Enhanced thermoelectric properties for p-type BiSbTe by incorporating multiferroic BiFeO3 nanoparticles

Thermoelectric materials can directly convert electrical energy and thermal energy by regulating carrier and phonon transport under electrical and thermal fields. However, further enhancement of thermoelectric properties is hindered by limited available methods that can synergistically tune transport properties. Here, multiferroic BiFeO3 nanoparticles with spontaneous electrical and magnetic polarization are synthesized and incorporated into p-type Bi0.5Sb1.5Te3, to probe the impact of simultaneous local electrical field and magnetic field on the transport properties of the BiFeO3/Bi0.5Sb1.5Te3 nanocomposites. The BiFeO3/Bi0.5Sb1.5Te3 atomic-resolution interfacial structure is revealed using aberration-corrected scanning transmission electron microscopy. The selective reaction of Sb cations leads to reduced carrier concentration and decreased electrical conductivity. The Seebeck coefficient is enhanced by additional scattering from local electrical and magnetic field. Phonon scattering is boosted by the nanostructures from interfacial reaction and local lattice distortion caused by the polarization. As a result, the ZT values and the cooling performance are improved by 9% and 31% for the nanocomposites, respectively.