Thermoelectric properties of polycrystalline (SnSe)1-x(AgSnSe2)x/2 alloys

SnSe is considered as a thermoelectric material with great potential and advantages due to the record of high thermoelectric figure of merit (ZT) of 2.6 ​at 923 ​K in single crystals. However, it is difficult to use single crystal SnSe in practice due to its poor mechanical properties and high manufacturing costs. Meanwhile, the polycrystalline SnSe also is also not suitable for applications due to its much lower thermoelectric performance compared with single crystal SnSe. Therefore, improving the thermoelectric properties of polycrystalline SnSe has become a hot research topic. In this paper, AgSnSe2 doped into SnSe to increase the carrier density of the system and thus improve its thermoelectric properties. It is found that the addition of AgSnSe2 can effectively improve the thermoelectric performance of polycrystalline SnSe. A peak ZT of 0.81 was obtained at 713 ​K for (SnSe)0.95(AgSnSe2)0.025, which is 305% higher than that of the undoped one. This reveals that AgSnSe2-doped SnSe alloy may become a thermoelectric material system with great application potential and significance.