1. Regulation of electronic and phonon transports of AgBiSe2-based solid solutions by entropy engineering.
- Author
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Xia, Qingrui, Ying, Pengzhan, Xia, Yafen, Li, Xie, and Cui, Jiaolin
- Subjects
SOLID solutions ,ENTROPY ,PHONONS ,CARRIER density ,TRANSITION temperature ,THERMAL conductivity ,PHONON scattering - Abstract
AgBiSe
2 is a promising thermoelectric (TE) candidate because of its intrinsically low thermal conductivity (κ = 0.4–0.5 W K−1 m−1 at ∼770 K) and optimal n-type carrier concentration (5.85 × 1018 cm−3 at 300 K). However, its TE figure of merit (ZT) is still low (0.3 at ∼770 K). Therefore, it is necessary to further improve its ZT. In this work, the solid solutions (AgBiSe2 )1− x (Ag2 Te)x (x = 0–0.125) have been designed through simple alloying Ag2 Te inspired by the entropy engineering concept, and the TE performance has been further regulated. The analyses show that the exothermic effects related to α/β and β/γ phase transitions weaken, and the transition temperature of β/γ decreases as the Ag2 Te content increases, which indicates the stabilization of the cubic γ-phase at high temperatures. Aside from that, the power factor (PF) enhances from 2.91 μW/cm K2 (x = 0) to 3.49 μW/cm K2 (x = 0.075), and at the same time, the lattice thermal conductivity reduces from 0.3 W K−1 m−1 to 0.1 W K−1 m−1 at ∼760 K. This directly improves the TE performance with the highest ZT value of 1.0, which is almost double that of the pristine AgBiSe2 . The result suggests that the entropy engineering is a very effective screening method in thermoelectrics. [ABSTRACT FROM AUTHOR]- Published
- 2021
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