scholarly journals Thermoelectric Properties of Carbon Nanotubes

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4561 ◽  
Author(s):  
Nguyen T. Hung ◽  
Ahmad R. T. Nugraha ◽  
Riichiro Saito
Keyword(s):  
Carbon Nanotubes ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Quantum Confinement Effect ◽  
Electrical Energy ◽  
High Seebeck Coefficient ◽  
Te Material ◽  
P Type ◽  
State Device ◽  
Solid State Device

Thermoelectric (TE) material is a class of materials that can convert heat to electrical energy directly in a solid-state-device without any moving parts and that is environmentally friendly. The study and development of TE materials have grown quickly in the past decade. However, their development goes slowly by the lack of cheap TE materials with high Seebeck coefficient and good electrical conductivity. Carbon nanotubes (CNTs) are particularly attractive as TE materials because of at least three reasons: (1) CNTs possess various band gaps depending on their structure, (2) CNTs represent unique one-dimensional carbon materials which naturally satisfies the conditions of quantum confinement effect to enhance the TE efficiency and (3) CNTs provide us with a platform for developing lightweight and flexible TE devices due to their mechanical properties. The TE power factor is reported to reach 700–1000 W / m K 2 for both p-type and n-type CNTs when purified to contain only doped semiconducting CNT species. Therefore, CNTs are promising for a variety of TE applications in which the heat source is unlimited, such as waste heat or solar heat although their figure of merit Z T is still modest (0.05 at 300 K). In this paper, we review in detail from the basic concept of TE field to the fundamental TE properties of CNTs, as well as their applications. Furthermore, the strategies are discussed to improve the TE properties of CNTs. Finally, we give our perspectives on the tremendous potential of CNTs-based TE materials and composites.

Spray-on thermoelectric energy harvester

MRS Advances ◽  
2018 ◽  
Vol 4 (15) ◽  
pp. 851-855 ◽  
Author(s):  
Robert E. Peale ◽  
Seth Calhoun ◽  
Nagendra Dhakal ◽  
Isaiah O. Oladeji ◽  
Francisco J. González
Keyword(s):  
Thin Films ◽  
Power Generation ◽  
Energy Harvester ◽  
Waste Heat ◽  
Spray Deposition ◽  
Electrical Energy ◽  
Seebeck Coefficients ◽  
Thermoelectric Energy ◽  
P Type ◽  
Energy From Waste

AbstractThermoelectric (TE) thin films have promise for harvesting electrical energy from waste heat. We demonstrate TE materials and thermocouples deposited by aqueous spray deposition on glass. The n-type material was CdO doped with Mn and Sn. Two p-type materials were investigated, namely PbS with co-growth of CdS and doped with Na and Na2CoO4. Seebeck coefficients, resistivity, and power generation for thermocouples were characterized.

Thermoelectric Transport in Silicon Germanium Nanocomposite

2008 ◽  
Author(s):  
Hohyun Lee ◽  
Daryoosh Vashaee ◽  
Xiaowei Wang ◽  
Giri Joshi ◽  
Gaohua Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Conversion ◽  
Silicon Germanium ◽  
Figure Of Merit ◽  
Waste Heat ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Thermoelectric Effects ◽  
Thermoelectric Transport ◽  
Potential Applications

Direct energy conversion between heat and electrical energy based on thermoelectric effects is attractive for potential applications in waste heat recovery and environmentally-friendly refrigeration. The energy conversion efficiency depends on the dimensionless figure of merit of thermoelectric materials, ZT, which is proportional to the electrical conductivity, the square of the Seebeck coefficient, and the inverse of the thermal conductivity. Currently, the low ZT values of available materials restrict the applications of this technology. However, significant enhancements in ZT were recently reported in nanostructured materials such as superlattices mainly due to their low thermal conductivities. According to recent studies, the reduced thermal conductivity of nanostructures is attributed to the large number of interfaces at which phonons are scattered. Based on this idea, nanocomposites are expected to have a lower thermal conductivity than their bulk counterparts with low fabrication cost just by mixing nano sized particles. In this work, we will discuss mechanisms of thermoelectric transport via modeling and provide experimental evidence on the enhancement of thermoelectric figure of merit in SiGe-based nanocomposites.

scholarly journals XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Новое направление применения термоэлектрических преобразователей энергии

2019 ◽  
Vol 53 (7) ◽  
pp. 875
Author(s):  
З.М. Дашевский ◽  
П.П. Константинов ◽  
C.Я. Скипидаров
Keyword(s):  
Cold Water ◽  
Waste Heat ◽  
Electrical Energy ◽  
Hot Water ◽  
Considerable Proportion ◽  
Thermoelectric Efficiency ◽  
Heating Systems ◽  
Additional Water ◽  
P Type ◽  
Thermoelectric Converters

