scholarly journals High thermoelectric cooling performance of n-type Mg3Bi2-based materials

Science ◽  
2019 ◽  
Vol 365 (6452) ◽  
pp. 495-498 ◽  
Author(s):  
Jun Mao ◽  
Hangtian Zhu ◽  
Zhiwei Ding ◽  
Zihang Liu ◽  
Geethal Amila Gamage ◽  
...  
Keyword(s):  
Bismuth Telluride ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Peltier Effect ◽  
Large Temperature ◽  
Thermoelectric Cooling ◽  
Bismuth Antimony Telluride ◽  
Cooling Devices ◽  
Art Room ◽  
P Type

Thermoelectric materials have a large Peltier effect, making them attractive for solid-state cooling applications. Bismuth telluride (Bi2Te3)–based alloys have remained the state-of-the-art room-temperature materials for many decades. However, cost partially limited wider use of thermoelectric cooling devices because of the large amounts of expensive tellurium required. We report n-type magnesium bismuthide (Mg3Bi2)–based materials with a peak figure of merit (ZT) of ~0.9 at 350 kelvin, which is comparable to the commercial bismuth telluride selenide (Bi2Te3–xSex) but much cheaper. A cooling device made of our material and p-type bismuth antimony telluride (Bi0.5Sb1.5Te3) has produced a large temperature difference of ~91 kelvin at the hot-side temperature of 350 kelvin. n-type Mg3Bi2-based materials are promising for thermoelectric cooling applications.

Development of Thermoelectric Cooling Devices with Graded Structure

2005 ◽  
Vol 492-493 ◽  
pp. 151-156 ◽  
Author(s):  
Hitoshi Kohri ◽  
Ichiro Shiota
Keyword(s):  
Bismuth Telluride ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Temperature Drop ◽  
Maximum Temperature ◽  
Large Temperature ◽  
Thermoelectric Cooling ◽  
Temperature Range ◽  
Graded Structure ◽  
Cooling Devices

Every thermoelectric material shows high performance at a specific narrow temperature range. The temperature range with high performance can be expanded by joining the materials with different peak temperature. This is the concept of a functionally graded material (FGM) for thermoelectric materials. Bismuth telluride is the best material for cooling devices at around room temperature. Then we investigated the thermoelectric cooling properties for bismuth telluride with two step graded structure. FGM samples were fabricated by three methods. The first FGM was synthesized by in situ method. The second one was fabricated by joining in a hot-press equipment. The last one was composed by joining with solder. Thermoelectric cooling properties were evaluated by observing the maximum temperature drop to electric current when the high temperature side was kept constant. The large temperature difference was obtained when the proper configuration of thermoelectric materials along the temperature gradient were performed. The coincidence of optimum electrical currents of composing materials is also essential to obtain the high cooling performance.

Thermoelectric Properties of Bi2Te3-ySey Bulk Materials Synthesized by Melting-Grinding Process

2018 ◽  
Vol 773 ◽  
pp. 145-151
Author(s):  
Min Soo Park ◽  
Gook Hyun Ha ◽  
Hye Young Koo ◽  
Yong Ho Park
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermal Characteristics ◽  
Grinding Process ◽  
Alloy Scattering ◽  
Temperature Range ◽  
P Type ◽  
Optimal Effect

The Bi–Te thermoelectric system shows an excellent figure of merit (ZT) near room temperature. Research on increasing the ZT value for n‑type Bi–Te is imperative because the thermoelectric properties of this compound are inferior to those of the p-type material. For this purpose, n-type Bi2Te3-ySey powders with various amounts of Se dopant (0.3 ≤ y ≤ 0.6) were synthesized by a vacuum melting-grinding process to improve the physical properties. The ZT value of the sintered bodies was investigated in the temperature range of 298–423 K with regard to the electrical and thermal characteristics. As the Se content increased, the electrical conductivity decreased owing to a reduction in the carrier concentration, which improved the overall value of ZT. The thermal conductivity clearly decreased as the Se content increased in the temperature range of 298–373 K due to increased alloy scattering, as well as a reduction in the lattice thermal conductivity caused by crystal grain boundary scattering. At room temperature, Bi2Te2.7Se0.3 (y = 0.3) exhibited the highest ZT of 0.85. At increased temperatures, the ZT value was highest for Bi2Te2.55Se0.45 (y = 0.45), indicating that the optimal effect of the Se dopants varies depending on the temperature range.

