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Synthèses et caractérisations de matériaux thermoélectriques nanostructurés

Abstract : The global thermoelectric markets are in expansion with a growing interest for the energy harvesting or the thermal management of electronic components. Despite numerous advantages, this technology development is limited by the materials performances. A way to improve them is to use nanostructures in order to decrease the lattice thermal conductivity.In this work, this approach is applied to bismuth telluride, material well known for its high performance around room temperature. Materials are obtained from solution synthesis of nanoparticles before hot press compaction.A first study focuses on the determination of an optimal grain size in the bulk materials. It is shown that control over the synthesis parameters allows control on the size of nanoparticles.Moreover, structural and physical analyses on the bulks after sintering show that the change of thesynthesis parameters allows control over the microstructure and thermoelectric properties of the bulks.A second study is based on the study of an optimal composition of Bi2Te3-xSex materials. Morphological analysis show a specific and complex structure with three phases in the bulks.It is postulated that these materials should have anisotropic transport properties. Consequently, their characterizations are difficult. Different characterization techniques are used in order to have a better understanding of their thermal conductivities. Thermal conductivity of the bulks is found low which confirm the interest of this approach. However the electrical conductivity is lower than the one of the materials obtained by more conventional methods. We show that the synthesis parameters of the particles can be optimized to increase the thermoelectric performances of the bulk materials.
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Submitted on : Friday, June 15, 2018 - 1:13:11 AM
Last modification on : Friday, July 3, 2020 - 9:28:03 AM
Long-term archiving on: : Monday, September 17, 2018 - 11:11:21 AM


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  • HAL Id : tel-01816180, version 1


Romain Bude. Synthèses et caractérisations de matériaux thermoélectriques nanostructurés. Autre. Université Paris-Saclay, 2018. Français. ⟨NNT : 2018SACLC032⟩. ⟨tel-01816180⟩



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