Excellent thermoelectricity performance of p-type SnSe along b axis

Highlights: • Temperature and carrier concentration dependent thermoelectric behavior of SnSe are studied. • The optimal ZT is 1.62 for Pnma phase and 4.33 for Cmcm phase, which is 1.8 and 1.65 times as much as the experimental value 0.89 and 2.61 respectively. - Abstract: The electronic and thermoelectric properties of SnSe were calculated using the first-principles calculations and the semiclassical Boltzmann theory. The accurate electronic structure (calculated by the TB-mBJ) resulted in the trend changing between the Seebeck coefficient and the electrical conductivity, which were in good agreement with the experimental data. During the Pnma phase, the maximal zT value increased from 0.32 to 1.62 as the temperature rose. During the Cmcm phase, the maximal zT value increased from 4.03 to 4.33 as the temperature rose. The theoretical investigation provided valuable insight into the relationship between the electronic structure and thermoelectric transport properties of SnSe material.