Speaker: Dr. Zhifeng Ren (University of Houston)

Host: Research Fellow Yang-Yuan Chen (Institute of Physics, Academia Sinica)

Time: 10:00, Friday, January 10, 2020

Place: 5F, 1^st Meeting Room, Institute of Physics, Academia Sinica

Abstract: Bi₂Te₃-based p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se₃ have been the only materials for thermoelectric cooling for decades. Even though the progress on advancing the thermoelectric figure-of-merit (ZT) has been significant especially the materials with peak ZT at high temperatures, materials with high enough ZT around room temperature are very rare. Up to now, in addition to Bi₂Te₃-based ones, the only reported is p-type MgAgSb with ZT of ~0.8 at room temperature. There is rare report on any n-type material exhibiting ZT similar to that of the n-type Bi₂Te_2.7Se₃. In this talk, Dr.Ren will present a new n-type material that has a ZT of ~0.7 at room temperature, which is comparable to that of n-type Bi₂Te_2.7Se₃. The cooling performance of a unicouple consisting of the new n-type material and the p-type Bi_0.5Sb_1.5Te₃ is also in par with the commercial legs consisting of the p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te_2.7Se₃. In addition, Dr.Ren will also discuss the recent progress on realizing thermal conductivity above 1200 W m^-1 K^-1 at room temperature in Boron Arsenide single crystals.