First Principles Modelling of Thermoelectric Materials
--> Naydenov, Genadi A. (2019) First Principles Modelling of Thermoelectric Materials. PhD thesis, University of York.
Thermoelectric semiconductor materials possess the unique ability to convert temperature differential into electricity or vice versa. This presents excellent opportunities for harvesting waste heat or cooling. Thermoelectric applications are found in many different areas ranging from medicine to space programs. The quality of the materials is determined by their thermoelectric properties like the Seebeck coefficient, electrical and thermal conductivity. In this thesis we model the thermoelectric properties from first principles. The materials of interest include Fe2VAl, NbFeSb, TaFeSb and Bi2Te3. The thermoelectric properties are analysed by considering the effects of doping, point defects, grain boundaries and size reduction. A number of key results are found. We show that the experimentally observed behaviour of the Seebeck coefficient in Fe2VAl can be theoretically modelled by enhancing the localisation of V electrons with the Hubbard model. We establish TaFeSb as a new thermoelectric material which exhibits 50 % better p-type thermoelectric properties than NbFeSb due to an increased scattering strength between Ta and potential dopants. We also note that mixing NbFeSb and TaFeSb does not have a negative impact on the electronic properties and could potentially lead to further improvements in the thermoelectric performance. We investigate the electronic thermoelectric properties of Bi2Te3 thin films. We find that the Seebeck coefficient increases dramatically when the film thickness is reduced to 1-2 nm. This leads to an overall increase in the power factor of the material and enhanced p-type thermoelectric performance. The successful calculation of the properties for a wide range of materials also shows that the developed in this project computational framework can be reliably used for further research on thermoelectrics.
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THESIS HIGH EFFICIENCY THERMOELECTRIC DEVICES FABRICATED USING QUANTUM WELL CONFINEMENT TECHNIQUES Submitted by Austin Lee Jurgensmeyer Department of Mechanical Engineering ... Thermoelectric generator modules based on an in-plane orientation of nano-scale, thin-film, superlattices have demonstrated very high performance and are appropriate for ...
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Modeling and Application of a Thermoelectric Generator David Yan Masters of Applied Science Graduate Department of Electrical and Computer Engineering University of Toronto 2011 Thermoelectric modules are an important alternative to heat engines in the harvesting of waste heat. Electrical-thermal analogues are often employed when studying heat ...
Design of Advanced Thermoelectric Materials. Laaya Shaabani PhD thesis University of Groningen, The Netherlands Zernike Institute for Advanced Materials PhD thesis series 2018-14 ISSN: 1570-1530 ISBN: 978-94-034-0560-5 (printed version) ISBN: 978-94-034-0561-2 (electronic version) The work described in this thesis was performed in the group ...
The thesis sets out to assess the feasibility and practicality of implementing a TEC-based thermal management system for use in electronic packaging and in particular, for spectrometers in the nanophotonics industry. A heat sink and fan were used as auxiliary components to aid the heat dissipation process.
manufacturing methods for high-throughput fabrication of thermoelectric devices leads to the high cost of thermoelectric systems and limitations in the areas of applications. In this Ph.D. thesis, one of the main goals is to develop a new manufacturing concept for industrial-scale automated manufacturing of thermoelectric devices.
Modeling and optimization of thermoelectric generator for waste heat ...
In this thesis, I perform first-principles modelling of the thermoelectric properties of half-Heusler alloys focused on analysis of XNiSn (X = Ti, Zr, Hf) and Nb1-xCoSb ySn1-y based compositions. Thermoelectric properties of complex defective supercells were performed using plane-wave DFT as implemented in CASTEP and by solving the phonon
Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Malik, S. A. (2018). Contacts and Interface Evolution in Thermoelectric Modules. ... Technical University of Denmark. Contacts and Interface Evolution in Thermoelectric Modules PhD Thesis by: Safdar Abbas Malik Principal Supervisor: Co-supervisor: Dr. Ngo ...
The quality of the materials is determined by their thermoelectric properties like the Seebeck coefficient, electrical and thermal conductivity. In this thesis we model the thermoelectric properties from first principles. The materials of interest include Fe2VAl, NbFeSb, TaFeSb and Bi2Te3. The thermoelectric properties are analysed by ...
The goal of this work was the development of tools for the evaluation of thermoelectric power generation units and devices. The modelling has been done on two size levels. On the large scale level a high number of thermoelectric modules have been integrated in a heat transfer unit, respectively a cross-flow heat exchanger.
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The work presented in this Ph.D. thesis deals with the synthesis, the structural and electronic properties characterization of the Cu22Fe8Ge4S32 copper sulfide, a material derived of the germanite ...
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This thesis aims to develop both simulation and experimental tools to study nanoscale electron, phonon and magnon transport and their interactions, with a particular emphasis on understanding the electron-phonon interaction at the single-mode level. This is among the most important forms of carrier interactions and determines the intrinsic ...
thermoelectric performance. Second, the role of crystal orientation in determining the thermoelectric properties of epitaxial Al doped ZnO (AZO) films is explained. Vertically aligned (c-axis) AZO films have superior thermoelectric properties compared to other films with different crystal orientations. Third, additional B-site doping of A-site ...
energy [3]. A thermoelect ric power generator (TEG) is also defined as. a Seebeck generator. It is a solid-state device which p rovides. direct energy conversion from thermal energy (heat) due to ...
ond, the thermoelectric coe cient is central to commercial, industrial, and scienti c application of thermoelectric devices, such as Peltier coolers and power generators. Therefore, if nanoscale materials are to be integrated into novel thermoelectric en-ergy conversion devices, thermoelectric properties must be investigated in detail. The
Thermoelectric generators are based on pairs of n- and p-type legs. In the paper by Wenjie Xie et al., the scandium substitution in NbCoSn has been shown to be efficient to generate a high power factor for a p-type thermoelectric half Heusler, which is the weak leg of thermoelectric pairs made on such intermetallic materials [Citation 6].
The rst thermoelectric setup introduced in the lab practical is the ther-mocouple. This simple device consists of two conductors, A and B, which are connected at one end held at temperature T 1. Meanwhile, the volt-age di erence between conductors A and B is measured at the opposite end held at temperature T 2. The thermocouple is shown in Fig ...
this thesis. Furthermore, the thermoelectric quantities are used to extract additional material parameters of the InAs nanowires such as carrier concentration and carrier mobility. In this thesis, the design, fabrication and characterization of InAs nanowire thermoelectric test structures is presented and discussed with the focus on: