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通过反相微乳液法制备不同形貌的CdSe纳米晶。利用X-射线衍射(XRD)和透射电子显微镜(TEM)技术对纳米晶的结构和形貌进行表征。结果表明,纳米晶主要由CdSe和Na2SO4组成,根据Sherrer公式计算得到CdSe(100)方向的晶粒尺寸D100=35nm;不同制备条件下,纳米晶的形貌有短链状CdSe纳米晶、项链状和竹节状CdSe纳米管。其形成机理是:由于界面膜处束缚水含量小于水核内部自由水含量,造成CdSe纳米球外层密度小于中心密度,浓度差驱使Se2-与Cd2+向外层扩散形成CdSe空心纳米球;最终在取向附生生长机制下,CdSe空心纳米球生长为项链状和竹节状纳米管。
CdSe nanocrystals with different morphologies were prepared by reverse microemulsion method. The structure and morphology of nanocrystals were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the nanocrystals consist mainly of CdSe and Na2SO4, and the grain size in the direction of CdSe (100) is calculated as D100 = 35nm according to the Sherrer formula. The morphology of the nanocrystals is short-chained CdSe nanocrystals with necklace And bamboo-like CdSe nanotubes. The formation mechanism is as follows: the bound water content at the interface membrane is smaller than the free water content in the water core, resulting in the outer density of the CdSe nanospheres being smaller than the center density, and the concentration difference driving the diffusion of Se2- and Cd2 + to the outer layer to form the CdSe hollow nanosphere; Under the orientation of epiphytic growth, CdSe hollow nanospheres grow into necklace-like and bamboo-like nanotubes.