High thermoelectric performance in the new cubic semiconductor AgSnSbSe3by high-entropy engineering

Yubo Luo, Shiqiang Hao, Songting Cai, Tyler J. Slade, Zhong Zhen Luo, Vinayak P. Dravid, Chris Wolverton, Qingyu Yan*, Mercouri G. Kanatzidis

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We investigate the structural and physical properties of the AgSnmSbSem+2 system with m = 1-20 (i.e., SnSe matrix and ∼5-50% AgSbSe2) from atomic, nano, and macro length scales. We find the 50:50 composition, with m = 1 (i.e., AgSnSbSe3), forms a stable cation-disordered cubic rock-salt p-type semiconductor with a special multi-peak electronic valence band structure. AgSnSbSe3 has an intrinsically low lattice thermal conductivity of ∼0.47 W m-1 K-1 at 673 K owing to the synergy of cation disorder, phonon anharmonicity, low phonon velocity, and low-frequency optical modes. Furthermore, Te alloying on Se sites creates a quinary high-entropy NaCl-type solid solution AgSnSbSe3-xTex with randomly disordered cations and anions. The extra point defects and lattice dislocations lead to glass-like lattice thermal conductivities of ∼0.32 W m-1 K-1 at 723 K and higher hole carrier concentration than AgSnSbSe3. Concurrently, the Te alloying promotes greater convergence of the multiple valence band maxima in AgSnSbSe1.5Te1.5, the composition with the highest configurational entropy. Facilitated by these favorable modifications, we achieve a high average power factor of ∼9.54 μW cm-1 K-2 (400-773 K), a peak thermoelectric figure of merit ZT of 1.14 at 723 K, and a high average ZT of ∼1.0 over a wide temperature range of 400-773 K in AgSnSbSe1.5Te1.5.

Original languageEnglish (US)
Pages (from-to)15187-15198
Number of pages12
JournalJournal of the American Chemical Society
Volume142
Issue number35
DOIs
StatePublished - Sep 2 2020

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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