Nanostructured CuFeSe2 Eskebornite: An efficient thermoelectric material with ultra-low thermal conductivity

• Published in: Materials science & engineering. B, Solid-state materials for advanced technology Vol. 284; p. 115914
• Main Authors: Moorthy, Manojkumar, Bhui, Animesh, Battabyal, Manjusha, Perumal, Suresh
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.10.2022; Elsevier BV
• Subjects: Electrical resistivity; Electron states; Ferromagnetism; Field emission; Figure of merit; Heat conductivity; Heat transfer; high zT; Nanomaterials; Nanoparticles; p-type CuFeSe2 eskebornite; Photomicrographs; Seebeck effect; Thermal conductivity; Thermoelectric materials; Thermoelectrics; Ultra-low thermal conductivity; X ray photoelectron spectroscopy; X ray powder diffraction; high zT; Thermoelectrics; Nanomaterials; p-type CuFeSe2 eskebornite; Ultra-low thermal conductivity
• DOI: 10.1016/j.mseb.2022.115914
• ISSN: 0921-5107

Schematic illustration of the synthesis process and thermal conductivity reduction in nano-CuFeSe2. [Display omitted] •Bulk and nano-CuFeSe2 samples have been successfully synthesized using vacuum melting and hydrothermal method, respectively.•From the TEM, the average particle size of nano-CuFeSe2 was calculated as ∼ 102 nm.•Ultra-low thermal conductivity of ∼ 0.22 W/mK at 645 K was observed for nano-CuFeSe2.•Thus, a maximum figure of merit (zT) of ∼ 0.02 at 645 K is achieved for nano-CuFeSe2. Bulk and nanoparticles of CuFeSe2 eskebornite have been synthesized using vacuum-sealed tube melting and facile hydrothermal method, respectively. The phase purity of bulk and nano-CuFeSe2 is confirmed through powder X-ray diffraction. Field emission-SEM micrographs of nano-CuFeSe2 depict the randomly distributed plate-like agglomerated particles. Further, TEM studies reconfirm the plate-like CuFeSe2 nanoparticles with an average particle size of ∼ 102 nm. The electronic states of Cu1+, Fe3+, and Se2- in CuFeSe2 are confirmed using XPS analysis. VSM measurements depict the weak ferromagnetic behavior in both bulk and nano-CuFeSe2 samples. The electrical conductivity of bulk CuFeSe2 is ∼ 0.6x104 S/m, and it reduces to 0.07x104 S/m at 300 K for nano-CuFeSe2, whereas the Seebeck coefficient increases from ∼ 12 µV/K to ∼ 48.4 µV/K at 300 K. Intriguingly, an ultra-low thermal conductivity of ∼ 0.73 W/mK at 300 K has been achieved for nano-CuFeSe2, which leads to the maximum figure of merit, zT of ∼ 0.02 at 645 K.