Low Thermal Conductivity in Heteroanionic Materials with Layers of Homoleptic Polyhedra

Chi Zhang, Jiangang He, Rebecca McClain, Hongyao Xie, Songting Cai, Lauren N. Walters, Jiahong Shen, Fenghua Ding, Xiuquan Zhou, Christos D. Malliakas, James M. Rondinelli, Mercouri G. Kanatzidis, Chris Wolverton, Vinayak P. Dravid*, Kenneth R. Poeppelmeier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Although BiAgOSe, an analogue of a well-studied thermoelectric material BiCuOSe, is thermodynamically stable, its synthesis is complicated by the low driving force of formation from the stable binary and ternary intermediates. Here we have developed a "subtraction strategy"to suppress byproducts and produce pure phase BiAgOSe using hydrothermal methods. Electronic structure calculations and optical characterization show that BiAgOSe is an indirect bandgap semiconductor with a bandgap of 0.95 eV. The prepared sample exhibits lower lattice thermal conductivities (0.61 W·m-1·K-1 at room temperature and 0.35 W·m-1·K-1 at 650 K) than BiCuOSe. Lattice dynamical simulations and variable temperature diffraction measurements demonstrate that the low lattice thermal conductivity arises from both the low sound velocity and high phonon-phonon scattering rates in BiAgOSe. These in turn result primarily from the soft Ag-Se bonds in the edge-sharing AgSe4 tetrahedra and large sublattice mismatch between the quasi-two-dimensional [Bi2O2]2+ and [Ag2Se2]2- layers. These results highlight the advantages of manipulating the chemistry of homoleptic polyhedra in heteroanionic compounds for electronic structure and phonon transport control.

Original languageEnglish (US)
Pages (from-to)2569-2579
Number of pages11
JournalJournal of the American Chemical Society
Volume144
Issue number6
DOIs
StatePublished - Feb 16 2022

ASJC Scopus subject areas

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

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