Recent Progress of Thermoelectric Nano-composites

Microstructure engineering is an effective avenue for tuning the thermal and electrical transports to optimize thermoelectric (TE) properties. Thermoelectric composites with nano-particle dispersion have been successfully developed by using extrinsic or in-situ formation methods. The lattice thermal conductivity can be depressed by the scattering effects of nano particles to the medium-long-wavelength phonons. The enhanced electron density of states at the Fermi level and the carrier filtering effects caused by the nano-sized grain boundary are also positive for enhancing Seebeck coefficients. The mixing, in-situ oxidation and phase-separation precipitation process supply possibility to realize the nano-particle dispersed structure for different material systems. This paper reviews the recent progress of the research on nano-structured and nano-composite thermoelectric materials. The effects of the nano-dispersion on the electrical and thermal transports will be also discussed.