Thermoelectric properties of Sn doped In₂O₃

The effects of Sn doping on thermoelectric transport properties of In₂O₃ were studied using the first-principles method and the semiclassical Boltzmann theory.. The calculations of formation energy show that Inb sites are most likely to be replaced by Sn. It should be noted that the calculated formation energies of the stable conjuration are negative for x = 1, which suggests that they are energetically stable at 0 K and may be synthesized under appropriate experimental conditions. However, the calculated formation energies are positive for x = 2 and 3, which indicates that they are thermodynamically unstable at 0 K. Thus in this paper, we only calculate the electronic structure and transport properties of In₃₁SnO₄₈. The calculation of electronic structure shows that Sn doping has little influence on the band structure of In₂O₃, but the Fermi level position would be moved toward the conduction band. Based on it, we predict that the electronic transport properties of In₂O₃ by using the semiclassical Boltzmann theory and rigid-band should be almost in agreement with that of In₃₁SnO₄₈. The transport properties change obviously with the chemical potential near the top of the valence band and the bottom of the conduction band. Between the top of the valence band and the bottom of the conduction band, ZeT close to unity and does not change with the temperature and chemical potential. Excitedly, comparison of the electronic transport properties of In₂O₃ by using the semiclassical Boltzmann theory and rigid-band with that of the experimental results, we find that the result of theoretical calculation is consistent with that of experimental study in the case of the same temperature and chemical potential. And the chemical potential is far above the bottom of the conduction band, which shows that the experimental evaluation of thermoelectric conversion efficiency is expected to be improved at lower doping level. (authors)