Effect of secondary phases on thermoelectric properties of Cu 2 SnSe 3

• DOI: 10.1016/j.ceramint.2017.02.126
• Publication Date: 2017-02-24T16:01:37Z
• Authors: Rui Ma; Guanghua Liu; Jiangtao Li; Yuyang Li; Kexin Chen; Yemao Han; Min Zhou; Laifeng Li
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract Cu 2 SnSe 3 samples with different secondary phases are prepared from compositions of Cu x SnSe 3 (x=1.8–2.2) and Cu 2 Sn y Se 3 (y=0.8–1.2), and their thermoelectric properties are investigated. For Cu x SnSe 3 samples, the secondary phase is SnSe 2 for x=1.8 and 1.9 and SnSe for x=2.2, and nearly single-phase Cu 2 SnSe 3 is obtained for x=2.0 and 2.1. For Cu 2 Sn y Se 3 samples, the secondary phase is CuSe for y=0.8 and SnSe for x=1.1 and 1.2, and single-phase Cu 2 SnSe 3 is produced for y=0.9 and 1.0. The lattice structure of synthesized Cu 2 SnSe 3 depends on the x and y values, which is cubic for x≤2.0 or y≤1.0 and monoclinic for x>2.0 or y>1.0. Compared with the single-phase Cu 2 SnSe 3 sample (ZT=0.4 2 at 77 3 K), the samples with SnSe 2 secondary phase show a greatly-enhanced ZT of 0.84 at 773 K, which is likely the best result for un-doped Cu 2 SnSe 3 up to now. The samples with SnSe secondary phase exhibit poor thermoelectric properties.