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Lattice Dislocations Enhancing Thermoelectric PbTe in Addition to Band Convergence
Author(s) -
Chen Zhiwei,
Jian Zhengzhong,
Li Wen,
Chang Yunjie,
Ge Binghui,
Hanus Riley,
Yang Jiong,
Chen Yue,
Huang Mingxin,
Snyder Gerald Jeffrey,
Pei Yanzhong
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201606768
Subject(s) - materials science , condensed matter physics , thermoelectric effect , phonon , thermoelectric materials , phonon scattering , lattice (music) , dislocation , scattering , nanostructure , crystallographic defect , figure of merit , thermal conductivity , nanotechnology , optoelectronics , optics , composite material , thermodynamics , physics , acoustics
Phonon scattering by nanostructures and point defects has become the primary strategy for minimizing the lattice thermal conductivity (κ L ) in thermoelectric materials. However, these scatterers are only effective at the extremes of the phonon spectrum. Recently, it has been demonstrated that dislocations are effective at scattering the remaining mid‐frequency phonons as well. In this work, by varying the concentration of Na in Pb 0.97 Eu 0.03 Te, it has been determined that the dominant microstructural features are point defects, lattice dislocations, and nanostructure interfaces. This study reveals that dense lattice dislocations (≈4 × 10 12 cm −2 ) are particularly effective at reducing κ L . When the dislocation concentration is maximized, one of the lowest κ L values reported for PbTe is achieved. Furthermore, due to the band convergence of the alloyed 3% mol. EuTe the electronic performance is enhanced, and a high thermoelectric figure of merit, zT , of ≈2.2 is achieved. This work not only demonstrates the effectiveness of dense lattice dislocations as a means of lowering κ L , but also the importance of engineering both thermal and electronic transport simultaneously when designing high‐performance thermoelectrics.