J. Mater. Sci. Technol. ›› 2020, Vol. 58: 10-15.DOI: 10.1016/j.jmst.2020.05.015

• Research Article • Previous Articles     Next Articles

From microstructure evolution to thermoelectric and mechanical properties enhancement of SnSe

Chi Maa, Xue Baia, Qiang Rena, Hongquan Liua,*(), Yijie Gub,**(), Hongzhi Cuia,*()   

  1. aCollege of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China
    bSchool of Mechanical-electronic and Vehicle Engineering, Weifang University, Weifang 261061, China
  • Received:2020-03-20 Accepted:2020-05-07 Published:2020-12-01 Online:2020-12-17
  • Contact: Hongquan Liu,Yijie Gu,Hongzhi Cui

Abstract:

Defect existing form and its evolution play an important role in the thermoelectric transport process. Here different forms of Pb into the SnSe system were introduced in order to improve the thermoelectric and mechanical properties of SnSe. Pb/SnSe samples were fabricated by vacuum melting, solid phase diffusion, spark plasma sintering and annealing treatment. The element valence mapping diagram and the X-ray photoelectron spectra (XPS) characteristic peaks of Pb show that a certain amount of elemental Pb exists in the initial state, and evolves into Pb2+ ion after annealing treatment. The micro-structure evolution leads to significant enhancement of the power factor and the ZT value. The power factor (PF) and the ZT value for Pb/SnSe increases to 623 μW/m/K2 and 1.12 at 773 K after annealing treatment, respectively. Compared with SnSe matrix, the hardness and fracture toughness of Pb/SnSe samples increased by about 40% and 10%, respectively. Reasonable control of microstructure evolution is expected to be a design idea to improve thermoelectric and mechanical properties of SnSe.

Key words: Thermoelectric material, SnSe, Valence mapping, Defect evolution, Power factor