Open AccessThermoelectric Enhancements in PbTe Alloys Due to Dislocation‐Induced Strains and Converged Bands
Author(s) -
Wu Yixuan,
Nan Pengfei,
Chen Zhiwei,
Zeng Zezhu,
Liu Ruiheng,
Dong Hongliang,
Xie Li,
Xiao Youwei,
Chen Zhiqiang,
Gu Hongkai,
Li Wen,
Chen Yue,
Ge Binghui,
Pei Yanzhong
Publication year - 2020
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201902628
Subject(s) - thermoelectric effect , dislocation , materials science , thermoelectric materials , condensed matter physics , engineering physics , nanotechnology , physics , thermodynamics , composite material
In‐grain dislocation‐induced lattice strain fluctuations are recently revealed as an effective avenue for minimizing the lattice thermal conductivity. This effect could be integratable with electronic enhancements such as by band convergence, for a great advancement in thermoelectric performance. This motivates the current work to focus on the thermoelectric enhancements of p‐type PbTe alloys, where monotelluride‐alloying and Na‐doping are used for a simultaneous manipulation on both dislocation and band structures. As confirmed by synchrotron X‐ray diffractions and Raman measurements, the resultant dense in‐grain dislocations induce lattice strain fluctuations for broadening the phonon dispersion, leading to an exceptionally low lattice thermal conductivity of ≈0. 4 W m‐K −1 . Band structure calculations reveal the convergence of valence bands due to monotelluride‐alloying. Eventually, the integration of both electronic and thermal improvements lead to a realization of an extraordinary figure of merit zT of ≈2.5 in Na 0.03 Eu 0.03 Cd 0.03 Pb 0.91 Te alloy at 850 K.