Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng, 475004, P. R. China.
Dalton Trans. 2010 Apr 7;39(13):3308-14. doi: 10.1039/b922130a. Epub 2010 Feb 23.
Using phosphine-free and "green" chalcogen precursors, controlled synthesis of high quality CdS/ZnSe/ZnS core/shell1/shell2 nanocrystals has been successfully carried out using different sized CdS nanocrystals as cores. The properties and structures of the synthesized nanocrystals were characterized by absorption spectroscopy, photoluminescence (PL) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and inductively coupled plasma mass spectroscopy (ICP-MS). By changing CdS core sizes and/or ZnSe shell thicknesses, the PL range of CdS/ZnSe core/shell nanocrystals could be adjusted from 500 nm to 630 nm with type-II optical characteristics. The PL quantum yields (QYs) of these nanocrystals were 50-60% after the growth of thick ZnS shells, their full width at half maximum (FWHM) was kept below 50 nm during the entire growth process, and the total Cd content was reduced to about 1% in atomic ratio. TEM images showed narrow size distributions and XRD results demonstrated the zinc blende structure of CdS was retained following subsequent growth of ZnSe and ZnS shells. More than 2 g of high quality CdS/ZnSe/ZnS nanocrystals were successfully prepared in a large scale synthesis with the use of only low-cost, green, and environmentally friendly reagents.
使用无膦和“绿色”硫属元素前体，以不同尺寸的 CdS 纳米晶为核，成功地进行了高质量的 CdS/ZnSe/ZnS 核/壳 1/壳 2 纳米晶的可控合成。通过吸收光谱、光致发光（PL）光谱、X 射线衍射（XRD）、透射电子显微镜（TEM）和电感耦合等离子体质谱（ICP-MS）对合成纳米晶的性质和结构进行了表征。通过改变 CdS 核的尺寸和/或 ZnSe 壳的厚度，可以将 CdS/ZnSe 核/壳纳米晶的 PL 范围从 500nm 调节到 630nm，具有 II 型光学特性。在生长厚的 ZnS 壳后，这些纳米晶的 PL 量子产率（QYs）为 50-60%，其全宽半最大值（FWHM）在整个生长过程中保持在 50nm 以下，总 Cd 含量以原子比计降低到约 1%。TEM 图像显示了窄的尺寸分布，XRD 结果表明，在随后生长 ZnSe 和 ZnS 壳后，CdS 的闪锌矿结构得以保留。在仅使用低成本、绿色和环保试剂的大规模合成中，成功制备了超过 2g 的高质量 CdS/ZnSe/ZnS 纳米晶。
