Cation Exchange: A Simple and Versatile Route to Inorganic Colloidal Spheres with the Same Size but Different Compositions and Properties

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• 作者：Pedro H. C. Camargo ; Young Hwan Lee ; Unyong Jeong ; Zhiqing Zou ; Younan Xia
• 刊名：Langmuir
• 出版年：2007
• 出版时间：March 13, 2007
• 年：2007
• 卷：23
• 期：6
• 页码：2985 - 2992
• 全文大小：730K
• 年卷期：v.23,no.6(March 13, 2007)
• ISSN：1520-5827

文摘

This paper describes a cation exchange approach to the synthesis of metal chalcogenide core-shell particles withthe same size but a number of different compositions. This method begins with the preparation of colloidal spheresof amorphous Se (a-Se), followed by their reaction with Ag atoms to form Se@Ag₂Se spheres. These core-shellspheres are then converted into Se@MSe (M = Zn, Cd, and Pb) via cation exchange with Zn²⁺, Cd²⁺, and Pb²⁺. Allthe colloidal spheres prepared using this method are monodispersed in size and characterized by a spherical shapeand a smooth surface. Starting from the same batch of Se@Ag₂Se, the resultant Se@MSe samples were essentiallythe same in size. Furthermore, these core-shell colloidal spheres can be easily made superparamagnetic by incorporatingFe₃O₄ nanoparticles into the a-Se cores. This synthetic approach provides a simple and versatile route to magnetoactivecore-shell spheres with the same size but a range of different compositions. This study also implies that it is feasibleto further increase the diversity of cations that can be used in the cation exchange of a colloidal system to producemultifunctional core-shell spheres with a variety of properties.