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1
Content available Investigation on Structural, Electronic, Thermal and Thermoelectric Properties of Al0.25B0.75As Alloy Under Pressure, Based on Density Functional Theory (DFT)
Kisomi Ali Fazeli, Mousavi S. J., Nedaee-Shakarab Bashir
Archives of Metallurgy and Materials
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2023
|
Vol. 68, iss. 3
875--880
EN
In this paper, structural, electronic, thermal, and thermoelectric properties of Al0.25B0.75As alloy, under pressures 0 GPa, 4 GPa and 8 GPa, have been calculated. The value of band gap at present work under 0 GPa, with GGA(PBE) exchange-correlation potential, is very close to other works with TB-mBJ method. This is a result of equal selection of muffin-tin radius spheres that are bigger than usual size for Al and B atoms. The values of band gap decrease by increasing pressure. In thermal properties, phonon contribution of heat capacity at constant volume and Debye temperature have been calculated in the range of 0K to 1000K temperatures and under 0 GPa, 4 GPa and 8 GPa pressures. Thermoelectric properties, under the same pressures and in the range of 100K to 1000K temperatures have been investigated.
2
Content available Review on thermoelectrical properties of selected imines in neat and multicomponent layers towards organic opto-electronics and photovoltaics
Bogdanowicz Krzysztof Artur, Iwan Agnieszka
Opto-Electronics Review
|
2021
|
Vol. 29, No. 4
201--212
EN
The present review is mainly focused on the extended analysis of the results obtained from coupled measurement techniques of a thermal imaging camera and chronoamperometry for imines in undoped and doped states. This coupled technique allows to identify the current-voltage characteristics of thin films based on imine, as well as to assess layer defects in thermal images. Additional analysis of results provides further information regarding sample parameters, such as resistance, conductivity, thermal resistance, and Joule power heat correlated with increasing temperature. As can be concluded from this review, it is possible not only to study material properties at the supramolecular level, but also to tune macroscopic properties of -conjugated systems. A detailed study of the structure-thermoelectrical properties in a series of eight unsymmetrical and symmetrical imines for the field of optoelectronics and photovoltaics has been undertaken. Apart from this molecular engineering, the imines properties were also tuned by supramolecular engineering via protonation with camphorsulfonic acid and by creation of bulk-heterojunction compositions based on poly(4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl) and/or [6,6]-phenyl-C71-butyric acid methyl ester, poly(3,4-ethylenedioxythiophene) towards the analysed donor or acceptor ability of imines in the active layer. The use of coupled measurement techniques of a thermal imaging camera and chronoamperometry allows obtaining comprehensive data on thermoelectric properties and defects indicating possible molecule rearrangement within the layer.
3
Content available The Ru Impurity Effect on Electronic, Optical and Thermoelectric Properties of MoS2 Nano-Sheet: a DFT Study
Dezfuli Firouzeh Motamad, Boochani Arash, Parhizgar Sara Sadat, Darabi Elham
Archives of Metallurgy and Materials
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2021
|
Vol. 66, iss. 2
461--468
EN
The electronic, optical and thermoelectric properties of MoS2 nano-sheet in presence of the ru impurity have been calculated by density functional theory framework with generalized gradient approximation. The MoRuS2 nano-sheet electronic structure was changed to the n-type semiconductor by 1.3 eV energy gap. The optical coefficients were shown that the loosing optical energy occurred in the higher ultraviolet region, so this compound is a promising candidate for optical sensing in the infrared and visible range. The thermoelectric behaviors were implied to the good merit parameter in the 100K range and room temperatures and also has high amount of power factor in 600K which made it for power generators applications.