AbstractIn southern countries, including European states, solar collectors for additional water-heating systems are widely used. However, the disadvantage of such systems is that a considerable proportion of solar energy cannot be used with increasing water temperature and dissipates into the environment. It is proposed to use waste heat at a high temperature, which is supplied to a thermoelectric generator (TEG) operating on the basis of a temperature difference between the hot water in the solar collector and cold water supplied to a radiator on the other TEG side. This is a new application of thermoelectric converters, in which the converter can act not only as a source of electrical energy but also as a source of low-potential heat coming from the radiator. The total conversion efficiency in such devices can reach 90%. It is shown that the use of p -type legs in a TEG with the cleavage planes of the legs parallel to the heat-flux direction instead of the conventional parallel orientation results in an increase in the thermoelectric efficiency by 25% on average in the temperature range of 100–300°C.

Synthesis and Thermolelectric Properties of Bi2Te3-GeTe Pseudo Binary System

2006 ◽  
Vol 46 ◽  
pp. 168-173
Author(s):  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi ◽  
Takashi Goto
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Waste Heat ◽  
Electrical Energy ◽  
Synergy Effect ◽  
Temperature Range ◽  
Binary Compounds ◽  
Energy From Waste

Bi2Te3 is the best compound for thermoelectric materials around the room temperature. If the temperature range is shifted to higher side, it is useful to obtain electrical energy from waste heat source which is abundant at the temperature around 500 K. In this experiment, Bi2Te3-GeTe pseudo binary compounds were investigated to shift the temperature range. The lattice thermal conductivity was remarkably decreased at 50 or 75 mol%GeTe by synergy effect of solid solution and grain boundaries. The peak temperature of figure of merit Z for Bi2Te3-GeTe pseudo binary compounds was higher than Bi2Te3.

Investigating the Thermoelectric and Structural Properties of Bismuth Telluride Thin Films for Harvesting Energy from Waste Heat

2012 ◽  
Vol 185 ◽  
pp. 77-80 ◽  
Author(s):  
Marcus Chiang Mun Leong ◽  
Fabian Chiang Mun Chun ◽  
Jae Lee Kai Wei ◽  
Peng Qi Zhen ◽  
Ye Ko San ◽  
...  
Keyword(s):  
Thin Films ◽  
Bismuth Telluride ◽  
Waste Heat ◽  
Electrical Energy ◽  
Energy Harvest ◽  
Atmospheric Conditions ◽  
Thermoelectric Thin Films ◽  
P Type ◽  
Energy From Waste

Recently, thermoelectric thin films have been gaining attention as potential thermoelectric generators that can be used to power external devices. Such films can recover electrical energy from waste heat and are environmentally friendly. Micro fabrication of thin films is achieved by sputtering on silicon films. In this study, the sputtering of Bismuth Telluride (N-type, P-type) films was investigated. Research has verified the efficiency of Bismuth Telluride films, but little is known about how the sputtering process affects the film's quality. Thus, the focus of this study explores how sputtering parameters of discontinuous sputtering intervals, exposure to normal atmospheric conditions and in situ annealing affect the thickness, thermoelectric properties, and microstructure of films. This will bring about a better understanding of the relationship between the sputtering process and the properties of the produced film for both N and P type materials. Recommendations based on this study can contribute to the production of more efficient thin films suitable for energy harvest application.

Enhanced thermoelectric properties of n-type Ti-doped PbTe

MRS Advances ◽  
2019 ◽  
Vol 4 (30) ◽  
pp. 1683-1689
Author(s):  
Ariel Loutati ◽  
Shir Zuarets ◽  
David Fuks ◽  
Yaniv Gelbstein
Keyword(s):  
Figure Of Merit ◽  
Fossil Fuels ◽  
Dopant Concentration ◽  
Waste Heat ◽  
Functionally Graded ◽  
Narrow Temperature Range ◽  
Donor Dopant ◽  
Diffusion Rates ◽  
P Type ◽  
Ti Doping

