Дисертації з теми "Nanocomposites for thermoelectric applications"
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GALLIANI, DANIELA. "Poly(3,4-ethylendioxythiophene) based materials for thermoelectric applications." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2018. http://hdl.handle.net/10281/199131.
Повний текст джерелаIntrinsically conductive polymers (ICPs) are a class of organic materials characterized by unique features. They are lightweight, flexible and easy to process and print, as expected from polymers, but, also, they can conduct electricity up to metallic conductivities. Such an exceptional pairing of characteristics enables the development of flexible and printed electronic devices, which are of a particularly appealing for portable electronic devices, even integrated in the human body (e.g. implantable biosensors) or worn (e.g. smartwatches). Even thermoelectric (TE) application of ICPs recently gained a lot of attention. An organic TE generator (OTEG) can convert heat into electrical energy by means of the Seebeck effect. This technology aims to recover heat produced as low-grade side-product of energy consumption and to transform it into exploitable energy. Even though ICPs showed promising TE properties, their use is still hindered by low TE efficiencies, which cannot compete with the inorganic benchmark (i.e. tellurides). The design of better ICPs for TE application must start from a deep knowledge of which techniques and treatments impact the charge transport features. The intrinsic complexity of ICP systems, however, often makes this task difficult, preventing a full comprehension of the phenomena involved. This PhD project focused on the impact of different parameters on TE properties of ICPs, aiming at the needed deeper understanding on how charge transport is affected. The specific ICP poly(3,4-ethylendioxythiophene) -PEDOT- was investigated modifying different parameters at three different levels of system perturbation. First, the role of polymerization conditions and post-polymerization treatments was studied. Different polymerization techniques, oxidants and solvents have been used for the same ICP, and the occurring changes have been investigated. Moreover, PEDOT oxidation level was tuned to optimize TE efficiency. At a second level, the monomer molecular structure was modified to prepare a PEDOT-based copolymer. The copolymer included conjugated (i.e. conductive) and not conjugated (i.e. not conductive) portions, which deeply impacted the charge transport behaviour. The results show the versatility of this strategy, still barely explored in TE field, and how final transport properties can be finely tuned by means of molecular modifications. Finally, at a third level, PEDOT macroscopic features were tuned by embedding inorganic nanostructure. Such a strategy is usually exploited to improve TE efficiency by means of nanostructuration beneficial effects already known in inorganic materials. Nanoparticles of two different metal oxides (CuO and Mn3O4) of different size and shape were dispersed in PEDOT matrix. Evaluation of humidity and oxidation level effects on charge transport features allowed to obtain novel insights into transport properties in nanocomposites.
Hsieh, Yu-Yun. "Nanostructured Carbon-Based Composites for Energy Storage and Thermoelectric Applications." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin157322525150617.
Повний текст джерелаHao, Qing. "Nanocomposites as thermoelectric materials." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61606.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references.
Thermoelectric materials have attractive applications in electric power generation and solid-state cooling. The performance of a thermoelectric device depends on the dimensionless figure of merit (ZT) of the material, defined as ZT = S2o-T / k, where S is the Seebeck coefficient, o is the electrical conductivity, k is the thermal conductivity, and T is the absolute temperature. In recent years, the idea of using nanotechnology to further improve the figure of merit of conventional thermoelectric materials has triggered active research and led to many exciting results. Most of the reported ZT enhancements are based on thin films and nanowires in which the thermal conductivity reduction plays a central role. We pursue the nanocomposite approach as an alternative to superlattices in the quest for high ZT materials. These nanocomposites are essentially nano-grained bulk materials that are synthesized by hot pressing nanoparticles into a bulk form. The interfaces inside a nanocomposite strongly scatter phonons but only slightly affect the charge carrier transport. Therefore, we can significantly reduce the lattice thermal conductivity and even somewhat increase the power factor S2 U, resulting in higher ZT than for bulk materials. Compared with expensive thin-film superlattices, nanocomposites will have significant advantages in mass production, device construction and operation. This thesis covers my studies on bismuth antimony telluride nanocomposites and some recent work on Co 4Sb12-based nanocomposites. In bismuth antimony telluride nanocomposites, we have achieved a peak ZT of 1.4 at 100 'C, a 40% increase in ZT over the bulk material. This is the first significant ZT increase in this material system in fifty years. The same approach has also yielded a peak ZT around 1.2 in Yb filled Co4Sbi 2 nanocomposites. During the process, great efforts were dedicated to