Synergistical Tuning Interface Barrier and Phonon Propagation in Au-Sb2Te3 Nanoplate for Boosting Thermoelectric Performance

Engineering of low-dimensional metal-semiconductor nanocomposites is expected to decouple electrical and thermal property, leading to substantially higher thermoelectric property. In this study, we rationally design a unique 0D-2D Au-Sb2Te3 architecture with beneficial interface barrier and strengthened phonon scattering, resulting in synergistically optimized electrical and thermal properties. In-situ growth of Au nanoparticles similar to 10 nm on Sb2Te3 nanoplates enables better manipulation of electron and phonon transport compared to traditional bulks. The energy barrier between Au and Sb2Te3 effectively filters low-energy holes, while the Au nanoparticles competently hinder the propagation of midto-long wavelength phonons. As a result, this unique 0D-2D Au- Sb2Te3 composite exhibits a concurrent increase in electrical conductivity and Seebeck coefficient, and a decrease in lattice thermal conductivity, which allows a double of ZT value (similar to 0.8 at 523 K) for 1 mol % Au-Sb2Te3 composites with respect to the pristine Sb2Te3 (similar to 0.39 at 523 K). This self-assembled heterostructure provides a direction to design other low-dimensional metal-semiconductor nanoassemblies for thermoelectric application.