Synergetic modulation of power factor and thermal conductivity for Cu3SbSe4-based system

Abstract

Many methods have been focused on improving the thermoelectric performance of Cu3SbSe4 based materials. However, no effective way can simultaneously achieve the significant improvement of power factor and the remarkable reduction of thermal conductivity. In this work, we introduce AgSb0.98Sn0.02Se2 particles into Cu3Sb0.96Sn0.04Se4 matrix forming Cu3Sb0.96Sn0.04Se4/x wt%AgSb0.98Sn0.02Se2 (x = 0, 1, 3, 5, 7) nanocomposites by milling and spark plasma sintering technique. Due to the reduced thermal conductivity and enhanced carrier mobility, a record-high ZT value of 1.17 is obtained for the sample Cu3Sb0.96Sn0.04Se4/5wt%AgSb0.98Sn0.02Se2. The reduced thermal conductivity is attributed to the enhanced phonon scattering caused by the second phase AgSb0.98Sn0.02Se2 with multiscale size and the enhanced power factor originated from increased carrier mobility due to the reduced carrier concentration, which is caused by the new acceptor energy level related to the interfacial defects. Present results demonstrate that excellent thermoelectric performance can be realized in Cu3Sb0.96Sn0.04Se4 matrix with AgSb0.98Sn0.02Se2 particles embedded.