4
Content available Reduction of Thermal Conductivity through the Dispersion of TiC Nanoparticles into a p-Type Bi0.5Sb1.5Te3 Alloy by Ball Milling and Spark Plasma Sintering
Nagarjuna Cheenepalli, Madavali Babu, Lee Myeong-Won, Yoon Suk-Min, Hong Soon-Jik
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 2
551--557
EN
The dispersion of nanoparticles in the host matrix is a novel approach to enhance the thermoelectric performance. In this work, we incorporate the TiC (x = 0, 1 and 2 wt.%) nanoparticles into a p-type Bi0.5Sb1.5Te3 matrix, and their effects on microstructure and thermoelectric properties were systematically investigated. The existence of TiC contents in a base matrix was confirmed by energy dispersive X-ray spectroscopy analysis. The grain size decreases with increasing the addition of TiC content due to grain boundary hardening where the dispersed nanoparticles acted as pinning points in the entire matrix. The electrical conductivity significantly decreased and the Seebeck coefficient was slightly enhanced, which attributes to the decrease in carrier concentration by the addition of TiC content. Meanwhile, the lowest thermal conductivity of 0.97 W/mK for the 2 wt.% TiC nanocomposite sample, which is ~16% lower than 0 wt.% TiC sample. The maximum figure of merit of 0.90 was obtained at 350 K for the 0 wt.% TiC sample due to high electrical conductivity. Moreover, the Vickers hardness was improved with increase the addition of TiC contents.
5
Content available Effect of Milling Time Parameter on the Microstructure and the Thermoelectric Properties of n-Type Bi2Te2.7Se0.3 Alloys
Sharief P., Madavali B., Koo J. M., Kim H. J., Hong S., Hong S.-J.
Archives of Metallurgy and Materials
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2019
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Vol. 64, iss. 2
585-590
EN
Nanostructured thermoelectric materials receiving great attention for its high thermoelectric performance. In this research, nanostructured n-type Bi2 Te2.7 Se0.3 alloys have prepared using high energy ball milling and followed by spark plasma sintering. Also, we have varied ball milling time to investigate milling time parameter on the thermoelectric properties of n-type Bi2 Te2.7 Se0.3 powder. The powders were discrete at 10 min milling and later particles tend to agglomerate at higher milling time due to cold welding. The bulk fracture surface display multi-scale grains where small grains intersperse in between large grains. The maximum Seebeck coefficient value was obtained at 20-min milling time due to their lower carrier density. The κ values were decreased with increasing milling time due to the decreasing trend observed in their κL values. The highest ZT of 0.7 at 350 K was observed for 30-min milling time which was ascribed to its lower thermal conductivity. The Vickers hardness values also greatly improved due to their fine microstructure.
6
Content available Investigation of the Microstructure and Thermoelectric Properties of P-Type BiSbTe Alloys by Usage of Different Revolutions Per Minute (RPM) During Mechanical Milling
Yoon S.-M., Madavali B., Yoon Y.-N., Hong S.-J.
Archives of Metallurgy and Materials
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2017
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Vol. 62, iss. 2B
1167--1171
EN
In this work, p-type Bi0.5Sb1.5Te3 alloys were fabricated by high-energy ball milling (MA) and spark plasma sintering. Different revolutions per minute (RPM)s were used in the MA process, and their effect on microstructure, and thermoelectric properties of p-type Bi0.5Sb1.5Te3 were systematically investigated. The crystal structure of milled powders and sintered samples were characterized using X-ray diffraction. All the powders exhibited the same morphology albeit with slight differences find at 1100 RPM conditions. A slight grain size refinement was observed on the fracture surfaces from 500 to 1100 RPM specimens. The temperature dependence of Seebeck coefficient, electrical conductivity, and power factors were measured as a function of temperature with different RPM conditions. The power factor shows almost same (~3.5 W/mK2 at RT) for all samples due to unchanged Seebeck and electrical conductivity values. The peak ZT of 1.07 at 375K is obtained for 1100 RPM specimen due to low thermal conductivity.
7
Content available Effect of Ga2O3 Nanoparticles Dispersion on Microstructure and Thermoelectric Properties of p-Type BiSbTe Based Alloys
Kim E.-B., Koo J.-M., Hong S.-J.
