scholarly journals Effect of Mechanical Deformation on Thermoelectric Properties of p-Type(Bi0.225Sb0.775)2Te3Alloys

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sung-Jin Jung ◽  
Seong Keun Kim ◽  
Hyung-Ho Park ◽  
Dow-Bin Hyun ◽  
Seung-Hyub Baek ◽  
...  
Keyword(s):  
Grain Size ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Annealing Time ◽  
Mechanical Deformation ◽  
Grain Structure ◽  
Thermoelectric Performance ◽  
Quartz Ampoule ◽  
P Type ◽  
Cold Pressed

The effect of mechanical deformation and annealing on thermoelectric properties of p-type (Bi0.225Sb0.775)Te3was performed. The ingots were prepared by melting, followed by quenching method using source materials with compositions of (Bi0.225Sb0.775)2Te3. Rectangular shaped specimens (5×5×12 mm3) were cut from ingots and then cold-pressed at 700 MPa for 2 to 20 times by changing the press direction perpendicular to previous one. The cold-pressed samples have been annealed in a quartz ampoule at 573 K. The grain size of the samples was controlled by the number of cold-pressing process and annealing time. Fine grain structure with a grain size of not more than 10 μm is obtained in highly deformed samples. The Seebeck coefficient of the deformed samples were gradually increased with annealing and converged to the similar value of about 225 μV/K after 30 hrs. The small grain size in highly deformed sample enables a rapid increase of Seebeck coefficient with annealing time (~2 hrs.), indicating that the thermal energy needed to recrystallize in highly deformed specimens is lower than that in low deformed specimens.Zvalues are rapidly increased with annealing time especially in highly deformed alloys, and converge to about3.0×10−3/K at room temperature. A higher thermoelectric performance could be expected by the optimization of composition and microstructural adjustment. The present study experimentally demonstrates a simple and cost-effective method for fabricating Bi-Te-based alloys with higher thermoelectric performance.

scholarly journals Thermoelectric Properties of Arsenic Triphosphide (AsP3) Monolayer: A First-Principles Study

2021 ◽  
Vol 7 ◽  
Author(s):  
Liangshuang Fan ◽  
Hengyu Yang ◽  
Guofeng Xie
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
First Principles ◽  
Transport Theory ◽  
Thermoelectric Performance ◽  
Performance Tuning ◽  
Boltzmann Transport ◽  
Boltzmann Transport Theory ◽  
P Type

Recently, monolayer of triphosphides (e.g., InP3, SnP3, and GaP3) attracts much attention due to their good thermoelectric performance. Herein, we predict a novel triphosphide monolayer AsP3 and comprehensively investigate its thermoelectric properties by combining first-principles calculations and semiclassical Boltzmann transport theory. The results show that AsP3 monolayer has an ultralow thermal conductivity of 0.36 and 0.55 Wm K−1 at room temperature along the armchair and zigzag direction. Surprisingly, its maximum Seebeck coefficient in the p-type doping reaches 2,860 µVK−1. Because of the ultralow thermal conductivity and ultrahigh Seebeck coefficient, the thermoelectric performance of AsP3 monolayer is excellent, and the maximum ZT of p-type can reach 3.36 at 500 K along the armchair direction, which is much higher than that of corresponding bulk AsP3 at the same temperature. Our work indicates that the AsP3 monolayer is the promising candidate in TE applications and will also stimulate experimental scientists’ interest in the preparation, characterization, and thermoelectric performance tuning.

High Thermoelectric Performance of p-Type Bi0.5Sb1.5Te3+xTe Crystals Prepared via Gradient Freezing

2012 ◽  
Vol 621 ◽  
pp. 167-171
Author(s):  
Tao Hua Liang ◽  
Shi Qing Yang ◽  
Zhi Chen ◽  
Qing Xue Yang
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
P Type

p-type Bi0.5Sb1.5Te3+xTe thermoelectric crystals with various percentages of Te (x = 0.00 wt.%–3.00 wt.%) excess were prepared by the gradient freeze method. By doping with different Te contents, anti-site defects, Te vacancies and hole carrier concentrations were controlled. The Seebeck coefficient, resistivity, thermal conductivity, carrier concentration, and mobility were measured. The relationships between the Te content and thermoelectric properties were investigated in detail. The results suggested that the thermoelectric figure of merit ZT of the Bi0.5Sb1.5Te3+0.09wt.% crystals was 1.36 near room temperature, the optimum carrier concentration was 1.25 × 1019 cm-3, and the mobility was 1480 cm2 V-1 S-1, respectively.

