Engineering Temperature-Dependent Carrier Concentration in Bulk Composite Materials via Temperature-Dependent Fermi Level Offset

AbstractThe single parabolic band (SPB) model has been widely used to preliminarily elucidate inherent transport behaviors of thermoelectric (TE) materials, such as their band structure and electronic thermal conductivity, etc. However, in the SPB calculation, it is necessary to determine some intermediate variables, such as Fermi level or the complex Fermi-Dirac integrals. In this work, we establish a direct carrier-concentration-dependent restructured SPB model, which eliminates Fermi-Dirac integrals and Fermi level calculation and emerges stronger visibility and usability in experiments. We have verified the reliability of such restructured model with 490 groups of experimental data from state-of-the-art TE materials and the relative error is less than 2%. Moreover, carrier effective mass, intrinsic carrier mobility and optimal carrier concentration of these materials are systematically investigated. We believe that our work can provide more convenience and accuracy for thermoelectric data analysis as well as instructive understanding on future optimization design.

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A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽

10.3390/polym13091393 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1393

Author(s):

Xiaochang Duan ◽

Hongwei Yuan ◽

Wei Tang ◽

Jingjing He ◽

Xuefei Guan

Keyword(s):

Composite Materials ◽

Constitutive Model ◽

Model Parameters ◽

Temperature Dependent ◽

Stress Strain ◽

Proposed Model ◽

Single Temperature ◽

Testing Data ◽

Bonded Composite ◽

Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

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

Journal of Materials Chemistry A ◽

10.1039/c8ta04993a ◽

2018 ◽

Vol 6 (39) ◽

pp. 18928-18937 ◽

Cited By ~ 11

Author(s):

Yuchong Qiu ◽

Ying Liu ◽

Jinwen Ye ◽

Jun Li ◽

Lixian Lian

Keyword(s):

Thermal Conductivity ◽

Fermi Level ◽

Carrier Concentration ◽

Power Factor ◽

Carrier Transport ◽

Lone Pair ◽

Thermoelectric Performance ◽

Degenerate Semiconductors ◽

Lone Pair Electrons

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.

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Multi-coating inhomogeneities approach for composite materials with temperature-dependent constituents under small strain and finite thermal perturbation assumptions

Composites Part B Engineering ◽

10.1016/j.compositesb.2016.12.040 ◽

2017 ◽

Vol 112 ◽

pp. 137-147 ◽

Cited By ~ 6

Author(s):

Yao Koutsawa

Keyword(s):

Composite Materials ◽

Small Strain ◽

Thermal Perturbation ◽

Temperature Dependent

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Charge carrier concentration and temperature dependent recombination in polymer-fullerene solar cells

Applied Physics Letters ◽

10.1063/1.3202389 ◽

2009 ◽

Vol 95 (5) ◽

pp. 052104 ◽

Cited By ~ 82

Author(s):

A. Foertig ◽

A. Baumann ◽

D. Rauh ◽

V. Dyakonov ◽

C. Deibel

Keyword(s):

Solar Cells ◽

Charge Carrier ◽

Carrier Concentration ◽

Charge Carrier Concentration ◽

Temperature Dependent

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Synergistic boost of output power density and efficiency in In-Li–codoped SnTe

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1911085116 ◽

2019 ◽

Vol 116 (44) ◽

pp. 21998-22003 ◽

Cited By ~ 5

Author(s):

Fengkai Guo ◽

Haijun Wu ◽

Jianbo Zhu ◽

Honghao Yao ◽

Yang Zhang ◽

...

Keyword(s):

Carrier Concentration ◽

Power Density ◽

Output Power ◽

Traditional Method ◽

Lattice Thermal Conductivity ◽

Heat Output ◽

Leg Length ◽

Temperature Dependent ◽

High Carrier Concentration ◽

High Carrier

We report enhanced thermoelectric performance of SnTe by further increasing its intrinsic high carrier concentration caused by Sn vacancies in contrast to the traditional method. Along with In2Te3 alloying, which results in an enhanced Seebeck coefficient, Li2Te is added to further increase the carrier concentration in order to maintain high electrical conductivity. Finally, a relatively high PFave of ∼28 μW cm−1 K−2 in the range between 300 and 873 K is obtained in an optimized SnTe-based compound. Furthermore, nanoprecipitates with extremely high density are constructed to scatter phonons strongly, resulting in an ultralow lattice thermal conductivity of ∼0.45 W m−1 K−1 at 873 K. Given that the Z value is temperature dependent, the (ZT)eng and (PF)eng values are adopted to accurately predict the performance of this material. Taking into account the Joule and Thomson heat, output power density of ∼5.53 W cm−2 and leg efficiency of ∼9.6% are calculated for (SnTe)2.94(In2Te3)0.02-(Li2Te)0.045 with a leg length of 4 mm and cold- and hot-side temperatures of 300 and 870 K, respectively.

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High-Temperature Thermoelectric Properties of Pb1-xSnxTe:In

MRS Proceedings ◽

10.1557/proc-1044-u04-09 ◽

2007 ◽

Vol 1044 ◽

Cited By ~ 2

Author(s):

Vladimir Jovovic ◽

Suraj Joottu Thiagarajan ◽

Joseph P. Heremans ◽

Dmitry Khokhlov ◽

Tanya Komissarova ◽

...

Keyword(s):

Electrical Resistivity ◽

Fermi Level ◽

Thermoelectric Properties ◽

Carrier Mobility ◽

Temperature Dependent ◽

Resonant Energy ◽

Properties Of Materials ◽

Valence Bands ◽

Increasing Temperature ◽

Positive Effect

AbstractIndium in Pb1-xSnxTe alloys forms a resonant energy level in the conduction or valence bands, depending on x. In this study we investigate temperature dependence of the In level from 80 to 400K, complementing our previous work at 80 K. Measurements of electrical resistivity, thermopower, Hall and transverse Nernst-Ettinghausen effect are used to assess carrier mobility, Fermi level and scattering coefficient. Measurements are performed on a set of p and n type Pb1-xSnxTe:In with 0 < x < 30 at% and In up to 3 at%. We show that with increasing temperature the Fermi level crosses into the gap. It had been suggested theoretically that hybridization of the In level with one band at the Fermi level could have had a positive effect on the thermoelectric properties of materials, but the present results illustrate the need for temperature-dependent modeling and experimentation.

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