Enhancement in power factor through rare-earth samarium doping in Cu 2 SnSe 3 system

Cu 2 SnSe 3 has drawn enough attention as a potential thermoelectric material due to its unique electronic and thermal properties. We present the impact of Sm doping on the Cu 2 SnSe 3 system’s Sn site. The polycrystalline samples of Cu 2 Sn 1- x Sm x Se 3 (0 ≤ x ≤ 0.08) were prepared using the solid-state reaction technique followed by conventional sintering. The crystal structure was characterized using XRD and the results reveal that the samples have a diamond cubic structure with a space group of F 4̄3 m . Scanning Electron Microscopy (SEM) analysis indicates a uniform surface homogeneity within the sample. Furthermore, the introduction of Sm causes a reduction in porosity. The electrical transport characteristics were studied in the mid temperature range of 300–650 K. The Seebeck coefficient of all the samples were found to be positive within the temperature range under study, suggesting that holes constitute the majority charge carriers. This is also confirmed by the Hall measurements as the carrier concentration was positive for all the samples. The inclusion of Sm has led to a reduction of electrical resistivity and Seebeck coefficient and hence power factor of ~539 μW mK −2 for x = 0.08 at 630 K which is ten times greater as compared to x = 0 whose power factor is ~56 μW mK −2 at 630 K is achieved which makes it suitable for thermoelectric applications.