Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multi-Scale Structuring and Band Alignment by FeTe2 Incorporation

Title
Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multi-Scale Structuring and Band Alignment by FeTe2 Incorporation
Authors
장혜정Weon Ho ShinJong Wook RohByungki RyuHyun Sik KimWon Seon SeoKyunghan AhnSoonil Lee
Keywords
thermoelectric; FeTe2 inclusion; nano-precipitate; valence band alignment; phonon scattering
Issue Date
2018-01
Publisher
ACS Applied Materials & Interfaces
Citation
VOL 10, NO 4-3698
Abstract
It has been in difficulty in forming well-distributed nano- and meso-sized inclusions in a Bi2Te3-based matrix and thereby realizing no degradation of carrier mobility at interfaces between matrix and inclusions for high thermoelectric performances. Herein, we successfully synthesize multi-structured thermoelectric Bi0.4Sb1.6Te3 materials with Fe-rich nano-precipitates and sub-micron sized FeTe2 inclusions by a conventional solid state reaction followed by melt-spinning and spark plasma sintering that could be a facile preparation method for scale-up production. This study presents a bismuth antimony telluride based thermoelectric material with a multi-scale structure whose lattice thermal conductivity is drastically reduced with a minimal degradation on its carrier mobility. This is possible because a carefully chosen FeTe2 incorporated in a matrix allows its interfacial valence band with the matrix to be aligned, leading to a significantly improved p-type thermoelectric power factor. Consequently, an impressively high ZT of 1.52 is achieved at 396 K for p-type Bi0.4Sb1.6Te3-8 mol.% FeTe2, which is 43 % enhancement in ZT compared to the pristine Bi0.4Sb1.6Te3. This work demonstrates not only the effectiveness of multi-scale structuring for lowering lattice thermal conductivities, but also the importance of interfacial band alignment between matrix and inclusions for maintaining high carrier mobilities when designing high performance thermoelectric materials.
URI
http://pubs.kist.re.kr/handle/201004/67211
ISSN
1944-8244
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KIST Publication > Article
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