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Flexible layer-structured Bi2Te3 thermoelectric on a carbon nanotube scaffold


Inorganic chalcogenides are traditional high-performance thermoelectric materials. However, they suffer from intrinsic brittleness and it is very difficult to obtain materials with both high thermoelectric ability and good flexibility. Here, we report a flexible thermoelectric material comprising highly ordered Bi2Te3 nanocrystals anchored on a single-walled carbon nanotube (SWCNT) network, where a crystallographic relationship exists between the Bi2Te3 <\(\bar{1}2\bar{1}0\)> orientation and SWCNT bundle axis. This material has a power factor of ~1,600 μW m−1 K−2 at room temperature, decreasing to 1,100 μW m−1 K−2 at 473 K. With a low in-plane lattice thermal conductivity of 0.26 ± 0.03 W m−1 K−1, a maximum thermoelectric figure of merit (ZT) of 0.89 at room temperature is achieved, originating from a strong phonon scattering effect. The origin of the excellent flexibility and thermoelectric performance of the Bi2Te3–SWCNT material is attributed, by experimental and computational evidence, to its crystal orientation, interface and nanopore structure. Our results provide insight into the design and fabrication of high-performance flexible thermoelectric materials.

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All relevant data supporting the findings of this study are available within the paper and its Supplementary Information. Additional data are available from the corresponding author upon request.


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The authors acknowledge financial support from the Ministry of Science and Technology of China (grants 2017YFA0700702 and 2016YFA0200101), the National Natural Science Foundation of China (grants 51402310, 51571193, 51625203, 51532008 and 51521091) and the Hundred Talents Program of the Chinese Academy of Sciences, the Equipment Development Project of the Chinese Academy of Sciences and Innovation Foundation of Institute of Metal Research.

Author information

Q.J., S.J., Y.Z., K.T. and C.L. conceived and designed the experiments. Q.J. fabricated the hybrids and characterized their thermoelectric properties and microstructures. S.J. prepared the free-standing high-quality SWCNT scaffold and carried out its characterization. Y.Z. and J.T. fabricated the thermal conductivity test devices and measured the thermal conductivity of the hybrids and pure SWCNTs. D.W. and N.G. conducted the MD simulations. D.T. carried out the in situ TEM nanomechanical test. D.S., P.H., X.C. and X.J. proposed ideas for materials synthesis, characterization and simulation. Q.J., S.J., J.Q., K.T., C.L. and H.M.C. analysed the data and wrote the manuscript. All authors discussed the results and commented on the manuscript.

Correspondence to Kaiping Tai or Ning Gao or Chang Liu.

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Supplementary information

Supplementary Information

Supplementary Notes 1–9, Supplementary Figures 1–23, Supplementary Table 1, Supplementary References 1–54

Supplementary Video 1

Reversible bending of hybrid Bi2Te3 flexible film performed using a non-contact electrostatic approach

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Fig. 1: Illustration of the fabrication and structure of a free-standing highly ordered Bi2Te3–SWCNT hybrid thermoelectric material.
Fig. 2: Bright-field TEM images of the Bi2Te3–SWCNT hybrid.
Fig. 3: Scanning electron microscopy and X-ray diffraction characterizations of the Bi2Te3–SWCNT hybrid.
Fig. 4: Thermoelectric characterization of the ~600-nm-thick (000l)-textured Bi2Te3–SWCNT hybrid (~3,000 s deposition) and a ~600-nm-thick dense Bi2Te3 film.
Fig. 5: Flexible bending tests of the Bi2Te3–SWCNT hybrid and MD simulations.