scholarly journals Excellent Room-Temperature Thermoelectricity of 2D GeP3: Mexican-Hat-Shaped Band Dispersion and Ultralow Lattice Thermal Conductivity

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6376
Author(s):  
Cong Wang ◽  
Zhiyuan Xu ◽  
Ke Xu ◽  
Guoying Gao
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Phonon Scattering ◽  
Quantum Confinement Effect ◽  
Boltzmann Transport Theory ◽  
Mexican Hat ◽  
P Type

Although some atomically thin 2D semiconductors have been found to possess good thermoelectric performance due to the quantum confinement effect, most of their behaviors occur at a higher temperature. Searching for promising thermoelectric materials at room temperature is meaningful and challenging. Inspired by the finding of moderate band gap and high carrier mobility in monolayer GeP3, we investigated the thermoelectric properties by using semi-classical Boltzmann transport theory and first-principles calculations. The results show that the room-temperature lattice thermal conductivity of monolayer GeP3 is only 0.43 Wm−1K−1 because of the low group velocity and the strong anharmonic phonon scattering resulting from the disordered phonon vibrations with out-of-plane and in-plane directions. Simultaneously, the Mexican-hat-shaped dispersion and the orbital degeneracy of the valence bands result in a large p-type power factor. Combining this superior power factor with the ultralow lattice thermal conductivity, a high p-type thermoelectric figure of merit of 3.33 is achieved with a moderate carrier concentration at 300 K. The present work highlights the potential applications of 2D GeP3 as an excellent room-temperature thermoelectric material.

Ultralow lattice thermal conductivity at room temperature in 2D KCuSe from first-principles calculations

2021 ◽  
Author(s):  
Zhiyuan Xu ◽  
Cong Wang ◽  
Xuming Wu ◽  
Lei Hu ◽  
Yuqi Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
First Principles ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
First Principles Calculations ◽  
Boltzmann Transport ◽  
Thermoelectric Figure ◽  
Boltzmann Transport Theory

Ultralow lattice thermal conductivity is crucial to achieve a high thermoelectric figure of merit for thermoelectric applications. In this work, using the first-principles and phonon Boltzmann transport theory, we investigate...

scholarly journals Formation of Dense Pore Structure by Te Addition in Bi0.5Sb1.5Te3: An Approach to Minimize Lattice Thermal Conductivity

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Syed Waqar Hasan ◽  
Hyeona Mun ◽  
Sang Il Kim ◽  
Jung Young Cho ◽  
Jong Wook Roh ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Pore Structure ◽  
Transport Properties ◽  
Power Factor ◽  
Thermal Transport ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Synergetic Effects ◽  
Spark Plasma ◽  
P Type

We herein report the electronic and thermal transport properties of p-type Bi0.5Sb1.5Te3polycrystalline bulks with dense pore structure. Dense pore structure was fabricated by vaporization of residual Te during the pressureless annealing of spark plasma sintered bulks of Te coated Bi0.5Sb1.5Te3powders. The lattice thermal conductivity was effectively reduced to the value of 0.35 W m−1 K−1at 300 K mainly due to the phonon scattering by pores, while the power factor was not significantly affected. An enhancedZTof 1.24 at 300 K was obtained in spark plasma sintered and annealed bulks of 3 wt.% Te coated Bi0.5Sb1.5Te3by these synergetic effects.

A High Thermoelectric Performance ZT in p-Type LaSe2 Crystal

2021 ◽  
Vol 871 ◽  
pp. 203-207
Author(s):  
Jian Liu
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
High Power ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
High Power Factor ◽  
P Type

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 .

scholarly journals Lattice Thermal Conductivity of mGeTe•nSb2Te3 Phase-Change Materials: A First-Principles Study

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 136 ◽  
Author(s):  
Yuanchun Pan ◽  
Zhen Li ◽  
Zhonglu Guo
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Data Storage ◽  
First Principles ◽  
Phase Change Materials ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Large Contribution ◽  
Thermal Transport Property ◽  
Boltzmann Transport Theory

As the most promising materials for phase-change data storage, the pseudobinary mGeTe•nSb2Te3 (GST) chalcogenides have been widely investigated. Nevertheless, an in-depth understanding of the thermal-transport property of GST is still lacking, which is important to achieve overall good performance of the memory devices. Herein, by using first-principles calculations and Boltzmann transport theory, we have systematically studied the lattice thermal conductivity along the out of plane direction of both stable hexagonal and meta-stable rock-salt-like phases of GST, and good agreement with available experiments has been observed. It is revealed that with the increase of the n/m ratio, the lattice thermal conductivity of hexagonal GST increases due to the large contribution from the weak Te-Te bonding, while an inverse trend is observed in meta-stable GST, which is due to the increased number of vacancies that results in the decrease of the lattice thermal conductivity. The size effect on thermal conductivity is also discussed. Our results provide useful information to manipulate the thermal property of GST phase-change materials.

