Date: Thursday, Nov 15th
Presenter: Prof. Jun Jiao, Department of Physics, Portland State University
In view of its high surface area to mass ratio (2600 m^2/g), superior charge-carrier mobility (2 × 10^5 cm^2/Vs) and excellent thermal conductivity of (4.84-5.30) x 10^3 W/mK, graphene has been considered an ideal substrate for growing and anchoring various metal and metal oxide nanocrystals (NCs) to form high-performance nano-composites. The manufacturing of such graphene hybrids would require not only that graphene sheets be produced inexpensively and in large quantities, but also that the attached metal/metal oxide NCs be incorporated and homogeneously distributed on the graphene surface. Up to now, many approaches have been developed to decorate graphene with metal/metal oxide NCs. However most of these techniques failed to provide consistent results, lead to graphene hybrid devices with poor performance and stability, and are cost prohibitive for large-scale production. In this seminar, we present a novel nanomanufacturing process which is simple, reliable, safe, and cost-effective and environmentally benign, capable of fabricating high quality graphene-based metal and metal oxide hybrids that are suitable for use in a variety of applications. During the manufacturing we were able to eliminate the surfactants and stabilizers using our Thermal Expansion--Liquid Exfoliation--Solvothermal Reaction (TELES) process. This allows the interface between the graphene and the metal or metal oxide NCs to remain very cleanimproving material properties and stabilitieswhile eliminating a potential environmental hazard. Our investigation also suggests that the production of these nanomaterials could be scaled to the industrial level.
Dr. Jun Jiao holds an M.S. in Physics and a Ph.D. in Materials Science and Engineering from the University of Arizona, and is currently a professor of physics and mechanical and materials science engineering at Portland State University (PSU). She is also the director of PSUs Center for Electron Microscopy and Nanofabrication, one of the signature research facilities for Oregon Nanoscience and Microtechnologies Institute (ONAMI).
Dr. Jiao's current research is focused on the development of nanofabrication techniques for the property-controlled growth of graphene-based nanohybrids, nanotubes, nanowires, and the investigation of these materials as building blocks for nanoelectronic devices. The results of her research are documented in more than 160 publications in refereed journals as well as four patents. Through her research, Dr. Jiao has collaborated with local high tech companies such as Intel, FEI, Sharp Labs of America and local research institutions including Oregon State University, University of Oregon, Washington State University and Oregon Health and Sciences University.
Dr. Jiao has been invited to national and international conferences and various workshops to give keynote talks and frequently serves as a panelist for the NSF. In May 2003, she was invited by the U.S. Senates Committee on Commerce, Science, and Transportation to testify in front of the full Committee in Washington, D.C., on The 21st Century Nanotechnology Research and Development Act. Dr. Jiao is a recipient of NSF-CAREER award and was honored by United States President George W. Bush in the White House with the 2004 Presidential Early Career Award for Scientists and Engineers (PECASE) the nations highest honor for professionals at the outset of their research careers whose work shows exceptional promise for leadership at the frontiers of scientific knowledge