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Article: Vacancy manipulation for thermoelectric enhancements in GeTe alloys

TitleVacancy manipulation for thermoelectric enhancements in GeTe alloys
Authors
KeywordsAntimony compounds
Germanium compounds
Point defects
Positive ions
Thermal conductivity
Issue Date2018
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html
Citation
Journal of the American Chemical Society, 2018, v. 140 n. 46, p. 15883-15888 How to Cite?
AbstractOptimization of carrier concentration plays an important role on maximizing thermoelectric performance. Existing efforts mainly focus on aliovalent doping, while intrinsic defects (e.g., vacancies) provide extra possibilities. Thermoelectric GeTe intrinsically forms in off-stoichiometric with Ge-vacancies and Ge-precipitates, leading to a hole concentration significantly higher than required. In this work, Sb2Te3 having a smaller cation-to-anion ratio, is used as a solvend to form solid solutions with GeTe for manipulating the vacancies. This is enabled by the fact that each substitution of 3 Ge2+ by only 2 Sb3+ creates 1 Ge vacancy, because of the overall 1:1 cation-to-anion ratio of crystallographic sites in the structure and by the charge neutrality. The increase in the overall Ge-vacancy concentration facilitates Ge-precipitates to be dissolved into the matrix for reducing the hole concentration. In a combination with known reduction in hole concentration by Pb/Ge-substitution, a full optimization on hole concentration is realized. In addition, the resultant high-concentration point defects including both vacancies and substitutions strongly scatter phonons and reduce the lattice thermal conductivity to the amorphous limit. These enable a significantly improved thermoelectric figure of merit at working temperatures of thermoelectric GeTe.
Persistent Identifierhttp://hdl.handle.net/10722/272236
ISSN
2017 Impact Factor: 14.357
2015 SCImago Journal Rankings: 7.123

 

DC FieldValueLanguage
dc.contributor.authorZhang, X-
dc.contributor.authorLi, J-
dc.contributor.authorWang, X-
dc.contributor.authorChen, Z-
dc.contributor.authorMAO, J-
dc.contributor.authorChen, Y-
dc.contributor.authorPei, Y-
dc.date.accessioned2019-07-20T10:38:20Z-
dc.date.available2019-07-20T10:38:20Z-
dc.date.issued2018-
dc.identifier.citationJournal of the American Chemical Society, 2018, v. 140 n. 46, p. 15883-15888-
dc.identifier.issn0002-7863-
dc.identifier.urihttp://hdl.handle.net/10722/272236-
dc.description.abstractOptimization of carrier concentration plays an important role on maximizing thermoelectric performance. Existing efforts mainly focus on aliovalent doping, while intrinsic defects (e.g., vacancies) provide extra possibilities. Thermoelectric GeTe intrinsically forms in off-stoichiometric with Ge-vacancies and Ge-precipitates, leading to a hole concentration significantly higher than required. In this work, Sb2Te3 having a smaller cation-to-anion ratio, is used as a solvend to form solid solutions with GeTe for manipulating the vacancies. This is enabled by the fact that each substitution of 3 Ge2+ by only 2 Sb3+ creates 1 Ge vacancy, because of the overall 1:1 cation-to-anion ratio of crystallographic sites in the structure and by the charge neutrality. The increase in the overall Ge-vacancy concentration facilitates Ge-precipitates to be dissolved into the matrix for reducing the hole concentration. In a combination with known reduction in hole concentration by Pb/Ge-substitution, a full optimization on hole concentration is realized. In addition, the resultant high-concentration point defects including both vacancies and substitutions strongly scatter phonons and reduce the lattice thermal conductivity to the amorphous limit. These enable a significantly improved thermoelectric figure of merit at working temperatures of thermoelectric GeTe.-
dc.languageeng-
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/journals/jacsat/index.html-
dc.relation.ispartofJournal of the American Chemical Society-
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in [JournalTitle], copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see [insert ACS Articles on Request author-directed link to Published Work, see http://pubs.acs.org/page/policy/articlesonrequest/index.html].-
dc.subjectAntimony compounds-
dc.subjectGermanium compounds-
dc.subjectPoint defects-
dc.subjectPositive ions-
dc.subjectThermal conductivity-
dc.titleVacancy manipulation for thermoelectric enhancements in GeTe alloys-
dc.typeArticle-
dc.identifier.emailChen, Y: yuechen@hku.hk-
dc.identifier.authorityChen, Y=rp01925-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1021/jacs.8b09375-
dc.identifier.pmid30265000-
dc.identifier.scopuseid_2-s2.0-85054981910-
dc.identifier.hkuros298945-
dc.identifier.volume140-
dc.identifier.issue46-
dc.identifier.spage15883-
dc.identifier.epage15888-
dc.publisher.placeUnited States-

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