多种ZnO纳米结构和ZnO/ZnS核壳结构的制备

以Zn(NO3)2.6H2O和CO(NH2)2为原料,采用均匀沉淀法,制备出了棒状、花状、球状纳米氧化锌(ZnO)。将ZnO微球体分散在Na2S溶液中,通过离子替代法,成功制备了ZnO/ZnS核壳结构。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)等测试手段对ZnO纳米结构和ZnO/ZnS核壳结构的晶体结构和表面形貌进行了表征,初步探讨了纳米ZnO和ZnO/ZnS核壳结构的生长机理。根据测试结果得知,ZnO纳米棒呈现六方纤锌矿结构,随着Zn2+浓度逐渐增加,ZnO纳米结构形貌由单分散的棒状聚集成花状,最后演变成球形。ZnO/ZnS复合结构为内核ZnO,外面包覆一层ZnS的核壳结构。所有的纳米ZnO均具有相似的发光特点,ZnO/ZnS核壳结构的发光性能有了很大的改善。

Preparation and Morphology Evolution of ZnO Nanostructure and ZnO/ZnS Core-Shell Structure

Rod-like, flower-like and sphere-like ZnO were prepared by homogeneous precipi-tation method with Zn(NO_3)_2· 6H_2O and urea as reactive materials. The ZnO/ZnS core/shell structure was formed through sulfuration conversion from ZnO microspheres in the Na_2S solution. The crystal structure and morphology of the as-synthesized samples were in-vestigated by means of X- ray diffraction(XRD), scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy(EDS). The results show that the as-synthesized ZnO crystals are hexagonal wurtzite structure. SEM images indicated that ZnO hexagonal nano-rods grew along c axis and the growth mechanism of ZnO nanorods was discussed. At low Zn~+ concentration, the morphology of the ZnO nanostructure is flower-like collection assem-bled from rod-like dispersed single crystals. With the increasing of Zn~(+2) concentration, the morphology of ZnO nanostructure changed into spherical collection. The core/shell structure is composed of both ZnO and ZnS. All the products of ZnO nanocrystals exhibited similar photoluminescence characteristics, while the core/shell structure showed an improved emission feature.