Heterogeneous Gas-Phase Synthesis and Molecular Dynamics Modeling of Janus and Core鈥揝atellite Si鈥揂g Nanoparticles

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• 作者：Vidyadhar Singh ; Cathal Cassidy ; Panagiotis Grammatikopoulos ; Flyura Djurabekova ; Kai Nordlund ; Mukhles Sowwan
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：June 26, 2014
• 年：2014
• 卷：118
• 期：25
• 页码：13869-13875
• 全文大小：486K
• ISSN：1932-7455

文摘

Heterogeneous gas-phase condensation is a promising method of producing hybrid multifunctional nanoparticles with tailored composition and microstructure but also intrinsically introduces greater complexity to the nucleation process and growth kinetics. Herein, we report on the synthesis and growth modeling of silicon鈥搒ilver (Si鈥揂g) hybrid nanoparticles using gas-aggregated cosputtering from elemental Si and Ag source targets. The final Si鈥揂g ensemble size was manipulated in the range 5鈥?5 nm by appropriate tuning of the deposition parameters, while variations in the Si鈥揂g sputtering power ratio, from 1.8 to 2.25, allowed distinctive Janus and core鈥搒atellite structures, respectively, to be produced. Molecular dynamics simulations indicate that the individual species first form independent clusters of Si and Ag without significant intermixing. Collisions between unlike species are unstable in the early stages of growth (<100 ns), with large temperature differences resulting in rapid energy exchange and separation. Upon further cooling and depletion of isolated Si and Ag atoms through collection by parent clusters (>100 ns), Si鈥揂g cluster collisions ultimately result in stable hybrid structures.