First principles calculations on the thermoelectric properties of bulk Au₂S with ultra-low lattice thermal conductivity

【摘要】 Sulfide nanocrystals and their composites have shown great potential in the thermoelectric（TE） field due to their extremely low thermal conductivity. Recently a solid and hollow metastable Au₂S nanocrystalline has been successfully synthesized. Herein, we study the TE properties of this bulk Au₂S by first-principles calculations and semiclassical Boltzmann transport theory, which provides the basis for its further experimental studies. Our results indicate that the highly twofold degeneracy of the bands appears at the Γ point in the Brillouin zone, resulting in a high Seebeck coefficient.Besides, Au₂S exhibits an ultra-low lattice thermal conductivity( 0.88 W·m^-1·K^-1 at 700 K). At 700 K, the thermoelectric figure of merit of the optimal p-type doping is close to 1.76, which is higher than 0.8 of Zr Sb at 700 K and 1.4 of Pt Te at 750 K. Our work clearly demonstrates the advantages of Au₂S as a TE material and would greatly inspire further experimental studies and verifications.更多还原

【Abstract】 Sulfide nanocrystals and their composites have shown great potential in the thermoelectric（TE） field due to their extremely low thermal conductivity. Recently a solid and hollow metastable Au₂S nanocrystalline has been successfully synthesized. Herein, we study the TE properties of this bulk Au₂S by first-principles calculations and semiclassical Boltzmann transport theory, which provides the basis for its further experimental studies. Our results indicate that the highly twofold degeneracy of the bands appears at the Γ point in the Brillouin zone, resulting in a high Seebeck coefficient.Besides, Au₂S exhibits an ultra-low lattice thermal conductivity( 0.88 W·m^-1·K^-1 at 700 K). At 700 K, the thermoelectric figure of merit of the optimal p-type doping is close to 1.76, which is higher than 0.8 of Zr Sb at 700 K and 1.4 of Pt Te at 750 K. Our work clearly demonstrates the advantages of Au₂S as a TE material and would greatly inspire further experimental studies and verifications.更多还原