Strain Engineering of Polar Optical Phonon Scattering Mechanism – An Effective Way to Optimize the Power-factor and Lattice Thermal Conductivity of ScN

2021 ◽  
Author(s):  
Iyyappa Rajan Panneerselvam ◽  
Man Hea Kim ◽  
Carlos Baldo III ◽  
Yan Wang ◽  
Mahalakshmi Sahasranaman
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Material Selection ◽  
Strain Engineering ◽  
Polar Optical Phonon ◽  
Thermoelectric Power Factor ◽  
Optical Phonon Scattering

The tug-of-war between the thermoelectric power factor and the figure-of-merit complicates thermoelectric material selection, particularly for mid-to-high temperature thermoelectric materials. Approaches to reduce lattice thermal conductivity while maintaining a high-power...

Vacancy Phonon Scattering and Thermoelectric Properties in In2Te3–SnTe Compounds

2010 ◽  
Vol 650 ◽  
pp. 126-131 ◽  
Author(s):  
Hong Fu ◽  
Peng Zhan Ying ◽  
J.L. Cui ◽  
Y.M. Yan ◽  
X.J. Zhang
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Point Defects ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Chemical Compositions ◽  
Thermoelectric Figure ◽  
Solid Solution Formation ◽  
Solution Formation

Solid solution formation is a common and effective way to reduce the lattice thermal conductivity for thermoelectric materials because of additional phonon scattering by point defects and grain boundaries. In the present work we prepared In2Te3–SnTe compounds using a mild solidification technique and evaluated their thermoelectric properties in the temperature range from 318705 K. Measurements reveal that the transport properties are strongly dependent on the chemical composition  In2Te3 content, and lattice thermal conductivity significantly reduces above a minimum In2Te3 concentration, which can possibly be explained by an introduction of the vacancy on the indium sublattice and periodical vacancy planes. The highest thermoelectric figure of merit ZT of 0.19 can be achieved at 705 K, and a big improvement of In2Te3 based alloys would be expected if a proper optimization to the chemical compositions and structures were made.

scholarly journals Prediction of higher thermoelectric performance in BiOCuSe by weakening electron-polar optical phonon scattering

2020 ◽  
Author(s):  
Tianqi Zhao ◽  
Quinn Gibson ◽  
Luke Daniels ◽  
Ben Slater ◽  
Furio Cora
Keyword(s):  
Carrier Mobility ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Phonon Scattering ◽  
Hole Mobility ◽  
Polar Optical Phonon ◽  
First Principles Calculations ◽  
Thermoelectric Figure ◽  
Optical Phonon Scattering ◽  
Electron Phonon Scattering

Abstract BiOCuSe is a promising thermoelectric material, but its applications are hindered by low carrier mobility. We use first principles calculations to analyse electron-phonon scattering mechanisms and evaluate their contributions to the thermoelectric figure of merit ZT. The combined scattering of carriers by polar optical (PO) and longitudinal acoustic (LA) phonons yields an intrinsic hole mobility of 32 cm2 V-1 s-1 at room temperature and a temperature power law of T-1.5, which agree well with experiments. We demonstrate that electron phonon scattering in the Cu-Se layer dominates at low T, while contributions from the Bi-O layer become increasingly significant at higher T. At room temperature, ZT is calculated to be 0.48 and can be improved by 30% through weakening PO phonon scattering in the Cu-Se layer. This finding agrees with the experimental observation that weakening the carrier-phonon interaction by Te substitution in the Cu-Se layer improves mobility and ZT. At high T, the figure of merit is improved by weakening phonon scattering in the Bi-O layer instead. The theoretical ZT limit of BiOCuSe is calculated to be 2.5 at 875 K.

scholarly journals Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4080 ◽  
Author(s):  
Se Yun Kim ◽  
Hyun-Sik Kim ◽  
Kyu Hyoung Lee ◽  
Hyun-jun Cho ◽  
Sung-sil Choo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Carrier Concentration ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Energy Conversion Efficiency ◽  
Thermoelectric Figure ◽  
Pd Doping ◽  
Effect Of Pd

Doping is known as an effective way to modify both electrical and thermal transport properties of thermoelectric alloys to enhance their energy conversion efficiency. In this project, we report the effect of Pd doping on the electrical and thermal properties of n-type Cu0.008Bi2Te2.7Se0.3 alloys. Pd doping was found to increase the electrical conductivity along with the electron carrier concentration. As a result, the effective mass and power factors also increased upon the Pd doping. While the bipolar thermal conductivity was reduced with the Pd doping due to the increased carrier concentration, the contribution of Pd to point defect phonon scattering on the lattice thermal conductivity was found to be very small. Consequently, Pd doping resulted in an enhanced thermoelectric figure of merit, zT, at a high temperature, due to the enhanced power factor and the reduced bipolar thermal conductivity.

