Carbon Lecture Series with Dr. Deborah Chung Professor, Department of Mechanical and Aerospace Engineering University at Buffalo, The State University of New York http://en.wikipedia.org/wiki/Deborah_Chung Friday, November 13, 2020 3:00-4:30pm Zoom (must register to receive link) “Carbon Dielectrics - A New Chapter In The Electrical Behavior Of Carbons - With Relevance To Energy, Conduction, Sensing and EMI Shielding” Dedicated to the memory of Professor M.S. Dresselhaus* Abstract: The electrical behavior of carbons in the graphite family (including graphite, turbostratic carbon, carbon ber/nanober/nanotube and graphene) has been widely studied, due to its relevance to electronic and electrochemical applications. The high electrical conductivity and carrier mobility in the plane of the carbon layers have attracted much attention, particularly in relation to graphene. However, the dielectric behavior has escaped attention, due to the presumption that the high conductivity makes the dielectric behavior negligible. Recent work by the speaker has shown that carbons exhibit signicant dielectric behavior that is important both scientically and technologically. The dielectric behavior occurs without the need for poling (in contrast to ceramic dielectrics that need to be poled) and stems from the interaction of a small fraction of the carriers (electrons/holes) with the atoms. The electric permittivity (a material property that relates directly to the capacitance) increases greatly with decreasing grain size, indicating that the carrier-atom interaction occurs at the grain boundaries. The polarization results in an opposing electric eld, which impedes conduction. Due to the carrier-atom interaction, the unpoled carbons are also electrets (permanent electric dipoles), thereby serving as energy sources that discharge upon short-circuiting and self-charge upon open-circuiting. The dielectric/electret behavior is affected by stress/strain and temperature, thus allowing the carbons to sense these attributes via electrical measurement. The dielectric behavior also explains carbons’ ability to absorb electromagnetic radiation, as needed for EMI shielding. Biographical Sketch: Professor Chung received her Ph.D. degree in Materials Science from Massachusetts Institute of Technology (under Professor M.S. Dresselhaus) and her B.S. degree from California Institute of Technology. She has authored or co-authored over 600 archival peer-reviewed international journal papers, in addition to authoring 9 books, which include Carbon Materials (World Sci., 2018), Carbon Composites (Elsevier, 2016), and Functional Materials (World Sci., 2010). Her Google Scholar h-index is ≥98, with ≥34345 citations. Chung is Fellow of ASM International and American Carbon Society. The honors that she has received include the Pettinos Award from the American Carbon Society, the Top Reviewer Award from the Carbon journal, the Niagara Mohawk Power Corporation Endowed Chair Professorship and the Chancellor's Award for Excellence in Scholarship from the State University of New York, the Honorary Doctorate degree from University of Alicante, Spain, and the Hardy Gold Medal from the American Institute of Mining, Metallurgical, and Petroleum Engineers. * D.D.L. Chung, "Mildred S. Dresselhaus (1930-2017)," Nature 543, 316 (2017). REGISTER TODAY! https://bit.ly/3lM795p.