Thermoelectric performance of XI2 (X = Ge, Sn, Pb) bilayers

2021 ◽  
Author(s):  
Nan Lu ◽  
Jie Guan
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Density Functional ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Boltzmann Transport ◽  
Functional Theory ◽  
Boltzmann Transport Theory ◽  
Dimensionless Figure Of Merit ◽  
Structure Calculations

Abstract We study the thermal and electronic transport properties as well as the TE performance of three two-dimensional XI2 (X = Ge, Sn, Pb) bilayers using density functional theory and Boltzmann transport theory. We compared the lattice thermal conductivity, electrical conductivity, Seebeck coefficient, and dimensionless figure of merit (ZT) for the XI2 monolayers and bilayers. Our results show that the lattice thermal conductivity at room temperature for the bilayers is as low as ~1.1-1.7 Wm-1K-1, which is about 1.6 times as large as the monolayers for all the three materials. Electronic structure calculations show that all the XI2 bilayers are indirect-gap semiconductors with the band gap values between 1.84 eV and 1.96 eV at PBE level, which is similar as the corresponding monolayers. The calculated results of ZT show that the bilayer structures display much less direction dependent TE efficiency and have much larger n-type ZT values compared with the monolayers. The dramatic difference between the monolayer and bilayer indicates that the inter-layer interaction plays an important role in the TE performance of XI2, which provides the tunability on their TE characteristics.

scholarly journals Phonon Transport and Thermoelectric Properties of Imidazole-Graphyne

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5604
Author(s):  
Yanyan Chen ◽  
Jie Sun ◽  
Wei Kang ◽  
Qian Wang
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Transport Theory ◽  
Hole Concentration ◽  
Chemical Properties ◽  
Phonon Transport ◽  
Thermoelectric Performance ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory ◽  
Carbon Based

The pentagon has been proven to be an important structural unit for carbon materials, leading to different physical and chemical properties from those of hexagon-based allotropes. Following the development from graphene to penta-graphene, a breakthrough has very recently been made for graphyne—for example, imidazole-graphyne (ID-GY) was formed by assembling experimentally synthesized pentagonal imidazole molecules and acetylenic linkers. In this work, we study the thermal properties and thermoelectric performance of ID-GY by combining first principle calculations with the Boltzmann transport theory. The calculated lattice thermal conductivity of ID-GY is 10.76 W/mK at 300 K, which is only one tenth of that of γ-graphyne (106.24 W/mK). A detailed analysis of the harmonic and anharmonic properties, including the phonon group velocity, phonon lifetime, atomic displacement parameter, and bond energy curves, reveals that the low lattice thermal conductivity can be attributed to the low Young’s modulus, low Debye temperature, and high Grüneisen parameter. Furthermore, at room temperature, ID-GY can reach a high ZT value of 0.46 with a 5.8 × 1012 cm−2 hole concentration, which is much higher than the value for many other carbon-based materials. This work demonstrates that changing structural units from hexagonal to pentagonal can significantly reduce the lattice thermal conductivity and enhance the thermoelectric performance of carbon-based materials.

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...

scholarly journals Phase Formation Behavior and Thermoelectric Transport Properties of P-Type YbxFe3CoSb12 Prepared by Melt Spinning and Spark Plasma Sintering

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 87 ◽  
Author(s):  
Kyu Hyoung Lee ◽  
Sang Hyun Bae ◽  
Soon-Mok Choi
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Melt Spinning ◽  
Carrier Transport ◽  
Phonon Scattering ◽  
Submicron Scale ◽  
Formation Behavior ◽  
Thermoelectric Transport Properties ◽  
Spinning Process ◽  
P Type

Formation of multiple phases is considered an effective approach for enhancing the performance of thermoelectric materials since it can reduce the thermal conductivity and improve the power factor. Herein, we report the in-situ generation of a submicron-scale (~500 nm) heterograin structure in p-type Yb-filled (Fe,Co)4Sb12 skutterudites during the melt spinning process. Mixed grains of YbxFe3−yCo1+ySb12 and YbzFe3+yCo1−ySb12 were formed in melt spun ribbons due to uneven distribution of cations. By the formation of interfaces between two different grains, the power factor was enhanced due to the formation of an energy barrier for carrier transport, and simultaneously the lattice thermal conductivity was reduced due to the intensified boundary phonon scattering. A high thermoelectric figure of merit zT of 0.66 was obtained at 700 K.

scholarly journals α-Bi2Sn2O7: a potential room temperature n-type oxide thermoelectric

2020 ◽  
Vol 8 (32) ◽  
pp. 16405-16420 ◽  
Author(s):  
Warda Rahim ◽  
Jonathan M. Skelton ◽  
David O. Scanlon
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Ab Initio ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
High Density ◽  
Earth Abundant ◽  
Scattering Events

Using ab initio methods, we predict α-Bi2Sn2O7 to have an ultra-low lattice thermal conductivity at room temperature due to the high density of phonon scattering events, which makes it a potential earth-abundant n-type low temperature thermoelectric.

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