Investigation on carrier mobility when comparing nanostructures and bands manipulation

Nanoscale ◽  
2020 ◽  
Vol 12 (24) ◽  
pp. 12741-12747
Author(s):  
Zhenghao Hou ◽  
Yu Xiao ◽  
Li-Dong Zhao

Nanostructuring as an effective strategy to reduce thermal conductivity was well developed to enhance thermoelectric performance in the past decades.

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Muchun Guo ◽  
Fengkai Guo ◽  
Jianbo Zhu ◽  
Li Yin ◽  
Qian Zhang ◽  
...  

CaMg2Bi2-based compounds, a kind of the representative compounds of Zintl phases, have uniquely inherent layered structure and hence are considered to be potential thermoelectric materials. Generally, alloying is a traditional and effective way to reduce the lattice thermal conductivity through the mass and strain field fluctuation between host and guest atoms. The cation sites have very few contributions to the band structure around the fermi level; thus, cation substitution may have negligible influence on the electric transport properties. What is more, widespread application of thermoelectric materials not only desires high ZT value but also calls for low-cost and environmentally benign constituent elements. Here, Ba substitution on cation site achieves a sharp reduction in lattice thermal conductivity through enhanced point defects scattering without the obvious sacrifice of high carrier mobility, and thus improves thermoelectric properties. Then, by combining further enhanced phonon scattering caused by isoelectronic substitution of Zn on the Mg site, an extraordinarily low lattice thermal conductivity of 0.51 W m-1 K-1 at 873 K is achieved in (Ca0.75Ba0.25)0.995Na0.005Mg1.95Zn0.05Bi1.98 alloy, approaching the amorphous limit. Such maintenance of high mobility and realization of ultralow lattice thermal conductivity synergistically result in broadly improvement of the quality factor β. Finally, a maximum ZT of 1.25 at 873 K and the corresponding ZTave up to 0.85 from 300 K to 873 K have been obtained for the same composition, meanwhile possessing temperature independent compatibility factor. To our knowledge, the current ZTave exceeds all the reported values in AMg2Bi2-based compounds so far. Furthermore, the low-cost and environment-friendly characteristic plus excellent thermoelectric performance also make the present Zintl phase CaMg2Bi2 more competitive in practical application.


Author(s):  
Jingdan Lei ◽  
Hexige Wuliji ◽  
Kunpeng Zhao ◽  
Tian-Ran Wei ◽  
Qing Xu ◽  
...  

Mg3Sb2-based thermoelectric materials have recently received heightened attentions due to its diverse merits of high band degeneracy, ultralow lattice thermal conductivity and high carrier mobility. However, the inherently low carrier...


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.


Author(s):  
Zihang Liu ◽  
Wenhao Zhang ◽  
Weihong Gao ◽  
Takao Mori

Discovering materials with the intrinsically low lattice thermal conductivity κlat is an important route for achieving high thermoelectric performance. In reality, the conventional synthetic approach, however, relies on trial and...


2021 ◽  
Vol 143 (15) ◽  
pp. 5978-5989
Author(s):  
Hongyao Xie ◽  
Shiqiang Hao ◽  
Trevor P. Bailey ◽  
Songting Cai ◽  
Yinying Zhang ◽  
...  

RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15486-15496
Author(s):  
Enamul Haque

The layered structure, and presence of heavier elements Rb/Cs and Sb induce high anharmonicity, low Debye temperature, intense phonon scattering, and hence, low lattice thermal conductivity.


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.


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