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Issue 1, 2016
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Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1−xBixTe

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Abstract

A promising thermoelectric figure of merit, zT, of ∼1.3 at 725 K was obtained in high quality crystalline ingots of Ge1−xBixTe. The substitution of Bi3+ in a Ge2+ sublattice of GeTe significantly reduces the excess hole concentration due to the aliovalent donor dopant nature of Bi3+. Reduction in carrier density optimizes electrical conductivity, and subsequently enhances the Seebeck coefficient in Ge1−xBixTe. More importantly, a low lattice thermal conductivity of ∼1.1 W m−1 K−1 for Ge0.90Bi0.10Te was achieved, which is due to the collective phonon scattering from meso-structured grain boundaries, nano-structured precipitates, nano-scale defect layers, and solid solution point defects. We have obtained a reasonably high mechanical stability for the Ge1−xBixTe samples. The measured Vickers microhardness value of the high performance sample is ∼165 HV, which is comparatively higher than that of state-of-the-art thermoelectric materials, such as PbTe, Bi2Te3, and Cu2Se.

Graphical abstract: Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1−xBixTe

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Publication details

The article was received on 31 Oct 2015, accepted on 17 Nov 2015 and first published on 18 Nov 2015


Article type: Research Article
DOI: 10.1039/C5QI00230C
Citation: Inorg. Chem. Front., 2016,3, 125-132
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    Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1−xBixTe

    S. Perumal, S. Roychowdhury and K. Biswas, Inorg. Chem. Front., 2016, 3, 125
    DOI: 10.1039/C5QI00230C

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