A low-temperature thermoelectric transport study of non-stoichiometric AgSbTe 2 .

In recent times, considerable attention has been given to examining the impact of micro/nanostructure on the thermoelectric characteristics of nonstoichiometric AgSbTe 2 . The present investigation employed direct melting of elements that produced p-type AgSbTe 2 with spontaneous nanostructuring due to cation ordering. The product predominantly features an Ag-deficient Ag 0.927 Sb 1.07 Te 2.005 phase with monoclinic Ag 2 Te nanoprecipitates and exhibits a degenerate semiconductor-like behavior with an energy band gap of 0.15 eV. A Seebeck coefficient of 251 μV K -1 and a power factor of 741 μW m -1 K -2 at near ambient temperature are attained with this composition. The variable range hopping (VRH) and linear magnetoresistance (LMR) confirmed that the low-temperature transport followed a VRH between the localized states. The composition also exhibited glass like thermal conductivity of 0.2 W m -1 K -1 arising from phonon scattering at all-scale hierarchical structures that led to a high ZT of 1.1 at room temperature. The direct melted ingots show a high relative density of ∼97%, Vickers hardness H v of ∼108.5 kgf mm -2 , and excellent thermal stability, making them an attractive choice for TEGs.