AbstractThermoelectric (TE) generators, converting waste heat to electricity regain their attractiveness for reduction of fossil fuels’ reliance, and consequently minimizing adverse environmental effects. Such generators are based on an electrical series connection of TE couples, which consist n- and p- type semiconducting legs divided by metallic bridges. While for intermediate temperatures of up to 500°C, n-type PbTe was extensively studied and employed in commercial TE power generation applications, its maximal efficiency, as was reflected by the TE figure of merit, ZT, was in most of the cases maximized at a narrow temperature range for any given donor dopant concentration. The most commonly applied donor dopants are iodine and bismuth. Yet, some interesting characteristics were recently proposed upon using Ti as a donor dopant. Up to date an impressive maximal ZT of ∼1.2 was obtained at 500°C, upon doping of PbTe by 0.1 at.% Ti, while no lower concentrations were ever investigated. In the current research a lower, 0.05 at.% Ti doping level was applied, leading to the highest ever reported ZT values, for any given Ti doped PbTe, up to 350°C. Since the chemical compatibility of Ti with PbTe, as a metallic bridge in such couples, is well established, mainly due to its low diffusion rates, the potential of generating a stable Ti-doped functionally graded n-type PbTe material, with enhanced TE performance, is currently being proposed.

Carbon Nanotube Gas Sensor Fabricated on Anodic Aluminum Oxide

2007 ◽  
Vol 124-126 ◽  
pp. 1309-1312
Author(s):  
Nguyen Duc Hoa ◽  
Nguyen Van Quy ◽  
Gyu Seok Choi ◽  
You Suk Cho ◽  
Se Young Jeong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Gas Sensor ◽  
Chemical Vapor ◽  
Fast Response ◽  
Device Fabrication ◽  
Alumina Oxide ◽  
Response And Recovery ◽  
New Type ◽  
P Type

A new type of gas sensor was realized by directly depositing carbon nanotube on nano channels of the anodic alumina oxide (AAO) fabricated on p-type silicon substrate. The carbon nanotubes were synthesized by thermal chemical vapor deposition at a very high temperature of 1200 oC to improve the crystallinity. The device fabrication process was also developed. The contact of carbon nanotubes and p-type Si substrate showed a Schottky behavior, and the Schottky barrier height increased with exposure to gases while the overall conductivity decreased. The sensors showed fast response and recovery to ammonia gas upon the filling (400 mTorr) and evacuation.

Effect of Electron-Phonon Coupling on Transport Properties of Monolayers of ZrS2, BiI3 and PbI2: A thermoelectric Perspective

2021 ◽  
Author(s):  
Gautam Sharma ◽  
Vineet Kumar Pandey ◽  
Shouvik Datta ◽  
Prasenjit Ghosh
Keyword(s):  
Relaxation Time ◽  
Band Structure ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Waste Heat ◽  
Transport Coefficients ◽  
Electrical Energy ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

Thermoelectric materials are used for conversion of waste heat to electrical energy. The transport coefficients that determine their thermoelectric properties depend on the band structure and the relaxation time of...

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

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.

scholarly journals Mechanosynthesis and Thermoelectric Properties of Fe, Zn, and Cd-Doped P-Type Tetrahedrite: Cu12-xMxSb4S13

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3448
Author(s):  
Francisco Arturo López Cota ◽  
José Alonso Díaz-Guillén ◽  
Oscar Juan Dura ◽  
Marco Antonio López de la Torre ◽  
Joelis Rodríguez-Hernández ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Powder Processing ◽  
High Energy ◽  
Secondary Phases ◽  
Ambient Conditions ◽  
Cadmium Sulfate ◽  
Electrical Conductivities ◽  
Compositional Changes ◽  
P Type

This contribution deals with the mechanochemical synthesis, characterization, and thermoelectric properties of tetrahedrite-based materials, Cu12-xMxSb4S13 (M = Fe2+, Zn2+, Cd2+; x = 0, 1.5, 2). High-energy mechanical milling allows obtaining pristine and substituted tetrahedrites, after short milling under ambient conditions, of stoichiometric mixtures of the corresponding commercially available binary sulfides, i.e., Cu2S, CuS, Sb2S3, and MS (M = Fe2+, Zn2+, Cd2+). All the target materials but those containing Cd were obtained as single-phase products; some admixture of a hydrated cadmium sulfate was also identified by XRD as a by-product when synthesizing Cu10Cd2Sb4S13. The as-obtained products were thermally stable when firing in argon up to a temperature of 350–400 °C. Overall, the substitution of Cu(II) by Fe(II), Zn(II), or Cd(II) reduces tetrahedrites’ thermal and electrical conductivities but increases the Seebeck coefficient. Unfortunately, the values of the thermoelectric figure of merit obtained in this study are in general lower than those found in the literature for similar samples obtained by other powder processing methods; slight compositional changes, undetected secondary phases, and/or deficient sintering might account for some of these discrepancies.

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