CdSe/ZnSe/ZnS多壳层结构量子点的制备与表征  

Synthesis and Characterization of the CdSe/ZnSe/ZnS Multishell Quantum Dots

作　　者：张庆彬[1,2] 曾庆辉[1] 郑金桔[1,2] 孔祥贵[1] 曲玉秋[1,2] 宋凯[1,2] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所激发态物理重点实验室,吉林长春130033 [2]中国科学院研究生院,北京100049

出　　处：《发光学报》2009年第6期842-846,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金(0674132;60771051)资助项目

摘　　要：展示了一种简捷的多壳层量子点合成路线。在含有过量Se源的CdSe体系中直接注入Zn源,"一步法"合成了CdSe/ZnSe量子点;进一步以CdSe/ZnSe为"核",表面外延生长ZnS壳层制备了核/壳/壳结构CdSe/ZnSe/ZnS量子点。相对于以往报道的多壳层结构量子点的制备方法,该方法通过减少壳层的生长步骤有效地简化了实验操作,缩短了实验周期,同时减少对原料的损耗。对量子点进行高温退火处理,能够大幅提高CdSe/ZnSe/ZnS量子点的发光量子产率。透射电镜、XRD以及光谱研究表明:所制备的量子点接近球形,核与壳层纳米晶均为闪锌矿结构,最终获得的CdSe/ZnSe/ZnS量子点的光致发光量子产率达到53%。为了实现量子点的表面生物功能化,通过巯基酸进行了表面配体交换修饰,使量子点表面具有水溶性的羧基功能团,并且能够维持较高的光致发光量子产率。In this work, we developed a simple method for synthesizing CdSe/ZnSe/ZnS multishell quantum dots （QDs）. CdSe/ZnSe core/shell QDs was synthesizd using one step injection of zinc precursor into the crude solution of the CdSe reaction system and then CdSe/ZnSe/ZnS core/shell/shell QDs were obtained by epitaxially growing a ZnS sheU on the CdSe/ZnSe surface. Introducing a middle shell （ZnSe） sandwiched between CdSe core and ZnS outer shell allows considerably reduce strain inside nanocrystals because ZnSe have the lattice parameter intermediate to those of CdSe and ZnS. In comparison with the method reported previously, our synthesis method effectively simplifies the experimental operation, shortens the experimental period and reduces the waste of the chemcals. The annealing process was used to improve the fluorescence quantum yield of the QDs after the shell growth. The resulting CdSe/ZnSe/ZnS muhishell QDs was further characterized in detail. Transmission electron microscopy indicated that the QDs are spherical and the shell is successfully coated on the surface of the CdSe QDs. The size of CdSe core is 2.8 nm, and the size of the CdSe cores with CdSe/ZnSe and CdSe/ZnSe/ZnS shells are determined to be 4 and 5 nm, respectively. The X-ray powder diffraction patterns suggested that the core （CdSe） and shell （ZnSe and ZnS） of the CdSe/ZnSe/ZnS QDs have a pure cubic phase. The luminescence properties of the QDs were investigated by means of photolumines- cence and ultraviolet-visible absorption spectra. The results indicated the CdSe/ZnSe/ZnS QDs exhibit a high photoluminescence quantum yield. Besides, it can be seen that the absorption and photoluminescence bands shift to the red during the shell growth due to the large extension of the electronic wave function into the shell material. For the potential biological application, the CdSe/ZnSe/ZnS QDs were transferred into water phase from an organic phase by surface ligand exchange with mereaptopropionic acid. The water-soluble QDs with a quantum yield o

关 键 词：CdSe/ZnSe/ZnS量子点 外延生长 配体交换 

分 类 号：O482.31[理学—固体物理]