Journal Article

FZJ-2022-06065

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Grain Boundary Complexions Enable a Simultaneous Optimization of Electron and Phonon Transport Leading to High-Performance GeTe Thermoelectric Devices

Zhang, C. (Corresponding author) ; Yan, G. ; Wang, Y. ; Wu, X. ; Hu, L. ; Liu, F. ; Ao, W. ; Cojocaru-Mirédin, O. ; Wuttig, M.FZJ* ; Snyder, G. J. ; Yu, Y. (Corresponding author)

2023
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/33839  doi:10.1002/aenm.202203361

Abstract: Grain boundaries (GBs) form ubiquitous microstructures in polycrystalline materials which play a significant role in tuning the thermoelectric figure of merit (ZT). However, it is still unknown which types of GB features are beneficial for thermoelectrics due to the challenge of correlating complex GB microstructures with transport properties. Here, it is demonstrated that GB complexions formed by Ga segregation in GeTe-based alloys can optimize electron and phonon transport simultaneously. The Ga-rich complexions increase the power factor by reducing the GB resistivity with slightly improved Seebeck coefficients. Simultaneously, they lower the lattice thermal conductivity by strengthening the phonon scattering. In contrast, Ga2Te3 precipitates at GBs act as barriers to scatter both phonons and electrons and are thus unable to improve ZT. Tailoring GBs combined with the beneficial alloying effects of Sb and Pb enables a peak ZT of ≈2.1 at 773 K and an average ZT of 1.3 within 300–723 K for Ge0.78Ga0.01Pb0.1Sb0.07Te. The corresponding thermoelectric device fabricated using 18-pair p-n legs shows a power density of 1.29 W cm−2 at a temperature difference of 476 K. This work indicates that GB complexions can be a facile way to optimize electron and phonon transport, further advancing thermoelectric materials.

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Contributing Institute(s):

1. JARA Institut Green IT (PGI-10)

Research Program(s):

1. 5233 - Memristive Materials and Devices (POF4-523) (POF4-523)

Appears in the scientific report 2023

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 25 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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