Advances in Thermoelectrics for Power Generation
Timothy P. Hogan
Professor and Associate Chair for Undergraduate Studies
Department of Electrical and Computer Engineering
Michigan State University, East Lansing, MI 48824, U.S.A.
The direct conversion of thermal energy to electric energy can be achieved in thermoelectric modules through a preferential diffusion of carriers from the hot side to the cold side of the device. Such modules have found traditional use in the power generation systems of extraterrestrial spacecraft particularly in applications where solar radiation is insufficient. The past two decades have shown a renewed interest in these materials stimulated, in part, by new material discoveries and predictions of significant enhancements in the efficiencies possible through quantum confined structures. The conversion efficiency is directly dependent on the electrical conductivity of the materials and on the thermopower squared. It is also inversely proportional to the thermal conductivity. This combination of material properties tends to be optimized in heavily doped, narrow bandgap semiconductors.
This talk will highlight some of the recent advancements in bulk thermoelectric materials through chemically induced nanostructuring, phonon crystal electron glass concepts, and investigations of earth abundant thermoelectric compounds. Our research focuses on the characterization of new compounds includes temperature dependent electrical conductivity, thermal conductivity, thermopower, Hall effect measurements, and impedance spectroscopy. Recent measurements of Sb doped earth abundant Mg2Si0.4Sn0.6 compounds fabricated using the B2O3 flux sealing technique will be presented.
Tim Hogan is a Professor in the Department of Electrical and Computer Engineering at Michigan State University in East Lansing, Michigan. He received his B.S. degree in Electrical Engineering in 1988 from Michigan Technological University and his Ph.D. from the Electrical Engineering and Computer Science Department at Northwestern University in 1996. He spent two years as a postdoctoral fellow in the Physics Department at the University of Houston and the Texas Center for Superconductivity. He joined Michigan State University in 1998 and has established a charge transport characterization and pulsed laser deposition laboratory. He has over 120 papers in print, editor for 4 books, two book chapters, and two patents. Dr. Hogan’s research interests are in the development of electronic materials and devices. Recent efforts have focused on thermoelectric materials and waste heat recovery devices, diamond electronics, nanowire growth, and surface enhanced Raman spectroscopy. He has gained experience in computer controlled, temperature dependent transport measurements including: ac and dc electrical conductivity, thermoelectric power, thermal conductivity, mutual inductance, Hall effect, and impedance spectroscopy.