assuring accurate and dependable property measurements of thermoelectric nanocomposites. In addition to comparing measurement results between the commercial setups and a homebuilt measurement system, the high ZT obtained in bismuth antimony telluride nanocomposites was further confirmed by a device cooling test. To better understand the measured thermoelectric properties of nanocomposites, theoretical analysis based on the Boltzmann transport equation was performed. Furthermore, frequency-dependent Monte Carlo simulations of the phonon transport were conducted on 2D periodic porous silicon and 3D silicon nanocomposites. In the thermoelectrics field, the latter one provided the first accurate prediction for phonon size effects in a given nanocomposite. For charge carriers in thermoelectric nanocomposites, their transport can be significantly affected by the interfacial electronic states. To address this, impedance measurements were conducted on nanocomposites to determine the electronic barrier height at the grain interfaces, which is critical for the detailed theoretical analysis of the interfacial charge transport and energy conversion processes. Although large amount of work has been done using this technique to understand the defect states and the barrier height on the grain boundaries of polycrystalline silicon or oxides, this method has not been applied to thermoelectric materials. Along another line, a simple bandgap measurement technique with nanopowders was developed based on the Fourier Transform Infrared Spectroscopy. This provided a convenient way to quickly check the bandgaps of various thermoelectric nanocomposites, which is also crucial for theoretical studies.
by Qing Hao.
Ph.D.
Muto, Andrew (Andrew Jerome). "Device testing and characterization of thermoelectric nanocomposites." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44915.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 67-68).
It has become evident in recent years that developing clean, sustainable energy technologies will be one of the world's greatest challenges in the 21st century. Thermoelectric materials can potentially make a contribution by increasing energy efficiency of some systems. Thermoelectric materials may play a role in the large scale energy industry, specifically in the applications of refrigeration and waste heat recovery. In this work a novel thermoelectric material will be tested for conversion efficiency. A Bi₂Te₃ nanocomposite has been developed by the joint effort of Prof. Gang Chen's group at MIT and Prof. Zhifeng Ren's group at Boston College. The material exhibits enhanced thermoelectric properties from optimized nanoscale structures and can be easily manufactured in large quantities. In order to better characterize its performance a novel power conversion measurement system has been developed that can measure the conversion efficiency directly. The measurement system design will be described in detail; important design considerations will be addressed such as measuring heat flux, optimizing the load matching condition and reducing electrical contact resistance. Finally the measured efficiency will be compared to the calculated efficiency from a temperature-dependent properties model. It will be shown that a Ni layer must be attached to the nanocomposite to allow soldering and power conversion testing. Results of this work will show that the nanocomposite efficiency is higher than the commercial standard. Electrical contact remains a challenge in realizing the potential efficiency.
by Andrew Muto.
S.M.
Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk, Денис Ігорович Курбатов, et al. "Thermoelectric properties of the colloidal Bi2S3-based nanocomposites." Thesis, Jadavpur University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65347.
Повний текст джерелаLee, Hohyun 1978. "Modeling and characterization of thermoelectric properties of SiGe nanocomposites." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/50589.
Повний текст джерелаPage 164 blank.
Includes bibliographical references.
Direct energy conversion between thermal and electrical energy based on thermoelectric effects is attractive for potential applications in waste heat recovery and environmentally-friendly refrigeration. The energy conversion efficiency is related to the thermoelectric figure of merit 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 large scale applications of this technology. Recently, however, significant enhancements in ZT were reported in nanostructured materials such as superlattices mainly due to their low thermal conductivities. According to the studies on heat transfer mechanisms in nanostructures, the reduced thermal conductivity of nanostructures is mainly attributed to the increased scattering of phonons at interfaces. Based on this idea, nanocomposites are also expected to have a lower thermal conductivity than their bulk counterparts of the same chemical configuration. Nanocomposites are materials with constituents of less than 100 nm in size. They can be fabricated with a low cost just by mixing nano sized particles followed by consolidation of nano sized powders. In this thesis, SiGe nanocomposites are investigated for power generation at high temperature. The material properties are characterized at different temperatures, and the optimized process conditions are explored experimentally. In addition, theoretical studies are carried out for better understanding of transport phenomena and our experimental results.
