Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multi-Scale Structuring and Band Alignment by FeTe2 Incorporation
- Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multi-Scale Structuring and Band Alignment by FeTe2 Incorporation
- 장혜정; Weon Ho Shin; Jong Wook Roh; Byungki Ryu; Hyun Sik Kim; Won Seon Seo; Kyunghan Ahn; Soonil Lee
- thermoelectric; FeTe2 inclusion; nano-precipitate; valence band alignment; phonon scattering
- Issue Date
- ACS Applied Materials & Interfaces
- VOL 10, NO 4-3698
- 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.
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