Thermoelectric properties of polycrystalline Bi2Se3−x by powder compaction sintering

2020 ◽  
Vol 34 (18) ◽  
pp. 2050206
Author(s):  
Ying Zhou ◽  
Zhenhua Ge ◽  
Jun Guo ◽  
Jing Feng
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Electrical Transport ◽  
Bulk Material ◽  
Powder Compaction ◽  
Electrical Transport Properties ◽  
X Ray

[Formula: see text] is a [Formula: see text] compound (where Pn = Bi and Sb, Ch = Te, Se, and S), which has attracted increasing attention as a candidate for use in thermoelectric applications. Previous studies demonstrated the advantage of [Formula: see text] thermoelectric materials, despite an inferior thermoelectric performance. Herein, a series of [Formula: see text] ([Formula: see text], 0.10, 0.15, 0.20, and 0.25) thermoelectric materials were prepared by powder compaction sintering. The effects of phase structures and microstructure of the [Formula: see text] bulk material were analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The thermoelectric properties, including Seebeck coefficient, electrical conductivity, and thermal conductivity, were measured systematically. The results show that carrier concentration increased with decreasing Se content, which in turn affected the electrical transport properties. Low Se contents gave larger power factor (PF) values than the pristine [Formula: see text] sample, the maximum PF value being [Formula: see text] at 320 K for [Formula: see text]. The variation in PF was attributed to the variations in electrical conductivity [Formula: see text] and Seebeck coefficient [Formula: see text] upon optimizing Se content. The [Formula: see text] samples showed an enhanced thermoelectric figure of merit (ZT) with increasing measurement temperature, due to the increased [Formula: see text] value, [Formula: see text], and decreased [Formula: see text]. The [Formula: see text] sample exhibited the highest ZT (0.28) at 575 K, while [Formula: see text] exhibited the lowest ZT (0.14) at 325 K. This indicated that tuning Se content was an effective way to enhance carrier concentration.

Influence of Cu Diffusion on Electrical Transport Properties of Bi0.5Sb1.5Te3

2013 ◽  
Vol 743-744 ◽  
pp. 70-75 ◽  
Author(s):  
Song Chen ◽  
Xin Wang ◽  
Zhi Gang Zou ◽  
Ke Feng Cai
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Electrical Transport ◽  
Impurity Phase ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
Bulk Materials ◽  
Measurement Temperature ◽  
X Ray ◽  
Before And After

Bi0.5Sb1.5Te3 nanoplates from gas induced reduction (GIR) strategy were hot-pressed into bulk materials for thermoelectric properties investigation. During the electrical conductivity and Seebeck coefficient measurements, we found that the Cu from Cu electrodes diffused into samples when the measurement temperature was above 600 K. The phase composition and fracture surface of the samples before and after Cu diffusion were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). We found that the Cu diffusion resulted in the composition deviation and formation of impurity phase, Cu1.8Te. When the electrical conductivity and Seebeck coefficient of the samples were measured again but below 600 K, the samples showed different electrical transport behavior and had enhanced power factors.

Thermoelectric Properties of n-type (Bi2Se3)x(Bi2Te3)1-x Crystals Prepared by Zone Melting

2008 ◽  
Vol 368-372 ◽  
pp. 547-549
Author(s):  
Jun Jiang ◽  
Ya Li Li ◽  
Gao Jie Xu ◽  
Ping Cui ◽  
Li Dong Chen
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Zone Melting ◽  
Chemical Compositions ◽  
Melting Method ◽  
Temperature Range

In the present study, n-type (Bi2Se3)x(Bi2Te3)1-x crystals with various chemical compositions were fabricated by the zone melting method. Thermoelectric properties, including Seebeck coefficient (α), electrical conductivity (σ) and thermal conductivity (κ), were measured in the temperature range of 300-500 K. The influence of the variations of Bi2Te3 and Bi2Se3 content on thermoelectric properties was studied. The increase of Bi2Se3 content (x) caused an increase in carrier concentration and thus an increase of σ and a decrease of α. The maximum figure of merit (ZT = α2σT/κ) of 0.87 was obtained at about 325 K for the composition of 93%Bi2Te3-7%Bi2Se3 with doping TeI4.

