No abstract

No abstract

No abstract

Lead‐free chalcogenide SnTe has been demonstrated to be an efficient medium temperature thermoelectric (TE) material. However, high intrinsic Sn vacancies as well as high thermal conductivity devalue its performance. Here, β‐Zn4Sb3 is incorporated into the SnTe matrix to regulate the thermoelectric performance of SnTe. Sequential in situ reactions take place between the β‐Zn4Sb3 additive and SnTe matrix, and an interesting “core–shell” microstructure (Sb@ZnTe) is obtained; the composition of SnTe matrix is also tuned and thus Sn vacancies are compensated effectively. Benefitting from the synergistic effect of the in situ reactions, an ultralow κlat ≈0.48 W m−1 K−1 at 873 K is obtained and the carrier concentrations and electrical properties are also improved successfully. Finally, a maximum ZT ≈1.32, which increases by ≈220% over the pristine SnTe, is achieved in the SnTe‐1.5% β‐Zn4Sb3 sample at 873 K. This work provides a new strategy to regulate the TE performance of SnTe and also offers a new insight to other related thermoelectric materials.

The effect of Al-, Ga-, and In-doping on the thermoelectric (TE) properties of CuSbSe has been comparatively studied on the basis of theoretical prediction and experimental validation. It is found that tiny Al/Ga/In substitution leads to a great enhancement of electrical conductivity with high carrier concentration and also large Seebeck coefficient due to the preserved high band degeneracy and thereby a remarkably high power factor. Ultimately, coupled with the depressed lattice thermal conductivity, all three elements (Al/Ga/In) substituted samples have obtained a highly improved thermoelectric performance with respect to undoped CuSbSe. Compared to the samples at the same Al/In doping level, the slightly Ga-doped sample presents better TE performance over the wide temperature range, and the CuSbGaSe sample presents a record high ZT value of 0.9 among single-doped CuSbSe at 623 K, which is about 80% higher than that of pristine CuSbSe. This work offers an alternative approach to boost the TE properties of CuSbSe by selecting efficient dopant to weaken the coupling between electrical conductivity and Seebeck coefficient.