期刊论文

Kang, Huijun

Wang, Tongmin,Li, Jinling,Liu, Yinqiao,Guo, Enyu,Chen, Zongning,Liu, Daquan,Fan, Guohua,Zhang, Yuwei,Jiang, Xue

2018-08-21

JOURNAL OF MATERIALS CHEMISTRY C

SCIE

J

6

31

8479-8487

2050-7526

Herein, we propose for the first time a novel recipe to improve the thermoelectric properties of BiCuSeO by doping with variable valence elements. Taking Yb-doped BiCuSeO as a typical example, the dimensionless figure of merit (ZT) is optimized by simultaneously doping with Yb2+ to increase the carrier concentration and by introducing Yb3+ to increase the carrier mobility. The mechanisms of valence fluctuation, the increase in carrier concentration and the increase in mobility are investigated by combining experimental results with first-principles calculations. By coupling high electronic conductivity, medium Seebeck coefficient, and low thermal conductivity, a maximum ZT value of 0.62 is achieved at 823 K for Bi0.7Yb0.3CuSeO, which is 1.55 times higher than that of pristine BiCuSeO. These findings undoubtedly provide a new strategy for the rational design of high-ZT thermoelectric materials.