Enhancement of thermoelectric figure of merit for Bi0.5Sb1.5Te3 by metal nanoparticle decoration

Abstract: Introducing nanoinclusions in thermoelectric materials is expected to lower the lattice thermal conductivity by intensifying the phonon scattering effect, thus enhancing their thermoelectric figure of merit ZT. We herein report a novel method of fabricating Bi0.5Sb1.5Te3 nanocomposite with nanoscale metal particles by using metal acetate precursor, which is low-cost and facile to scale-up for mass production. Ag and Cu particles of ？40 nm were successfully near-monodispersed at grain boundaries of Bi0.5Sb1.5Te3 matrix. The well-dispersed metal nanoparticles reduce the lattice thermal conductivities extensively, while enhancing the power factor. Consequently, ZT was enhanced by more than 25％ near room temperature and by more than 300％ at 520 K compared to a reference sample Bi0.5Sb1.5Te3. The peak ZT of 1.35 was achieved at 400 K for the 0.1 wt.％ Cu-decorated Bi0.5Sb1.5Te3.