Is NiCo2S4 really a semiconductor?

Handle URI:
http://hdl.handle.net/10754/576874
Title:
Is NiCo2S4 really a semiconductor?
Authors:
Xia, Chuan ( 0000-0003-4526-159X ) ; Li, Peng ( 0000-0001-8633-9045 ) ; Gandi, Appala; Schwingenschlögl, Udo ( 0000-0003-4179-7231 ) ; Alshareef, Husam N. ( 0000-0001-5029-2142 )
Abstract:
NiCo2S4 is a technologically important electrode material that has recently achieved remarkable performance in pseu-docapacitor, catalysis, and dye-synthesized solar cell applications.[1-5] Essentially, all reports on this material have pre-sumed it to be semiconducting, like many of the chalcogenides, with a reported band-gap in the range of 1.2-1.7 eV.[6,7] In this report, we have conducted detailed experimental and theoretical studies, most of which done for the first time, which overwhelmingly show that NiCo2S4 is in fact a metal. We have also calculated the Raman spectrum of this mate-rial and experimentally verified it for the first time, hence clarifying inconsistent Raman spectra reports. Some of the key results that support our conclusions include: (1) the measured carrier density in NiCo2S4 is 3.18×1022 cm-3, (2) Ni-Co2S4 has a room temperature resistivity of around 103 µΩ cm which increases with temperature, (3) NiCo2S4 exhibits a quadratic dependence of the magnetoresistance on magnetic field, (4) thermopower measurements show an extremely low Seebeck coefficient of 5 µV K-1, (5) first principles calculations confirm that NiCo2S4 is a metal. These results sug-gest that it is time to re-think the presumed semiconducting nature of this promising material. They also suggest that the metallic conductivity is another reason (besides the known significant redox activity) behind the excellent perfor-mance reported for this material.
KAUST Department:
Materials Science and Engineering Program
Citation:
Is NiCo2S4 really a semiconductor? 2015:150831132451002 Chemistry of Materials
Publisher:
American Chemical Society (ACS)
Journal:
Chemistry of Materials
Issue Date:
31-Aug-2015
DOI:
10.1021/acs.chemmater.5b01843
Type:
Article
ISSN:
0897-4756; 1520-5002
Additional Links:
http://pubs.acs.org/doi/10.1021/acs.chemmater.5b01843
Appears in Collections:
Articles; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorXia, Chuanen
dc.contributor.authorLi, Pengen
dc.contributor.authorGandi, Appalaen
dc.contributor.authorSchwingenschlögl, Udoen
dc.contributor.authorAlshareef, Husam N.en
dc.date.accessioned2015-09-06T13:57:05Zen
dc.date.available2015-09-06T13:57:05Zen
dc.date.issued2015-08-31en
dc.identifier.citationIs NiCo2S4 really a semiconductor? 2015:150831132451002 Chemistry of Materialsen
dc.identifier.issn0897-4756en
dc.identifier.issn1520-5002en
dc.identifier.doi10.1021/acs.chemmater.5b01843en
dc.identifier.urihttp://hdl.handle.net/10754/576874en
dc.description.abstractNiCo2S4 is a technologically important electrode material that has recently achieved remarkable performance in pseu-docapacitor, catalysis, and dye-synthesized solar cell applications.[1-5] Essentially, all reports on this material have pre-sumed it to be semiconducting, like many of the chalcogenides, with a reported band-gap in the range of 1.2-1.7 eV.[6,7] In this report, we have conducted detailed experimental and theoretical studies, most of which done for the first time, which overwhelmingly show that NiCo2S4 is in fact a metal. We have also calculated the Raman spectrum of this mate-rial and experimentally verified it for the first time, hence clarifying inconsistent Raman spectra reports. Some of the key results that support our conclusions include: (1) the measured carrier density in NiCo2S4 is 3.18×1022 cm-3, (2) Ni-Co2S4 has a room temperature resistivity of around 103 µΩ cm which increases with temperature, (3) NiCo2S4 exhibits a quadratic dependence of the magnetoresistance on magnetic field, (4) thermopower measurements show an extremely low Seebeck coefficient of 5 µV K-1, (5) first principles calculations confirm that NiCo2S4 is a metal. These results sug-gest that it is time to re-think the presumed semiconducting nature of this promising material. They also suggest that the metallic conductivity is another reason (besides the known significant redox activity) behind the excellent perfor-mance reported for this material.en
dc.language.isoenen
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/10.1021/acs.chemmater.5b01843en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/10.1021/acs.chemmater.5b01843.en
dc.titleIs NiCo2S4 really a semiconductor?en
dc.typeArticleen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalChemistry of Materialsen
dc.eprint.versionPost-printen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorXia, Chuanen
kaust.authorLi, Pengen
kaust.authorGandi, Appalaen
kaust.authorSchwingenschlögl, Udoen
kaust.authorAlshareef, Husam N.en
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