(cont.) Grain boundaries in nanocomposites can scatter phonons, when their mean free paths are longer than the grain size. Mean free paths of electrons are usually shorter than the grain size of nanocomposites, so that the electrical conductivities of nanocomposites are not expected to change significantly. However, the experimental results show that nanostructures indeed affect electron transport. The grain boundary effects on electron transport are investigated to explain the experiments. Furthermore, the effects of nanosized pores are explored. Our experimental results show that pores in nanocomposites degrade the electrical conductivity more than predicted by effective medium theories. A scattering model is developed to understand the transport phenomena in porous materials. These modeling studies can also be used to guide sample preparation conditions.
by Hohyun Lee.
Ph.D.
Yelgel, Ovgu Ceyda. "Thermoelectric properties of V-VI semiconductor alloys and nanocomposites." Thesis, University of Exeter, 2013. http://hdl.handle.net/10871/14110.
Повний текст джерелаDai, Prè Marta/M. "Nanocomposites for optical applications." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422168.
Повний текст джерелаNegli ultimi anni le nanotecnologie sono diventate uno dei maggiori campi di interesse e di rilevanza scientifica e la ricerca di nuovi materiali riguarda la chimica, la fisica, la medicina e anche l'ingegneria. I nanomateriali vengono classificati in base alla loro dimensione ed al rapporto superficie/volume, caratteristiche che permettono il loro impiego in numerose applicazioni, soprattutto nel campo ottico. In questi lavoro di tesi sono stati valutati differenti nanocompositi sintetizzati con tecniche messe a punto in modo tale da ottenere peculiari caratteristiche di dimensione, distribuzione, omogeneità e di facile produzione, anche a livello industriale. Il progetto di dottorato può essere suddiviso in due parti: a) nanoparticelle e nanocompositi per applicazioni nel fotovoltaico; b) nanoparticelle e nanocompositi che emettono nel NIR. La prima parte del lavoro si inserisce nel progetto Europeo ORION, ovvero "ottimizzazione di celle solari al silicio, materiali plastici e tecnologie per lo sviluppo di più efficienti sistemi fotovoltaici a concentrazione". Ha riguardato principalmente la messa a punto di materiali e di tecnologie dei sistemi a concentrazione tali da riuscire a ridurre il rapporto costo/watt ed aumentare l'efficienza. Sono stati quindi studiati e sviluppati nanocompositi plastici contenenti nanoparticelle che sono in grado di modificare lo spettro solare e di aumentare di conseguenza l'efficienza di assorbimento delle celle solari. Inoltre le proprietà funzionali dei materiali sviluppati sono state messe a punto in termini di processabilità e di prestazioni. Infatti il materiale deve avere buone proprietà ottiche tra cui una trasmittanza dell'85-92% per 1-2 mm di spessore ed una conversione della luce nel range tra 300-500 nm e 600-900 nm. Il polimetilmetacrilato (PMMA) è risultato essere il polimero di selezione per applicazioni ottiche. Diversi tipi di nanoparticelle che assorbono nell'UV, tra cui ZnS:Mn, CdS:Mn e ZnO, sono state sintetizzate utilizzando tecniche colloidali. Sono stati messi a punto protocolli di precipitazione-ridispersione in modo da purificare, concentrare le nanoparticelle e ridisperdere in seguito in appositi solventi organici, dove è solubile anche il PMMA. Dal momento che la maggior parte dell'energia dissipata (~ 52%) dipende dal mismatch spettrale, definito come perdita termica o quantica, mentre la grande parte ad alta energia viene persa sotto forma di calore legato allo scattering di fotoni e quindi riduce maggiormente l'efficienza di conversione dell'energia delle celle solari a base di silicio. La parte dell'ultravioletto (UV) dello spettro solare (circa 7% dell'intero spettro) non può essere sfruttato completamente dalle celle solari al Si. Sono state così valutate le caratteristiche elettro-ottiche prima e dopo deposizione sulla superficie delle celle solari delle stesse nanoparticelle inserite nel polimero determinando l'effetto antiriflesso e della down-shifting sull'efficienza. La seconda parte del lavoro si è focalizzata sulla sintesi di nanoparticelle di Seleniuro di Piombo (PbSe) and di core-shell, dove l'interno di PbSe è rivestito da uno strato di CdSe, così da stabilizzare le proprietà di emissione di questi materiali. Infine queste nanoparticelle sono state incorporate in diverse matrici, tra cui Ormocer e PMMA mantenendo le loro proprietà di luminescenza. Questi nuovi materiali trovano future applicazioni in microcavità ottiche che incorporano quantum dots e litografia.
