Chemical Control of Defects for Optimizing Thermoelectric Performance of Lead Telluride
A surprisingly large portion of energy is lost as waste heat every year due to inefficient utilization.1 Thermoelectric (TE) materials may increase the overall efficiency of our energy utilization by directly converting waste heat to electricity.2 It is essential to have high efficiency in both p and n type semiconducting materials to achieve a high performance in thermoelectric generators. However, the efficiency of a TE material depends on the dimensionless figure of merit that involves a complex relation between the electronic and thermal properties as stated by the Wiedemann-Franz law.2 This presents a serious roadblock in the optimization of thermoelectric performance of any material.
In this seminar, I will present effective strategies to circumvent this problem in lead telluride (PbTe) which is a benchmark thermoelectric material via chemical control of point defects in the matrix. I will discuss the mechanisms to decouple the electronic and thermal properties of this system. I will further elaborate how these defects affect the electronic band structure of p and n type PbTe leading to modulation of the carrier concentration over a broad temperature range to facilitate high thermoelectric performance.3,4
In the later part of the seminar, I will discuss my future research plans related to thermal energy harvesting using environment friendly materials and the study of their structure-property correlations.
1. Rattner, A. S.; Garimella S. Energy 2011, 36(10), 6172–6183
2. He, J.; Tritt, T. M. Science 2017, 357 (6358), eaak9997
3. Sarkar, S.; Zhang, X.; Hao, S.; Hua, X.; Bailey, T. P.; Uher, C.; Wolverton, C.; Dravid, V.; Kanatzidis, M. G. ACS Energy Lett. 2018, 3 (10), 2593–2601
4. Sarkar, S.; Hua, X.; Hao, S.; Zhang, X.; Bailey, T. P.; Slade, T. J.; Yasaei, P.; Korkotz, R.; Tan, G.; Uher, C.; Wolverton, C.; Dravid, V. P.; Kanatzidis, M. G. Chem. Mater. 2021, 33, 5, 1842–1851