Effect of Nanostructuring on the Thermoelectric Properties of β-FeSi2

Linda Abbassi (1, 2) , David Mesguich (2) , David Berthebaud (3) , Sylvain Le Tonquesse (3) , Bhuvanesh Srinivasan (3) , Takao Mori (3) , Loïc Coulomb (1) , Geoffroy Chevallier (2, 4) , Claude Estournès (2) , Emmanuel Flahaut (2) , Romain Viennois (1) , Mickaël Beaudhuin (1)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 LINK - Laboratory for Innovative Key Materials and Structures
4 PNF2 - Plateforme Nationale de Frittage Flash

Nanostructured β-FeSi2 and β-Fe0.95Co0.05Si2 specimens with a relative density of up to 95% were synthesized by combining a top-down approach and spark plasma sintering. The thermoelectric properties of a 50 nm crystallite size β-FeSi2 sample were compared to those of an annealed one, and for the former a strong decrease in lattice thermal conductivity and an upshift of the maximum Seebeck’s coefficient were shown, resulting in an improvement of the figure of merit by a factor of 1.7 at 670 K. For β-Fe0.95Co0.05Si2, one observes that the figure of merit is increased by a factor of 1.2 at 723 K between long time annealed and nanostructured samples mainly due to an increase in the phonon scattering and an increase in the point defects. This results in both a decrease in the thermal conductivity to 3.95 W/mK at 330 K and an increase in the power factor to 0.63 mW/mK2 at 723 K.

Mots clés: Powder technology; Sintering; Nanocrystalline materials; Thermal properties; Semiconductors; Energy storage and conversion

Domaines: Matériaux

Linda Abbassi, David Mesguich, David Berthebaud, Sylvain Le Tonquesse, Bhuvanesh Srinivasan, et al.. Effect of Nanostructuring on the Thermoelectric Properties of β-FeSi2. Nanomaterials, 2021, 11 (11), pp.2852. ⟨10.3390/nano11112852⟩. ⟨hal-03431689⟩