报告题目：Achieving Enhanced Thermoelectric Performance in SnSe2 nanostructures
主 讲 人：新加坡南洋理工大学 颜清宇教授
Qingyu Yan is currently an associate professor in School of Materials Science and Engineering in Nanyang Technology University. He obtained his BS in Materials Science and Engineering, Nanjing University. He finished his PhD from Materials Science and Engineering Department of State University of New York at Stony Brook. After that, He joined the Materials Science and Engineering Department of Rensselaer Polytechnic Institute as a postdoctoral research associate. He joined School of Materials Science and Engineering of Nanyang Technological University as an assistant professor in early 2008 and became an associate Professor in 2013. He is the board member of Materials Research Express, (an IOP Journal) since 2016. Yan has published more than 250 papers on two research area: (1) thermoelectric materials; (2) electrochemical properties of nanocrystals, with a total citation of 14757 and a h-Index of 62.
Thermoelectric (TE) materials, which can convert heat into electricity and generate temperature gradient for cooling purpose, have been extensively studied for clean and reliable energy harvesting systems. I will discuss some of the progress in my group regarding the devleopment of TE materials including PbTe, carbon based ones. In particular, I will discuss on a defect chemistry approach in SnSe2 nanoplate-based pellets, in which the nanoplates show preferable orientation of the (001) planes along the primary surface of the pellet (in-plane). After simultaneous introduction of Se deficiency and Cl doping, the Fermi level of SnSe2 shifts towards the conduction band, resulting in two orders of magnitude increase in carrier concentration and a transition degenerate transport behaviour. In addition, all-scale hierarchical phonon scattering centres, such as point defects, nanograin boundaries, stacking faults and the layered nanostructures cooperate to produce very low lattice thermal conductivity. As a result, an enhanced in-plane ZTmax of 0.63 was achieved for 1.5 at% Cl doped SnSe1.95 pellet at 673 K, which is much higher than the corresponding in-plane ZT of pure SnSe2 (0.08).