Thermoelectric Module of P-Type Ca-Co-O/N-Type ZnO Thin Films

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.

2012 ◽  
Vol 538-541 ◽  
pp. 60-63 ◽  
Author(s):  
Zhao Kun Cai ◽  
Ping Fan ◽  
Zhuang Hao Zheng ◽  
Xing Min Cai ◽  
Dong Ping Zhang ◽  
...  

N-type Bi2Te3 and p-type Sb2Te3 thermoelectric thin films have been prepared by RF and DC co-sputtering. The Seebeck coefficient of n-type Bi2Te3 and p-type Sb2Te3 thin films is about -122 μVK-1 and 108 μVK-1, the power factor is about 0.82×10-3 Wm-1K-2 and 1.60×10-3 Wm-1K-2. Then, the films have been selected to fabricate the thin film thermoelectric generator. The results show that the open-circuit voltage of 12.2 mV and the output power of 3.32 μW are obtained for a thin film generator with the temperature difference at 60 K.


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.


Author(s):  
Daniel Sanin-Villa ◽  
Oscar D. Monsalve-Cifuentes ◽  
Jorge Sierra Del Rio

In 2020 the COVID-19 pandemic has suddenly stopped society and changed human interaction. In this work, a thermoelectric generator wearable device for early fever detection symptoms is presented as a possible solution to avoid higher propagation of this disease. To identify a possible fever symptom, numerical and parametric simulations are developed using a highquality-refined hexahedral mesh. At first, a 2-pair-leg thermoelectric module has undergone simulations to establish temperature conditions, open-circuit voltage, and power output generation; and secondly, these previous results are extrapolated for a larger thermoelectric module containing 28 pair-leg of N-P type material. The numerical study shows that a maximum value of electrical power of 60.70 mW was reached for 28-pair-leg N-P type thermocouples under a constant temperature difference of 20 K.


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.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1435
Author(s):  
Kaneez Fatima ◽  
Hadia Noor ◽  
Adnan Ali ◽  
Eduard Monakhov ◽  
Muhammad Asghar

Over the past few years, thermoelectrics have gained interest with regard to thermoelectricity interconversion. The improvement in the efficiency of the thermoelectric material at an ambient temperature is the main problem of research. In this work, silicon–germanium (SiGe) thin films, owing to superior properties such as nontoxicity, high stability, and their integrability with silicon technologies, were studied for thermoelectric applications. P-type SiGe thin films were deposited on quartz substrates by DC/RF magnetron sputtering and annealed at three different temperatures for 1 hour. Significant enhancement in the Seebeck coefficient was achieved for the sample annealed at 670 °C. A high power factor of 4.1 μWcm−1K−2 was obtained at room temperature.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jyun-Min Lin ◽  
Ying-Chung Chen ◽  
Chi-Pi Lin

Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.


Author(s):  
Shrikant Saini ◽  
Ajay Kumar Baranwal ◽  
Tomohide Yabuki ◽  
Shuzi Hayase ◽  
Koji Miyazaki

Abstract Thermoelectric materials can convert thermal energy into electrical energy without any moving part which leads its path of application to the era of printed and flexible electronics. CsSnI3 perovskite can be a promising thermoelectric material for the next-generation energy conversion due to its intrinsic ultra-low thermal conductivity and large Seebeck coefficient but enhancement of electrical conductivity is still required. CsSnI3 can be prepared by wet process which can reduce the cost of flexible thermoelectric module. In this work, CsSnI3 thin films were fabricated by spin coating wet process. Thin films were structurally and chemically characterized using XRD and SEM. Thermoelectric properties such as electrical conductivity, Seebeck coefficient, and thermal conductivity were measured at 300 K. Uni-leg thermoelectric modules were fabricated on a glass substrate using CsSnI3 thin films. The maximum output is about 0.8 nW for 5 legs (25 mm × 3 mm × 600 nm) modules for the temperature difference of about 5°C. These results will open a new pathway to thermoelectric modules for flexible electronics in spite of low output power.


Entropy ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. 803 ◽  
Author(s):  
Armin Feldhoff

The basic principles of thermoelectrics rely on the coupling of entropy and electric charge. However, the long-standing dispute of energetics versus entropy has long paralysed the field. Herein, it is shown that treating entropy and electric charge in a symmetric manner enables a simple transport equation to be obtained and the power conversion and its efficiency to be deduced for a single thermoelectric material apart from a device. The material’s performance in both generator mode (thermo-electric) and entropy pump mode (electro-thermal) are discussed on a single voltage-electrical current curve, which is presented in a generalized manner by relating it to the electrically open-circuit voltage and the electrically closed-circuited electrical current. The electrical and thermal power in entropy pump mode are related to the maximum electrical power in generator mode, which depends on the material’s power factor. Particular working points on the material’s voltage-electrical current curve are deduced, namely, the electrical open circuit, electrical short circuit, maximum electrical power, maximum power conversion efficiency, and entropy conductivity inversion. Optimizing a thermoelectric material for different working points is discussed with respect to its figure-of-merit z T and power factor. The importance of the results to state-of-the-art and emerging materials is emphasized.


Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3706 ◽  
Author(s):  
Ochai Oklobia ◽  
Giray Kartopu ◽  
Stuart J. C. Irvine

As-doped polycrystalline ZnTe layers grown by metalorganic chemical vapor deposition (MOCVD) have been investigated as a back contact for CdTe solar cells. While undoped ZnTe films were essentially insulating, the doped layers showed significant rise in conductivity with increasing As concentration. High p-type carrier densities up 4.5 × 1018 cm−3 was measured by the Hall-effect in heavily doped ZnTe:As films, displaying electrical properties comparable to epitaxial ZnTe single crystalline thin films in the literature. Device incorporation with as-deposited ZnTe:As yielded lower photovoltaic (PV) performance compared to reference devices, due to losses in the open-circuit potential (VOC) and fill factor (FF) related to reducing p-type doping density (NA) in the absorber layer. Some minor recovery observed in absorber doping following a Cl-free post–ZnTe:As deposition anneal in hydrogen at 420 °C contributed to a slight improvement in VOC and NA, highlighting the significance of back contact activation. A mild CdCl2 activation process on the ZnTe:As back contact layer via a sacrificial CdS cap layer has been assessed to suppress Zn losses, which occur in the case of standard CdCl2 anneal treatments (CHT) via formation of volatile ZnCl2. The CdS sacrificial cap was effective in minimising the Zn loss. Compared to untreated and non-capped, mild CHT processed ZnTe:As back contacted devices, mild CHT with a CdS barrier showed the highest recovery in absorber doping and an ~10 mV gain in VOC, with the best cell efficiency approaching the baseline devices.


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