Akdogan, Volkan. "Thermoelectric power generator for automotive applications." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/37702/.
Повний текст джерелаAlothman, Abdulmohsen Abdulrahman. "Modeling and Applications of Thermoelectric Generators." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/79846.
Повний текст джерелаPh. D.
Perrot, Solène. "Semi-metallic polymers for thermoelectric applications." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0043.
Повний текст джерелаThermoelectric (TE) materials have the potential to convert vast amounts of waste heat directly into electricity, therefore reducing the dependence on fossil fuel. In thermoelectrics, the concept of a phonon glass/electron crystal is often used to describe an ideal thermoelectric material. According to this concept, a good TE material should inhibit the conduction of phonons (thus having a low thermal conductivity) while efficiently conducting electronic charge carriers (high electrical conductivity). In order to quantify the efficiency of TE systems, the figure of merit, ZT, is used as a measure of performance. Recently, conducting polymers have gained momentum in the TE community for applications at room temperature. Their great advantage is an intrinsically low thermal conductivity at room temperature (0.2-0.6 W.m-1K-1) that is complemented by their easy processability and their low cost. Thin films of poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives doped with p-toluenesulfonate (Tos) molecules can exhibit a ZT as high as 0.25 at room temperature underlining the high potential of such systems for future applications. In this thesis, we focused on the understanding of PEDOT:Tos thin films properties by playing on the polymerization method. We demonstrated that the electrical conductivity can be improved by adding additives to the formulation of PEDOT:Tos materials. Moreover, the concentration of p-toluenesulfonate is an important parameter to tune the electrical conductivity without changing the Seebeck coefficient. Finally, the hybridization of PEDOT:Tos precursors with block copolymers allows us to design PEDOT:Tos nanostructures
Thiagarajan, Suraj Joottu. "Thermoelectric properties of rare-earth lead selenide alloys and lead chalcogenide nanocomposites." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196263620.
Повний текст джерелаThiagarajan, Suraj Joottu. "Thermoelectric properties of rare-earth lead selenide alloys and lead chalcogenide nanocomposites." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196263620.
Повний текст джерелаMaheshwari, Gunjan. "Carbon Nanocomposites for Industrial Applications." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1226522545.
Повний текст джерелаSchwall, Michael [Verfasser]. "Heusler compounds for thermoelectric applications / Michael Schwall." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1062496027/34.
Повний текст джерелаHamawandi, Bejan. "Formation of NiGeSn Material for Thermoelectric Applications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143781.
Повний текст джерелаKatayoun, Zahmatkesh Encheh Keikanlou. "Characterization of SiGe Nanowire for Thermoelectric Applications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180955.
Повний текст джерелаBrun, Mathieu. "Électrodes nanocomposites pour applications en microfluidique." Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00744588.
Повний текст джерелаFogelström, Linda. "Polymer Nanocomposites in Thin Film Applications." Doctoral thesis, KTH, Ytbehandlingsteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12400.
Повний текст джерелаQC20100621
Parsons, James. "Nanoparticles and nanocomposites for display applications." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/84573.
Повний текст джерелаCiocan, Cristina Elena. "Matériaux lamellaires nanocomposites : synthèse et applications." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2010. http://www.theses.fr/2010ENCM0008.
