Performance of Nanoscale Quantum Well Thermoelectrics

Author(s):  
Daniel Krommenhoek ◽  
Norbert Elsner ◽  
Saeid Ghamaty ◽  
Velimir Jovanovic

Alternating 10 nm thermoelectric films of N-type Si/SiGe and P-type Si/SiGe and B4C/B9C have been fabricated on various substrates, electrically joined and thermoelectric properties measured from 40°K up to 700°K. These nanoscale thermoelectric films demonstrate excellent thermoelectric power factors significantly higher than current bulk thermoelectric materials. The implications of the measured thermoelectric Seebeck coefficient data and electrical resistivity data for alternating 10 nm films that are grown to thicknesses of one to 10 microns means efficiencies of 15% at 200°C temperature differences and efficiencies of 30% at 400°C temperature differences. Utilizing Seebeck and resistivity data obtained by Hi-Z and UCSD, along with published bulk thermal conductivity data, which is conservative, unique thermoelectric module and generator concept designs for both power generation and cooling are presented over wide temperature and power ranges.

2016 ◽  
Vol 675-676 ◽  
pp. 679-682 ◽  
Author(s):  
Kunchit Singsoog ◽  
Chanchana Thanachayanont ◽  
Anek Charoenphakdee ◽  
Tosawat Seetawan

The Ca3Co4O9 (CCO) and Sr0.87La0.13TiO3 (SLTO) are good property of oxide thermoelectric (TE) materials. They synthesized by solid state reaction (SSR) method to study thermoelectric properties and fabrication of thermoelectric module. It was found that, synthesis of CCO shows that Seebeck coefficient, electrical resistivity, thermal conductivity and values are 130 μV K–1, 8.31 mΩ cm, 0.82 W m–1 K–1 and 0.08, respectively at 473 K. The Seebeck coefficient, electrical resistivity, thermal conductivity and ZT values of SLTO are –359 μV K–1, 2.9 mΩ m, 18.09 W m–1 K–1 and 1.13×10–3, respectively at 473 K. TE modules of CCO and SLTO were fabricated by ultra sonic soldering method. The power generation of TE modules were measured with temperature difference (ΔT) of 10–180 K. The 1 pair and 2 pairs TE modules for a maximum power generation of matching load are 19 k and 30 k, respectively. The maximum output power of 2 pairs TE module is larger than 1 pair TE module about two times.


2012 ◽  
Vol 622-623 ◽  
pp. 726-733 ◽  
Author(s):  
Weerasak Somkhunthot ◽  
Nuwat Pimpabute ◽  
Tosawat Seetawan

Thin films thermoelectric module fabricated by pulsed-dc magnetron sputtering system using Ca3Co4O9(p-type) and ZnO (n-type) targets of 60 mm diameter and 2.5 mm thickness, which were made from powder precursor, and obtained by solid state reaction. Thin films of p-Ca-Co-O (Seebeck coefficient = 143.85 µV/K, electrical resistivity = 4.80 mΩm, power factor = 4.31 µW/m K2) and n-ZnO (Seebeck coefficient =229.24 µV/K, electrical resistivity = 5.93 mΩm, power factor = 8.86 µW/m K2) were used to make a thermoelectric module, which consist of four pairs of legs connected by copper electrodes (0.5 mm thickness, 3.0 mm width, and 3.0-8.0 mm length). Each leg is 3.0 mm width, 20.0 mm length, and 0.44 µm thickness on a glass substrate of 1.0 mm thickness in dimension 25.0x50.0 mm2. For preliminary test, a module was used to thermoelectric power generation. It was found that the open circuit voltage increased with increasing temperature difference from 3 mV at 5 K up to 20 mV at 78 K. The internal resistance of a module reached a value of 14.52 MΩ. This test indicated that a module can be generated the electrical power. Therefore, it can be used as an important platform for further thin films thermoelectric module research.


2021 ◽  
Vol 143 (12) ◽  
Author(s):  
Ding Luo ◽  
Ruochen Wang

Abstract When analyzing and optimizing the performance of thermoelectric (TE) devices in theory, Seebeck coefficient, thermal conductivity, and electrical resistivity are indispensable TE properties. However, most manufacturers do not provide or overestimate these data. Under the consideration of temperature dependence, this paper discloses an experimental measurement approach to estimate the equivalent Seebeck coefficient, thermal conductivity, and electrical resistivity of a TE module. A thermal resistance network is also established to work out the hot and cold side temperatures of TE legs. Based on a designed test bench, required temperature and electrical parameters in both open circuit and closed circuit are measured and recorded, where the data of open circuit are used to calculate the equivalent Seebeck coefficient and thermal conductivity, and the data of closed circuit are used to calculate the equivalent electrical resistivity. To eliminate the error of parasitic internal resistance, a thermal-electric finite element model is adopted to modify the equivalent electrical resistivity. The modification results indicate that the equivalent internal resistance is about 1.033 times the real internal resistance, and the ratio is related to the working temperature. This work provides a new idea to obtain the TE material properties via an experimental test.


