Publication Date

6-10-2021

Department

Ames Laboratory; Chemistry

Campus Units

Ames Laboratory, Chemistry

OSTI ID+

1798868

Report Number

IS-J 10520

DOI

10.1021/acs.chemmater.1c01053

Journal Title

Chemistry of Materials

Volume Number

33

Issue Number

12

First Page

4586

Last Page

4595

Abstract

Two new ternary tetrel pnictide phases, Li1.08Ge4.92As7 and Cs0.11Zn0.05Si0.95As, have been synthesized. Both compounds crystallize in new structure types, which demonstrate the flexibility of Ge(Si)–As layers when accommodating electropositive cations of various sizes. Li1.08Ge4.92As7 displays a Ge-As layer motif that has not been observed in ternary Ge-As systems, while Cs0.11Zn0.05Si0.95As exhibits a 3D framework composed of fragments of the 2D parent-phase SiAs. For Li1.08Ge4.92As7, a combination of computational modeling and solid-state 7Li MAS NMR was used to establish the correct crystal structure with one mixed occupied Ge/Li site. The compositions of the phases were confirmed through energy-dispersive X-ray spectroscopy. Transport properties and UV–Vis spectroscopy reveal both reported compounds to be semiconductors. Cs0.11Zn0.05Si0.95As shows high thermal stability with congruent melting at 1300 K and an exceptionally low thermal conductivity of 0.5 W m–1 K–1 at 300 K. Temperature-dependent Li-ion hopping dynamics in Li1.08Ge4.92As7 was characterized using 7Li solid-state NMR.

DOE Contract Number(s)

AC02-07CH11358

Language

en

Publisher

Iowa State University Digital Repository, Ames IA (United States)

Available for download on Friday, June 10, 2022

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