Chemistry Seminar Series: Jian He

Jian He ​​​​​​
Department of Physics and Astronomy
Clemson University

Monday, January 13, 2019
10:00 a.m.
C2-361 (Reading Room)

Abstract: 

High entropy thermoelectrics is a synergy of thermoelectric materials research and high entropy alloys. In this talk, I briefly review the role of entropy in thermoelectrics, the four core effects of high entropy alloys, and present a case study in SnTe. Upon entropy engineering, the solubility of Mn is extended in favor of carrier concentration, band gap, and band convergence, which compensate for the degraded carrier mobility; the carrier scattering mechanism crossovers from electron-phonon scattering to alloying scattering; despite a simple fcc structure, the lattice thermal conductivity is suppressed by multi-scale hierarchical microstructures and severe lattice distortion. As a result, a promising figure of merit ~1.42 is attained in (Sn_0.74Ge_0.2Pb_0.1)_0.75Mn_0.275Te at 900 K. These results attest to the efficacy of entropy engineering towards high-entropy thermoelectrics.

Dr. Jian He is an associate professor in the Department of Physics and Astronomy at Clemson University, where he has been a faculty member since 2008. He completed his Ph.D. at the University of Tennessee, Knoxville and his undergraduate studies at Jilin University, China, both in condensed matter physics. His research interests cover several subareas of condensed matter physics and materials science: single crystal growth of oxides and intermetallic compounds, novel materials synthesis techniques, electrical, thermal, magnetic characterization, and thermoelectric materials research. He has authored or co-authored over 160 peer reviewed publications with a H-index of 41.