Повний текст джерелаThe objective of this thesis was the optimization of the synthesis and catalytic performances of nanocomposites materials containing W and Mo in the oxidation with H2O2 of a wide range of model organic compounds. The work achieved during this thesis is the development of new heterogeneous catalysts for the oxidation reaction who is carried out selectively in homogeneous catalytic systems, heterogeneous catalysis is still much more promising in future. The oxidation reaction of sulfur compounds has great interest, especially in the removal of organic sulfur compounds (thiophene, sulfide) contained in fuels and petroleum fractions, performed in mild conditions of temperature and pressure in the presence of H2O2. In this study were as follows : 1. elaboration of materials : a) preparation of precursors of type hydrotalcites (HDL) based on Mg-Al-NO3, Mg-Al-Ni-terephthalate and Mg-Al-NO3. b) preparation of hybrid materials by intercalation species of Mo and W by two synthetic routes : reaction of anion-exchange and hydrothermal synthesis. 2. characterization of the structure, texture and nature of catalytic sites by different techniques : XRD, nitrogen adsorption, TGA, Raman spectroscopy and UV-Vis, SEM, etc. 3. application of these catalysts in the reaction of oxidation of sulfur compounds (sulfides, thiophenes, sulfoxides), epoxidation of cyclooctene and oxidation of anthracene. The catalysts were stable under operating conditions
Baker, M. Christina Opimo. "Applications of polyaniline nanofibers and nanocomposites." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1666392621&sid=19&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Повний текст джерелаSaotome, Tsuyoshi. "Transparent polymer nanocomposites for aerospace applications." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1970611211&sid=54&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Повний текст джерелаLuo, Jinji. "Investigation of Polymer Based Materials in Thermoelectric Applications." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-170961.
Повний текст джерелаMit den Weiterentwicklungen der Drahtlosen Sensornetzwerke (engl. WSN, wireless sensor networks) stellen immer mehr Anwendungen die Forderung einer langen Lebensdauer der Sensorknoten. Energiegewinnungssysteme (engl. Energy Harvesters) wie z.B. thermoelektrische Generatoren (TEGs) können genutzt werden, um die Lebensdauer und Leistungsfähigkeit der WSN zu steigern. Mit der Integration von Energy Harvesters können WSN ohne äußere Stromversorgung realisiert und somit die Möglichkeit zur Wartungsfreiheit geschaffen werden. TEGs liefern Energie durch die Umwandlung einer Temperaturdifferenz in Elektrizität. Die Effektivität der TEG ist direkt verbunden mit der Material-Kennzahl ZT und ist gegeben durch ZT=σS^2 T/k, wobei σ die elektrische Leitfähigkeit ist, S der Seebeck Koeffizient, k die thermische Leifähigkeit, T die Temperatur und σS^2 der Leistungsfaktor. Herkömmliche thermoelektrische (TE) Materialien basieren auf anorganischen Materialien, von denen die thermische Leitfähigkeit hoch ist. Im Laufe des letzten Jahrzehnts konnte durch den Einsatz der Nanostrukturierung die thermische Leitfähigkeit verringern werden um damit die Effizienz von TE-Materialien zu steigern. Die Steifigkeit dieser Materialien ist ein anderer Aspekt. Als Alternative für anorganische TE Materialien sind Polymer basierte TE Materialien zum Fokus der Forschung geworden aufgrund einer intrinsisch niedrigen thermischen Leitfähigkeit, hohen Flexibilität und hohen elektrischen Leitfähigkeit. Des Weiteren können diese Polymere in gelöster Form verarbeitet werden, was die Möglichkeit für den Einsatz von Drucktechnologien und damit geringeren Produktionskosten gibt. Anders als der herkömmliche Ansatz den Leistungsfaktor der Polymerfilme durch die Ergänzung von sekundären Dotanten in PEDOT:PSS Lösungen zu verändern, wurde in dieser Arbeit eine effizientere Methode zur Verbesserung der TE Eigenschaften gesucht. In dieser Arbeit wird zum ersten Mal gezeigt, dass die Nachbehandlung von PEDOT:PSS Schichten mit sekundären Dotanten Dimethylsulfoxid (DMSO) als Medium der Nachbehandlung zu einem viel höheren Leistungsfaktor führt als bei der Zugabemethode und außerdem die sonst erforderliche Mischprocedur vermeidet. Es wurden verschiedene Lösungsmittel ausgewählt um die Einflussfaktoren bei der Modifikation des Leistungsfaktors durch die Nachbehandlung von Polymerschichten zu diskutieren. Die Nachbehandlung von PEDOT:PSS Schichten wurde nachfolgend erweitert um das umweltfreundliche Lösungsmittel EMIMBF4 (eine