Enhanced thermoelectric performance through carrier scattering at heterojunction potentials in BiSbTe based composites with Cu3SbSe4 nanoinclusions

2015 ◽  
Vol 3 (27) ◽  
pp. 7045-7052 ◽  
Author(s):  
Yuanyue Li ◽  
Di Li ◽  
Xiaoying Qin ◽  
Xiuhui Yang ◽  
Yongfei Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Carrier Scattering ◽  
Interface Scattering

Owing to enhanced power factor and reduced lattice thermal conductivity through interface scattering, a largest thermoelectric figure of merit ZT = 1.61 is achieved at 467 K for BiSbTe based composite with Cu3SbSe4 nanoinclusions.

scholarly journals Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 643 ◽  
Author(s):  
Bhuvanesh Srinivasan ◽  
David Berthebaud ◽  
Takao Mori
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Short Communication ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

Enhancement in Figure-Of-Merit with Superlattice Structures for Thin-Film Thermoelectric Devices

1997 ◽  
Vol 478 ◽  
Author(s):  
R. Venkatasubramanian ◽  
T. Colpitts
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
Power Factor ◽  
Electrical Transport ◽  
Figure Of Merit ◽  
State Of The Art ◽  
Periodic Structures ◽  
Thermoelectric Device ◽  
Thermoelectric Power Factor ◽  
Short Period

AbstractThin-film superlattice (SL) structures in thermoelectric materials are shown to be a promising approach to obtaining an enhanced figure-of-merit, ZT, compared to conventional, state-of-the-art bulk alloyed materials. In this paper we describe experimental results on Bi2Te3/Sb2Te3 and Si/Ge SL structures, relevant to thermoelectric cooling and power conversion, respectively. The short-period Bi2Te3/Sb2Te3 and Si/Ge SL structures appear to indicate reduced thermal conductivities compared to alloys of these materials. From the observed behavior of thermal conductivity values in the Bi2Te3/Sb2Te3 SL structures, a distinction is made where certain types of periodic structures may correspond to an ordered alloy rather than an SL, and therefore, do not offer a significant reduction in thermal conductivity values. Our study also indicates that SL structures, with little or weak quantum-confinement, also offer an improvement in thermoelectric power factor over conventional alloys. We present power factor and electrical transport data in the plane of the SL interfaces to provide preliminary support for our arguments on reduced alloy scattering and impurity scattering in Bi2Te3/Sb2Te3 and Si/Ge SL structures. These results, though tentative due to the possible role of the substrate and the developmental nature of the 3-ω method used to determine thermal conductivity values, suggest that the short-period SL structures potentially offer factorial improvements in the three-dimensional figure-of-merit (ZT3D) compared to current state-of-the-art bulk alloys. An approach to a thin-film thermoelectric device called a Bipolarity-Assembled, Series-Inter-Connected Thin- Film Thermoelectric Device (BASIC-TFTD) is introduced to take advantage of these thin-film SL structures.

scholarly journals First-principles prediction of structural stability and thermoelectric properties of SrGaSnH

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3304-3314
Author(s):  
Enamul Haque ◽  
Mizanur Rahaman
Keyword(s):  
Thermal Conductivity ◽  
Structural Stability ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

Weak anharmonicity: the weak anharmonicity leads to weak phonon scattering in SrGaSnH. Thus, SrGaSnH intrinsically possesses a high lattice thermal conductivity (kl).. Such large κl dramatically reduces the thermoelectric figure of merit.

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>

Low-Temperature Thermoelectric Properties of Zn4Sb3 Prepared by Hot Pressing

2006 ◽  
Vol 510-511 ◽  
pp. 1070-1073 ◽  
Author(s):  
Il Ho Kim ◽  
J.B. Park ◽  
Tae Whan Hong ◽  
Soon Chul Ur ◽  
Young Geun Lee ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Hot Pressing ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Thermoelectric Figure Of Merit ◽  
Total Thermal Conductivity ◽  
Thermoelectric Figure ◽  
Scattering Centers

Zn4Sb3 was successfully produced by a hot pressing technique, and its thermoelectric properties were investigated in the temperature range from 4K to 300K. The Seebeck coefficient, electrical conductivity, thermal conductivity, and thermoelectric figure of merit showed a discontinuity in variation at 242K, indicating the α-Zn4Sb3 to β-Zn4Sb3 phase transformation. Lattice thermal conductivity was found to be dominant in the total thermal conductivity of Zn4Sb3. Therefore, it is expected that thermoelectric properties can be improved by reducing the lattice thermal conductivity inducing phonon scattering centers.

Enhanced figure of merit in Mg2Si0.877Ge0.1Bi0.023/multi wall carbon nanotube nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (80) ◽  
pp. 65328-65336 ◽  
Author(s):  
Nader Farahi ◽  
Sagar Prabhudev ◽  
Matthieu Bugnet ◽  
Gianluigi A. Botton ◽  
Jianbao Zhao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Power Factor ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Thermoelectric Performance ◽  
Multi Wall Carbon Nanotubes ◽  
Energy Filtering ◽  
Multi Wall Carbon Nanotube

Adding multi wall carbon nanotubes to Mg2Si0.877Ge0.1Bi0.023 led to an increased power factor via energy filtering as well as a lowered thermal conductivity via increased phonon scattering, and thus an enhanced thermoelectric performance.

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