Temperature-dependent thermoelectric transport in Ag-doped Tl₈.₃₃Sb₁.₆₇Te₆ nanoparticles

In the present study, we examine how Ag doping affects the electrical and thermal characteristics of Tl 8.33 Sb 1.67-x Ag x Te 6 (1.29 ≤ x ≤ 1.38) Chalcogenide nanoparticles, which are made by ball milling and solid-state processes in sealed silica tubes. The x-ray diffraction verified that all of these compounds were phase pure structurally. Four probe resistivity techniques were used to examine the electrical conductivity, and the results showed that the electrical conductivity drops with temperature. Because of the enhanced Umklapp phonon scattering, the thermal conductivity of nano compounds was estimated as well from a temperature range of 305K–550 K. An increase in temperature decreases the thermal conductivity. The Seebeck coefficient (S), which was calculated for every substance under study, increased steadily as the temperature increased from 305 K to 550 K. S stayed positive over the whole temperature spectrum, indicating that the substances were p-type semiconducting. Improved power factor and dimensionless figure of merit (ZT) values were a result of the temperature-dependent increase in S. The composition with x = 1.29 in particular showed a ZT of 0.58 at 305 K, which progressively rose to 0.84 at 500 K. Furthermore, ZT value also rises as doping concentration does as well; at 410 K the sample Tl 8.33 Sb 0.29 Ag 1.38 Te 6 exhibits the greatest value of 1.31in all the others samples. The development of high-performance flexible TE devices based on ductile TE materials would be guided by the results of this investigation. • Ag doping optimizes electrical and thermal behavior. • XRD confirms phase-pure chalcogenide nanoparticle structure. • Electrical conductivity decreases with increasing temperature. • Seebeck coefficient rises, confirming p-type semiconductivity. • Maximum ZT of 1.31 achieved at 410 K.