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Thermoelectric Prediction from Material Descriptors Using Machine Learning Technique
(2023-04-19)
Sungphueng, Pakawat
;
Amnuyswat, Kittiphong
In this work, we employed a machine learning framework to predict the thermoelectric power factors of materials based on their composition and structure. To generate a broad range of materials for analysis, we sourced an existing dataset from the Materials Project database. The electronic transport properties, which serve as the output variables, were obtained from the same database via a Boltzmann transport theory calculation beyond ab-initio method. These properties were used to generate input data, or material descriptors, which rely solely on atomic information and crystal structure without recourse to density functional theory calculations. The descriptors were transformed into numerical features using the open-source software Matminer. Non-linear machine learning regression models were trained and tested on the transformed datasets, and their performance was evaluated. The optimized random forest model produced the most accurate predictions, with a yield of 88%. The ultimate goals of this research were to develop material selection strategies that bypass the need for self-consumption in density functional theory calculations, and to demonstrate the potential of machine learning models to describe the thermoelectric properties of existing materials datasets.
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Cost-Effective Experimental Setup for Studies of Spin Seebeck Effect and Electrical Transport in Thermoelectric Materials
(2020-06-01)
Wongjom, Poramed
;
Thongsamrit, Wannisa
;
Ramamoorthy, Harihara
;
Chinwong, Suriya
;
Somphonsane, Ratchanok
In this article, we report on the design of a low-cost, accurate, and easy-to-implement roomerature experimental setup to comprehensively study the spin Seebeck effect (SSE) in ferrimagnetic insulators (FIs). Neodymium permanent magnets (NdPMs) are used to generate a fixed uniform magnetic field while the sample is staged in a custom-designed vacuum chamber containing thermal baths (for generating the required temperature gradient) and a complete 360° sample rotation mechanism (for studying the magnetic field angle dependence). Our experiments reveal excellent magnetic field uniformity (±1%) formed between the magnet poles, a highly accurate temperature gradient stability (±1%), and excellent agreement of the longitudinal SSE (LSSE) response for the Pt/YIG structure studied here with those reported in the literature. We also measure the anomalous Nernst effect (ANE) exhibited in a graphite sample, demonstrating the capability of our setup to accurately measure this parameter. Finally, we demonstrate that our setup can also be used to measure the conventional Seebeck effect (SE) and the electrical resistivity of commercially obtained Bi<inf>2</inf>Te<inf>3</inf> samples, making it a versatile tool for the broad characterization of thermoelectric materials.
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The Property Investigation of Solder Mixed with Thermoelectrics Alzno by Using Digital Holography
(2018-08-10)
Prakobsang, Tawipon
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Plaipichit, Suwan
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Kanlayasiri, Kannachai
;
Buranasiri, Prathan
In this paper in-line digital holography(DH) technique was used to investigate some properties of solder paste mixed with different percent weight of thermoelectric type AlZnO. By using reconstructed image results different properties of the compound solder pastes i.e. the contact angles, flux thickness were investigated. In addition, their electrical resistance also measured. From our reconstructed image results DH technique plus some computer programming would be one of efficient technique using in electronic industry in the future.
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[Bi]:[Te] Control, Structural and Thermoelectric Properties of Flexible BixTey Thin Films Prepared by RF Magnetron Sputtering at Different Sputtering Pressures
(2017-11-01)
Nuthongkum, Pilaipon
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Sakdanuphab, Rachsak
;
Horprathum, Mati
;
Sakulkalavek, Aparporn
In this work, flexible Bi<inf>x</inf>Te<inf>y</inf> thin films were prepared by radio frequency (RF) magnetron sputtering using a Bi<inf>2</inf>Te<inf>3</inf> target on polyimide substrate. The effects of sputtering pressures, which ranged between 0.6 Pa and 1.6 Pa on the [Bi]:[Te] ratio, and structural and thermoelectric properties were investigated. The [Bi]:[Te] ratio of thin film was determined by energy-dispersive spectrometry (EDS). The EDS spectra show the variation of the [Bi]:[Te] ratio as the sputtering pressure is varied. The film deposited at 1.4 Pa almost has a stoichiometric composition. The selective films with different [Bi]:[Te] ratios and sputtering pressures were characterized by their surface morphologies, crystal and chemical structures by field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD) and Raman spectroscopy, respectively. Electrical transport properties, including carrier concentration and mobility, were measured by Hall effect measurements. Seebeck coefficients and electrical conductivities were simultaneously measured by a direct current four-terminal method (ZEM-3). The XRD and Raman spectroscopy results show a difference in microstructure between BiTe and Bi<inf>2</inf>Te<inf>3</inf> depending on the [Bi]:[Te] ratio. Electrical conductivity and Seebeck coefficient are related to the crystal and chemical structures. The maximum power factor of the Bi<inf>2</inf>Te<inf>3</inf> thin film is 9.5 × 10−4 W/K2 m at room temperature, and it increases to 12.0 × 10−4 W/K2 m at 195°C.
