Hierarchical Phonon Scattering from Nano to Macro Scale in Ag-Nano/TiO-Micro Particle-Decorated p-type Bismuth Telluride Bulk Composites.

We study the thermoelectric properties of a p-type BiSbTe (BST) composite with Ag nanoparticle-decorated TiO microparticles (US-Ag/TiO). The dispersion of US-Ag/TiO particles, synthesized by an ultrasonication (US) method, into the matrix effectively decreases lattice and bipolar thermal conductivity, attributed to the scattering centers formed at nano and micro scales. The electron backscattering diffraction (EBSD) measurements revealed smaller grain sizes within the BST composite when paired with the US-Ag/TiO particle dispersion.