Hongxia Liu,Shun Zhang,Yan Zhang,Shuotong Zong,Wang Li,Can Zhu,Feng Luo,Jian Wang,Zhigang Sun
SnSe is a promising medium-temperature thermoelectric material due to its extremely low thermal conductivity and tunable electronic transport properties. In this work, n-type SnSe0.95 polycrystals doped with CeCl3 are synthesized by a melting method combined with a spark plasma sintering (SPS) process. The samples have highly textured structures and anisotropic thermoelectric properties. CeCl3 doping has a favorable effect on the electronic transport above 473 K, which may benefit from the excitation of the introduced impurity energy level. Moreover, the thermal conductivity is significantly reduced due to the phonon scattering by point defects. Finally, a peak ZT value of 1.17 is obtained at 773 K in SnSe0.95–0.5 mol % CeCl3, which paves the way for improving the thermoelectric performance of n-type SnSe via rare-earth halide doping.
At present, Ag-based thermoelectric materials have received extensive attention and have demonstrated excellent performance in related device application. Among them, AgBiSe 2 is a lead-free thermoelectric material that exhibits significant n -type doping characteristics. It has been previously reported that R Cl 3 -doping ( R denotes the rare earth elements) has achieved excellent results in some n -type thermoelectric materials. However, there is still a lack of systematic research on the effect of R Cl 3 doping on AgBiSe 2 based materials. In this work, n -type AgBiSe 1.98 polycrystalline materials doped with CeCl 3 (0.5–2 mol%) are successfully synthesized by the melting method in combination with spark plasma sintering (SPS) technique. Compared with AgBiSe 2 , the CeCl 3 -doped AgBiSe 1.98 samples have achieved a significant increase in thermoelectric figure of merit ( ZT ) value, which should be attributed to the higher power factor ( PF = S 2 σ ) and inherently low thermal conductivity. Specifically, a large ZT max of ∼ 0.65 is achieved at 733 K in the 2 mol% CeCl 3 -doped AgBiSe 1.98 sample, which shows an increase of 41 %. This study demonstrates that CeCl 3 -doping, as a novel strategy that can improve simultaneously n H and m *, reveals excellent optimization effects in the thermoelectric performance regulation of AgBiSe 2 -based materials.
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