Glassy thermal conductivity in the two-phase Cu_xAg_3−xSbSeTe₂alloy and high temperature thermoelectric behavior

Abstract

We have measured the thermal transport properties over the temperature range 1.8 K<T<700 K of a two-phase alloy synthesized by reacting AgSbTe(2) and Ag(2)Se in a 1:1 molar ratio. Typical electrical resistivity values at 700 K are in the range ∼4 mΩ cm≤ρ≤20 mΩ cm, while low thermal conductivity values (κ<1 W m(-1) K(-1)) were obtained. We find that the thermal conductivity of this crystalline alloy has a temperature dependence strikingly similar to those of amorphous solids. In addition the thermal conductivity, thermopower, and electrical resistivity decouple. This result makes it possible to optimize thermoelectric performance by minimizing the electrical resistivity. It is therefore envisaged that this system has potential as a high performance bulk thermoelectric.

Realizing High Thermoelectric Performance in Sb-Doped Ag2Te Compounds with a Low-Temperature Monoclinic Structure

“…Besides, the sound velocities of the Ag 2 Sb x Te 1– x ( x = 0–0.03) compounds are very low (see Table ). The transverse wave velocity v t and longitudinal wave velocity v l of pristine Ag 2 Te are 1333 and 3150 m/s, respectively, which are much smaller than those of the conventional thermoelectric material, such as GeTe ( v t = 2432 m/s and v l = 3426 m/s), PbTe ( v t = 1610 m/s and v l = 3590 m/s), and SnTe ( v t = 2869 m/s and v l = 3171 m/s). ,, All of these factors result in a low lattice thermal conductivity in Ag 2 Te. − …”

The effect of Ag concentration on the structural, electrical and thermal transport behavior of Pb:Te:Ag:Se mixtures and improvement of thermoelectric performance via Cu doping

“…The maximum thermoelectric performance obtained in the non-Cu-doped composites is ZT ∼ 0.45 [14] and we have shown in this article that ZT ∼ 0.54 can be achieved via Cu doping. The thermoelectric efficiency is too low to be competitive, but higher ZT values have been obtained in AgSbTe 2 :Ag 2 Se composites [20]. However, further lattice manipulation and processing may result in higher ZT values.…”

Morphological evolution of Ag2Te precipitates in thermoelectric PbTe

“…For instance, Ag 2 Te precipitates have been analyzed in AgSbTe 2 [13,16] and in the closely related Cu x Ag 3−x SbSeTe 2 system [17]. The LAST system (lead-antimony-silver-telluride), which has a general composition of the form AgPb m SbTe 2+m has received much attention due to the high ZT values reported [8,18,19].…”