Enhanced thermoelectricity of three-dimensionally mesostructured BiSbTe nanoassemblies: from micro-scaled open gaps to isolated sealed mesopores.

We describe an innovative interfacial design concept and nanostructuring of novel BiSbTe (BST) nanoassembled films comprising unique air-solid interfaces from micro-scaled open gaps to isolated sealed mesopores, and high-quality solid-solid ones including the coherent grain boundaries and specific twins, utilizing pulsed laser deposition (PLD), for potentially activating multiple thermoelectric enhancing mechanisms. The unusual mesopore embedded BST films exhibit the highest power factor of ∼33 μW cm K, which is comparable to or higher than the previously reported values for BST, and the corresponding relatively low thermal diffusivity in contrast to that for dense pore-less BST films evidently reveals the crucial role of the three-dimensionally and densely arranged air-solid interfaces in significantly arising the phonon scattering.

Smart assembling of multi-scaled functional interfaces in thermoelectric Ga₂Te₃/Te hetero-nanocomposites.

We describe an innovative concept and facile approach in fabricating laterally assembled Ga₂Te₃/Te binary nanocomposite films, which comprise two-dimensional quasi-periodic Ga₂Te₃ nanoassemblies surrounded by interlocking highly-conductive Te single crystals for comprehensively establishing subnano- to micro-scaled multi-style versatile interfaces. The distinct Ga₂Te₃/Te nanocomposite film exhibits a power factor that is about 60 times higher than the reported conventional Ga₂Te₃ and Te materials, mainly due to the 2- to 3-order improved electrical conductivity and the comparable Seebeck coefficient.

Great enhancements in the thermoelectric power factor of BiSbTe nanostructured films with well-ordered interfaces.

An innovative concept of twin-enhanced thermoelectricity was proposed to fundamentally resolve the high electrical resistance while not degrading the phonon scattering of the thermoelectric nanoassemblies. Under this frame, a variety of highly oriented and twinned bismuth antimony telluride (BixSb2-xTe3) nanocrystals were successfully fabricated by a large-area pulsed-laser deposition (PLD) technique on insulated silicon substrates at various deposition temperatures. The significant presence of the nonbasal- and basal-plane twins across the hexagonal BiSbTe nanocrystals, which were experimentally and systematically observed for the first time, evidently contributes to the unusually high electrical conductivity of ~2700 S cm(-1) and the power factor of ~25 μW cm(-1) K(-2) as well as the relatively low thermal conductivity of ~1.