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Structural Evolution of High-Performance Mn-Alloyed Thermoelectric Materials: A Case Study of SnTe.
Sun, Qiang; Chen, Zhi-Yu; Li, Meng; Shi, Xiao-Lei; Xu, Sheng-Duo; Yin, Yu; Dargusch, Matthew; Zou, Jin; Ang, Ran; Chen, Zhi-Gang.
  • Sun Q; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Chen ZY; Key Laboratory of Radiation Physics and Technology, Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, 610064, China.
  • Li M; Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu, 610065, China.
  • Shi XL; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Xu SD; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Yin Y; Centre for Future Materials, University of Southern Queensland, Springfield Central, Brisbane, Queensland, 4300, Australia.
  • Dargusch M; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Zou J; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Ang R; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
  • Chen ZG; School of Mechanical and Mining Engineering, University of Queensland, Brisbane, Queensland, 4072, Australia.
Small ; 17(25): e2100525, 2021 Jun.
Article en En | MEDLINE | ID: mdl-34032362
ABSTRACT
Mn alloying in thermoelectrics is a long-standing strategy for enhancing their figure-of-merit through optimizing electronic transport properties by band convergence, valley perturbation, or spin-orbital coupling. By contrast, mechanisms by which Mn contributes to suppressing thermal transports, namely thermal conductivity, is still ambiguous. A few precedent studies indicate that Mn introduces a series of hierarchical defects from the nano- to meso-scale, leading to effective phonon scattering scoping a wide frequency spectrum. Due to insufficient insights at the atomic level, the theory remains as phenomenological and cannot be used to quantitatively predict the thermal conductivity of Mn-alloyed thermoelectrics. Herein, by choosing the SnTe as a case study, aberration-corrected transmission electron microscopy (TEM)/scanning transmission electron microscopy (STEM) to characterize the lattice complexity of Sn1.02- x Mnx Te is employed. Mn as a "dynamic" dopant that plays an important role in SnTe with respect to different alloying levels or post treatments is revealed. The results indicate that Mn precipitates at x = 0.08 prior to reaching solubility (≈10 mol%), and then splits into MnSn substitution and γ-MnTe hetero-phases via mechanical alloying. Understanding such unique crystallography evolution, combined with a modified Debye-Callaway model, is critical in explaining the decreased thermal conductivity of Sn1.02- x Mnx Te with rational phonon scattering pathways, which should be applicable for other thermoelectric systems.
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Texto completo: 1 Banco de datos: MEDLINE Tipo de estudio: Prognostic_studies / Qualitative_research Idioma: En Año: 2021 Tipo del documento: Article

Texto completo: 1 Banco de datos: MEDLINE Tipo de estudio: Prognostic_studies / Qualitative_research Idioma: En Año: 2021 Tipo del documento: Article