Preparation and Characterization of Monodisperse Carbon Nanotube Materials and Devices

ChEMS Seminar

Featuring Mark C. Hersam, Ph.D.
Professor, Materials Science and Engineering and Chemistry
Northwestern University

Location:  Donald Bren Hall, Room 1300
Free and open to the public
Co-sponsored by UC Irvine's Institute for Surface and Interface Science

Abstract:
Large-scale production of high purity carbon nanotubes has the potential to enable or improve many applications.  Recently, we have developed a scalable and flexible technique for sorting single-walled carbon nanotubes (SWNTs) by their physical and electronic structure using density gradient ultracentrifugation (DGU).  Diameter-sorted metallic SWNTs yield semi-transparent conductive films with tunable optical absorption.  On the other hand, semiconducting SWNTs enable thin film transistors with high switching ratios and drive currents.  Most recently, chiral surfactants have been utilized for DGU-based sorting of SWNT enantiomers.  In all cases, analytical ultracentrifugation measurements allow the SWNT surfactant loading to be quantified and optimized for improved DGU sorting.  This talk will also delineate DGU sorting of double-walled carbon nanotubes (DWNTs).  Since DWNTs possess a buoyant density that is intermediate between SWNTs and multi-walled carbon nanotubes, a two-step DGU process has been developed for high purity DWNTs.  DGU-sorted DWNTs enable characterization of the fundamental properties of DWNTs and yield high performance transparent conductive films.

About the Speaker:
Dr. Mark C. Hersam earned a B.S. in electrical engineering from the University of Illinois at Urbana-Champaign (UIUC) in 1996, M.Phil. in physics from the University of Cambridge in 1997, and a Ph.D. in electrical engineering from UIUC in 2000.  In 1999, he also performed research at the IBM T. J. Watson Research Laboratory under the support of an IBM Distinguished Fellowship. His research interests include single molecule chemistry, nanofabrication, scanning probe microscopy, semiconductor surfaces, and carbon nanomaterials. As a faculty member, Dr. Hersam has received several awards including the Beckman Young Investigator Award (2001), NSF CAREER Award (2001), ARO Young Investigator Award (2005), ONR Young Investigator Award (2005), Sloan Research Fellowship (2005), Presidential Early Career Award for Scientists and Engineers (2005), TMS Robert Lansing Hardy Award (2006), AVS Peter Mark Award (2006), and two Teacher of the Year Awards (2003, 2007). In recognition of his early career accomplishments, Dr. Hersam was directly promoted from assistant professor to full professor with tenure in 2006. In 2007, Dr. Hersam co-founded NanoIntegris, which is a start-up company focused on supplying high performance carbon nanomaterials.