Enhanced thermoelectric properties in Ag-rich AgSbSe2

In this paper, we report remarkably improved thermoelectric properties of p-type Ag-rich AgSbSe 2 . Polycrystalline bulk samples of Ag 1+ x Sb 1- x Se 2 (x ​= ​0, 0.01, 0.02, 0.03) were prepared from high purity elements and densified by spark plasma sintering. The X-ray diffraction analysis indicates the formation of solid solution and Ag 2 Se second phase in Ag-rich samples. The existence of Ag 2 Se precipitates is further confirmed by differential scanning calorimetric measurements and scanning electron microscopy images. The increased carrier concentrations combined with the modified band structures lead to the enhanced power factor in Ag 1+ x Sb 1- x Se 2 . Ag 2 Se particles act as phonon scattering centres and reduce the lattice thermal conductivity. This, together with the increased power factor, further enhances the thermoelectric figure of merit ZT . The maximum ZT value at 673 ​K increases from 0.44 for pristine AgSbSe 2 to 1.02 for Ag 1.02 Sb 0.98 Se 2 , which is more than two times enhancement.