Six Quaternary Chalcogenides of the Pavonite Homologous Series with Ultralow Lattice Thermal Conductivity

Jing Zhao, Shiqiang Hao, Saiful M. Islam, Haijie Chen, Gangjian Tan, Shulan Ma, Christopher Wolverton, Mercouri G. Kanatzidis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Six new quaternary chalcogenides belonging to the pavonite sulfosalt mineral family with the general formula M n+1 (Bi/Sb) 2 Q n+5 (n = 2-7) were synthesized by direct reactions of the elements at high temperatures. The compounds include InPbBi 3 S 7 (n = 2), In 0.5 Mn 2 Bi 3.5 Se 8 (n = 3), CdPb 2 Bi 4 S 9 (n = 4), Ag 1.5 CdBi 5.5 Se 10 (n = 5), Ag 2 CdBi 6 Se 11 (n = 6), and Ag 2.5 CdSb 6.5 Se 12 (n = 7) and crystallized in the monoclinic space group C2/m. The pavonite structure consists of two alternating slabs, a thinner slab composed of pairs of monocapped trigonal prisms separated by octahedra and a thicker slab with a galena-like structure motif. In the general formula, n corresponds to the number of octahedra along the diagonal direction of the galena-like slab. The complex compositions, mixed occupancies of the cations, and quasi-two-dimensional structures endow compounds of this family with extremely low thermal conductivity. The charge and thermal transport properties of CdPb 2 Bi 4 S 9 and CdAg 2 Bi 6 Se 11 were characterized from 300 to 810 K, and both materials exhibited n-type semiconductor behaviors and ultralow lattice thermal conductivities of less than 0.35 W·m -1 ·K -1 for CdAg 2 Bi 6 Se 11 and 0.73 W·m -1 ·K -1 for CdPb 2 Bi 4 S 9 in the measured temperature range. Density functional theory calculations revealed the origins of this low lattice thermal conductivity to be a combination of the low Debye temperature, small phonon velocities, and large Grüneisen parameters. Thermoelectric properties were measured, and the highest ZT values of 0.53 and 0.95 for undoped CdPb 2 Bi 4 S 9 and CdAg 2 Bi 6 Se 11 , respectively, were attained at 775 K.

Original languageEnglish (US)
Pages (from-to)3430-3439
Number of pages10
JournalChemistry of Materials
Volume31
Issue number9
DOIs
StatePublished - May 14 2019

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Six Quaternary Chalcogenides of the Pavonite Homologous Series with Ultralow Lattice Thermal Conductivity'. Together they form a unique fingerprint.

Cite this