Improvement of thermoelectric properties and their correlations with electron effective mass in Cu1.98SxSe1−x.

Autor: Zhao, Lanling, Fei, Frank Yun, Wang, Jun, Wang, Funing, Wang, Chunlei, Li, Jichao, Wang, Jiyang, Cheng, Zhenxiang, Dou, Shixue, Wang, Xiaolin
Zdroj: Scientific Reports; 1/20/2017, p40436, 1p
Abstrakt: Sulphur doping effects on the crystal structures, thermoelectric properties, density-of-states, and effective mass in Cu1.98SxSe1−x were studied based on the electrical and thermal transport property measurements, and first-principles calculations. The X-ray diffraction patterns and Rietveld refinements indicate that room temperature Cu1.98SxSe1−x (x = 0, 0.02, 0.08, 0.16) and Cu1.98SxSe1−x (x = 0.8, 0.9, 1.0) have the same crystal structure as monoclinic-Cu2Se and orthorhombic-Cu2S, respectively. Sulphur doping can greatly enhance zT values when x is in the range of 0.8≤ × ≤1.0. Furthermore, all doped samples show stable thermoelectric compatibility factors over a broad temperature range from 700 to 1000 K, which could greatly benefit their practical applications. First-principles calculations indicate that both the electron density-of-sates and the effective mass for all the compounds exhibit non-monotonic sulphur doping dependence. It is concluded that the overall thermoelectric performance of the Cu1.98SxSe1−x system is mainly correlated with the electron effective mass and the density-of-states. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index