Lattice expansion enables interstitial doping to achieve a high average ZT in n‐type PbS

Autor: Zhengtao Liu, Tao Hong, Liqing Xu, Sining Wang, Xiang Gao, Cheng Chang, Xiangdong Ding, Yu Xiao, Li‐Dong Zhao
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Interdisciplinary Materials, Vol 2, Iss 1, Pp 161-170 (2023)
Druh dokumentu: article
ISSN: 2767-441X
DOI: 10.1002/idm2.12056
Popis: Abstract Lead sulfide (PbS) presents large potential in thermoelectric application due to its earth‐abundant S element. However, its inferior average ZT (ZTave) value makes PbS less competitive with its analogs PbTe and PbSe. To promote its thermoelectric performance, this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n‐type PbS. First, the lattice parameter of 5.93 Å in PbS is linearly expanded to 6.03 Å in PbS0.5Se0.5 with increasing Se alloying content. This expanded lattice in Se‐alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials. Based on the PbS0.6Se0.4 content with the minimal lattice thermal conductivity, Cu interstitials are introduced to improve the electron density, thus boosting the peak power factor, from 3.88 μW cm−1 K−2 in PbS0.6Se0.4 to 20.58 μW cm−1 K−2 in PbS0.6Se0.4−1%Cu. Meanwhile, the lattice thermal conductivity in PbS0.6Se0.4−x%Cu (x = 0–2) is further suppressed due to the strong strain field caused by Cu interstitials. Finally, with the lowered thermal conductivity and high electrical transport properties, a peak ZT ~1.1 and ZTave ~0.82 can be achieved in PbS0.6Se0.4 − 1%Cu at 300–773K, which outperforms previously reported n‐type PbS.
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