Structural properties of the thermoelectric material CuCrS2 and of deintercalated CuxCrS2 on different length scales: X-ray diffraction, pair distribution function and transmission electron microscopy studies

DOI: 10.1039/C7TC02983G

Authors: Wolfgang Bensch (Kiel University) , Anna-lena Hansen (Kiel University) , Torben Dankwort (Kiel University) , Hendrik Groß (Kiel University) , Martin Etter (Deutsches Elektronen-Synchrotron (DESY)) , Jan Daniel König (Fraunhofer Institute for Physical Measurement Techniques IPM) , Viola Duppel (Max Planck Institute for Solid State Research) , Lorenz Kienle (Kiel University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: J. Mater. Chem. C

State: Published (Approved)
Published: August 2017
Diamond Proposal Number(s): 14816

Abstract: We report on the structural alterations of the thermoelectric material CuCrS2 introduced by the removal of 1/3 of the Cu+ ions which are located between CrS2 layers. X-ray diffraction (XRD) and pair distribution function (PDF) analyses revealed a newly formed Cu0.66CrS2 phase with monoclinic symmetry and a 3a superstructure. Simultaneously, a distortion of CrS6 octahedra is observed strongly indicating the oxidation of Cr3+  Cr4+ leading to a Jahn-Teller distortion. The structural features extracted form XRD indicate a pronounced disorder in the cationic sub-lattice at moderate temperatures (400 K). Transmission electron microscopy (TEM) examination elucidates the formation of a second Cu0.66CrS2 phase without the superstructure, caused by incipient Cu+ mobility upon beam irradiation. The synergetic combination of high temperature XRD and TEM investigations unveiled the complete mechanism of the phase transition occurring at 503 K, where a transformation into the spinel CuCr2S4 and stoichiometric CuCrS2 occurs.

Subject Areas: Materials, Chemistry


Instruments: I15-Extreme Conditions

Other Facilities: Petra III (DESY, Hamburg)

Added On: 29/08/2017 10:01

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