title: Cation exchange: a simple and versatile route to inorganic colloidal spheres with the same size but different compositions and properties.
abstract: This paper describes a cation exchange approach to the synthesis of metal chalcogenide core-shell particles with the same size but a number of different compositions. This method begins with the preparation of colloidal spheres of amorphous Se (a-Se), followed by their reaction with Ag atoms to form Se@Ag2Se spheres. These core-shell spheres are then converted into Se@MSe (M = Zn, Cd, and Pb) via cation exchange with Zn2+, Cd2+, and Pb2+. All the colloidal spheres prepared using this method are monodispersed in size and characterized by a spherical shape and a smooth surface. Starting from the same batch of Se@Ag2Se, the resultant Se@MSe samples were essentially the same in size. Furthermore, these core-shell colloidal spheres can be easily made superparamagnetic by incorporating Fe3O4 nanoparticles into the a-Se cores. This synthetic approach provides a simple and versatile route to magnetoactive core-shell spheres with the same size but a range of different compositions. This study also implies that it is feasible to further increase the diversity of cations that can be used in the cation exchange of a colloidal system to produce multifunctional core-shell spheres with a variety of properties.
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA.
authors.forename: Pedro H C
authors.initials: PH
authors.lastname: Camargo
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Lee
authors.forename: Unyong
authors.initials: U
authors.lastname: Jeong
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Zou
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
mesh_terms: D002104:Cadmium / Q000737:chemistry; D002412:Cations; D002627:Chemistry, Physical / Q000379:methods*; D003102:Colloids / Q000737:chemistry; D003460:Crystallization; D007474:Ion Exchange; D007854:Lead / Q000737:chemistry; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D012834:Silver / Q000737:chemistry*; D012995:Solubility; D013499:Surface Properties; D013696:Temperature; D014961:X-Ray Diffraction; D015032:Zinc / Q000737:chemistry
chemical_list: D002412:Cations; D003102:Colloids; D002104:Cadmium; D007854:Lead; D012834:Silver; D015032:Zinc