ionische Flüssigkeit) als das Medium einzusetzen. EMIMBF4 ist bekannt für den Austausch von Ionen mit PEDOT:PSS Schichten, so dass EMIM Kationen in der Schicht verbleiben, die Oxidationsstufe der PEDOT-Ketten senken und damit den Seebeck-Koeffizient und die elektrische Leitfähigkeit beeinflussen. Des Weiteren konzentriert sich diese Arbeit auf TE Materialien basierend auf Kompositen aus Polymeren mit Nanoeinlagerungen. Erfolgreiche Syntheseansätze wurden für Tellur-Nanostrukturen entwickelt, bei denen keine giftigen Reduktionsmittel und keine giftigen Tellur-Quellen zur Verwendung kamen. Es erfolgte die Erzeugung von kontrollierten Tellur-Nanostrukturen, einschließlich Nanostäben, Nanodrähten und Nanoröhren, mit nass-chemischer und hydrothermaler Synthese. Die so hergestellten Nanodrähte wurden dann in PEDOT:PSS Lösungen integriert für die Herstellung von Komposite-Schichten. Dabei konnte ein hoher Seebeck-Koeffizienten, bis zu 200 μV/K, festgestellt werden
Tang, Shuang Ph D. Massachusetts Institute of Technology. "Materials Physics for Thermoelectric and Related Energetic Applications." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98735.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (pages 118-122).
Thermoelectrics study the direct inter-conversion between heat flow and electrical power, which has a wide range of applications including power generation and refrigeration. The performance of thermoelectricity generation and the refrigeration is characterized by a dimensionless number called the Figure-of-Merit (ZT), defined as ZT = [sigma]-S 2T / [kappa], where a is the electrical conductivity, K is the thermal conductivity, S is the Seebeck coefficient, and T is the absolute temperature. Before 1993, the upper-limit of ZT was barely 1. After the efforts of more than twenty years, the upper-limit of ZT has been pushed up to ~2. However, for the thermoelectric technology to be commercially attractive, the value of ZT and the cost of production have to be further improved. Most of the ZT enhancing strategies that have been proposed since 1993 involve the changing and the controlling of the dimension of materials systems, the scattering mechanism(s) of carriers, the shape of the electronic band structure and the density of states, and the magnitude of the band gap. As further research is carried out, it is found that these strategies do not always work to enhance ZT. Even for a working materials system, the improvement margin of increasing ZT can be small. The balancing between [sigma] and S 2 / [kappa] has significantly limited the improvement margin for our ZT enhancing goal. Therefore, we have two problems to explore: (1) how can we deal with the strong correlation between [sigma] and S2 / [kappa] , when trying to enhance ZT, and (2) how can we make the above mentioned strategies more convergent as we change the dimension of materials systems, the scattering mechanism(s) of carriers, the shape of electronic band structure, and the magnitude of the band gap? This thesis aims to explore the solutions to these two major problems at the research frontier of thermoelectric ZT enhancement. The first problem is discussed by providing a new framework of pseudo-ZTs, where the electronic contribution (zte) and the lattice contribution (ztL) to the overall ZT can be treated in a relatively separate manner. The second problem is discussed under this new framework of pseudo-ZTs, through four subsections: (i) scattering and system dimension; (ii) band structure; (iii) density of states; (iv) band gap. The one-to-one correspondence relation between the carrier scattering mechanism(s) and the maximum Seebeck coefficient is further studied. A new tool for scattering mechanism(s) inference and for the Seebeck coefficient enhancement is provided. For the band structure and the band gap part, advanced band engineering methods are provided to study nanostructured narrow-gap materials, the Dirac cone materials, and the anisotropic materials, which are historically found to be good thermoelectric materials. To further demonstrate the newly developed theories, this thesis has also illustrated the application of these models in some specific materials systems, including the graphene system, the transition metal dichalcogenides monolayer materials systems, the Bi1 -xSbx alloys system, the In1.xGaxN alloys system, and the (BiiySby) 2(S1_xTex)3 alloys system.
by Shuang Tang.
Ph. D.
Jovovic, Vladimir. "Engineering of Thermoelectric Materials for Power Generation Applications." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1248125874.
