ChBE Seminar Series: Silicon and Germanium Nanocrystals, Nanorods and Nanowires
Speaker: Brian A. Korgel, Professor & Rashid Engineering Regents Chair, Dept of Chemical Engineering, University of Texas, Austin
Our research involves the development of chemical methods for a variety of nanomaterials with unique size-dependent properties—including optical, electronic and mechanical—that might be used in applications. This presentation will cover the synthesis, properties and some applications of silicon (Si) and germanium (Ge) nanocrystals, nanorods and nanowires. Si provides the foundation of the semiconductor industry, but lacks some useful properties as a bulk material. For example, it is a poor light emitter because of its indirect band gap. Silicon nanocrystals (and nanorods) on the other hand can be made to emit light efficiently and offer new applications for Si. The influences of size and surface on Si nanocrystal light emission will be discussed. Si nanowires also offer unique properties. Bulk Si crystals are rigid and brittle; whereas, nanowires are mechanically flexible and strong, which provides a way to use Si in lithium ion batteries as an electrode material, or as a structural material in fabrics and aerogels. Ge is also a Group IV semiconductor, and widely used commercially. Like Si, it also has an indirect band gap that makes it a poor light emitter. Although there are many chemical similarities between Si and Ge, there are some distinct differences as well. The synthesis and properties of Si and Ge nanostructures will be discussed and compared.
Brian A. Korgel is the Rashid Engineering Regents Chair Professor in the McKetta Department of Chemical Engineering at The University of Texas at Austin. He directs the Industry/University Research Center (IUCRC) for Next Generation Photovoltaics and the Emerging Technologies area of the UT|Portugal program; he is the Education and Outreach Director for the NSF-funded Center for Dynamics and Control of Materials MRSEC at UT Austin; and he is an Associate Editor of Chemistry of Materials. He received his PhD in Chemical Engineering from UCLA in 1997 and was a post-doctoral fellow at University College Dublin, Ireland, in the Department of Chemistry. He works at the intersection of nano & mesoscopic materials chemistry and complex fluids, tackling problems in energy storage, chemical transformations, energy harvesting and conversion, and medicine. He is also an artist, exploring collaboration, language and human-artificial intelligence/robot cohabitation. He has published more than 280 papers with an h-index of 82 and has been a Visiting Professor at the University of Alicante in Spain, the Université Josef Fourier in France and the Chinese Academy of Sciences in Beijing. He has co-founded two companies, Innovalight and Piñon Technologies, and received various honors including the Professional Progress Award from the American Institute of Chemical Engineers (AIChE), election to Fellow of the American Association for the Advancement of Science (AAAS) and is a member of the National Academy of Engineering (NAE).