| 초록 |
Bi2Te3 has historically served as representative thermoelectric (TE) material near ambient temperature. However, commercial applications of Bi2Te3-based TE modules have been stagnant. TE power conversion efficiency of the module directly depends on TE figure of merit (ZT) over the entire operating temperature region rather than peak ZT at specific temperature. It is hence essential to increase average ZT in the full range of operating temperatures. Here, we report the unusual effects of MnTe2 dopant to Bi2Te3 TE system. Inclusion of MnTe2 increases both carrier concentration and mobility simultaneously contrary to the general behavior of semiconductors. As a result, the power factor of ~45μWcm-1K-2 at 327K is achieved, which is one of the highest values reported to date. At the same time, it also effectively reduces lattice thermal conductivity down to ~0.50Wm-1K-1 at 373K. These synergetic effects enable a remarkably high average ZT of ~1.21 from 300 to 500K and ZTmax ~1.34 at 400K. |
