Chemistry Seminar
Dr. Yugang Sun
Center for Nanoscale Materials, Argonne National Laboratory
Friday, April 17, 2015 3:00pm Chem-Sci 101
Interfaced Heterogeneous Nanodimers
Abstract:
Synthesis of interfaced nanoparticle dimers made of asymmetric compositions (i.e., interfaced heterodimers) is challenging because it is difficult to manipulate the nanoparticles’ surface properties to control the assembly and/or growth of different nanoparticles. In this presentation, the general principle will be first introduced for the formation of interfaced heterogeneous dimers made of different inorganic nanodomains that exhibit either crystalline or amorphous structures. Although many different combinations are possible, the heterodimers containing plasmonic components (e.g., gold and silver nanodomains) will be focused in this presentation to highlight a number of synthetic methods and unique properties observed in heterodimers. For example, a seed-mediated, surface-confined epitaxial overgrowth strategy is capable of synthesizing high-quality interfaced Au-Ag heterodimers with varying sizes. Au and Ag share a common face-centered cubic lattice and have nearly identical lattice constants, which facilitates epitaxial overgrowth and allows direct contact between the Au and Ag domains. The interfaced Ag nanodomains can be chemical transformed to hollow nanoshells of other materials through a galvanic replacement reaction, resulting in the formation of interfaced dimers made of solid Au nanoparticles and hollow nanoshells. Due to the direct contact between the two components in each interfaced dimer, strong coupling between them are expected to induce new properties that cannot be observed from any individual components.
Biography:
Dr. Yugang Sun is a Scientist at the Center for Nanoscale Materials, Argonne National laboratory. He received his B.S. and PhD degrees from University of Science and Technology of China in 1996 and 2011, respectively. He worked as a Postdoc at University of Washington at Seattle (with Prof. Younan Xia) from 2001 to 2003. During 2004-2004, he had been working with Prof. John Rogers at University of Illinois at Urbana-Champaign as a postdoctoral fellow. In August 2008, he was appointed as an Assistant Scientist at Argonne National laboratory. He was promoted to Scientist in January 2010.
Dr. Sun’s research interests focus on developing novel approaches for the synthesis of a wide range of nanostructures including metal nanoparticles with well-controlled morphologies, single-crystal semiconductor nanostructures with mechanical flexibility, and metal/semiconductor nanocomposites with multiple functionalities. As of now, he has published more than 130 research papers, with an h-index = 47 and citation times > 23,400. He was honored as one of the “Top 100 Materials Scientists with highest impact score (2000-2010), Rank #5” by Thomson Reuters.