TY - JOUR
T1 - Long-Range Cationic Order Collapse Triggered by S/Cl Mixed-Anion Occupancy Yields Enhanced Thermoelectric Properties in Cu5Sn2S7
AU - Guelou, Gabin
AU - Fornari, Marco
N1 - Funding Information:
The authors gratefully thank Christelle Bilot and Jerôme Lecourt for technical support. The authors acknowledge SOLEIL for the provision of synchrotron radiation facilities (proposal 20200538) and would like to thank Landrot Gautier and Zitolo Andrea for assistance in using beamline Samba. The authors acknowledge the financial support of the French Agence Nationale de la Recherche LabEx EMC3 through the Project FACTO (Grant No. ANR-10-LABX-09-01), the Normandy Region (Réseau d’Intérêt Normand-Label d’excellence), and FEDER.
Funding Information:
The authors acknowledge the financial support of the French Agence Nationale de la Recherche LabEx EMC3 through the Project FACTO (Grant No. 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
Y1 - 2021
N2 - To investigate pathways to adjust the charge carrier concentration and optimize the thermoelectric properties, we characterized structural properties, thermal stability, and thermoelectric performance of pristine and Cl-doped Cu5+ϵSn2-ϵS7. We demonstrate that Cl doping in Cu5Sn2S7-type monoclinic compounds induces a collapse of the long-range cationic ordering, ultimately leading to a sphalerite-type cubic phase characterized by ordered [Sn(S,Cl)4]x clusters. The change in crystal structure symmetry upon Cl doping is analyzed by Rietveld refinements against X-ray powder diffraction data, transmission electron microscopy, Mössbauer and X-ray absorption spectroscopy, and low-and high-temperature transport property measurements. The thermoelectric properties of the so-obtained cubic sphalerite Cu5+ϵSn2-ϵS7-yCly (0 ≤ ϵ ≤ 0.133, y = 0.35, 0.70) are strongly enhanced with respect to the undoped Cu5Sn2S7: the power factor improves slightly while both electronic and lattice contributions to the thermal conductivity are reduced. Overall, single-phase Cl-doped Cu5.133Sn1.866S7-yCly (y = 0.35, 0.70) compounds exhibit high thermoelectric performance, reaching a maximum ZT of 0.45 at 670 K.
AB - To investigate pathways to adjust the charge carrier concentration and optimize the thermoelectric properties, we characterized structural properties, thermal stability, and thermoelectric performance of pristine and Cl-doped Cu5+ϵSn2-ϵS7. We demonstrate that Cl doping in Cu5Sn2S7-type monoclinic compounds induces a collapse of the long-range cationic ordering, ultimately leading to a sphalerite-type cubic phase characterized by ordered [Sn(S,Cl)4]x clusters. The change in crystal structure symmetry upon Cl doping is analyzed by Rietveld refinements against X-ray powder diffraction data, transmission electron microscopy, Mössbauer and X-ray absorption spectroscopy, and low-and high-temperature transport property measurements. The thermoelectric properties of the so-obtained cubic sphalerite Cu5+ϵSn2-ϵS7-yCly (0 ≤ ϵ ≤ 0.133, y = 0.35, 0.70) are strongly enhanced with respect to the undoped Cu5Sn2S7: the power factor improves slightly while both electronic and lattice contributions to the thermal conductivity are reduced. Overall, single-phase Cl-doped Cu5.133Sn1.866S7-yCly (y = 0.35, 0.70) compounds exhibit high thermoelectric performance, reaching a maximum ZT of 0.45 at 670 K.
M3 - Article
SN - 0897-4756
VL - 33
SP - 9425
EP - 9438
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 23
ER -