Low temperature synthesis of cubic phase zinc sulfide quantum dots
Low temperature synthesis of cubic phase zinc sulfide quantum dots
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DOI：
10.2478/s11532-011-0108-5
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发表时间：
2012-02-01
影响因子：
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通讯作者：
Muhammed, Mamoun
中科院分区：
文献类型：
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作者：
Shahid, Robina;Toprak, Muhammet S.;Muhammed, Mamoun
在这项研究中，我们报告了一种合成 ZnS 量子点 (QD) 的新方法。该合成是通过锌离子与新鲜还原的硫离子在乙醇作为反应介质中的化学反应在低温下进行的。氯化锌和元素硫分别作为锌源和硫源，水合肼作为强还原剂，将元素硫(S(8))转化为高活性的硫离子(S(2-))，硫离子与锌离子自发反应。这种简便、毒性较小、廉价的路线可以高产率合成高质量的金属硫化物量子点。透射电子显微镜（TEM）图像分析和选区电子衍射（SAED）表明ZnS QD的直径小于3 nm，并且具有立方晶相。紫外-可见吸收光谱显示在 253 nm 处有一个吸收峰，对应的带隙为 4.9 eV，与 3.68 eV 的体值相比较高，表明具有很强的量子限制。在 314 nm 和 439 nm 处观察到 PL 发射跃迁，并且与 ZnS QD 中的点缺陷有关。
In this study, we report on a new method for the synthesis of ZnS quantum dots (QDs). The synthesis was carried out at low temperature by a chemical reaction between zinc ions and freshly reduced sulfide ions in ethanol as reaction medium. Zinc chloride and elemental sulfur were used as zinc and sulfur sources, respectively and hydrazine hydrate was used as a strong reducing agent to convert elemental sulfur (S(8)) into highly reactive sulfide ions (S(2-)) which react spontaneously with zinc ions. This facile, less toxic, inexpensive route has a high yield for the synthesis of high quality metal sulfide QDs. Transmission electron microscopy (TEM) image analysis and selected area electron diffraction (SAED) reveal that ZnS QDs are less than 3 nm in diameter and are of cubic crystalline phase. The UV-Vis absorption spectrum shows an absorption peak at 253 nm corresponding to a band gap of 4.9 eV, which is high when compared to the bulk value of 3.68 eV revealing strong quantum confinement. PL emission transitions are observed at 314 nm and 439 nm and related to point defects in ZnS QDs.