Archives of Metallurgy and Materials
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2017
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Vol. 62, iss. 2B
993--997
EN
In this study, p-type Bi0.5Sb1.5Te3 based nanocomposites with addition of different weight percentages of Ga2O3 nanoparticles are fabricated by mechanical milling and spark plasma sintering. The fracture surfaces of all Bi0.5Sb1.5Te3 nanocomposites exhibited similar grain distribution on the entire fracture surface. The Vickers hardness is improved for the Bi0.5Sb1.5Te3 nanocomposites with 6 wt% added Ga2O3 due to exhibiting fine microstructure, and dispersion strengthening mechanism. The Seebeck coefficient of Bi0.5Sb1.5Te3 nanocomposites are significantly improved owing to the decrease in carrier concentration. The electrical conductivity is decreased rapidly upon the addition of Ga2O3 nanoparticle due to increasing carrier scattering at newly formed interfaces. The peak power factor of 3.24 W/mK2 is achieved for the base Bi0.5Sb1.5Te3 sintered bulk. TheBi0.5Sb1.5Te3 nanocomposites show low power factor than base sample due to low electrical conductivity.
8
Content available Microstructure And Thermoelectric Properties Of TAGS-90 Compounds Fabricated By Mechanical Milling Process
Kim H.-S., Babu M., Hong S.-J.
Archives of Metallurgy and Materials
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2015
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Vol. 60, iss. 2B
1231--1234
EN
TAGS-90 compound powder was directly prepared from the elements by high-energy ball milling (HEBM) and subsequently consolidated by a spark plasma sintering (SPS). Effect of milling time on the microstructure and thermoelectric properties of the samples were investigated. The particle size of fabricated powders were decreased with increasing milling time, finally fine particles with ~1μm size was obtained at 90 min. The SPS samples exhibited higher relative densities (>99%) with fine grain size. X-ray diffraction analysis (XRD) and energy dispersion analysis (EDS) results revealed that all the samples were single phase of GeTe with exact composition. The electrical conductivity of samples were decreased with milling time, whereas Seebeck coefficient increased over the temperature range of RT~450°C. The highest power factor was 1.12×10-3 W/mK2 obtained for the sample with 90 min milling at 450°C.
9
Content available remote New method of determining electric and thermal characteristics of Peltier device
Lozbin V., Bylicki P., Cuba V.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 3b
303--305
EN
In this article authors propose a new method for experimental research of electric and thermal characteristics of Peltier device. Presented method differs from commonly as summary Seebeck coefficient, internal resistance, thermal conductivity coefficient of thermoelectric material and summarized thermal resistance of copper connections, join surfaces with structure of a heating system are simultaneously determined without interfere into tested element structures. The main assumption of the method is the comparison of the heat fluxes flowing through the tested thermoelectric element in open and short circuits.
PL
W artykule proponowana jest nowa metoda eksperymentalnego wyznaczania elektrycznych i termicznych charakterystyk ogniw Peltiera. Prezentowana metoda w odróżnieniu od obecnie stosowanych umożliwia uzyskanie współczynnika Seebecka, wewnętrznej rezystancji elektrycznej, przewodności cieplnej materiału termoelektrycznego, przewodności cieplnej obudowy ogniwa wraz z powierzchniami styku w jednym eksperymencie bez konieczności ingerencji do wnętrza badanego elementu. Metoda w głównej mierze polega na porównaniu strumieni cieplnych przepływających przez badane ogniwo Peltiera znajdujące się w stanie zwarcia i rozwarcia obwodu elektrycznego.
10
Content available remote Using the test method for optimization the Peltier device for achievement superconducting transition temperatures
Lozbin V., Hotra O., Bylicki P.
