Journal article

Publication year: 2020

Journal: Applied Physics Letters

Volume number: 116

Issue number: 19

ISSN: 0003-6951

eISSN: 1077-3118

Open access status: Hybrid

DOI Link: https://doi.org/10.1063/5.0003749

Publisher: American Institute of Physics

Abstract: 
The thermoelectric figure of merit ZT, which is defined using electrical conductivity, Seebeck coefficient, thermal conductivity, and absolute temperature T, has been widely used as a simple estimator of the conversion efficiency of a thermoelectric heat engine. When material properties are constant or slowly varying with T, a higher ZT ensures a higher maximum conversion efficiency of thermoelectric materials. However, as material properties can vary strongly with T, efficiency predictions based on ZT can be inaccurate, especially for widetemperature applications. Moreover, although ZT values continue to increase, there has been no investigation of the relationship between ZT and the efficiency in the higher ZT regime. In this paper, we report a counterintuitive situation by comparing two materials: although one material has a higher ZT value over the whole operating temperature range, its maximum conversion efficiency is smaller than that of the other. This indicates that, for material comparisons, the evaluation of exact efficiencies as opposed to a simple comparison of ZTs is necessary in certain cases. (C) 2020 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.

Harvard Citation style: Ryu, B., Chung, J., Choi, E., Ziolkowski, P., Muller, E. and Park, S. (2020) Counterintuitive example on relation between ZT and thermoelectric efficiency, Applied Physics Letters, 116(19), Article 193903. https://doi.org/10.1063/5.0003749

APA Citation style: Ryu, B., Chung, J., Choi, E., Ziolkowski, P., Muller, E., & Park, S. (2020). Counterintuitive example on relation between ZT and thermoelectric efficiency. Applied Physics Letters. 116(19), Article 193903. https://doi.org/10.1063/5.0003749