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Enhanced thermoelectric performance of n-type Nb-doped PbTe by compensating resonant level and inducing atomic disorder
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DOI:10.1016/j.mtphys.2022.100677.png)
Abstract
En 中文
The inferior thermoelectric performance of n-type PbTe limits the overall conversion efficiency in PbTebased thermoelectric devices. Here, we introduce Sb and Cu2Te into n-type Nb-doped PbTe for achieving ultra-high thermoelectric performance. The co-doping of Sb and Cu effectively optimizes carrier concentration to compensate for the resonant level in Nb-doped PbTe alloys, and consequently achieves superior electrical performance over a wide temperature range. Meanwhile, by combining extended Xray absorption fine structure and exhaustive electron microscopy investigations, we found Nb and Sb substitutions at Pb sites induce atomic disorders, such local mass fluctuation and local strain variation, in the lattice, and Cu2Te further results in microsized segregations and nanoprecipitates, which significantly suppress lattice thermal conductivity. Eventually, a peak ZT of-1.32 at 823 K and a high average ZT(ave)-1.01 in the range from 323 to 823 K are achieved in the Pb0.975Nb0.02Sb0.005Te-0.004Cu(2)Te. Based on our findings, we innovatively employ comprehensive characterization to reveal the origin of ultrahigh thermoelectric performance in n-type Nb-doped PbTe within a wide temperature range, which should be generalized to other thermoelectric materials. (c) 2022 Elsevier Ltd. All rights reserved.
Keywords:
Thermoelectric
n-type PbTe
Resonant levels
Atomic disorder
EXAFS
Journal
IF:
9.7
Papers:
2.0K
Citations:
1.2W
