1. Enhancing thermoelectric performance of n-type PbTe through separately optimizing phonon and charge transport properties.
- Author
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Yang, Zhi, Wang, Siqi, Sun, Yuejun, Xiao, Yu, and Zhao, Li-Dong
- Subjects
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CARRIER density , *PHONONS , *TERNARY alloys , *THERMAL conductivity , *TRANSPORT theory - Abstract
The n -type PbTe still maintains relatively low thermoelectric performance compared with its p -type counterpart. Thus, to promote its performance in n -type PbTe, we conduct successive strategies that firstly suppressing the lattice thermal conductivity (κ lat) through alloying with ternary compound AgSbSe 2 , and then optimizing carrier density with Sb, Bi or I doping. In AgSbSe 2 -alloyed PbTe samples, the κ lat can be evidently reduced, and the minimum κ lat decreases from ∼1.1 Wm−1K−1 in undoped PbTe to ∼0.8 Wm−1K−1 in PbTe–5%AgSbSe 2. Based on PbTe–5%AgSbSe 2 matrix, several dopants (Sb, Bi or I) are used to optimize its carrier density, and found that I element is verified to be the most effective dopant to enhance its electrical transport properties. In I-doped PbTe–5%AgSbSe 2 samples, the carrier density raises from ∼2.49 × 1016 cm−3 in PbTe–5%AgSbSe 2 to ∼1.15 × 1019 cm−3 in PbTe 0.992 I 0.008 -5%AgSbSe 2 , which contributes to the maximum power factor ∼14.8 μWcm−1K−2. Combining the reduced lattice thermal conductivity and improved power factor, the maximum ZT max and average ZT ave values in PbTe 0.992 I 0.008 -5%AgSbSe 2 are boosted to ∼1.0 at 723 K and ∼0.77 at 300–823 K, respectively. This work points out a valid avenue to improve thermoelectric transport property in n -type PbTe with separately successive strategies to adjust its thermal and electrical performance. • κ min ∼0.8 Wm−1K−1 was achieved in n -type PbTe through introducing AgSbSe 2. • PF max of n -type PbTe was significantly enhanced from ∼3.4 μWcm−1K−2 to ∼14.8 μWcm−1K−2 by I doping. • ZT max of n -type PbTe was enhanced from ∼0.45 to ∼1.00. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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