Abstract
As a lead-free material, GeTe has drawn growing attention in thermoelectrics, and a figure of merit (ZT) close to unity was previously obtained via traditional doping/alloying, largely through hole carrier concentration tuning. In this report, we show that a remarkably high ZT of ∼1.9 can be achieved at 773 K in Ge0.87Pb0.13Te upon the introduction of 3 mol % Bi2Te3. Bismuth telluride promotes the solubility of PbTe in the GeTe matrix, thus leading to a significantly reduced thermal conductivity. At the same time, it enhances the thermopower by activating a much higher fraction of charge transport from the highly degenerate ∑ valence band, as evidenced by density functional theory calculations. These mechanisms are incorporated and discussed in a three-band (L + ∑ + C) model and are found to explain the experimental results well. Analysis of the detailed microstructure (including rhombohedral twin structures) in Ge0.87Pb0.13Te + 3 mol % Bi2Te3 was carried out using transmission electron microscopy and crystallographic group theory. The complex microstructure explains the reduced lattice thermal conductivity and electrical conductivity as well.
| Original language | English |
|---|---|
| Pages (from-to) | 11412-11419 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 136 |
| Issue number | 32 |
| DOIs | |
| Publication status | Published - Aug 13 2014 |
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ASJC Scopus subject areas
- Chemistry(all)
- Catalysis
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Origin of the high performance in GeTe-based thermoelectric materials upon Bi2Te3 doping. / Wu, Di; Zhao, Li Dong; Hao, Shiqiang; Jiang, Qike; Zheng, Fengshan; Doak, Jeff W.; Wu, Haijun; Chi, Hang; Gelbstein, Y.; Uher, C.; Wolverton, C.; Kanatzidis, Mercouri G; He, Jiaqing.
In: Journal of the American Chemical Society, Vol. 136, No. 32, 13.08.2014, p. 11412-11419.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Origin of the high performance in GeTe-based thermoelectric materials upon Bi2Te3 doping
AU - Wu, Di
AU - Zhao, Li Dong
AU - Hao, Shiqiang
AU - Jiang, Qike
AU - Zheng, Fengshan
AU - Doak, Jeff W.
AU - Wu, Haijun
AU - Chi, Hang
AU - Gelbstein, Y.
AU - Uher, C.
AU - Wolverton, C.
AU - Kanatzidis, Mercouri G
AU - He, Jiaqing
PY - 2014/8/13
Y1 - 2014/8/13
N2 - As a lead-free material, GeTe has drawn growing attention in thermoelectrics, and a figure of merit (ZT) close to unity was previously obtained via traditional doping/alloying, largely through hole carrier concentration tuning. In this report, we show that a remarkably high ZT of ∼1.9 can be achieved at 773 K in Ge0.87Pb0.13Te upon the introduction of 3 mol % Bi2Te3. Bismuth telluride promotes the solubility of PbTe in the GeTe matrix, thus leading to a significantly reduced thermal conductivity. At the same time, it enhances the thermopower by activating a much higher fraction of charge transport from the highly degenerate ∑ valence band, as evidenced by density functional theory calculations. These mechanisms are incorporated and discussed in a three-band (L + ∑ + C) model and are found to explain the experimental results well. Analysis of the detailed microstructure (including rhombohedral twin structures) in Ge0.87Pb0.13Te + 3 mol % Bi2Te3 was carried out using transmission electron microscopy and crystallographic group theory. The complex microstructure explains the reduced lattice thermal conductivity and electrical conductivity as well.
AB - As a lead-free material, GeTe has drawn growing attention in thermoelectrics, and a figure of merit (ZT) close to unity was previously obtained via traditional doping/alloying, largely through hole carrier concentration tuning. In this report, we show that a remarkably high ZT of ∼1.9 can be achieved at 773 K in Ge0.87Pb0.13Te upon the introduction of 3 mol % Bi2Te3. Bismuth telluride promotes the solubility of PbTe in the GeTe matrix, thus leading to a significantly reduced thermal conductivity. At the same time, it enhances the thermopower by activating a much higher fraction of charge transport from the highly degenerate ∑ valence band, as evidenced by density functional theory calculations. These mechanisms are incorporated and discussed in a three-band (L + ∑ + C) model and are found to explain the experimental results well. Analysis of the detailed microstructure (including rhombohedral twin structures) in Ge0.87Pb0.13Te + 3 mol % Bi2Te3 was carried out using transmission electron microscopy and crystallographic group theory. The complex microstructure explains the reduced lattice thermal conductivity and electrical conductivity as well.
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U2 - 10.1021/ja504896a
DO - 10.1021/ja504896a
M3 - Article
VL - 136
SP - 11412
EP - 11419
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 32
ER -