Enhanced thermoelectric performance through carrier scattering at heterojunction potentials in BiSbTe based composites with Cu3SbSe4 nanoinclusions

Abstract

Thermoelectric materials with the thermoelectric figure of merit, ZT, being much larger than unit at near room temperature are vital for power generation by using low-grade waste heat. Here we show that by incorporating very small proportion (1 vol%) of Cu₃SbSe₄ nanoparticles into the BiSbTe matrix to form nanocomposites, besides large (∼50%) reduction of lattice thermal conductivity, both enhanced thermopower through energy-dependent scattering and alleviated reduction of carrier mobility via carrier scattering at heterojunction potentials occur at elevated temperatures, which allow the thermoelectric power factor of the composite material to reach ∼37 μW cm⁻¹ K⁻² at 467 K. Consequently, a largest value of ZT = 1.6 is achieved at 476 K. Moreover, it has excellent performance in a broad temperature range (say, ZT = 1.0 at 300 K and ZT = 1.5 at 500 K), which makes this material attractive for cooling and power generation.