Layered structure of alumina/graphene-augmented-inorganic-nanofibers with directional electrical conductivity
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Authors
Shamshirgar, Ali Saffar
Rojas Hernandez, Rocio Estefania
Tewari, Girish C.
Ivanov, Roman
Mikli, Valdek
Karppinen, Maarit
Hussainova, Irina
Date
2020-10-15
Department
Department of Chemistry and Materials Science
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Mcode
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Language
en
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Carbon
Abstract
Implementation of layered structures with strong nanoscale optimized interfaces, enables engineering of materials with functional properties. In this work, anisotropic functional multi-layered structures are produced by integration of a thin hybrid inter-layer of graphene-augmented-nanofibers/alumina into α-alumina through an ex-situ strategy of precipitating the tailored hybrid from a solution. Spark plasma sintering was used to consolidate the layered structures at 1150 and 1450 °C under 75 and 50 MPa pressure. Raman spectroscopy suggests presence of C–H bonds and sp3 hybridization for the samples sintered at 1150 °C, while graphene structure is purified at the sintering temperature of 1450 °C. The multilayer structures demonstrate a high in-plane electrical conductivity which can be modulated, ranging from 300 to 1800 S m−1 as a function of the interlayer thickness and the carbon content. A p-type conduction at room temperature and n-type down to 4 K in graphene-augmented nano-fillers was observed in Hall measurement. However, the multilayered systems display a p-type conduction in the entire temperature range. Hardness was preserved despite the high concentration of the graphene-augmented nano-fillers in the hybrid interlayer leaving a highest value of ∼22 GPa. The results have the potential to fuel the development of functional electronic enclosures with additional functionalities such as electromagnetic interference shielding.Description
Keywords
Hierarchical structures, Hybrid materials, Ceramics, Graphene, Anisotrophy
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Shamshirgar, A S, Rojas Hernandez, R E, Tewari, G C, Ivanov, R, Mikli, V, Karppinen, M & Hussainova, I 2020, ' Layered structure of alumina/graphene-augmented-inorganic-nanofibers with directional electrical conductivity ', Carbon, vol. 167, pp. 634-645 . https://doi.org/10.1016/j.carbon.2020.06.038