From Sphere to Multipod: Thermally Induced Transitions of CdSe Nanocrystals Studied by Molecular Dynamics Simulations

详细信息    查看全文

• 作者：Zhaochuan Fan ; Anil O. Yalcin ; Frans D. Tichelaar ; Henny W. Zandbergen ; Elise Talgorn ; Arjan J. Houtepen ; Thijs J. H. Vlugt ; Marijn A. van Huis
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：April 17, 2013
• 年：2013
• 卷：135
• 期：15
• 页码：5869-5876
• 全文大小：565K
• 年卷期：v.135,no.15(April 17, 2013)
• ISSN：1520-5126

文摘

Molecular dynamics (MD) simulations are used to show that a spherical zinc blende (ZB) nanocrystal (NC) can transform into a tetrapod or an octapod as a result of heating, by a local zincblende-to-wurtzite phase transformation taking place in the NC. The partial sphere-to-tetrapod or sphere-to-octapod transition occurs within simulation times of 30 ns and depends on both temperature and NC size. Surprisingly, the wurtzite (WZ) subdomains are not formed through a slip mechanism but are mediated by the formation of highly mobile Cd vacancies on the ZB{111} Cd atomic planes. The total potential energy of a tetrapod is found to be lower than that of a ZB sphere at the same numbers of atoms. The simulation results are in good agreement with experimental high-resolution transmission electron microscopy (HR-TEM) data obtained on heated colloidal CdSe NCs.