posted on 2022-08-18, 18:20authored byCan Zhu, Jian Wang, Feng Luo, Shun Zhang, Jiafu Wang, Yan Zhang, Hongxia Liu, Zhigang Sun
Incorporated nanoscale phases in thermoelectric (TE)
materials
can optimize the electronic and thermal transport properties to obtain
high-performance TE materials. The rapid spark plasma sintering (SPS)
technique is adopted to synthesize Ge0.96Bi0.06Te composites incorporated with soft magnetic Fe nanoparticles (nano-Fe)
and their thermoelectric performance is researched in this study.
With the phase transition of the Ge0.96Bi0.06Te matrix from the low-temperature rhombohedral phase to the high-temperature
cubic one, the interface contact between Ge0.96Bi0.06Te and nano-Fe is transformed from Schottky contact to Ohmic one,
which improves its electronic transport performance at high temperatures.
At the same time, the additional Fe nanoprecipitation phonon scattering
can reduce the lattice thermal conductivity to ∼0.66 W m–1 K–1. These mechanisms result in
a high ZT value of 1.65 and a relatively highquality
factor B of 1.05 at 785 K for Ge0.96Bi0.06Te/2 mol % Fe. This work suggests that the thermoelectric
performance of composite materials can be enhanced by introducing
a variable interface band structure.