LOW TEMPERATURE THERMOELECTRIC PROPERTIES AND AGING PHENOMENA OF NANOSTRUCTURED p-TYPE Bi2-XSbXTe3 (x = 1.46, 1.48, 1.52 AND 1.55)

2013 ◽  
Vol 06 (05) ◽  
pp. 1340008 ◽  
Author(s):  
DALE HITCHCOCK ◽  
YEN-LIANG LIU ◽  
YUFEI LIU ◽  
TERRY M. TRITT ◽  
JIAN HE ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Thermoelectric Properties ◽  
Optimal Composition ◽  
Ambient Conditions ◽  
Bulk Materials ◽  
The Past ◽  
Aging Phenomena ◽  
P Type ◽  
Cold Pressed

Over the past decade the widely used p-type ( Bi 2-x Sb x) Te 3 bulk thermoelectric materials have been subject to various nanostructuring processes for higher thermoelectric performance. However, these nanostructuring processing were conducted on compositions optimized for bulk materials (x ~ 1.52–1.55). This leads to the question of whether the optimal composition for bulk materials is the same for their nanoscale counterparts. In this work we hydrothermally grew Bi 2-x Sb x Te 3 nanopowders (nominally, x = 1.46, 1.48, 1.52 and 1.55) and measured their thermoelectric properties on cold-pressed vacuum-sintered pellets (74–78% of the theoretical density) below 300 K. The measurements were conducted 18 months apart to probe the aging phenomena, with the samples stored in ambient conditions. We have found that (i) the peak of thermopower shifts to lower temperatures upon nanostructuring but it shifts back to higher temperatures upon aging; (ii) the electrical conductivity degrades by a factor of 1.5–2.3 upon aging while the temperature dependence is largely retained; and (iii) the ZT of freshly made samples is sensitive to the x value, a maximum ZT ~ 1.25(~ 0.62) at ~ 270 K (~ 255 K) was attained in the freshly made sample x = 1.55(x = 1.46), respectively; while the ZT of aged samples is significantly lowered by a factor of 2–4 but lesser x-dependent. These observations have been discussed in the context of charge buildup and compensation at grain boundaries.

scholarly journals Effect of Grain Size and Film Thickness on the Thermoelectric Properties of Flexible Sb2Te3 Thin Films

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Pornsiri Wanarattikan ◽  
Piya Jitthammapirom ◽  
Rachsak Sakdanuphab ◽  
Aparporn Sakulkalavek
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Film Thickness ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Flexible Substrate ◽  
Rf Magnetron Sputtering ◽  
Mean Free Path

In this work, stoichiometric Sb2Te3 thin films with various thicknesses were deposited on a flexible substrate using RF magnetron sputtering. The grain size and thickness effects on the thermoelectric properties, such as the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and thermal conductivity (k), were investigated. The results show that the grain size was directly related to film thickness. As the film thickness increased, the grain size also increased. The Seebeck coefficient and electrical conductivity corresponded to the grain size of the films. The mean free path of carriers increases as the grain size increases, resulting in a decrease in the Seebeck coefficient and increase in electrical conductivity. Electrical conductivity strongly affects the temperature dependence of PF which results in the highest value of 7.5 × 10−4 W/m·K2 at 250°C for film thickness thicker than 1 µm. In the thermal conductivity mechanism, film thickness affects the dominance of phonons or carriers. For film thicknesses less than 1 µm, the behaviour of the phonons is dominant, while both are dominant for film thicknesses greater than 1 µm. Control of the grain size and film thickness is thus critical for controlling the performance of Sb2Te3 thin films.

Microstructure Investigation of Non-equilibrium Synthesized Filled Skutterudite CeFe4Sb12

2010 ◽  
Vol 1267 ◽  
Author(s):  
Juan Zhou ◽  
Qing Jie ◽  
Qiang Li
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Grain Boundaries ◽  
Thermoelectric Properties ◽  
Conventional Solid State Reaction ◽  
Filled Skutterudite ◽  
Filled Skutterudites ◽  
Higher Carrier Mobility ◽  
P Type ◽  
Non Equilibrium

AbstractWe have prepared a variety of filled skutterudites through non-equilibrium synthesis by converting melt-spun ribbons into single phase polycrystalline bulk under pressure. In general, better thermoelectric properties are found in these samples. In this work, we performed microstructure characterization of non-equilibrium synthesized p-type filled skutterudite CeFe4Sb12 by X-ray diffraction, scanning electron microscopy and transmission electron microscopy in order to understand the structural origin of the improved thermoelectric properties. It is found that the non-equilibrium synthesized samples have smaller grain size and cleaner grain boundaries when compared to the samples prepared by the conventional solid-state reaction plus long term annealing. While smaller grain size can help reduce the lattice thermal conductivity, cleaner grain boundaries ensure higher carrier mobility and subsequently, higher electrical conductivity at the application temperatures.

