First-principles study on doping and temperature dependence of thermoelectric property of Bi_2S_3 thermoelectric material

摘要

The electronic structure and thermoelectric property of Bi_2S_3 are investigated. The electron and hole effective mass of Bi_2S_3 is analyzed in detail, from which we find that the thermoelectric transportation varies in different directions in Bi_2S_3 crystal. Along ac plane the higher figure of merit (ZT) could be achieved. For n-type doped Bi_2S_3, the optimal doping concentration is found in the range of (1.0-5.0) × 10~(19)cm~(-3),in which the maximal ZT reaches 0.21 at 900 K, but along ZZ direction, the maximal ZT reaches 0.36. These findings provide a new understanding of thermoelectricity-dependent structure factors and improving ZT ways. The donor concentration N increases as Tincreases at one bar of pressure under a suitable chemical potential μ, but above this chemical potential u,, the donor concentration N keeps a constant.