Selective Cation Exchange in the Core Region of Cu2鈥?i>xSe/Cu2鈥?i>xS Core/Shell Nanocrystals

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• 作者：Karol Miszta ; Graziella Gariano ; Rosaria Brescia ; Sergio Marras ; Francesco De Donato ; Sandeep Ghosh ; Luca De Trizio ; Liberato Manna
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 30, 2015
• 年：2015
• 卷：137
• 期：38
• 页码：12195-12198
• 全文大小：429K
• ISSN：1520-5126

文摘

We studied cation exchange (CE) in core/shell Cu_2鈥?i>xSe/Cu_2鈥?i>xS nanorods with two cations, Ag⁺ and Hg²⁺, which are known to induce rapid exchange within metal chalcogenide nanocrystals (NCs) at room temperature. At the initial stage of the reaction, the guest ions diffused through the Cu_2鈥?i>xS shell and reached the Cu_2鈥?i>xSe core, replacing first Cu⁺ ions within the latter region. These experiments prove that CE in copper chalcogenide NCs is facilitated by the high diffusivity of guest cations in the lattice, such that they can probe the whole host structure and identify the preferred regions where to initiate the exchange. For both guest ions, CE is thermodynamically driven as it aims for the formation of the chalcogen phase characterized by the lower solubility under the specific reaction conditions.