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%.