Cu-Embedded SnSe with a High Figure of Merit at Ecofriendly Temperature.

There are many studies concentrated on high-temperature performance of SnSe, but few studies were conducted on low-temperature properties of embedded SnSe. In this work, a series of SnCu Se ( = 0, 0.01, 0.02, and 0.05) layered structures have been successfully synthesized by a melt quenching, mechanical milling process, and spark plasma sintering (SPS) method. Meanwhile, the thermal and electrical transport properties of all synthesized samples are measured. These results suggest that the embedding of Cu into SnSe results in a high carrier concentration (10/cm). In addition, the enhancement of defect and interfacial phonon scattering caused by Cu embedding as well as the weak van der Waals force between layers makes a low thermal conductivity (0.81 W/mK) for the SnCuSe at 300 K. Moreover, the maximum ZT is acquired up to 0.75 for the SnCuSe sample at 300 K, which is about 2 orders of magnitude higher than the pristine sample (0.009). These features indicate that Cu-embedded SnSe can be a promising thermoelectric material at gentle temperature.