Shape Evolution of CdSe Nanoparticles Controlled by Halogen Compounds

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• 作者：Michaela Meyns ; Fabiola Iacono ; Cristina Palencia ; Jan Geweke ; Mauricio D. Coderch ; Ursula E. A. Fittschen ; Jos茅 M. Gallego ; Roberto Otero ; Beatriz H. Ju谩rez ; Christian Klinke
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：March 11, 2014
• 年：2014
• 卷：26
• 期：5
• 页码：1813-1821
• 全文大小：565K
• 年卷期：v.26,no.5(March 11, 2014)
• ISSN：1520-5002

文摘

Halogen compounds are capable of playing an important role in the manipulation of nanoparticle shapes and properties. In a new approach, we examined the shape evolution of CdSe nanorods to hexagonal pyramids in a hot-injection synthesis under the influence of halogenated additives in the form of organic chlorine, bromine and iodine compounds. Supported by density functional theory calculations, this shape evolution is explained as a result of X-type ligand coordination to sloped and flat Cd-rich facets and an equilibrium shape strongly influenced by halides. Synchrotron XPS measurements and TXRF results show that the shape evolution is accompanied by a modification in the chemical composition of the ligand sphere. Our experimental results suggest that the molecular structure of the halogenated compound is related to the degree of the effect on both rod growth and further shape evolution. This presents a new degree of freedom in nanoparticle shape control and highlights the role of additives in nanoparticle synthesis and their possible in situ formation of ligands.