Enhancement of Thermoelectric Properties in Pd-In Co-Doped SnTe and Its Phase Transition Behavior

Zheng Ma; Jingdan Lei; De Zhang; Chao Wang; Jianli Wang; Zhenxiang Cheng; Yuanxu Wang

doi:10.1021/acsami.9b08564

Enhancement of Thermoelectric Properties in Pd-In Co-Doped SnTe and Its Phase Transition Behavior

ACS Appl Mater Interfaces. 2019 Sep 18;11(37):33792-33802. doi: 10.1021/acsami.9b08564. Epub 2019 Sep 6.

Authors

Zheng Ma¹, Jingdan Lei¹, De Zhang¹, Chao Wang¹, Jianli Wang¹, Zhenxiang Cheng^{1

2}, Yuanxu Wang¹

Affiliations

¹ Institute for Computational Materials Science, School of Physics and Electronics , Henan University , Kaifeng 475004 , P. R. China.
² Institute for Superconducting and Electronic Materials , University of Wollongong , Squires Way , North Wollongong , 2522 , Australia.

PMID: 31454222
DOI: 10.1021/acsami.9b08564

Abstract

SnTe has attracted more and more attention due to the similar band and crystal structure with high performance thermoelectric materials PbTe. Here, we introduced Pd into SnTe and the valence band convergence was confirmed by first-principles calculation. In the experimental process, we found that Pd-doped SnTe exhibit a reduced thermal conductivity because of softening chemical bonds and grain refining effects. To further improve the thermoelectric performance, Pd-In codoped SnTe samples were prepared, and the abnormal change of thermal conductivity was observed. The results of synchrotron powder diffraction suggest that the local phase transition (local structural distortions) near 400 K results in the first turn on thermal conductivity. Similarly, the second local phase transition in near 600 K observed by neutron powder diffraction lead to a decrease thermal conductivity of the sample. Finally, a peak thermoelectric figure of merit (ZT) ≈ 1.51 has been obtained in Sn_0.98Pd_0.025In_0.025Te at 800 K.

Keywords: NPD; SPD; SnTe; local phase transition; thermoelectric performance.