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Remarkable Roles of Cu To Synergistically Optimize Phonon and Carrier Transport in n-Type PbTe-Cu 2 Te

2017; American Chemical Society; Volume: 139; Issue: 51 Linguagem: Inglês

10.1021/jacs.7b11662

1943-2984

Yu Xiao, Haijun Wu, Wei Li, Meijie Yin, Yanling Pei, Yang Zhang, Liangwei Fu, Yuexing Chen, Stephen J. Pennycook, Li Huang, Jiaqing He, Li‐Dong Zhao,

Thermal Expansion and Ionic Conductivity

High thermoelectric performance of n-type PbTe is urgently needed to match its p-type counterpart. Here, we show a peak ZT ∼ 1.5 at 723 K and a record high average ZT > 1.0 at 300–873 K realized in n-type PbTe by synergistically suppressing lattice thermal conductivity and enhancing carrier mobility by introducing Cu2Te inclusions. Cu performs several outstanding roles: Cu atoms fill the Pb vacancies and improve carrier mobility, contributing to an unexpectedly high power factor of ∼37 μW cm–1 K–2 at 423 K; Cu atoms filling Pb vacancies and Cu interstitials both induce local disorder and, together with nano- and microscale Cu-rich precipitates and their related strain fields, lead to a very low lattice thermal conductivity of ∼0.38 Wm–1 K–1 in PbTe-5.5%Cu2Te, approaching the theoretical minimum value of ∼0.36 Wm–1 K–1. This work provides an effective strategy to enhance thermoelectric performance by simultaneously improving electrical and thermal transport properties.