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Issue 41, 2013
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Nanograined thermoelectric Bi2Te2.7Se0.3 with ultralow phonon transport prepared from chemically exfoliated nanoplatelets

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Abstract

Herein, we report on a scalable synthesis of surfactant-free Bi2Te2.7Se0.3 nanocrystals by chemical exfoliation and subsequent spark plasma sintering to fabricate nanostructured thermoelectric bulk materials. The exfoliated n-type Bi2Te2.7Se0.3 nanoplatelets were shown to transform into nanoscroll-type crystals (∼5 nm in diameter, ∼50 nm in length) by ultrasonication. The thermoelectric performance of the Bi2Te2.7Se0.3 nanocrystals was found to be recoverable by minimizing surface oxides by chemical reduction of the exfoliated suspensions. Nanostructured bulk materials, composed of plate-like grains with ∼50 nm thickness, were prepared by sintering of the ultrasonicated sample using a spark plasma sintering technique. The resulting compound showed drastic reduction of lattice thermal conductivity (0.31 W m−1 K−1 @ 400 K) due to enhanced phonon scattering at highly dense grain boundaries without deterioration of the power factor (21.0 × 10−4 W m−1 K−2 @ 400 K). The peak ZT value of the present compound (∼0.8 @400 K) is comparable to that of n-type single crystalline Bi2(Te,Se)3, which is one of the highest among the reported values for n-type materials synthesized by a soft chemical route.

Graphical abstract: Nanograined thermoelectric Bi2Te2.7Se0.3 with ultralow phonon transport prepared from chemically exfoliated nanoplatelets

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Publication details

The article was received on 05 Jul 2013, accepted on 28 Aug 2013 and first published on 29 Aug 2013


Article type: Paper
DOI: 10.1039/C3TA12623D
J. Mater. Chem. A, 2013,1, 12791-12796

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    Nanograined thermoelectric Bi2Te2.7Se0.3 with ultralow phonon transport prepared from chemically exfoliated nanoplatelets

    J. Ko, J. Kim, S. Choi, Y. S. Lim, W. Seo and K. H. Lee, J. Mater. Chem. A, 2013, 1, 12791
    DOI: 10.1039/C3TA12623D

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