scholarly journals Development of Spark Plasma Syntering (SPS) technology for preparation of nanocrystalline p-type thermoelctrics based on (BiSb)2Te3

2020 ◽  
Vol 21 (4) ◽  
pp. 628-634
Author(s):  
O. Kostyuk ◽  
B. Dzundza ◽  
M. Maksymuk ◽  
V. Bublik ◽  
L. Chernyak ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Antimony Telluride ◽  
Bismuth Antimony Telluride ◽  
Thermoelectric Figure ◽  
Temperature Range ◽  
Plasma Sintering ◽  
Different Temperatures ◽  
Spark Plasma ◽  
P Type

Bismuth antimony telluride is the most commonly used commercial thermoelectric material for power generation and refrigeration over the temperature range of 200–400 K. Improving the performance of these materials is a complected balance of optimizing thermoelectric properties. Decreasing the grain size of Bi0.5Sb1.5Te3 significantly reduces the thermal conductivity due to the scattering phonons on the grain boundaries. In this work, it is shown the advances of spark plasma sintering (SPS) for the preparation of nanocrystalline p-type thermoelectrics based on Bi0.5Sb1.5Te3 at different temperatures (240, 350, 400oC). The complex study of structural and thermoelectric properties of Bi0.5Sb1.5Te3 were presented. The high dimensionless thermoelectric figure of merit ZT ~ 1 or some more over 300–400 K temperature range for nanocrystalline p-type Bi0.5Sb1.5Te3 was obtained.

Electrical Properties and Figures of Merit for New Chalcogenide-Based Thermoelectric Materials

1997 ◽  
Vol 478 ◽  
Author(s):  
Jon L. Schindler ◽  
Tim P. Hogan ◽  
Paul W. Brazis ◽  
Carl R. Kannewurf ◽  
Duck-Young Chung ◽  
...  
Keyword(s):  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Figures Of Merit ◽  
Lattice Symmetry ◽  
Thermoelectric Refrigeration ◽  
Polychalcogenide Flux ◽  
P Type

AbstractNew Bi-based chalcogenide compounds have been prepared using the polychalcogenide flux technique for crystal growth. These materials exhibit characteristics of good thermoelectric materials. Single crystals of the compound CsBi4Te6 have shown conductivity as high as 2440 S/cm with a p-type thermoelectric power of ≈ +110 μV/K at room temperature. A second compound, β-K2Bi8Se13 shows lower conductivity ≈ 240 S/cm, but a larger n-type thermopower ≈ −200 μV/K. Thermal transport measurements have been performed on hot-pressed pellets of these materials and the results show comparable or lower thermal conductivities than Bi2Te3. This improvement may reflect the reduced lattice symmetry of the new chalcogenide thermoelectrics. The thermoelectric figure of merit for CsBi4Te6 reaches ZT ≈ 0.32 at 260 K and for β-K2Bi8Se13 ZT ≈ 0.32 at room temperature, indicating that these compounds are viable candidates for thermoelectric refrigeration applications.

Enhanced Thermoelectric Figure-of-merit at Room Temperature in Bulk Bi(Sb)Te(Se) With Grain Size of ∼100nm

2013 ◽  
Vol 1543 ◽  
pp. 93-98 ◽  
Author(s):  
Tsung-ta E. Chan ◽  
Rama Venkatasubramanian ◽  
James M. LeBeau ◽  
Peter Thomas ◽  
Judy Stuart ◽  
...  
Keyword(s):  
Grain Size ◽  
Mechanical Alloying ◽  
Grain Boundaries ◽  
Figure Of Merit ◽  
Room Temperature ◽  
High Energy ◽  
High Density ◽  
Nanocrystalline Powders ◽  
Bulk Materials ◽  
P Type

