Strong enhancement of phonon scattering through nanoscale grains in lead sulfide thermoelectrics

By Haijun Wu, Jesús Carrete, Zhiyun Zhang, Y. Qu, Xuetao Shen, Zhao Wang, Li-dong Zhao, Jiaqing He. 2014

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Thermoelectric materials that transform waste heat generated by equipment or buildings into electricity are emerging as an important green energy technology. Currently, researchers are trying to improve thermoelectric substances by embedding within them nanoscale precipitates that allow these materials to capture more heat. An international team led by Jiaqing He from the South University of Science and Technology of China has now discovered a way to improve this process by systematically introducing nanoscale crystal structure defects, or ‘nanograins’, into lead sulfide (PbS) particles. Their approach tripled the thermoelectric performance of this low-cost mineral from its bulk state without introducing charge-disrupting centers commonly associated with nanoscale precipitates. Detailed analysis revealed that the densely packed nanograins trap heat by scattering solid-state vibrations, or phonons, while simultaneously suppressing ‘bipolar’ interactions between charge carriers that can diminish thermoelectric power.

Subfields: Civil and Structural Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/315a915537a039893489ea3ab624f5a7e6f0f4f6