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Title: Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1-xBixTe
Authors: Perumal, Suresh
Roychowdhury, Subhajit
Biswas, Kanishka
Keywords: Chemistry
Performance Bulk Thermoelectrics
Germanium Antimony Tellurides
Valence-Band Convergence
Issue Date: 2016
Publisher: Chinese Chemical Society
Citation: Perumal, S.; Roychowdhury, S.; Biswas, K., Reduction of thermal conductivity through nanostructuring enhances the thermoelectric figure of merit in Ge1-xBixTe. Inorganic Chemistry Frontiers 2016, 3 (1), 125-132
Inorganic Chemistry Frontiers
Abstract: A promising thermoelectric figure of merit, zT, of similar to 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 similar to 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 similar to 165 H-V, which is comparatively higher than that of state-of-the-art thermoelectric materials, such as PbTe, Bi2Te3, and Cu2Se.
Description: Open Access (Manuscript)
ISSN: 2052-1553
Appears in Collections:Research Papers (Kaniska Biswas)

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