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Friday, January 25

Shape-Controlled Synthesis of Metal Nanocrystals

Younan Xia, Georgia Institute of Technology, Atlanta
Chemical Sciences Division Seminar
10:00 AM — 11:00 AM, SNS Central Laboratory and Office Building (8600),
Iran Thomas Auditorium (Room A-103)
Contact: Sheng Dai (, 865.576.7307


Controlling the shape of nanocrystals may initially seem like a scientific curiosity, but its goal goes far beyond aesthetic appeal. For metal nanocrystals, shape not only determines their intrinsic chemical, plasmonic, and catalytic properties but also their relevance for electronic, optical, and sensing applications. Part of our research over the last decade has focused on shape-controlled synthesis of noble-metal nanocrystals. While the synthetic methodology mainly involves solution-phase redox chemistry, we have been working diligently to understand the complex physics behind the simple chemistry – that is, the nucleation and growth mechanism leading to the formation of nanocrystals with specific shapes. Polyol synthesis of silver nanocrystals provides a good example to illustrate this concept. We discovered that the shape of silver nanocrystals are dictated by both the crystallinity and shape of nanocrystallite seeds, which are, in turn, controlled by factors such as reduction rate, oxidative etching, and surface capping. The same mechanism also works for other systems including gold, palladium, and platinum. The success of these syntheses has enabled us to tailor the electronic, plasmonic, catalytic, and surface properties of metal nanocrystals for a range of applications.

About the speaker
Younan Xia is the Brock Family Chair and GRA Eminent Scholar in Nanomedicine in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Institute of Technology and Emory University, with joint appointments in School of Chemistry & Biochemistry and School of Chemical & Biomolecular Engineering. His research interests include development of new methodologies for controlling the synthesis of nanomaterials and exploration of their applications in biomedical and energy research. He received a Ph.D. degree in physical chemistry from Harvard University (with Professor George M. Whitesides) in 1996. He has received a number of awards, including ACS Award in the Chemistry of Materials (2013); MRS Fellow (2009); NIH Director's Pioneer Award (2006); ACS Leo Hendrik Baekeland Award (2005); Camille Dreyfus Teacher Scholar (2002); David and Lucile Packard Fellow in Science and Engineering (2000); NSF CAREER Award (2000); Alfred P. Sloan Research Fellow (2000); ACS Victor K. LaMer Award (1999); and Camille and Henry Dreyfus New Faculty Award (1997). He has co-authored more than 500 publications in peer-reviewed journals. He was ranked a Top 10 Chemist and Materials Scientist based on the number of citation per paper. He is an Associate Editor of Nano Letters.