本信息】 山东师范大学 ， 分析化学， 2007， 硕士

【摘要】 量子点,即一种特殊的纳米微粒,也称半导体量子点(quantum dots,QDs)或半导体纳米微晶体(semiconduct nanocrystals),以其优良、独特的光学特性及特殊的光电性质,在生命科学、分析科学、材料科学、免疫医学、检验检疫等传统及新兴领域发挥出越来越大的作用。与传统的有机荧光染料相比,量子点具有宽的激发波长范围及窄的发射波长范围,发射峰窄而对称,发射波长可通过控制它的大小和组成来调谐,荧光强度及稳定性是普通荧光染料的100倍左右,几乎没有光褪色现象,生物相容性好等优点,可以作为荧光探针对生物样品和细胞进行成功染色。一维纳米材料(纳米棒、纳米带、纳米管以及纳米线),由于其在介观物理及纳米器件制造领域独特的应用潜力,而逐步成为新的研究热点,同时一维半导体纳米材料也因呈现出许多不同的光学性质近年来发展速度极快。与球形半导体纳米晶体相比,CdSe纳米棒的斯托克斯位移要大的多,同时,在沿聚乙烯-丁烯整齐排列的长轴方向上出现极化发射现象,这将对纳米棒用于生物材料标记时确定标记材料的取向很有帮助;CdSe/CdS/ZnS纳米棒用作荧光标记的探针要比半导体量子点亮的多。最近相继报道了分别在水溶液中直接合成表面带正电荷和负电荷的CdTe纳米棒,且纳米棒的量子产率高。然而,尚未见在水溶液中合成其他半导体纳米材料。众所周知,纳米金在紫外可见光区域有吸收。15nm的金纳米粒子在520nm处有最大吸收,且吸收系数很大,与CdTe量子点的荧光峰位置匹配,利用它们可以组建荧光共振能量转移体系(FRET)。FRET因其对距离的敏感性,广泛地被用于生物大分子结构、性质、反应机理以及定量分析等方面的研究。本文综述了半导体量子点在荧光分析中的应用,一维半导体纳米材料的制备进展、光学性质和潜在应用,基于量子点和金纳米颗粒的荧光共振能量转移的应用近况。在水溶液中合成了水溶性的一维CdHgTe量子棒,实验了不同汞的含量对荧光发射波长的影响,进一步讨论了不同pH值对CdHgTe量子棒光学性质的影响。基于FRET的原理,将金纳米颗粒和CdTe量子点用硼酸酯键连接起来,利用D-果糖与苯硼酸有强的络合作用,加入D-果糖后阻止了荧光共振能量转移,CdTe的荧光恢复,达到测定果糖的目的。更多还原

【Abstract】 Quantum dots (QDs) have great applications in life science, analytical chemistry, material chemistry, immunology and so on with unique optical properties and special optoelectronic properties. Compared to conventional organic dyes, QDs possess many advantages, such as narrower emission spectra, tunable maximum emission wavelength with changeable sizes and compositions, photostability, high brightness and biocompatibility, which have been successfully used as fluorescent probe in imaging of biological samples and cells. One-dimensional (1D) nanomaterials (nanorods, nanobelts, nanotubes and nanowires) have drawn more attention particularly in view of physical and nanoapparatus applications. In the meantime, 1D semiconductor nanomaterials appears different optical properties, which have attracted more interest. The photoemission of CdSe nanorods is highly polarized along the longer axis and surface-modified CdSe/CdS/ZnS core/shell QRs as a biological label can be used in a variety of bioimaging applications. Furthermore, for single molecule fluorescence imaging, they are much brighter than QDs. Recently positively and negatively capped CdTe nanorods were directly synthesized in aqueous media, which had high quantum yields. However, little study on the synthesis of any other 1D water-soluble semiconductor nanomaterials.It is well known that Au nanoparticles have absorbance in UV region. 15nm Au nanoparticles (NPs) have a characteristic absorption band centered at 520nm with a high molar extinction coefficient (εat 520 nm). The fluorescence resonance energy transfer (FRET) process is highly efficient when there is an appreciable overlap between the emission spectrum of the CdTe QDs donor and the absorption spectrum of the Au NPs acceptor. FRET is widely used for the research in molecule structures, properties, reaction mechanism and quantitative analysis.In this study, reviews were given on the application of QDs in fluorescence analysis, the synthetic methods of 1D semiconductor materials. The novel optical properties and potential applications of 1D semiconductor materials were discussed. The application of FRET with CdTe and Au nanoparticles was also discussed. Then water-soluble alloyed CdHgTe nanorods were synthesized in aqueous media using CdTe nanorods as template. Their emission spectra were in the near-infrared and tunable according to material compositions (red-shifted with increased Hg content). The effect of pH values on the luminescence of CdHgTe nanorods were also studied. D-fructose was determined by FRET between Au nanoparticles and CdTe QDs.更多还原