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ACS Nano. 2019 Jun 25;13(6):7146-7154. doi: 10.1021/acsnano.9b02574. Epub 2019 Jun 10.

Precision Interface Engineering of an Atomic Layer in Bulk Bi2Te3 Alloys for High Thermoelectric Performance.

Author information

1
Center for Electronic Materials , Korea Institute of Science and Technology (KIST) , Seoul 02792 , Korea.
2
School of Materials Science and Engineering , Yonsei University , Seoul 03722 , Korea.
3
Materials Architecturing Research Center , Korea Institute of Science and Technology , Seoul 02792 , Korea.
4
Institute of Photonics and Information Technology (IPIT) and Department of Physics , Chonbuk National University , Jeonju 54896 , Korea.
5
Division of Nano and Information Technology, KIST School , Korea University of Science and Technology , Seoul 02792 , Korea.

Abstract

Grafting nanotechnology on thermoelectric materials leads to significant advances in their performance. Creation of structural defects including nano-inclusion and interfaces via nanostructuring achieves higher thermoelectric efficiencies. However, it is still challenging to optimize the nanostructure via conventional fabrication techniques. The thermal instability of nanostructures remains an issue in the reproducibility of fabrication processes and long-term stability during operation. This work presents a versatile strategy to create numerous interfaces in a thermoelectric material via an atomic-layer deposition (ALD) technique. An extremely thin ZnO layer was conformally formed via ALD over the Bi0.4Sb1.6Te3 powders, and numerous heterogeneous interfaces were generated from the formation of Bi0.4Sb1.6Te3-ZnO core-shell structures even after high-temperature sintering. The incorporation of ALD-grown ZnO into the Bi0.4Sb1.6Te3 matrix blocks phonon propagation and also provides tunability in electronic carrier density via impurity doping at the heterogeneous grain boundaries. The exquisite control in the ALD cycles provides a high thermoelectric performance of zT = 1.50 ± 0.15 (at 329-360 K). Specifically, ALD is an industry compatible technique that allows uniform and conformal coating over large quantities of powders. The study is promising in terms of the mass production of nanostructured thermoelectric materials with considerable improvements in performance via an industry compatible and reproducible route.

KEYWORDS:

ZnO; atomic layer deposition; bismuth antimony telluride; heterogeneous interface; p-type; thermoelectric

PMID:
31180627
DOI:
10.1021/acsnano.9b02574

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