Thermoelectric Properties of the Quaternary Chalcogenides BaCu 5.9 STe 6 and BaCu 5.9 SeTe 6
2014; American Chemical Society; Volume: 54; Issue: 3 Linguagem: Inglês
10.1021/ic502055z
ISSN1520-510X
AutoresMohamed Oudah, Katja M. Kleinke, Holger Kleinke,
Tópico(s)Magnetic and transport properties of perovskites and related materials
ResumoThese quaternary chalcogenides are isostructural, crystallizing in a unique structure type comprising localized Cu clusters and Te(2)(2-) dumbbells. With less than six Cu atoms per formula unit, these materials are p-type narrow-gap semiconductors, according to the balanced formula Ba(2+)(Cu(+))6Q(2-)(Te(2)(2-))3 with Q = S, Se. Encouraged by the outstanding thermoelectric performance of Cu(2-x)Se and the low thermal conductivity of cold-pressed BaCu(5.7)Se(0.6)Te(6.4), we determined the thermoelectric properties of hot-pressed pellets of BaCu(5.9)STe(6) and BaCu(5.9)SeTe(6). Both materials exhibit a high Seebeck coefficient and a low electrical conductivity, combined with very low thermal conductivity below 1 W m(-1) K(-1). Compared to the sulfide-telluride, the selenide-telluride exhibits higher electrical and thermal conductivity and comparable Seebeck coefficient, resulting in superior figure-of-merit values zT, exceeding 0.8 at relatively low temperatures, namely, around 600 K.
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