The influential mechanism of Ti doping on thermoelectric properties of Bi0.5Sb1.5Te3 alloy

The Ti-doped bismuth telluride-based thermoelectric material was prepared by high-temperature smelting combined with powder metallurgy, and the electron and phonon transporting mechanism was studied by a combination of first-principle calculations and experimental tests. The results show that Ti doping will introduce impurity levels, and its 3d orbits could significantly increase the density of states near the Fermi level, thereby increasing the effective mass, carrier concentration, and electrical conductivity and reducing the Seebeck coefficient. Ti doping will introduce a larger stress field, increase phonon scattering, and reduce lattice thermal conductivity. The maximum ZT value of the sample reached 1.25 at 340 K, which is 21.36% higher than that of the undoped sample.

Automated summary

The Ti-doped bismuth telluride-based thermoelectric material showed improved electrical conductivity, reduced Seebeck coefficient, and lower lattice thermal conductivity, leading to higher thermoelectric performance compared to the undoped sample.