ABSTRACTGrain boundaries are known to be able to impede phonon transport in the material. In the thermoelectric application, this phenomenon could help improve the figure-of-merit (ZT) and enhance the thermal to electrical conversion. Bi2Te3 based alloys are renowned for their high ZT around room temperature but still need improvements, in both n- and p-type materials, for the resulting power generation devices to be more competitive. To implement high density of grain boundaries into the bulk materials, a bottom-up approach is employed in this work: consolidations of nanocrystalline powders into bulk disks. Nanocrystalline powders are developed by high energy cryogenic mechanical alloying that produces Bi(Sb)Te(Se) alloy powders with grain size in the range of 7 to 14 nm, which is about 25% finer compared to room temperature mechanical alloying. High density of grain boundaries are preserved from the powders to the bulk materials through optimized high pressure hot pressing. The consolidated bulk materials have been characterized by X-ray diffraction and transmission electron microscope for their composition and microstructure. They mainly consist of grains in the scale of 100 nm with some distributions of finer grains in both types of materials. Preliminary transport property measurements show that the thermal conductivity is significantly reduced at and around room temperature: about 0.65 W/m-K for the n-type BiTe(Se) and 0.85 W/m-K for the p-type Bi(Sb)Te, which are attributed to increased phonon scattering provided by the nanostructure and therefore enhanced ZT about 1.35 for the n-type and 1.21 for the p-type are observed. Detailed transport properties, such as the electrical resistivity, Seebeck coefficient and power factor as well as the resulting ZT as a function of temperature will be described.

scholarly journals Transition from n- to p-type conduction concomitant with enhancement of figure-of-merit in Pb doped bismuth telluride: Material to device development

2018 ◽  
Vol 159 ◽  
pp. 127-137 ◽  
Author(s):  
Anil K. Bohra ◽  
Ranu Bhatt ◽  
Ajay Singh ◽  
Shovit Bhattacharya ◽  
Ranita Basu ◽  
...  
Keyword(s):  
Bismuth Telluride ◽  
Figure Of Merit ◽  
Device Development ◽  
P Type ◽  
Type Conduction

Fabrication and Characterization of Brush-Printed p-Type Bi0.5Sb1.5Te3 Thick Films for Thermoelectric Cooling Devices

2016 ◽  
Vol 46 (5) ◽  
pp. 2950-2957 ◽  
Author(s):  
Han Wu ◽  
Xing Liu ◽  
Ping Wei ◽  
Hong-Yu Zhou ◽  
Xin Mu ◽  
...  
Keyword(s):  
Thick Films ◽  
Thermoelectric Cooling ◽  
Cooling Devices ◽  
Fabrication And Characterization ◽  
P Type

Thermoelectric Micro-Cooler of Bismuth Telluride Thin Films

2007 ◽  
Author(s):  
Koji Miyazaki ◽  
Jun-Ichiro Kurosaki ◽  
Masayuki Takashiri ◽  
Bertrand Lenoir ◽  
Hiroshi Tsukamoto
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Thermoelectric Power ◽  
Bismuth Telluride ◽  
Figure Of Merit ◽  
Flash Evaporation ◽  
3Ω Method ◽  
Fine Powders ◽  
P Type

In this study, we fabricated bismuth-telluride thin films and their in-plane thermoelectric micro-coolers (4mm×4mm) by using the flash evaporation method. We prepared fine powders of Bi2.0Te2.7Se0.3 (n-type) and Bi0.4Te3.0Sb1.6 (p-type). The thermoelectric properties of as-grown thin films are lower than those of bulk materials. Therefore the as-grown thin films were annealed in hydrogen at atmospheric pressure for 1 hour in a temperature range of 200 to 400°C. By optimizing the annealing temperature, thin films with high thermoelectric power factors of 8.8 μW/(cm·K2) in n-type and 13.8 μW/(cm·K2) in p-type are obtained. To evaluate the figure of merit of the thin film, the thermal conductivity of the n-type thin film is measured by the 3ω method. The thin film annealed at 200 °C exhibited a cross-plane thermal conductivity of 1.2 W/(m·K). Micro-coolers of flash-evaporated bismuth-telluride thin films are fabricated using three shadow masks. The shadow masks are prepared by standard micro-fabrication processes such as nitridation of Si, dry etching, and wet etching. Thermoelectric power of the as-grown thin film devices with 16 pairs of p-n legs are measured by YAG laser heating at the center of the devices. The thermoelectric power of thermoelectric legs is evaluated to be 180μV/K per one p-n leg pair. According to the Kelvin’s law, it corresponds to 54mV Peltier coefficient per p-n pair.

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