Dissociation of GaSb in n-Type PbTe: Off-Centered Gallium Atom and Weak Electron-Phonon Coupling Provide High Thermoelectric Performance

Sumanta Sarkar, Xia Hua, Shiqiang Hao, Xiaomi Zhang, Trevor P. Bailey, Tyler J. Slade, Poya Yasaei, Rachel J. Korkosz, Gangjian Tan, Ctirad Uher, Vinayak P. Dravid, Chris Wolverton, Mercouri G. Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Many strategies have been employed to maintain an "optimal carrier concentration"to achieve a high thermoelectric power factor in n-type PbTe. Here, we show that a high power factor can also be achieved over a broad temperature range without attaining the optimal carrier concentration by alloying n-type PbTe with GaSb. We find that GaSb dissociates into Ga and Sb and dissolves into the PbTe matrix. Ga atoms introduce impurity levels above the valence band of PbTe giving rise to diminished electron-phonon coupling and an increased carrier effective mass leading to a high Seebeck coefficient of -87 μV K-1 and a high carrier mobility of 810 cm2 V-1s-1 at 300 K. As a result, a high power factor of 29 μW cm-1 K-2 at 323 K is achieved. Phonon band-structure calculations show that Ga is off-centered (0.05 Å) from Pb site along the «111»direction leading to a reduced lattice thermal conductivity of 0.7 W m-1 K-1 and a maximum thermoelectric figure of merit of 1.35 at 773 K in PbTe0.997I0.003-2 mol % GaSb. The dissolution of III-V semiconductors in lead telluride is a new finding with broader implications and opens new avenues in controlling thermal and charge transport in advanced thermoelectric materials.

Original languageEnglish (US)
Pages (from-to)1842-1851
Number of pages10
JournalChemistry of Materials
Volume33
Issue number5
DOIs
StatePublished - Mar 9 2021

Funding

This work was supported by the Department of Energy, Office of Science Basic Energy Sciences under grant DE-SC0014520, DOE Office of Science. Access to facilities of high performance computational resources at Northwestern University is gratefully acknowledged. This work made use of EPIC (JEOL 2100F TEM) facility of the Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the Materials Processing and Microfabrication Facility (NUFAB-COOK) supported by the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Temperature-dependent Hall measurements were supported by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under Award Number DE-SC-0008574.

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry

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