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Improved Electrical, Thermal, and Thermoelectric Properties Through Sample‐to‐Sample Fluctuations in Near‐Percolation Threshold Composite Materials

  • Effective medium theories (EMT) are powerful tools to calculate sample averaged thermoelectric material properties of composite materials. However, averaging over the heterogeneous spatial distribution of the phases can lead to incorrect estimates of the thermoelectric transport properties and the figure of merit ZT in compositions close to the percolation threshold. This is particularly true whenEffective medium theories (EMT) are powerful tools to calculate sample averaged thermoelectric material properties of composite materials. However, averaging over the heterogeneous spatial distribution of the phases can lead to incorrect estimates of the thermoelectric transport properties and the figure of merit ZT in compositions close to the percolation threshold. This is particularly true when the phases’ electronic properties are rather distinct leading to pronounced percolation effects. The authors propose an alternative model to calculate the thermoelectric properties of multi‐phased materials that are based on an expanded nodal analysis of random resistor networks (RRN). This method conserves the information about the morphology of the individual phases, allowing the study of the current paths through the phases and the influence of heterogeneous charge transport and cluster formation on the effective material properties of the composite. The authors show that in composites with strongly differing phases close to the percolation threshold the thermoelectric properties and the ZT value are always dominated exclusively by one phase or the other and never by an average of both. For these compositions, the individual samples display properties vastly different from EMT predictions and can be exploited for an increased thermoelectric performance.show moreshow less

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Metadaten
Author:Andres Georg Rösch, Fabian Giunta, Md. Mofasser Mallick, Leonard Franke, André Gall, Jasmin Aghassi-HagmannORCiDGND, Jörg Schmalian, Uli Lemmer
Publisher:Wiley-VCH GmbH
Year of Publication:2021
Date of first Publication:2021/06/05
Page Number:8
Language:English
Tag:composite materials; effective medium theory; electrical conductivity; percolation; random resistor networks; sample‐to‐sample fluctuation; thermoelectrics
Parent Title (English):Advanced Theory and Simulations
Volume:4
Issue:6
ISSN:2513-0390
Document Type:Article (reviewed)
Open Access:Frei zugänglich
Institutes:Bibliografie
Release Date:2021/09/23
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International
URN:urn:nbn:de:bsz:ofb1-opus4-50477
DOI:https://doi.org/10.1002/adts.202000284