Synergetic enhancement of thermoelectric performances by localized carrier and phonon scattering in Cu2Se with incorporated fullerene nanoparticles

Abstract

C₆₀/Cu₂Se thermoelectric nanocomposites were synthesized with various amounts of fullerene (C₆₀; 0.03, 0.3, 0.5, 0.7 mol%) incorporated in Cu₂Se. The thermoelectric figures of merits (zT) of the C₆₀/Cu₂Se nanocomposites were enhanced by 20-30% compared to that of pure Cu₂Se, reaching a value of 1.4 at 773 K. The primary cause of zT enhancement is the synergetic effect of thermal conductivity reduction by phonon scattering and Seebeck coefficient increase by carrier localization that results from incorporation of C₆₀ nanoparticles. Theoretical calculations for Seebeck coefficient enhancement and lattice thermal conductivity reduction were performed. The Seebeck coefficients of C₆₀/Cu₂Se nanocomposites were around 43% higher than that of pure Cu₂Se, whereas the reduction of lattice thermal conductivity with incorporation of C₆₀ was around 40-50%.