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By optimizing the concentration of the substitutional defect PrMg1, Mg3.2Pr0.02Sb1.5Bi0.5 exhibits a peak zT value of 1.70 at 725 K.

N-type MgSb-based Zintl compounds are proved to be high-performance thermoelectric materials with multiple degenerate valleys and low lattice thermal conductivity. Here, we investigate the electronic band structure and the thermoelectric properties of n-type MgSb using first-principles density functional theory. A high ZT of 3.1 at 725 K is obtained when the minimum lattice thermal conductivity and the optimal carrier concentration are reached. The calculated thermoelectric performance demonstrates that MgSb possesses an isotropic character in thermoelectric transport. Furthermore, the calculated lattice thermal conductivity κ reveals that the unusually low κ in MgSb predominantly originates from the large Grüneisen parameter γ.

Thermoelectric performance can be largely enhanced by forming solid solutions and biaxial strain.

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How to further improve the thermoelectric performance in Cu3SbSe4-based materials after optimizing its carrier concentration is a difficult issue. The present study attempts to address the issue by investigating thermoelectric performance of Cu3SbSe4 after Sn and La codoping, and all the samples were obtained by using a microwave-assisted hydrothermal synthesis method followed with the spark plasma sintering (SPS) process. First, a series of Cu3Sb1–x Sn x Se4 (x = 0–0.03) compounds have been synthesized, and the hole carrier concentration obviously increased with increasing the Sn content. In addition, La doping subsequently was employed to the Cu3Sb0.98Sn0.02Se4 sample to further increase its power factor by band flattening, resulting in a typical high power factor of 1156.5 μWm–1 K–2 and zT of 0.67 in Cu3Sb0.92Sn0.02La0.06Se4 at 623 K. Our study provides a novel methodology through regulating its carrier concentration and band structure for designing high thermoelectric performance Cu3SbSe4-based materials.