Xiao Yu, Wang Dongyang, Zhang Yang, Chen Congrun, Zhang Shuxuan, Wang Kedong, Wang Guangtao, Pennycook Stephen J, Snyder G Jeffrey, Wu Haijun, Zhao Li-Dong
School of Materials Science and Engineering , Beihang University , Beijing 100191 , P. R. China.
Department of Materials Science and Engineering , National University of Singapore , 9 Engineering Drive 1 , Singapore 117575 , Singapore.
J Am Chem Soc. 2020 Feb 26;142(8):4051-4060. doi: 10.1021/jacs.0c00306. Epub 2020 Feb 14.
Low-cost and earth-abundant PbS-based thermoelectrics are expected to be an alternative for PbTe, and have attracted extensive attentions from thermoelectric community. Herein, a maximum () ≈ 1.3 at 923 K in -type PbS is obtained through synergistically optimizing quality factor with Sn alloying and PbTe phase incorporation. It is found that Sn alloying in PbS can sharpen the conduction band shape to balance the contradictory interrelationship between carrier mobility and effective mass, accordingly, a peak power factor of ∼19.8 μWcmK is achieved. Besides band sharpening, Sn alloying can also narrow the band gap of PbS so as to make the conduction band position between PbSnS and PbTe well aligned, which can benefit high carrier mobility. Therefore, incorporating the PbTe phase into the PbSnS matrix can not only favorably maintain the carrier mobility at ∼150 cmVs but also suppress the lattice thermal conductivity to ∼0.61 WmK in PbSnS-8%PbTe, which contributes to a largely enhanced quality factor. Consequently, an average () ≈ 0.72 in 300-923 K is achieved in PbSnS-8%PbTe that outperforms other -type PbS-based thermoelectric materials.
低成本且储量丰富的硫化铅基热电材料有望成为碲化铅的替代品，并已引起热电领域的广泛关注。在此，通过用锡合金化和引入碲化铅相协同优化品质因数，在923K时n型硫化铅中获得了最大( )≈1.3。研究发现，硫化铅中的锡合金化可以锐化导带形状，以平衡载流子迁移率和有效质量之间的矛盾相互关系，因此，实现了约19.8μWcmK的峰值功率因数。除了能带锐化之外，锡合金化还可以缩小硫化铅的带隙，以使导带位置在PbSnS和碲化铅之间良好对齐，这有利于高载流子迁移率。因此，将碲化铅相引入PbSnS基体中，不仅可以将载流子迁移率良好地保持在150 cmVs，而且还可以将PbSnS-8%PbTe中的晶格热导率抑制到0.61 WmK，这有助于大大提高品质因数。因此，PbSnS-8%PbTe在300-923K范围内实现了平均( )≈0.72，优于其他n型硫化铅基热电材料。