Thermoelectric Performance of Glass Microsphere Dispersed Bi-Sb Composites at Low Temperature

2013 ◽  
Vol 743-744 ◽  
pp. 120-125
Author(s):  
Zhen Chen ◽  
Ye Mao Han ◽  
Min Zhou ◽  
Rong Jin Huang ◽  
Yuan Zhou ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Sem Analysis ◽  
Glass Microsphere ◽  
Thermoelectric Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Measurement Results

In the present study, the glass microsphere dispersed Bi-Sb thermoelectric materials have been fabricated through mechanical alloying followed by pressureless sintering. The phase composition and the microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured in the temperature range of 77~300 K. The ZT values were calculated according to the measurement results. The results showed that the electrical conductivity, Seebeck coefficient and thermal conductivity decreased by adding glass microsphere into Bi-Sb thermoelectric materials. However, the optimum ZT value of 0.24 was obtained at 260 K, which was increased 10% than that of the Bi-Sb matrix. So it is confirmed that the thermoelectric performance of Bi-Sb-based materials can be improved by adding moderate glass microspheres.

Ensemble-machine-learning-based correlation analysis of internal and band characteristics of thermoelectric materials

2020 ◽  
Vol 8 (37) ◽  
pp. 13079-13089
Author(s):  
Lihao Chen ◽  
Ben Xu ◽  
Jia Chen ◽  
Ke Bi ◽  
Changjiao Li ◽  
...  
Keyword(s):  
Machine Learning ◽  
Electrical Conductivity ◽  
Correlation Analysis ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Ensemble Machine Learning ◽  
Properties Of Materials

Machine learning can significantly help to predict the thermoelectric properties of materials, such as the Seebeck coefficient and electrical conductivity.

Thermoelectric properties of PbTe thin films prepared by gas evaporation method

1999 ◽  
Vol 14 (1) ◽  
pp. 209-212 ◽  
Author(s):  
Masatoshi Ito ◽  
Won-Son Seo ◽  
Kunihito Koumoto
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Seebeck Coefficient ◽  
Grain Boundaries ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Carrier Mobility ◽  
Evaporation Method

PbTe thin films with fine grains were successfully fabricated by the gas evaporation method. Thermoelectric properties, i.e., Seebeck coefficient and electrical conductivity, both decreased with decreasing grain size. This was attributed to the decrease in carrier mobility exceeding the increase in carrier concentration with decreasing grain size. It was clarified that the effects of grain boundaries and of oxidation on carrier mobility are considerably large.

Synthesis and High Temperature Thermoelectric Properties of Alkaline-Earth Metal Hexaborides MB6 (M=Ca, Sr, Ba)

2003 ◽  
Vol 793 ◽  
Author(s):  
Masatoshi Takeda ◽  
Yosuke Kurita ◽  
Keisuke Yokoyama ◽  
Takahiro Miura ◽  
Tsuneo Suzuki ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Thermoelectric Device ◽  
Alloying Effect ◽  
P Type

ABSTRACTPolycrystalline alkaline-earth hexaborides (MB6: M =Ca, Sr, Ba) were synthesized and their thermoelectric and transport properties were examined to discuss their possibility as high temperature thermoelectric materials. Hall measurements showed that carrier concentration of the BaB6 was the highest among the three hexaborides and that of CaB6 was the lowest. Substitution of part of the alkaline earth metals with one of the others changed the carrier concentration of the hexaboride. As the carrier concentration increased, Seebeck coefficient increased and electrical conductivity decreased. These results suggest that the thermoelectric properties of the divalent hexaborides depend largely on the carrier concentration, and optimum carrier concentration which gives maximum power factor was estimated to be approximately 2x1026 m−3. Consequently, such a substitution enables us to control Seebeck coefficient and electrical conductivity of the hexaborides, and will also be effective to reduce the lattice heat conduction due to the alloying effect. A thermoelectric device was fabricated using SrB6 and boron carbide thin films as n-type and p-type elements, respectively. To the best of our knowledge, this is the first demonstration of a thermoelectric device composed of only boron-rich solids.

scholarly journals Thermoelectric Properties of Bi2Te3: CuI and the Effect of Its Doping with Pb Atoms

2017 ◽  
Author(s):  
Mi-Kyung Han ◽  
Yingshi Jin ◽  
Da-Hee Lee ◽  
Sung-Jin Kim
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Thermal Transport ◽  
Co Doping ◽  
Thermal Transport Properties ◽  
Co Doped

