TY - JOUR
T1 - Local-Disorder-Induced Low Thermal Conductivity in Degenerate Semiconductor Cu22Sn10S32
AU - Kumar, Ventrapati Pavan
AU - Lemoine, Pierric
AU - Carnevali, Virginia
AU - Guélou, Gabin
AU - Lebedev, Oleg I.
AU - Raveau, Bernard
AU - Al Rahal Al Orabi, Rabih
AU - Fornari, Marco
AU - Candolfi, Christophe
AU - Prestipino, Carmelo
AU - Menut, Denis
AU - Malaman, Bernard
AU - Juraszek, Jean
AU - Suekuni, Koichiro
AU - Guilmeau, Emmanuel
N1 - Funding Information:
The authors gratefully thank Christelle Bilot, Jerôme Lecourt, Vincent Dorcet, Francis Gouttefangeas, and Loïc Joanny for technical support. The authors acknowledge SOLEIL for the provision of synchrotron radiation facilities, CDIFX for single-crystal XRD facilities, and CMEBA (platform of the ScanMAT unit, UMS 2001, University of Rennes 1) for SEM-EDS analyses. The authors acknowledge financial support of the French Agence Nationale de la Recherche LabEx EMC3 through the Project FACTO (Grant ANR-10-LABX-09-01), the Normandy Region (Réseau d’Intérêt Normand - Label d’excellence), CARNOT ESP, and FEDER.
Publisher Copyright:
© 2021 American Chemical Society.
PY - 2021/11/1
Y1 - 2021/11/1
N2 - S-based semiconductors are attracting attention as environmentally friendly materials for energy-conversion applications because of their structural complexity and chemical flexibility. Here, we show that the delicate interplay between the chemical composition and cationic order/disorder allows one to stabilize a new sphalerite derivative phase of cubic symmetry in the Cu-Sn-S diagram: Cu22Sn10S32. Interestingly, its crystal structure is characterized by a semiordered cationic distribution, with the Cu-Sn disorder being localized on one crystallographic site in a long-range-ordered matrix. The origin of the partial disorder and its influence on the electronic and thermal transport properties are addressed in detail using a combination of synchrotron X-ray diffraction, Mössbauer spectroscopy, transmission electron microscopy, theoretical modeling, and transport property measurements. These measurements evidence that this compound behaves as a pseudogap, degenerate p-type material with very low lattice thermal conductivity (0.5 W m-1 K-1 at 700 K). We show that localized disorder is very effective in lowering κL without compromising the integrity of the conductive framework. Substituting pentavalent Sb for tetravalent Sn is exploited to lower the hole concentration and doubles the thermoelectric figure of merit ZT to 0.55 at 700 K with respect to the pristine compound. The discovery of this semiordered cubic sphalerite derivative Cu22Sn10S32 furthers the understanding of the structure-property relationships in the Cu-Sn-S system and more generally in ternary and quaternary Cu-based systems.
AB - S-based semiconductors are attracting attention as environmentally friendly materials for energy-conversion applications because of their structural complexity and chemical flexibility. Here, we show that the delicate interplay between the chemical composition and cationic order/disorder allows one to stabilize a new sphalerite derivative phase of cubic symmetry in the Cu-Sn-S diagram: Cu22Sn10S32. Interestingly, its crystal structure is characterized by a semiordered cationic distribution, with the Cu-Sn disorder being localized on one crystallographic site in a long-range-ordered matrix. The origin of the partial disorder and its influence on the electronic and thermal transport properties are addressed in detail using a combination of synchrotron X-ray diffraction, Mössbauer spectroscopy, transmission electron microscopy, theoretical modeling, and transport property measurements. These measurements evidence that this compound behaves as a pseudogap, degenerate p-type material with very low lattice thermal conductivity (0.5 W m-1 K-1 at 700 K). We show that localized disorder is very effective in lowering κL without compromising the integrity of the conductive framework. Substituting pentavalent Sb for tetravalent Sn is exploited to lower the hole concentration and doubles the thermoelectric figure of merit ZT to 0.55 at 700 K with respect to the pristine compound. The discovery of this semiordered cubic sphalerite derivative Cu22Sn10S32 furthers the understanding of the structure-property relationships in the Cu-Sn-S system and more generally in ternary and quaternary Cu-based systems.
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U2 - 10.1021/acs.inorgchem.1c02105
DO - 10.1021/acs.inorgchem.1c02105
M3 - Article
C2 - 34643373
AN - SCOPUS:85118231851
VL - 60
SP - 16273
EP - 16285
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 21
ER -