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

Abstract

C-60/Cu2Se thermoelectric nanocomposites were synthesized with various amounts of fullerene (C-60; 0.03, 0.3, 0.5, 0.7 mol%) incorporated in Cu2Se. The thermoelectric figures of merits (zT) of the C-60/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 C-60 nanoparticles. Theoretical calculations for Seebeck coefficient enhancement and lattice thermal conductivity reduction were performed. The Seebeck coefficients of C-60/Cu2Se nanocomposites were around 43% higher than that of pure Cu2Se, whereas the reduction of lattice thermal conductivity with incorporation of C-60 was around 40-50%.