Temperature-dependent elastic moduli of lead telluride-based thermoelectric materials

2009 ◽  
Vol 89 (2) ◽  
pp. 143-167 ◽  
Author(s):  
F. Ren ◽  
E.D. Case ◽  
J.E. Ni ◽  
E.J. Timm ◽  
E. Lara-Curzio ◽  
...  
Keyword(s):  
Thermoelectric Materials ◽  
Elastic Moduli ◽  
Lead Telluride ◽  
Temperature Dependent

scholarly journals Temperature-Dependent Raman Scattering of Large Size Hexagonal Bi2Se3 Single-Crystal Nanoplates

2018 ◽  
Vol 8 (10) ◽  
pp. 1794 ◽  
Author(s):  
Fang Zhou ◽  
Yujing Zhao ◽  
Weichang Zhou ◽  
Dongsheng Tang
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Temperature Coefficient ◽  
Thermoelectric Materials ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
Large Size ◽  
Transmission Electron ◽  
High Figure

Bi 2 Se 3 has extensive application as thermoelectric materials. Here, large-scale Bi 2 Se 3 single-crystal hexagonal nanoplates with size 7.50–10.0 μ m were synthesized successfully by hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi 2 Se 3 nanoplates, which confirm the single-crystal quality and smooth surface morphology with large size. Micro-Raman spectra over a temperature range of 83–603 K were furthermore used to investigate the lattice dynamics of Bi 2 Se 3 nanoplates. Both 2A g 1 and 1E g 2 modes shift evidently with reduced temperature. The line shape demonstrates a significant broadening of full width at half maximum (FWHM) and red-shift of frequency with increased temperature. The temperature coefficient of A 1 g 1 , E g 2 , A 1 g 2 modes were determined to be −1.258 × 10 − 2 cm − 1 /K, −1.385 × 10 − 2 cm − 1 /K, −2.363 × 10 − 2 cm − 1 /K, respectively. Such low temperature coefficient may favor the obtaining of a high figure of merit (ZT) and indicate that Bi 2 Se 3 nanoplates were used as excellent candidates of thermoelectric materials.

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 Design of Nano-Structured Micro-Thermoelectric Generator: Load Resistance and Inflections in the Efficiency

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 224
Author(s):  
Carlos Badillo-Ruiz ◽  
Miguel Olivares-Robles ◽  
Jose Chanona-Perez
Keyword(s):  
Thermoelectric Materials ◽  
Fossil Fuels ◽  
Load Resistance ◽  
Structure Type ◽  
Temperature Dependent ◽  
Temperature Ranges ◽  
Operation Control ◽  
Micro Thermoelectric Generator ◽  
Nanostructured Thermoelectric Materials

In recent years the interest for the harvest of energy with micro thermoelectric generators ( μ TEG) has increased, due to its advantages compared to technologies that use fossil fuels. There are three ways to improve the performance of the device, by modifying its structure, type of material and operation control. In this study, the role of the load resistance R L on the performance of a μ TEG with nanostructured materials is investigated. The interaction of the load resistance with the thermoelements exhibits interesting features, arising from the coupling of the temperature-dependent electrical and thermal transport properties at different temperature ranges and the architecture of nanostructured thermoelectric materials. This coupling results in inflections on the efficiency, i.e., maximum and minimum values of the efficiency at higher temperatures, 600–900 K. We show the explicit dependence of the performance of the μ TEG in terms of the load resistance and discuss the underlying physics. The unusual features of the efficiency of nanostructured thermoelectric materials are a result of the behavior of the power factor and the nonequilibrium properties of the system. We also analyze the effect of the geometric shape of the thermoelements on the device. We determine the performance of the μ TEG, evaluating the generation power and its efficiency. The results show that the efficiency of the device can decrease or increase depending on the value of R L , while the power decreases with an increase of the load resistance.

scholarly journals Vibrational spectra of Pb2Bi2Te3, PbBi2Te4, and PbBi4Te7 topological insulators: temperature-dependent Raman and theoretical insights from DFT simulations

2019 ◽  
Vol 21 (27) ◽  
pp. 15030-15039 ◽  
Author(s):  
Priyanath Mal ◽  
G. Bera ◽  
G. R. Turpu ◽  
Sunil K. Srivastava ◽  
A. Gangan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Frequency Shift ◽  
Vibrational Spectra ◽  
Topological Insulators ◽  
Lead Telluride ◽  
Phonon Modes ◽  
Temperature Dependent ◽  
Dft Simulations

Insertion of lead and lead telluride in Bi2Te3 leads to a change in the thermal conductivity, frequency shift, and the broadening of phonon modes.

Strain-Dependent Properties of Polymers I

1966 ◽  
Vol 39 (5) ◽  
pp. 1421-1427 ◽  
Author(s):  
G. E. Warnaka ◽  
H. T. Miller
Keyword(s):  
Loss Factor ◽  
Elastic Moduli ◽  
Dynamic Properties ◽  
Amorphous Polymers ◽  
Temperature Dependent ◽  
Strain Dependence ◽  
Self Heating ◽  
Dynamic Elastic Moduli ◽  
Temperature Dependent Properties ◽  
Strain Dependent

Abstract Dynamic elastic moduli of homogeneous, amorphous polymers decrease at moderate to high strains. Under the same strain magnitudes the loss factor goes through a broad maximum. At low strains, dynamic properties are independent of strain amplitude. This paper shows that strain dependence is a basic property of homogeneous, amorphous polymers. Strain dependence is shown to occur in gum, as well as filled, vulcanizates. In addition it is shown that self heating due to flexing at high strains cannot fully explain strain dependent dynamic properties. Testing has been performed on specimens with greatly varying geometries (and, hence, different amounts of self-heating) and at controlled specimen temperatures. These tests have verified the existence of a basic strain-dependency. Strain dependence is here related to time-temperature dependent properties of polymers as described by the well-known work of Williams, Landel, and Ferry. The magnitude of strain dependence and the strain amplitudes at which strain dependence occurs appear to be controlled by the time-temperature dependence of polymers.

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