Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics

Sang Il Kim, Kyu Hyoung Lee, Hyeon A. Mun, Hyun Sik Kim, Sung Woo Hwang, Jong Wook Roh, Dae Jin Yang, Weon Ho Shin, Xiang Shu Li, Young Hee Lee, G. Jeffrey Snyder, Sung Wng Kim

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Abstract

The widespread use of thermoelectric technology is constrained by a relatively low conversion efficiency of the bulk alloys, which is evaluated in terms of a dimensionless figure of merit (zT).The zTof bulk alloys can be improved by reducing lattice thermal conductivity through grain boundary and point-defect scattering, which target low-and high-frequency phonons. Dense dislocation arrays formed at low-energy grain boundaries by liquid-phase compaction in Bi0.5Sb1.5Te3 (bismuth antimony telluride) effectively scatter midfrequency phonons, leading to a substantially lower lattice thermal conductivity. Full-spectrum phonon scatteringwithminimal charge-carrier scattering dramatically improved the zT to 1.86 ± 0.15 at 320 kelvin (K). Further, a thermoelectric cooler confirmed the performance with amaximum temperature difference of 81 K, which is much higher than current commercial Peltier cooling devices.

Original languageEnglish
Pages (from-to)109-114
Number of pages6
JournalScience
Volume348
Issue number6230
DOIs
Publication statusPublished - 2015 Apr 3

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Cite this

Kim, S. I., Lee, K. H., Mun, H. A., Kim, H. S., Hwang, S. W., Roh, J. W., Yang, D. J., Shin, W. H., Li, X. S., Lee, Y. H., Snyder, G. J., & Kim, S. W. (2015). Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics. Science, 348(6230), 109-114. https://doi.org/10.1126/science.aaa4166