Effect of Pb doping on electronic and thermoelectric properties of thallium antimony telluride (Tl8.33Sb1.67_xPbxTe6) nano-compound: A combined experimental and theoretical investigations

Here, in this manuscript, we studied the structural, electronic, and thermoelectric properties of Pb doped thallium antimony telluride crystal structure both experimentally and theoretically. Lead (Pb) doped thallium antimony telluride with different concentration (x) have been prepared by solid state reaction method and Ball milling technique. X-Ray Diffraction reveals that the crystal structure of Tl8.33Sb1.67_xPbxTe6 nano-structured compounds are iso-structural with Tl4SbTe3 compound. We showed that increasing the Pb concentrations results in an increase of the electrical conductivity and Seebeck coefficient, and is also confirmed by DensityFunctional Theory (DFT) calculations. The power factor (PF = S2?) enhanced by a larger factor as compared to the enhancement of the electronic thermal conductivity that was achieved simultaneously through Pb doping in thallium antimony telluride nano-compounds. This significantly increases the ratio of PF/? that results in an enormously enhanced figure-of-merit (ZT) value from 0.19 to 0.46 at T = 560 K. DFT calculations also show the enhancement in S due to the reduction in density of states (DOS) at Fermi energy. The highest ZT = 0.46(0.22) was recorded for Pb doped thallium antimony telluride compound experimentally (theoretically). These results indicate a route to harness the thermoelectric properties of thallium antimony telluride based materials for electronic and thermoelectric applications.

Automated summary

The study demonstrates that increasing the Pb concentration in thallium antimony telluride leads to an increase in electrical conductivity and Seebeck coefficient, improving the thermoelectric properties of the material and enhancing its performance.