Przegląd Elektrotechniczny
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2012
|
R. 88, nr 6
95-97
EN
A new method for determining electric and thermal characteristics of Peltier devices is analyzed with the aim of optimization of Peltier devices. Obtained results give the possibility to optimize thermoelectric cooler systems to reach most efficient operating state and to achieve the lowest possible temperature. In optimized by proposed method four stage Peltier cooling cascade the achieved temperature could be near to the superconducting transition temperature of HgBa2CaCu2O6+?. Peltier device is not damaged during the test process and still can be used.
PL
W artykule przeanalizowano nową metodę wyznaczania elektrycznych oraz termicznych parametrów ogniw Peltiera. Otrzymane wyniki dają możliwość optymalizowania chłodziarek termoelektrycznych w celu osiągnięcia najbardziej efektywnego punktu pracy. W czterostopniowej chłodziarce termoelektrycznej zoptymalizowanej przy użyciu proponowanej metody otrzymana temperatura może być bardzo bliska temperaturze nadprzewodnictwa HgBa2CaCu2O6. Badany element Peltiera nie ulega uszkodzeniu podczas testu i może być dalej używany.
11
Content available remote Fast preparation and thermoelectric properties of Zn4Sb3 by HPHT
Su T., Zhu H., Ma H., Li S., Hu M.
Materials Science Poland
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2012
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Vol. 30, No. 4
355--358
EN
In this paper, crack-free bulk thermoelectric material Zn4Sb3 was prepared rapidly by high pressure and high temperature (HPHT) method. Near a single-phase Zn4Sb3 specimen was obtained using nominal stoichiometric powder mixtures, which were indexed by powder X-ray diffraction. The temperature-dependent thermoelectric properties including the Seebeck coefficient and electrical resistivity were studied. The maximum power factor of Zn4Sb3 specimen prepared by HPHT reaches 10.8 žW/(cmK 2)at 637 K, which is comparable to the published data. The results show that the HPHT offers potential processing route to produce the thermoelectric material Zn4Sb3 quickly and effectively.
12
Content available remote Otrzymywanie wybranych materiałów termoelektrycznych metodą krystalizacji kierunkowej i ich charakterystyka
Schmidt M, Zybała R., Wojciechowski K.T.
Materiały Ceramiczne
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2010
|
T. 62, nr 1
56-59
PL
Celem pracy było otrzymanie monokryształów związków AgSbSe2, Ag0,9Sb1,1Se2 oraz BiSbTe3 metodą Bridgmana. Materiały otrzymywano dwoma wariantami metody różniącymi się wytwarzanym gradientem temperatur w obszarze frontu krystalizacji. Obserwacje mikrostrukturalne oraz składu chemicznego przeprowadzono skaningowym mikroskopem elektronowym (SEM) z analizatorem dyspersji energii promieniowania rentgenowskiego (EDS) oraz za pomocą emisyjnej spektroskopii atomowej (AES). Badania jednorodności właściwości termoelektrycznych przeprowadzono za pomocą mikrosondy Seebecka w temperaturze pokojowej. Stwierdzono, że współczynnik Seebecka dla materiału AgSbSe2 zmienia się monotonicznie w zakresie od 250 do 1000 μVK-1. Dla związku Ag0,9Sb1,1Se2 współczynnik Seebecka wynosi od -500 do -750 μVK-1. Monokryształy BiSbTe3 cechują się małymi zmianami wartości współczynnika Seebecka w przedziale od 200 do 280 μVK-1.
EN
The aim of this work was to prepare single crystals of AgSbSe2, Ag0,9Sb1,1Se2 and BiSbTe3 by the Bridgman method. Materials were prepared by means of two variants of this method, differing in temperature gradients in the area of the crystallization front. Microstructural and chemical analysis were done using Scanning Electron Microscope (SEM) with Energy-Dispersive X-ray Spectroscopy (EDS) and Atomic Emission Spectroscopy (AES). Analysis of homogeneity of thermoelectric properties was carried out using the Seebeck microprobe at room temperature. It was found that the Seebeck coefficient for AgSbSe2 changed monotonically in the range from 250 to 1000 μVK-1. For Ag0,9Sb1,1Se2, the Seebeck coefficient is in range from -500 to -750 μVK-1. Single crystals of BiSbTe3 exhibit small changes of the Seebeck coefficient in the range from 200 to 280 μVK-1.