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RSM Base Study of the Effect of Argon Gas Flow Rate and Annealing Temperature on the [Bi]:[Te] Ratio and Thermoelectric Properties of Flexible Bi-Te Thin Film
(2017-05-01)
Nuthongkum, Pilaipon
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Sakulkalavek, Aparporn
;
Sakdanuphab, Rachsak
Bismuth telluride (Bi-Te) thin films coated on a flexible substrate were prepared by RF (radio frequency) magnetron sputtering technique. A response surface methodology based on a central composite design was used to optimize deposition parameters, including the amount of Ar gas flow rate (100.5–106.5 sccm) in the sputtering process and the annealing temperature (250–320°C) for stoichiometric Bi<inf>2</inf>Te<inf>3</inf> thin films. The mathematical model was validated and proven to be statistically sufficient and accurate in predicting a response (Te content). The stoichiometric Bi<inf>2</inf>Te<inf>3</inf> thin films can be prepared on terms appropriate to the Ar flow rate and annealing temperature under several conditions, such as at the Ar flow rate of 103.5 sccm followed by an annealing temperature of 285°C. The characterization of the crystal structure and surface morphology of selected samples with different [Bi]:[Te] content were analyzed by x-ray diffraction (XRD) and a field emission scanning electron microscope, respectively. The XRD spectra showed Bi-Te and Bi<inf>2</inf>Te<inf>3</inf> structures that corresponded with the ratio of [Bi]:[Te]. The Seebeck coefficient and electrical conductivity were simultaneously measured at room temperature and up to 300°C by a direct current four-terminal method. The maximum power factor of the stoichiometric Bi<inf>2</inf>Te<inf>3</inf> thin film was 61×10−5 W/K2m at 243°C.
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Microstructure and Electrical Properties of Antimony Telluride Thin Films Deposited by RF Magnetron Sputtering on Flexible Substrate Using Different Sputtering Pressures
(2017-05-01)
Khumtong, T.
;
Sukwisute, P.
;
Sakulkalavek, A.
;
Sakdanuphab, R.
The microstructural, electrical, and thermoelectric properties of antimony telluride (Sb<inf>2</inf>Te<inf>3</inf>) thin films have been investigated for thermoelectric applications. Sb<inf>2</inf>Te<inf>3</inf> thin films were deposited on flexible substrate (polyimide) by radiofrequency (RF) magnetron sputtering from a Sb<inf>2</inf>Te<inf>3</inf> target using different sputtering pressures in the range from 4 × 10−3 mbar to 1.2 × 10−2 mbar. The crystal structure, [Sb]:[Te] ratio, and electrical and thermoelectric properties of the films were analyzed by grazing-incidence x-ray diffraction (XRD) analysis, energy-dispersive x-ray spectroscopy (EDS), and Hall effect and Seebeck measurements, respectively. The XRD spectra of the films demonstrated polycrystalline structure with preferred orientation of (015), (110), and (1010). A high-intensity spectrum was found for the film deposited at lower sputtering pressure. EDS analysis of the films revealed the effects of the sputtering pressure on the [Sb]:[Te] atomic ratio, with nearly stoichiometric films being obtained at higher sputtering pressure. The stoichiometric Sb<inf>2</inf>Te<inf>3</inf> films showed p-type characteristics with electrical conductivity, carrier concentration, and mobility of 35.7 S cm−1, 6.38 × 1019 cm−3, and 3.67 cm2 V−1 s−1, respectively. The maximum power factor of 1.07 × 10−4 W m−1 K−2 was achieved for the film deposited at sputtering pressure of 1.0 × 10−2 mbar.

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