Theoretical and experimental search for ZnSb-based thermoelectric materials.

We report a combined theoretical and experimental search for thermoelectric materials based on semiconducting zinc antimony. Influence of three new doping elements (sodium, potassium and boron) on the electronic properties was investigated as well as the carrier concentration and temperature dependence of the thermoelectric coefficients obtained through density-functional calculations and Boltzmann transport theory. Distortion of the electron arrangement caused by the doping elements is displayed as a deformation charge density around the atoms. Based on the band structures, the density of states, and the transport properties, we found that the presence of Na and K in the ZnSb matrix leads to a slightly improved p-type conductivity, whereas the B substitution leads to a n-type doping. Because of the stronger need for obtaining n-type ZnSb-based material, the B(0.01)Zn(0.99)Sb structure has been transferred to the laboratory to be synthesized by direct melting. The sample was investigated using x-ray diffraction and scanning electron microscopy.