13
Content available remote Otrzymywanie i właściwości CoSb3 domieszkowanego Ag
Wojciechowski K., Nieroda P., Toboła J., Zybała R.
Materiały Ceramiczne
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2010
|
T. 62, nr 1
60-64
PL
Przedmiotem pracy były badania wpływu domieszki Ag na wartość współczynnika efektywności termoelektrycznej, ZT, trójantymonku kobaltu CoSb3. W tym celu przygotowano serię próbek o składach nominalnych AgxCo8Sb24, gdzie x = 0-0,5. Badania strukturalne oraz składu fazowego wykonano za pomocą dyfrakcji rentgenowskiej XRD. Zbadano wpływ domieszki na przewodnictwo elektryczne, współczynnik Seebecka oraz przewodnictwo cieplne otrzymanych materiałów w zakresie temperatur od 300 do 560K. Na podstawie uzyskanych wyników wyznaczono zależności współczynnika efektywności termoelektrycznej, ZT, od temperatury.
EN
The aim of this work was to examine the influence of Ag additive on thermoelectric figure of merit, ZT, of cobalt triantimonide CoSb3. A series of samples with nominal composition of AgxCo8Sb24, (x = 0-0,5) was prepared. Structural properties and phase composition was analyzed by XRD diffraction method. The influence of Ag content on electrical conductivity, Seebeck coefficient, thermal conductivity and crystal structure parameter was investigated. The temperature dependence of thermoelectric figure of merit, ZT, was determined using measured thermal and electrical parameters.
14
Content available remote Assessment of Co(II), Co(III) and Co(IV) Content in Thermoelectric Cobaltites
Sopicka-Lizer M., Kozłowska K., Bobrowska-Grzesik E., Plewa J., Altenburg H.
Archives of Metallurgy and Materials
|
2009
|
Vol. 54, iss. 4
881-888
EN
The precise content of cobalt at a given oxidation state in layered sodium or calcium cobaltites is crucial for their thermoelectric performance and stability at elevated temperature. The paper presents results of searching for an effective method of measuring cobalt ions concentration coexisting at various oxidation state in a solid state. Application of the specific properties of reagents gave possibility to determine Co3+ concentration in the presence of Co4+ by the wet chemical methods. The accuracy and usefulness of the method was checked by comparison of the results from independent measurement of the total cobalt content and sum of the cobalt concentration at various oxidation state. It has been found that separate concentration of cobalt at a various valence state can be precisely measured if no Co3O4 was present in the synthesized powders.
PL
Dokładne oznaczenie zawartości kobaltu na danym stopniu utlenienia w warstwowych kobaltanach sodowych lub wapniowych ma zasadnicze znaczenie dla ich sprawności jako materiału termoelektrycznego oraz stabilności w podwyższonmej temperaturze. Artykuł przedstawia wyniki badań nad znalezieniem skutecznej metody oznaczania stezenia jonów kobaltu wystepujących obok siebie na różnym stopniu utlenienia w stanie stałym. Wykorzystanie szczególnych właściwości reagentów umożliwiło oznaczenie stężenia Co3+ obok Co4+ metodą analizy w fazie ciekłej. Dokładność i powtarzalność metody została potwierdzona przez porównanie wyników niezależnych pomiarów całkowitej zawartości kobaltu i sumowania zawartości kobaltu na różnych stopniach utlenienia w tych samych próbkach. Stwierdzono, że precyzyjne oznaczenie zawartości kobaltu na różnych stopniach utlenienia jest możliwe jeśli w próbce nie występuje Co3O4 w syntetyzowanych proszkach.
