Lattice expansion enables interstitial doping to achieve a high average ZT in n‐type PbS. Issue 1 (8th August 2022)

• Record Type: Journal Article
• Authors: Liu, Zhengtao; Hong, Tao; Xu, Liqing; Wang, Sining; Gao, Xiang; Chang, Cheng; Ding, Xiangdong; Xiao, Yu; Zhao, Li‐Dong
• Is Part Of: Interdisciplinary materials. Volume 2:Issue 1(2023)
• Page Start: 161
• Page End: 170
• Publication Date: 2022-08-08
• Subjects: electrical transport properties -- interstitial doping -- PbS -- thermal conductivity -- ZTave; Materials science; Science; Periodicals; 620.11
• DOI: 10.1002/idm2.12056
• Languages: English
• ISSNs: 2767-4401

Abstract

Abstract: Lead sulfide (PbS) presents large potential in thermoelectric application due to its earth‐abundant S element. However, its inferior average ZT ( ZT ave ) 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 PbS0.5 Se0.5 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 PbS0.6 Se0.4 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 PbS0.6 Se0.4 to 20.58 μW cm −1 K −2 in PbS0.6 Se0.4 −1%Cu. Meanwhile, the lattice thermal conductivity in PbS0.6 Se0.4 − 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 ZT ave ~0.82 can be achieved in PbS0.6 Se0.4 − 1%Cu at 300–773K, which outperforms previously reported n ‐type PbS. Abstract : Cu interstitial doping is realized in n ‐type PbS‐based thermoelectric material by expanding its lattice space, resulting in synergistically optimized carrier and phonon transport properties, thus contributing to a high ZT ave value of 0.82 at 300–773 K.