scholarly journals Physical Intuition to Improve Electronic Properties of Thermoelectrics

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Yang Samuel Lim ◽  
Danwei Zhang ◽  
Solco Samantha Faye Duran ◽  
Xian Yi Tan ◽  
Chee Kiang Ivan Tan ◽  
...  
Keyword(s):  
High Performance ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Charge Carrier Concentration ◽  
Advanced Materials ◽  
Commercial Application ◽  
Large Fluctuation ◽  
Theoretical Estimation ◽  
Earth Abundant

Thermoelectrics convert heat to electricity and vice versa. They are of technological importance in cooling and energy harvesting. Their performances are defined by figure of merit, zT. Decades of studies have largely focused on the development of novel and advanced materials reaching higher performance in devices. To date, the lack of sufficiently high-performance thermoelectrics, especially among Earth-abundant and lightweight materials, is one of the reasons why there is no broad commercial application of thermoelectric devices yet. This challenge is due to the complex correlations of parameters that make up the zT. Theoretical estimation can reveal the optimal charge carrier concentration, which can provide a good idea of doping compositions. Depending on the material characteristics, decoupling these intercorrelated parameters could be viable. Broadly speaking, increasing carrier mobility, inducing a large fluctuation in density of states (DOS) at the Fermi level, and lowering the lattice thermal conductivity lead to better thermoelectric performance. In this mini review, we provide a broad picture of electronic property optimization for thermoelectric materials. This work will be a useful guide to quickly take readers to the forefront of thermoelectric research.

High thermoelectric performance in low-cost SnS0.91Se0.09 crystals

Science ◽  
2019 ◽  
Vol 365 (6460) ◽  
pp. 1418-1424 ◽  
Author(s):  
Wenke He ◽  
Dongyang Wang ◽  
Haijun Wu ◽  
Yu Xiao ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Thermoelectric Materials ◽  
High Performance ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Toxic Elements ◽  
Low Cost ◽  
Thermoelectric Performance ◽  
Tin Sulfide ◽  
Temperature Dependent ◽  
Earth Abundant

Thermoelectric technology allows conversion between heat and electricity. Many good thermoelectric materials contain rare or toxic elements, so developing low-cost and high-performance thermoelectric materials is warranted. Here, we report the temperature-dependent interplay of three separate electronic bands in hole-doped tin sulfide (SnS) crystals. This behavior leads to synergistic optimization between effective mass (m*) and carrier mobility (μ) and can be boosted through introducing selenium (Se). This enhanced the power factor from ~30 to ~53 microwatts per centimeter per square kelvin (μW cm−1 K−2 at 300 K), while lowering the thermal conductivity after Se alloying. As a result, we obtained a maximum figure of merit ZT (ZTmax) of ~1.6 at 873 K and an average ZT (ZTave) of ~1.25 at 300 to 873 K in SnS0.91Se0.09 crystals. Our strategy for band manipulation offers a different route for optimizing thermoelectric performance. The high-performance SnS crystals represent an important step toward low-cost, Earth-abundant, and environmentally friendly thermoelectrics.

scholarly journals Thermoelectric Properties of NiCl3 Monolayer: A First-Principles-Based Transport Study

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 411
Author(s):  
Jing Liu ◽  
Xiaorui Chen ◽  
Yuhong Huang ◽  
Hongkuan Yuan ◽  
Hong Chen
Keyword(s):  
First Principles ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Dimensionless Figure Of Merit ◽  
Structural And Electronic Properties ◽  
High Carrier Mobility ◽  
High Carrier ◽  
Potential Matrix

By employing the first-principles-based transport theory, we investigate the thermoelectric performance based on the structural and electronic properties of NiCl 3 monolayer. The NiCl 3 monolayer is confirmed to be a stable Dirac spin gapless semiconductor with the linear energy dispersion having almost massless carrier, high carrier mobility and fully spin-polarization. Further, NiCl 3 monolayer processes the optimum power factor of 4.97 mWm − 1 K − 2 , the lattice thermal conductivity of 1.89 Wm − 1 K − 1 , and the dimensionless figure of merit of 0.44 at room temperature under reasonable carrier concentration, indicating that NiCl 3 monolayer may be a potential matrix for promising thermoelectrics.