15
The transport properties of sputter-deposited Ge-Sb-V thin films
Beensh-Marchwicka G., Prociów E., Berlicki T.
Elektronika : konstrukcje, technologie, zastosowania
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2007
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Vol. 48, nr 12
49-50
EN
Temperature-dependent transport properties of p-type Ge-Sb-V films prepared by the pulse magnetron sputtering technique have been studied. Doping of Ge by Sb and V and post-deposition annealing in air atmosphere at 823 or 923 K were the necessary preconditions of obtaining enhanced p-type conduction and considerable high values of Seebeck coefficient ranging from 400 to 160 µV/K. The temperature of post-deposition annealing and V content were taken as varying parameters to observe any variations in temperature dependent resistivity and thermoelectric power in the film and tried to explain the electrical transport mechanism therefrom. The structural analysis showed that films 3 µm thick remained microcrystalline and the variable range hopping (VRH) in three dimension system was dominant mechanism for d.c. charge transport.
PL
Analizowano temperaturowo zależne własności transportu warstw Ge-Sb-V, otrzymywanych techniką impulsowego rozpylania magnetronowego, wykazujących przewodnictwo typu p. Domieszkowanie Sb i V germanu i starzenie po wytworzeniu w atmosferze powietrza przy 823 lub 923 K było warunkiem koniecznym otrzymania przewodnictwa typu p i bardzo dużej wartości współczynnika Seebecka od 400 do 160 µV/K. Temperaturę wygrzewania warstw po nanoszeniu i zawartość wanadu w warstwie przyjęto jako zmienne parametry do badania wpływu na zachowanie się rezystywności i siły termoelektrycznej w funkcji temperatury i na tej podstawie próbowano określić mechanizm transportu nośników w warstwach. Analiza struktury wykazała, że warstwy o grubości około 3 µm pozostają mikrokrystaliczne oraz, że dominującym mechanizmem transportu nośników dla prądu stałego był trójwymiarowy hopping zmienno-zasięgowy (VHR).
16
Wpływ warunków wytwarzania na strukturę i własności termoelektryczne warstw Ge-Au.
Beensh-Marchwicka G., Mielcarek W., Prociów E.
Prace Naukowe Instytutu Podstaw Elektrotechniki i Elektrotechnologii Politechniki Wrocławskiej. Konferencje
|
1998
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Vol. 34, nr 10
141-144
PL
W niniejszej pracy opisano własności termoelektryczne i strukturę warstw germanowych otrzymanych w procesie rozpylania targetu dwuskładnikowego Ge-Au w układzie magnetronowym zasilanym impulsowo. Własności warstw analizowano jako funkcję domieszkowania złotem w ilości 2 i 5 %at oraz temperatury podłoża podczas kondensacji w zakresie 360-1040 K. Strukturę i skład fazowy warstw badano za pomocą dyfrakcji rentgenowskiej. Stwierdzono, że warstwy zawierają krystality obu faz: Ge o strukturze regularnej typu diamentu oraz Au o strukturze regularnej ściennie centrowanej. Współczynnik Seebecka i elektryczna konduktywność warstw rosły ze wzrostem temperatury podłoża podczas nanoszenia. Towarzyszył temu wzrost wymiarów krystalitów obu faz.
EN
The results of investigations concerning the structural and the thermoelectric properties of Ge-Au sputtered films under pulsed voltage operation of magnetron are described. The film properties are discussed as a function of doping with gold (2 and 5 at%)and the substrate temperature during deposition (360-1040 K). The structure and phase composition of the films were investigated by X-ray diffraction method. It has been found that almost all as-deposited films were policrystaline and contained crystallites of both Ge and Au phases. The Seeback coefficient and the electrical conductivity were observed to increase with increasing substrate temperature during sputtering. It was connected with the increase in the crystallite dimensions of both Ge and Au phases.
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