David G. Cahill, University of Illinois at Urbana-Champaign
From Isotopically-Enriched Crystals to Fullerene Derivatives and (Almost) Everything in Between—Measurement of Thermal Conductivity by Time-Domain Thermoreflectance
The Innovation in Materials Characterization Award honors an outstanding advance in materials characterization that notably increases knowledge of the structure, composition, in situ behavior under outside stimulus, electronic behavior, or other characterization feature, of materials. It is not limited to the method of characterization or the class of materials observed.
“for developing transformative methods for characterizing the thermal transport properties of materials and their interfaces using time-domain thermoreflectance (TDTR) and related approaches”
The flow of heat in materials is generally perceived to be a slow process—in oxide glasses, heat diffuses a distance 1 mm on a timescale of 1 sec—and therefore pump-probe techniques originally developed for ultrafast time-resolved optical spectroscopies are not an obvious source of technologies for advances in thermal property measurement. Nevertheless, over the past 15 years, the work of approximately 30 highly dedicated students and postdocs in Cahill's group at Illinois (together with many critical contributions from the groups of colleagues at several institutions in the United States, Europe and Asia) has developed time-domain thermoreflectance (TDTR) into a nearly universal, high-throughput tool for measuring the thermal conductivity of materials and the thermal conductance of materials interfaces. Cahill will illustrate the power of TDTR and open questions in the science of heat conduction in materials with recent examples drawn from (1) the thermal conductivity of high thermal conductivity crystals of BP, BAs, GaN and SiC; (2) ultralow thermal conductivity in thin films of fullerene derivatives; (3) structure–property relationships for thermal conductivity of amorphous polymers; and (4) thermal conductivity switching in liquid crystal networks and azopolymers.
About David G. Cahill
David G. Cahill is the Willett Professor and Department Head of Materials Science and Engineering at the University of Illinois at Urbana-Champaign. He joined the faculty there after earning his PhD degree in condensed matter physics from Cornell University, and working as a postdoctoral research associate at the IBM T.J. Watson Research Center. His research program focuses on developing a microscopic understanding of thermal transport at the nanoscale; the discovery of materials with enhanced thermal function; the interactions between phonons, electrons, photons and spin; and advancing fundamental understanding of interfaces between materials and water. He received the 2015 Touloukian Award of The American Society of Mechanical Engineers and the Peter Mark Memorial Award from the American Vacuum Society (AVS); is a Fellow of the AVS, American Physical Society (APS) and Materials Research Society (MRS); and a past chair of the Division of Materials Physics of the APS.