An enhanced Seebeck coefficient and high thermoelectric performance in p-type In and Mg co-doped Sn1−xPbxTe via the co-adjuvant effect of the resonance level and heavy hole valence band

2017 ◽  
Vol 5 (23) ◽  
pp. 5737-5748 ◽  
Author(s):  
Subhajit Roychowdhury ◽  
U. Sandhya Shenoy ◽  
Umesh V. Waghmare ◽  
Kanishka Biswas
Keyword(s):  
Synergistic Effect ◽  
Seebeck Coefficient ◽  
Valence Band ◽  
Heavy Hole ◽  
Resonance Level ◽  
Thermoelectric Performance ◽  
Adjuvant Effect ◽  
P Type ◽  
Co Doped

Remarkable enhancement of the Seebeck coefficient of an Sn rich Sn1−xPbxTe system due to the synergistic effect of resonance level formation and valence band convergence.

Effect of FAPAS Process on the Thermoelectric Properties of β-FeSi2

2010 ◽  
Vol 650 ◽  
pp. 137-141
Author(s):  
Qing Sen Meng ◽  
Wen Hao Fan ◽  
L.Q. Wang ◽  
L.Z. Ding
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Phase Transformation ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Annealing Time ◽  
Figure Of Merit ◽  
Iron Disilicide ◽  
Temperature Range ◽  
Average Grain Size

Iron disilicide (-FeSi2, and -FeSi2+Cu0.1wt%) were prepared by a field-activated pressure assisted synthesis(FAPAS) method from elemental powders and the thermoelectric properties were investigated. The average grain size of these products is about 0.3m. The thermal conductivity of these materials is 3-4wm-1K-1in the temperature range 300-725K. These products’ figure of merit is 28.50×10-4 in the temperature range 330-450K. The additions of Cu promote the phase transformation of -Fe2Si5 + -FeSi → β-FeSi2 and shorten the annealing time. It is proved that FAPAS is a benign and rapid process for sintering of -FeSi2 thermoelectric materials.

scholarly journals Влияние легирования ванадием на термоэлектрические свойства сплавов Гейслера Fe-=SUB=-2-=/SUB=-Ti-=SUB=-1-x-=/SUB=-V-=SUB=-x-=/SUB=-Sn

2019 ◽  
Vol 53 (6) ◽  
pp. 777
Author(s):  
А.И. Таранова ◽  
А.П. Новицкий ◽  
А.И. Воронин ◽  
С.В. Таскаев ◽  
В.В. Ховайло
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Experimental Study ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Pristine Sample ◽  
Electrical Conductivity Behavior ◽  
P Type ◽  
Conductivity Behavior

In this work the results of an experimental study of Fe2Ti1-xVxSn alloys (x = 0; 0.06; 0.15; 0.2) are presented. According to the temperature dependencies of the electrical conductivity, Seebeck coefficient and thermal conductivity, it is established, that the studied compositions exhibit transport properties typical for semiconductors. The substitution of V at the Ti site leads to a change of the p-type electrical conductivity behavior to n-type; the pristine sample of Fe2TiSn has the best thermoelectric properties.

Improving the thermoelectric performance of p-type PbSe via synergistically enhancing the Seebeck coefficient and reducing electronic thermal conductivity

2020 ◽  
Vol 8 (9) ◽  
pp. 4931-4937 ◽  
Author(s):  
Zhiwei Huang ◽  
Dongyang Wang ◽  
Caiyun Li ◽  
Jinfeng Wang ◽  
Guangtao Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Performance ◽  
Seebeck Coefficients ◽  
Electronic Thermal Conductivity ◽  
P Type

CdTe alloying dramatically enhanced the thermoelectric performance of p-type PbSe by enhancing Seebeck coefficients and reducing electronic thermal conductivity.

Remarkably high thermoelectric performance of Cu2−xLixSe bulks with nanopores

2018 ◽  
Vol 6 (46) ◽  
pp. 23417-23424 ◽  
Author(s):  
Qiujun Hu ◽  
Zheng Zhu ◽  
Yuewen Zhang ◽  
Xin-Jian Li ◽  
Hongzhang Song ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Thermoelectric Performance ◽  
Practical Applications ◽  
P Type

Cu2Se is a p-type semiconducting compound that possesses excellent thermoelectric properties which exhibit great potential for practical applications.

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