時間：2026-07-08(三) 15:45 pm

講題：Silicide-based thermoelectric materials and devices

講者 :  Prof. Navaneethan Mani

服務單位：Nanotechnology Research Center (NRC), Faculty of Engineering and Technology, SRM Institute of Science and Technology  

地點：4樓創意講堂

主持人：許梅娟教授

摘要：

Thermoelectric (TE) power conversion has a potential solution for the existing global energy crisis. The conversion efficiency of TE-materials was assessed by figure of merit (zT). An ideal thermoelectric (TE) material effectively converts the heat into electricity, which requires low thermal conductivity (ԟ_T) and high Seebeck coefficient (S) values. However, the mutuality between the parameters needs to be decoupled cautiously to minimize the thermal conductivity without interrupting the electrical transport properties. Notably, the silicide-based thermoelectric materials such as n-type magnesium silicide and p-type manganese silicide are highly suitable for the intermediate energy conversion applications due to its limited toxicity, earth abundant, and tuning carrier concentration. The materials were prepared by solid-state synthesis followed by Hot-press and spark plasma sintering (SPS) techniques. The introduction of heavy element Bi activates a lattice-dynamic pathway for synergistic carrier-phonon manipulation, dominated by the alloy-induced point defects in n-type Mg₂Si_0.6Sn_0.4. As a result, a record high TE figure of merit (zT_Max) of 1.6 @753 K is obtained by a superior power factor of 3 mW. m^-1 K^-2 via carrier band engineering and suppressed lattice thermal conductivity of 1.02 W. m^-1 K^-1 arising from multiscale phonon distortion defects. In addition, the carbon nanofiber was incorporated in p-type thermoelement MnSi which significantly enhanced the Seebeck coefficient of 307 µV/K and reduced the thermal conductivity to 1.95 W/mK without affecting the electrical transport by interfacial energy filtering effect. Owing to the effects, it results a maximum power factor of 1755 µW/mK² and the zT of 0.64 at 803 K. These optimized n and p-type thermoelement will be used to fabricate a uni-couple thermoelectric device for energy conversion applications.

經歷：

Research Associate Professor, SRM Institute of Science and Technology (formerly known as SRM University), India July 2022-
Research Assistant Professor, SRM Institute of Science and Technology (formerly known as SRM University), India August 2017- July 2022
Assistant Professor,  Shizuoka University, Japan April 2016- August 2017
Scientific Researcher, Shizuoka University, Japan October 2014 – March 2016
JSPS Fellow Shizuoka University, Japan October 2012 – September 2014