Thermoelectric properties of Co4Sb12 with Bi2Te3 nanoinclusions. (12th February 2018)

• Record Type: Journal Article
• Authors: Ghosh, Sanyukta; Bisht, Anuj; Karati, Anirudha; Rogl, Gerda; Rogl, Peter; Murty, B S; Suwas, Satyam; Mallik, Ramesh Chandra
• Is Part Of: Journal of physics. Volume 30:Number 9(2018)
• Publication Date: 2018-02-12
• Subjects: thermoelectric materials -- skutterudite -- bismuth telluride -- nanocomposites; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aaa5ea
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The figure of merit ( zT ) of a thermoelectric material can be enhanced by incorporation of nanoinclusions into bulk material. The presence of bismuth telluride (Bi2 Te3 ) nanoinclusions in Co4 Sb12 leads to lower phonon thermal conductivity by introducing interfaces and defects; it enhances the average zT between 300–700 K. In the current study, Bi2 Te3 nanoparticles were dispersed into bulk Co4 Sb12 by ball-milling. The bulk was fabricated by spark plasma sintering. The presence of Bi2 Te3 dispersion in Co4 Sb12 was confirmed by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron back scattered diffraction technique. Energy dispersive spectroscopy showed antimony (Sb) as an impurity phase for higher contents of Bi2 Te3 in the sample. The Seebeck coefficient ( S ) and electrical conductivity (σ) were measured in the temperature range of 350–673 K. The negative value of S indicates that most of the charge carriers were electrons. A decrease in S and increase in σ with Bi2 Te3 content are due to the increased carrier concentration, as confirmed by Hall measurement. The thermal conductivity, measured between 423–673 K, decreased due to the increased phonon scattering at interfaces. A maximum zT of 0.17 was achieved at 523 K and it did not vary much throughout the temperature range. The experimental results of composites were compared by using effective medium theories.