Thermoelectric properties of Sn 2 SSe via band engineering with Ge alloying

The thermoelectric properties of Sn 2 SSe are investigated via band engineering using Ge alloying. In this work, the electronic and thermoelectric properties of Sn 2 SSe doped with Ge at different concentrations (x=0, 0.25, 0.5, 0.75, and 1) are investigated using density functional theory and Boltzmann transport theory. At 300K, the Seebeck coefficient and electrical conductivity are enhanced with Ge alloying from −960 μ V/K to −1535 μ V/K and from 3.4 × 10 5 S/cm to 4.1 × 10 5 S/cm respectively. However, the lowest value of lattice thermal conductivity is observed at 700 K which is 2.7W/mK. At x = 1, A remarkably high ZT value 1.7 is achieved at 700 K for Sn 2 ( 1 − x ) Ge 2 ( x ) SSe . The high ZT value is 1.8 times greater than pure compound.