Повний текст джерелаVijayakumar, Vishnu. "Highly oriented conducting polythiophene films for thermoelectric applications." Thesis, Strasbourg, 2020. http://www.theses.fr/2020STRAE004.
Повний текст джерелаThe aim of this thesis is to develop new polymeric thermoelectric (TE) materials based on oriented polythiophene (PBTTT) films. High-temperature rubbing produces oriented films of controlled orientation and crystallinity. Various doping methods with suitable dopants (F4TCNQ, F6TCNNQ and FeCl3) produced enhanced TE properties along the rubbing direction. A combination of polarized UV-Vis-NIR spectroscopy and TEM uncovered the amount and orientation of dopants intercalated in the crystals of PBTTT. The diffusion coefficient of dopants is correlated to the length of alkyl side chains : PBTTT with C12 side chains shows the best TE properties because of a fast and effective diffusion of dopants in the polymer films. Finally, we evaluated the impact of dopant (geometry, electronegativity) on the TE properties. Doping oriented PBTTT with FeCl3 helped reach record electrical conductivity of 2×105 S/cm and TE power factors of 1 mW/mK2
Goyal, Amita. "Titanium dioxide-germanium nanocomposites for photovoltaic applications." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file Mb., 104 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435250.
Повний текст джерелаChu, Chun. "Development of polymer nanocomposites for automotive applications." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37128.
Повний текст джерелаXu, Bin. "Shape memory polymeric nanocomposites for biological applications." Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2489.
Повний текст джерелаsang, zhen. "CONDUCTIVE ELASTOMER NANOCOMPOSITES FOR STRAIN SENSORS APPLICATIONS." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1554126739899435.
Повний текст джерелаLiu, Tingting. "Novel Hierarchically Structured Nanocomposites for Biomedical Applications." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/55103.
Повний текст джерелаAthikam, Pradeep kumar. "Thermoelectric Properties of Polydimethylsiloxane (PDMS) - Carbon Nanotube (CNT) Composites." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595848598234548.
Повний текст джерелаKulwongwit, Nuth. "P-type, misfit layered structure cobaltite for thermoelectric applications." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/ptype-misfit-layered-structure-cobaltite-for-thermoelectric-applications(c967ef03-5dd2-444d-b99b-1a1f784d10f0).html.
Повний текст джерелаShelley, Matthew. "Theory and simulation of semiconducting nanowires for thermoelectric applications." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/6860.
Повний текст джерелаMitra, Sunanda. "Chalcogenide of type I-V-VI₂ for thermoelectric applications." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS562/document.
Повний текст джерелаHere, we report on a series of samples with nominal compositions AgBiSe2-xSx (with x= 0 to 2) belonging to the class of ternary chalcogenides of type I-V-VI₂. The structural and thermal analysis result shows a complete solid solution without miscibility gap and phase transitions for all compositions. We have succeeded in obtaining single phase compounds, of both hexagonal and cubic phase, and the high temperature XRD study showed the rhombohedral phase too for selected compositions (x=1 to 2 in AgBiSexS2-x). The DSC results confirmed the presence of the phase transitions for all compositions, with a shift of the temperature of transition as a function of the sulfur/selenium fraction. The high pressure XRD investigation of the compound AgBiSe₂ showed a pressure induced phase transition from hexagonal-to-rhombohedral-to-cubic phase. In this respect, chemical pressure with 30% Sb on the Bi site has been successfully applied to stabilize the cubic phase for all compositions. Nb doping in the Sb-substituted samples does not show any change in the phase behavior at RT in comparison with the undoped samples. The influence of doping on transport properties was analyzed. The negative value of S for all compositions indicates n-type semiconducting behavior over the range (50-300K). Further, the results not only shows very low value of κ but the ∣S∣ and ρ value also decreases for each composition from Nb fraction 0.02 to 0.04. This gives us the opportunity to optimize the power factor in order to improve the ZT value. At last, collaborative study with Chinese team showed that ZT of 1.3 at 890 K can be achieved for AgPbmSnSe2+m (m = 50)
SOFFIENTINI, ALESSANDRO. "Synthesis and characterization of nanostructured oxides for thermoelectric applications." Doctoral thesis, Università degli studi di Pavia, 2018. http://hdl.handle.net/11571/1214883.
