Effect of Bi3+ Doping on the Electronic Structure and Thermoelectric Properties of (Sr0.889-xLa0.111Bix)TiO2.963: First-Principles Calculations

The electronic structure and thermoelectric properties of Bi3+-doped (Sr0.889-xLa0.111Bix)TiO2.963 were studied by the first principles method. Doping Bi3+ can increase the cell parameters, cell asymmetry and band gap. With increasing Bi3+ content, the asymmetry of DOS relative to the Fermi level increases, which results in an enhanced Seebeck coefficient, increasing carrier mobility and decreasing carrier concentration. An appropriate Bi3+-doping concentration (7.4–14.8%) can increase the lattice distortion and reduce the lattice thermal conductivity of the material. An appropriate Bi3+-doping concentration (7.4%) can effectively optimize the electrical transport performance and improve the thermoelectric properties of strontium titanate. The optimal Bi3+-doping concentration is 7.4%, and Sr0.815La0.111Bi0.074TiO2.963 obtains a maximum ZT of 0.48. This work shows the mechanism of Bi3+ doping in enhancing the thermoelectric properties of strontium titanate.