Key Role of Defects in Thermoelectric Performance of TiMSn (M = Ni, Pd, and Pt) Half-Heusler Alloys
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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en
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10
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Journal of Physical Chemistry C, Volume 124, issue 28, pp. 14997-15006
Abstract
Half-Heusler alloys are thermoelectric materials that enable direct conversion of waste heat to electricity. A systematic study of these alloys has never been attempted using local Gaussian type orbitals (GTOs) and hybrid density functional theory methods within a periodic approach. In this work, we study the thermoelectric properties of TiMSn (M = Ni, Pd, and Pt) alloys with space group F4¯ 3m using the CRYSTAL code. We, first, set benchmarks for TiNiSn by comparing our data to existing literature values of Seebeck coefficient, power-factor, and thermoelectric figure-of-merit. Our results agree well. We, then, extend these calculations to TiPdSn and TiPtSn, for which consistent previous data are limited. Our computations show that all TiMSn (M = Ni, Pd, and Pt) alloys prefer p-type carriers and exhibit a figure-of-merit of ≈1 at a chosen carrier concentration and temperature. In addition, we aim to explain the low band-gap of TiNiSn by modeling defects in the pure system. Our defect model proves to have a smaller band-gap, and its power-factor is found to be almost twice of the pure TiNiSn.Description
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Dasmahapatra, A, Daga, L E, Karttunen, A J, Maschio, L & Casassa, S 2020, 'Key Role of Defects in Thermoelectric Performance of TiMSn (M = Ni, Pd, and Pt) Half-Heusler Alloys', Journal of Physical Chemistry C, vol. 124, no. 28, pp. 14997-15006. https://doi.org/10.1021/acs.jpcc.0c03243