Повний текст джерелаGnanaseelan, Minoj [Verfasser], Brigitte [Gutachter] Voit, and Nikhil Kumar [Gutachter] Singha. "Development of thermoelectric materials based on polymer nanocomposites / Minoj Gnanaseelan ; Gutachter: Brigitte Voit, Nikhil Kumar Singha." Dresden : Technische Universität Dresden, 2019. http://d-nb.info/1226902200/34.
Повний текст джерелаAydin, Erkin. "Biodegradable Polymer - Hydroxyapatite Nanocomposites For Bone Plate Applications." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612252/index.pdf.
Повний текст джерелаs Modulus was observed. Although this increase was not high was not high probably due to the low fiber content in the final plates, this approach was found to be promising for the production of biodegradable polymeric bone plates with mechanical values closer to that of cortical bones. Biological compatibility of fibers was validated with in vitro testing. The osteoblasts attached and spread on the fibers indicating that bone fractures fixed with these could attract of bone forming osteoblasts into defect area and help speed up healing.
Satarkar, Nitin S. "REMOTE CONTROLLED HYDROGEL NANOCOMPOSITES: SYNTHESIS, CHARACTERIZATION, AND APPLICATIONS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/85.
Повний текст джерелаPolisski, Sergej. "Porous silicon/noble metal nanocomposites for catalytic applications." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545317.
Повний текст джерелаHeine, Jason Randall 1972. "Characterization and device applications of II-VI nanocomposites." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8447.
Повний текст джерелаIncludes bibliographical references.
This thesis describes the synthesis and characterization of CdSe core - ZnS shell (CdSe)ZnS nanocrystals, which behave as quantum dots (QDs), their incorporation into transparent polymers and ZnS, and possible device applications of the resulting luminescent materials. The crystalline structure of these quantum dots is examined using XRD. The nature of the core-shell interface is inferred by comparison of the XRD spectra with calculated spectra and in consideration of TEM images of the QDs. The influence the addition of a shell material over the CdSe core has on the QD exciton energy is examined by comparing the measured and calculated change in band edge emission energy when ZnS or CdS are used as overcoat materials. Methods of incorporating the QDs into various polymers are considered and the emission of a GaN LED/ QD-containing polymer composite structure is simulated and compared with the output of actual devices. The simulation is also used as a design tool in the production of a white-light LED. Embedding the QDs into ZnS films via an electrospray technique is carried out and the resulting films characterized with x-ray diffraction and photoluminesence measurements. QD film / ZnS film structures are also considered, with atomic layer deposition used as the method for depositing the ZnS to improve the film uniformity as well as to maintain high quality deposition at temperatures low enough to be compatible with the presence of QDs. Finally, thin film devices are synthesized and the behavior of the QD photoluminescence when an electric field is applied is studied.
(cont.) Significant levels of photoluminescence quenching is observed when a voltage is applied across an ITO/ZnS/QD/ZnS/Al, and similar, devices. Various reasons for this quenching are considered.
by Jason Randall Heine.
Ph.D.
Pooyan, Parisa. "Bio-inspired polymer nanocomposites for tissue engineering applications." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53439.
Повний текст джерелаAbeywickrama, Thulitha Madawa. "Metal-Organic Hybrid Nanocomposites For Energy Harvesting Applications." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1748.
Повний текст джерелаKhlebtsov, B. N., and N. G. Khlebtsov. "Theranostic Applications of Au-Ag Nanocages and Nanocomposites." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34937.
Повний текст джерелаLi, Molan. "Thermoelectric-Generator-Based DC-DC Conversion Network for Automotive Applications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-42358.
Повний текст джерелаMangelis, Panagiotis. "Structural and physical properties of chalcogenide materials for thermoelectric applications." Thesis, University of Reading, 2017. http://centaur.reading.ac.uk/76846/.
Повний текст джерелаHojabri, Arash. "Synthesis and characterization of Germanium quantum dots for thermoelectric applications." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180953.
Повний текст джерелаIyengar, Ananth Shalvapulle. "Synthesis and characterization of micro/nano material for thermoelectric applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1276182370.
Повний текст джерелаWei, Kaya. "Skutterudite Derivatives: A Fundamental Investigation with Potential for Thermoelectric Applications." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5152.
Повний текст джерела