Enhanced thermoelectric figure of merit in p-type β-Zn4Sb3/Bi0.4Sb1.6Te3 nanocomposites

Abstract

The thermoelectric properties of Bi_0.4Sb_1.6Te₃-based composites incorporated with β-Zn₄Sb₃ nanoparticles are investigated in the temperature range from 300 K to 500 K. The results show that ∼5% increase in Seebeck coefficient and ∼32% reduction of lattice thermal conductivity at 443 K are concurrently realized in the nanocomposite system with 1.3 vol% of β-Zn₄Sb₃, which originates from energy filtering effect as well as enhanced phonon scattering at dispersed nanoparticles and phase boundaries, respectively. As a result, the largest figure of merit ZT = 1.43 is achieved at 443 K for the sample with 1.3 vol% of β-Zn₄Sb₃ nanoinclusions, which is ∼18% larger than that (=1.21) of the Bi_0.4Sb_1.6Te₃ matrix.