Synergistic optimization of carrier transport and thermal conductivity in Sn-doped Cu2Te

2018 ◽  
Vol 6 (39) ◽  
pp. 18928-18937 ◽  
Author(s):  
Yuchong Qiu ◽  
Ying Liu ◽  
Jinwen Ye ◽  
Jun Li ◽  
Lixian Lian

Doping Sn into the Cu2Te lattice can synergistically enhance the power factor and decrease thermal conductivity, leading to remarkably optimized zTs. The lone pair electrons from the 5s orbital of Sn can increase the DOS near the Fermi level of Cu2Te to promote PF and reduce κe by decreasing the carrier concentration. This study explores a scalable strategy to optimize the thermoelectric performance for intrinsically highly degenerate semiconductors.

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1637 ◽  
Author(s):  
Lihong Huang ◽  
Junchen Wang ◽  
Xiaobo Mo ◽  
Xiaobo Lei ◽  
Sude Ma ◽  
...  

The effects of V vacancy on the thermoelectric performance of the half-Heusler compound VCoSb have been investigated in this study. A certain amount of CoSb secondary phase is generated in the VCoSb matrix when the content of V vacancy is more than 0.1 at%. According to the results, a ZT value of 0.6, together with a power factor of 29 μW cm−1 K−2 at 873 K, were achieved for the nonstoichiometric sample V0.9CoSb. This proved that moderate V vacancy could improve the thermoelectric (TE) properties of VCoSb. The noticeable improvements are mainly owing to the incremental Seebeck coefficient, which may benefit from the optimized carrier concentration. However, too much V vacancy will result in more CoSb impurity and deteriorate the TE performances of VCoSb owing to the increased thermal conductivity.


Author(s):  
Wenjing Xu ◽  
Zhongwei Zhang ◽  
Chengyan Liu ◽  
Jie Gao ◽  
Zhenyuan Ye ◽  
...  

AbstractEco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe; yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal conductivity. In this work, we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity, contributing to a final promotion of figure of merit. On one hand, the carrier concentration and band offset between valence bands are concurrently reduced, promoting the power factor to a highest value of ∼2436 µW·m−1·K−2 at 873 K. On the other hand, lots of dislocations (∼3.16×107 mm−2) associated with impurity precipitates are generated, resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m−1·K−1 at 873 K. As a result, a substantial thermoelectric performance enhancement up to zT ≈ 1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te, which is twice that of the pristine SnTe (zT ≈ 0.49 at 873 K). This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.


2021 ◽  
Vol 5 (6) ◽  
pp. 1734-1746
Author(s):  
D. Sidharth ◽  
A. S. Alagar Nedunchezhian ◽  
R. Akilan ◽  
Anup Srivastava ◽  
Bhuvanesh Srinivasan ◽  
...  

The power factor of GeSe enhanced and thermal conductivity decreased by Te substitution and thereby, GeSe0.80Te0.20 exhibits high ZT.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Natsumi Komatsu ◽  
Yota Ichinose ◽  
Oliver S. Dewey ◽  
Lauren W. Taylor ◽  
Mitchell A. Trafford ◽  
...  

AbstractLow-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an ultrahigh value of power factor (14 ± 5 mW m−1 K−2) for macroscopic weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. The observed giant power factor originates from the ultrahigh electrical conductivity achieved through excellent sample morphology, combined with an enhanced Seebeck coefficient through Fermi energy tuning. We fabricate a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrates high thermoelectric performance, weavability, and scalability. The giant power factor we observe make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.


2021 ◽  
Vol 871 ◽  
pp. 203-207
Author(s):  
Jian Liu

In this work, we use first principles DFT calculations, anharmonic phonon scatter theory and Boltzmann transport method, to predict a comprehensive study on the thermoelectric properties as electronic and phonon transport of layered LaSe2 crystal. The flat-and-dispersive type band structure of LaSe2 crystal offers a high power factor. In the other hand, low lattice thermal conductivity is revealed in LaSe2 semiconductor, combined with its high power factor, the LaSe2 crystal is considered a promising thermoelectric material. It is demonstrated that p-type LaSe2 could be optimized to exhibit outstanding thermoelectric performance with a maximum ZT value of 1.41 at 1100K. Explored by density functional theory calculations, the high ZT value is due to its high Seebeck coefficient S, high electrical conductivity, and low lattice thermal conductivity .


2017 ◽  
Vol 19 (27) ◽  
pp. 17560-17567 ◽  
Author(s):  
Tongzhou Wang ◽  
Congcong Liu ◽  
Fengxing Jiang ◽  
Zhaofen Xu ◽  
Xiaodong Wang ◽  
...  

The content of rGO could alter the carrier transport barrier, and the optimizing power factor was achieved at rGO–MS2 junctions.


2017 ◽  
Vol 5 (31) ◽  
pp. 7845-7852 ◽  
Author(s):  
Yao Yao ◽  
Bo-Ping Zhang ◽  
Jun Pei ◽  
Yao-Chun Liu ◽  
Jing-Feng Li

A series of single-phased Cu2S1−xSex bulks were prepared by using mechanical alloying (MA) combined with spark plasma sintering (SPS). Our results suggest that the TE properties of Cu2S can be greatly enhanced by simultaneously increasing PF and decreasing κ via doping a sole Se element.


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