2011 ◽  
Vol 312-315 ◽  
pp. 223-228
Author(s):  
Il Ho Kim

Sn-filled and Fe-doped CoSb3 skutterudites were synthesized by encapsulated induction melting. A single δ-phase was obtained by subsequent annealing, as confirmed by X-ray diffraction. The as-solidified ingot consisted of mixed phases of -CoSb, -CoSb2, δ-CoSb3 and elemental Sb. The phases could be transformed by annealing, and the phases of the as-solidified ingot annealed at 773 K for 24 h transformed to δ-CoSb3. The temperature dependence of the Seebeck coefficient, electrical resistivity and thermal conductivity were examined from 300 K to 700 K. The positive Seebeck coefficient confirmed p-type conduction. The electrical resistivity increased with increasing temperature, which showed that the SnzCo3FeSb12 skutterudite is highly degenerate. The thermal conductivity was reduced by Sn-filling because the filler atoms acted as phonon scattering centers in the skutterudite lattice. The thermoelectric figure of merit was enhanced by Sn filling and its optimum composition was considered to be Sn0.3Co3FeSb12.


2006 ◽  
Vol 510-511 ◽  
pp. 1122-1125
Author(s):  
Won Seung Cho ◽  
Dong Choul Cho ◽  
Cheol Ho Lim ◽  
C.H. Lee ◽  
Woon Suk Hwang ◽  
...  

The microstructure and thermoelectrical properties of the 4wt% Te doped p-type Bi0.5Sb1.5Te3 compounds, fabricated by using spark plasma sintering in the temperature ranging from 250°C to 350°C, were characterized. The density of the sintered compounds was increased to 99.2% of theoretical density by carrying out the consolidation at 350oC for 2 min. The Seebeck coefficient, thermal conductivity and electrical resistivity were dependent on hydrogen reduction process and sintering temperature. The Seebeck coefficient increased with reduction process while the electrical resisitivity significantly decreased. Also, the electrical resistivity decreased and thermal conductivity increased with sintering temperature. The results suggest that the carrier density and mobility vary with reduction process and sintering temperature. The highest figure of merit of 3.5×10-3/K was obtained for the compounds spark plasma sintered at 350°C for 2 min by using the hydrogen-reduced powders.


2008 ◽  
Vol 1102 ◽  
Author(s):  
S. Budak ◽  
S. Guner ◽  
T. Hill ◽  
M. Black ◽  
S. B. Judah ◽  
...  

AbstractThermoelectric materials are being important due to their application in both thermoelectric power generation and microelectronic cooling. The thermoelectric power generations convert the heat change to electricity. The waste of heat could be useful if the thermoelectric power generation is applied. Effective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. A high thermal conductivity causes too much heat leakage through heat conduction. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2σT/K, where S is the Seebeck coefficient, σ is the electrical conductivity, T is the absolute temperature and K is the thermal conductivity. ZT can be increased by increasing S, increasing σ, or decreasing K. In this study, we prepared thermoelectric generator devices of SiGe at the thickness of 112 nm using the ion beam assisted deposition (IBAD) system. Rutherford Backscattering Spectrometry (RBS) analysis was used for the elemental analysis. The 5 MeV Si ion bombardment was performed using the AAMU Pelletron ion beam accelerator to make quantum clusters in the film to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardment we measured the cross plane Seebeck coefficient, electrical conductivity by Van der Pauw method, and thermal conductivity by 3w method for different fluences.


2007 ◽  
Vol 280-283 ◽  
pp. 397-400 ◽  
Author(s):  
Jing Liu ◽  
Jing Feng Li

Bi2Te3-based alloys are currently best-known, technological thermoelectric materials near room temperature. In this paper, Bi2Te3 and nano-SiC dispersed Bi2Te3 were prepared by mechanical alloying followed by spark plasma sintering (SPS). Raw powders of Bi, Te and SiC were mixed and mechanically alloyed in an argon atmosphere using a planetary ball mill. The SPS temperature was 623K, and the holding time was 5 minutes. The samples were characterized by X-ray Diffraction (XRD) and Scanning electron Microscope (SEM). The thermoelectric properties: i.e. Seebeck coefficient, electrical resistivity and thermal conductivity were measured at temperatures from room temperature to 573K, followed by the evaluation of figure of merit. The results revealed that the SiC dispersion in the Bi2Te3 matrix increased Seebeck coefficient. Although the electrical resistivity was increased somewhat, the thermal conductivity was reduced by the SiC dispersion, indicating that promising thermoelectric materials with enhanced mechanical properties may be obtained in the nano-SiC dispersed Bi2Te3 composites with optimal compositions.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.


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