High Performance Thermoelectrics from Earth-Abundant Materials: Enhanced Figure of Merit in PbS by Second Phase Nanostructures

2011 ◽  
Vol 133 (50) ◽  
pp. 20476-20487 ◽  
Author(s):  
Li-Dong Zhao ◽  
Shih-Han Lo ◽  
Jiaqing He ◽  
Hao Li ◽  
Kanishka Biswas ◽  
...  
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
Second Phase ◽  
Earth Abundant

Thermal Conductivity of Zn4−xCdxSb3 Solid Solutions

1997 ◽  
Vol 478 ◽  
Author(s):  
T. Caillat ◽  
A. Borshchevsky ◽  
J. -P. Fleurial
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
State Of The Art ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Jet Propulsion ◽  
P Type ◽  
Electrical Conductors

Abstractβ-Zn4Sb3 was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy β-Zn4Sb3 with isostructural compounds because of the expected decrease in lattice thermal conductivity. We have grown Zn4−xCdxSb3 crystals with 0.2≤x<1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn4−xCdxSb3 alloys are significantly lower than those measured for β-Zn4Sb3 and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

scholarly journals Improved Thermoelectric Performance in N-Type Half-Heusler NbCoSn by Heavy-Element Pt Doping

2020 ◽  
Author(s):  
Federico Serrano Sanchez ◽  
Ting Luo ◽  
Junjie Yu ◽  
Wenjie Xie ◽  
Gudrun Auffermann ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Heavy Element ◽  
Lattice Thermal Conductivity ◽  
Electrical Power ◽  
Heusler Compounds ◽  
Strong Point

Half-Heusler compounds with a valence electron count of 18, including ZrNiSn, ZrCoSb, and NbFeSb, are good thermoelec-tric materials owing to favourable electronic structures. Previous computational studies had predicted a high electrical power factor in another half-Heusler compound NbCoSn, but it has not been extensively investigated experimentally. Herein, the synthesis, structural characterization, and thermoelectric properties of the heavy-element Pt-doped NbCoSn compounds are reported. Pt is found to be an effective dopant enabling the optimization of electrical power factor, simul-taneously leading to a strong point defect scattering of phonons, and thereby suppressing the lattice thermal conductivity. Annealing significantly improves the carrier mobility, which is ascribed to the decreased grain boundary scattering. As a result, a maximum power factor of ~3.4 mWm-1K-2 is obtained at 600 K. In conjunction with the reduced lattice thermal conductivity, a maximum figure of merit zT of ~0.6 is achieved at 773 K for the post-annealed NbCo0.95Pt0.05Sn, an increase of 100% compared to the undoped NbCoSn. This work highlights the important roles of the doping element and micro-structure on the thermoelectric properties of half-Heusler compounds<br><p></p>

scholarly journals Low-Toxic, Earth-Abundant Nanostructured Materials for Thermoelectric Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 895
Author(s):  
Farheen F. Jaldurgam ◽  
Zubair Ahmad ◽  
Farid Touati
Keyword(s):  
Nanostructured Materials ◽  
High Performance ◽  
Figure Of Merit ◽  
Cost Effective ◽  
Critical Aspect ◽  
Research Directions ◽  
Earth Abundant ◽  
Recent Developments ◽  
Low Toxic ◽  
Future Direction

This article presents recent research directions in the study of Earth-abundant, cost-effective, and low-toxic advanced nanostructured materials for thermoelectric generator (TEG) applications. This study’s critical aspect is to systematically evaluate the development of high-performance nanostructured thermoelectric (TE) materials from sustainable sources, which are expected to have a meaningful and enduring impact in developing a cost-effective TE system. We review both the performance and limitation aspects of these materials at multiple temperatures from experimental and theoretical viewpoints. Recent developments in these materials towards enhancing the dimensionless figure of merit, Seebeck coefficient, reduction of the thermal conductivity, and improvement of electrical conductivity have also been discussed in detail. Finally, the future direction and the prospects of these nanostructured materials have been proposed.

