Enhanced thermoelectric performance and high-temperature thermal stability of p-type Ag-doped β-Zn₄Sb₃

Abstract

Ag doping in β-Zn4Sb3 leads to the enhanced thermoelectric figure-of-merit (zT) and improved high-temperature thermal stability.

Transport Properties of Ag‐doped ZnSb

“…(Zn 1– x Ag x ) 4 Sb 3 ) for which an optimum doping situation was found when employing a synthesis mixture (Zn 0.9925 Ag 0.0075 ) 4 Sb 3 . [ 21 ] Effective doping of ZnSb takes place already for 0.2 at.% Ag, which implies that x attains very low values (which we estimate to be in a range 0.001–0.002). “Over”‐doping, as indicated in bipolar conduction for the sample ZnSb‐1.0 %Ag, may introduce a donor impurity band.…”

“…[ 15 ] This is also in contrast with a recent study on Ag‐doped Zn 4 Sb 3 where the presence of Ag 5 Zn 8 was detected in samples doped as low as 0.5 at.% Ag. [ 21 ]…”

“…It also significantly exceeds the ZT values of Xiong et al's 0.2 % Ag‐doped ZnSb sample and state‐of‐the art (Zn 0.9925 Ag 0.0075 ) 4 Sb 3 which are 0.75 and 0.8, respectively, at this temperature. [ 15,21 ]…”

“…This results in a decrease of the resistivity by a similar factor and, interestingly, in an increase of the thermopower by about 20 %. [ 21 ]…”

Ge‐Doped ZnSb/β‐Zn4Sb3 Nanocomposites with High Thermoelectric Performance

“…Taking advantage of this low thermal conductivity and a significant Seebeck coefficient, several elements have been introduced in small quantities to optimize the charge carrier concentration of this material and to maximize in this way its ZT , e.g., Al, Ga, In, Hg, Cd, Nb, Te, Mg, Ag, Cu, Fe, Bi, Se, Pb, and Ge . Numerous studies have been also devoted to study the thermal decomposition of this phase, its major issue, and to improve it through doping with elements such as Pb, Cd, and Ag . However, these progresses have not yet meet all the requirements for practical applications, and improving stability remains as a major challenge to be solved for this material.…”