Thermoelectric properties of Sn2SSe via band engineering with Ge alloying

The thermoelectric properties of Sn2SSe are investigated via band engineering using Ge alloying. In this work, the electronic and thermoelectric properties of Sn2SSe 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 -960μV/K to -1535 μV/K and from 3.4 ×105 S/cm to 4.1 ×105 S/cm respectively. However, the lowest value of lattice thermal conductivity is observed at 700K which is 2.7W/mK. At x=1, A remarkably high ZT value 1.7 is achieved at 700 K for Sn2(1−x)Ge2(x)SSe. The high ZT value is 1.8 times greater than pure compound.