Defect Clustering and Nanostructure Formation in PbTe-based Bulk Thermoelectrics

2007 ◽  
Vol 1044 ◽  
Author(s):  
Khang Hoang ◽  
S. D. Mahanti
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Pair Interaction ◽  
Interaction Energies ◽  
Thermoelectric Figure ◽  
Ionic Model ◽  
Pb Ions ◽  
Mc Simulation

AbstractIn recent years, LAST-m (AgPbmSbTem+2) and related materials have emerged as potential high performance high temperature thermoelectrics. One example is LAST-18. When optimally doped, this compound has thermoelectric figure of merit ZT=1.7 at 700K. This large ZT is most likely due to the low lattice thermal conductivity, caused by phonon scattering from nanostructures. These nanostructures involve clustering and ordering of Ag, Sb, and Pb ions. The origin of these nanostructures has been studied using Monte Carlo (MC) simulation of an ionic model and ab initio studies of pair interaction energies. Effects of these substitutions on the band structure near the gap and their implications on transport properties are briefly discussed.

scholarly journals Detrimental Effects of Doping Al and Ba on the Thermoelectric Performance of GeTe

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2237 ◽  
Author(s):  
Bhuvanesh Srinivasan ◽  
Alain Gellé ◽  
Jean-François Halet ◽  
Catherine Boussard-Pledel ◽  
Bruno Bureau
Keyword(s):  
Carrier Mobility ◽  
Figure Of Merit ◽  
Charge Carrier Concentration ◽  
Energy Separation ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Higher Temperature ◽  
Valence Bands ◽  
P Type

GeTe-based materials are emerging as viable alternatives to toxic PbTe-based thermoelectric materials. In order to evaluate the suitability of Al as dopant in thermoelectric GeTe, a systematic study of thermoelectric properties of Ge1−xAlxTe (x = 0–0.08) alloys processed by Spark Plasma Sintering are presented here. Being isoelectronic to Ge1−xInxTe and Ge1−xGaxTe, which were reported with improved thermoelectric performances in the past, the Ge1−xAlxTe system is particularly focused (studied both experimentally and theoretically). Our results indicate that doping of Al to GeTe causes multiple effects: (i) increase in p-type charge carrier concentration; (ii) decrease in carrier mobility; (iii) reduction in thermopower and power factor; and (iv) suppression of thermal conductivity only at room temperature and not much significant change at higher temperature. First principles calculations reveal that Al-doping increases the energy separation between the two valence bands (loss of band convergence) in GeTe. These factors contribute for Ge1−xAlxTe to exhibit a reduced thermoelectric figure of merit, unlike its In and Ga congeners. Additionally, divalent Ba-doping [Ge1−xBaxTe (x = 0–0.06)] is also studied.

High performance thermoelectrics from earth-abundant materials: Enhanced figure of merit in PbS through nanostructuring grain size

2016 ◽  
Vol 664 ◽  
pp. 411-416 ◽  
Author(s):  
Cheng Chang ◽  
Yu Xiao ◽  
Xiao Zhang ◽  
Yanling Pei ◽  
Fu Li ◽  
...  
Keyword(s):  
Grain Size ◽  
High Performance ◽  
Figure Of Merit ◽  
Earth Abundant

scholarly journals Bipolar doping and thermoelectric properties of Zintl arsenide Eu5In2As6

2021 ◽  
Author(s):  
Naoki Tomitaka ◽  
Yosuke Goto ◽  
Kota Morino ◽  
Kazuhisa Hoshi ◽  
Yuki Nakahira ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
High Performance ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
High Resistivity ◽  
Dimensionless Figure Of Merit ◽  
Recent Developments ◽  
P Type

Zintl compounds exhibit promising thermoelectric properties because of the feasibility of the chemical tuning of their electrical and thermal transport. While most Zintl pnictides are known to show p-type polarity, recent developments in high-performance n-type Mg3Sb2-based thermoelectric materials have encouraged further identification of n-type Zintl pnictides. In this study, we demonstrate the bipolar dopability of the Zintl arsenide Eu5In2As6. The electrical resistivity at 300 K with n-type polarity was decreased to 7.6 x 10^-1 ohmcm using La as an electron dopant. In contrast to the relatively high resistivity of n-type Eu5In2As6, the p-type resistivity at 300 K was decreased to 5.9 x 10^-3 ohmcm with a carrier concentration of 2.8 x 10^20 /cm3 using Zn as a hole dopant. This doping asymmetry is discussed in terms of the weighted mobility of electrons and holes. Furthermore, a very low lattice thermal conductivity of 0.7 W/mK was observed at 773 K, which is comparable to that of the Sb-containing analogue Eu5In2Sb6. The dimensionless figure of merit ZT = 0.29 at 773 K for Zn-doped p-type Eu5In2As6. This study shows that bipolar dopable Eu5In2As6 can be a platform to facilitate a better understanding of the doping asymmetry in Zintl pnictides.

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