In order to understand the effect of Pb-CuI co-doping on the thermoelectric performance of Bi2Te3, n-type Bi2Te3 co-doped with x at% CuI and 1/2x at% Pb (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.10) were prepared via high temperature solid state reaction and consolidated using spark plasma sintering. Electron and thermal transport properties, i.e., electrical conductivity, carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity, of CuI-Pb co-doped Bi2Te3 were measured in the temperature range from 300 K to 523 K and compared to corresponding x% of CuI-doped Bi2Te3 and undoped Bi2Te3. The addition of a small amount of Pb significantly decreased the carrier concentration, which could be attributed to the holes from Pb atoms, thus the CuI-Pb co-doped samples show a lower electrical conductivity and a higher Seebeck coefficient compared to CuI-doped samples with similar x values. The incorporation of Pb into CuI-doped Bi2Te3 rarely changed the power factor because of the trade-off relationship between the electrical conductivity and the Seebeck coefficient. The total thermal conductivity(κtot) of co-doped samples (κtot ~1.4 W/m∙K at 300 K) is slightly lower than that of 1% CuI-doped Bi2Te3 (κtot~1.5 W/m∙K at 300 K) and undoped Bi2Te3 (κtot ~1.6 W/m∙K at 300 K) due to the alloy scattering. The 1% CuI-Pb co-doped Bi2Te3 sample shows the highest ZT value of 0.96 at 370 K. All data on electrical and thermal transport properties suggest that the thermoelectric properties of Bi2Te3 and its operating temperature can be controlled by co-doping.

Fabrication and Thermoelectric Properties of Bi2Te3 Prepared by Combining Chemical Bath Method and Hot Pressing

2013 ◽  
Vol 743-744 ◽  
pp. 65-69 ◽  
Author(s):  
Feng Yuan Li ◽  
Yuan Yuan Wang ◽  
Song Chen ◽  
Zhen Qin ◽  
Ke Feng Cai
Keyword(s):  
Thermoelectric Properties ◽  
Electrical Transport ◽  
Hot Pressing ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
Bulk Materials ◽  
X Ray ◽  
Synthesis Conditions ◽  
Sulfur Addition ◽  
Before And After

Bi2Te3 bulk materials were prepared by combining chemical bath method and hot pressing at 80 MPa and 375 °C for 1 h. The samples before and after hot pressing were examined by X-ray diffraction, and the fracture surface of the bulk materials was observed by field emission scanning electron microscopy (FESEM). The electrical transport properties of the bulk materials were measured from room temperature up to 250 °C under Ar. The results indicate that sulfur addition can prevent the oxidation of Bi2Te3 nanostructures; however, it is not good to the thermoelectric properties of Bi2Te3 under the present synthesis conditions.

scholarly journals Electronic and Thermoelectric Properties of V2O5, MgV2O5, and CaV2O5

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 453 ◽  
Author(s):  
Xiaofei Sheng ◽  
Zhuhong Li ◽  
Yajuan Cheng
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Van Der Waals ◽  
Thermoelectric Performance ◽  
Extreme Condition ◽  
Electronic Band ◽  
Classical Transport

Developing new thermoelectric materials with high performance can broaden the thermoelectric family and is the key to fulfill extreme condition applications. In this work, we proposed two new high-temperature thermoelectric materials—MgV2O5 and CaV2O5—which are derived from the interface engineered V2O5. The electronic and thermoelectric properties of V2O5, MgV2O5, and CaV2O5 were calculated based on first principles and Boltzmann semi-classical transport equations. It was found that although V2O5 possessed a large Seebeck coefficient, its large band gap strongly limited the electrical conductivity, hence hindering it from being good thermoelectric material. With the intercalation of Mg and Ca atoms into the van der Waals interfaces of V2O5, i.e., forming MgV2O5 and CaV2O5, the electronic band gaps could be dramatically reduced down to below 0.1 eV, which is beneficial for electrical conductivity. In MgV2O5 and CaV2O5, the Seebeck coefficient was not largely affected compared to V2O5. Consequently, the thermoelectric figure of merit was expected to be improved noticeably. Moreover, the intercalation of Mg and Ca atoms into the V2O5 van der Waals interfaces enhanced the anisotropic transport and thus provided a possible way for further engineering of their thermoelectric performance by nanostructuring. Our work provided theoretical guidelines for the improvement of thermoelectric performance in layered oxide materials.

Na-Site Doping of NaCo2O4 Thermoelectric Materials

2007 ◽  
Vol 336-338 ◽  
pp. 802-804 ◽  
Author(s):  
Ying Li ◽  
Li Hua Zhang ◽  
Shu Lan Wang ◽  
Gui Ying Xu ◽  
Mao Fa Jiang
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Maximum Power ◽  
Reaction Method

The K, Ca, Sr and Ce doped and non-doped γ-NaxCo2O4 samples were prepared by the solid-state reaction method. Results show that the Na-site doping might lead to an increase in the Seebeck coefficient and a decrease in the electrical conductivity of the samples. The maximum power factors of the K, Ca and Sr doped samples are respectively 2.04, 1.93 and 1.9 W·m-1·K-2, corresponding to an increase by 58%, 50% and 47% compared with that of the non-doped samples. Thus, the Na-site doping can improve the thermoelectric properties of γ-NaxCo2O4 oxides.

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