Cu-Embedded SnSe2 with a High Figure of Merit at Ecofriendly Temperature.

There are many studies concentrated on high-temperature performance of SnSe2, but few studies were conducted on low-temperature properties of embedded SnSe2. In this work, a series of SnCu x Se2 (x = 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 SnSe2 results in a high carrier concentration (1019/cm3). 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 SnCu0.01Se2 at 300 K. Moreover, the maximum ZT is acquired up to 0.75 for the SnCu0.01Se2 sample at 300 K, which is about 2 orders of magnitude higher than the pristine sample (0.009). These features indicate that Cu-embedded SnSe2 can be a promising thermoelectric material at gentle temperature.