核壳结构CdS:Mn/ZnS纳米晶的制备与光学性能研究

Synthesis and optical properties of CdS∶Mn/ZnS core/shell nanocrystals

以3-巯基丙酸为稳定剂,采用共沉淀法在水相中合成了CdS∶Mn掺杂纳米晶,然后进一步将ZnS包覆于CdS∶Mn纳米晶表面,制备了CdS∶Mn/ZnS核壳结构纳米晶。利用X射线衍射(XRD),透射电子显微镜(TEM)和紫外-可见吸收光谱(UV-Vis)对纳米晶的结构、形貌和光学性质进行了表征,发现制备的纳米晶具有优秀的单分散性,确认合成了CdS∶Mn/ZnS核壳结构纳米晶。通过荧光光谱(PL)研究了纳米晶的发光性质和光稳定性,结果表明包覆壳层后纳米晶的发光强度显著提高,最高可达8倍,且Mn2+离子的发光峰峰位置随着ZnS壳层数的增加而红移。此外,核壳纳米晶的光稳定性大大提高。

With 3-mercaptopropionic acid as stabilizer,CdS∶Mn nanocrystals were synthesized by a co-precipitation technique in aqueous phase,and then CdS∶Mn/ZnS core/shell nanocrystals were prepared by ZnS epitaxial coated on the surface of CdS∶Mn nanocrystals.The crystal structure,morphology and optical property of the nanocrystals were characterized by X-ray diffraction,transmission electron microscopy and UV-Vis absorption spectroscopy.The results showed that nanocrystals were nearly monodisperse and confirmed that ZnS was grown on the surface of CdS∶Mn nanocrystals.Luminescence and photostability of the nanocrystals were researched with photoluminescence emission spectroscopy.Luminescence intensity of the core/shell nanocrystals was significantly enhanced up to eight times,and the Mn2＋ photoluminescence peak was gradually red-shifted as the ZnS shell increased.Furthermore,a strongly improved photostability of the optical properties was observed.