Microstructural design of Bi₂Te₃-In₂Te₃ thermoelectric composites

Internal interfaces are known to play a key role for the performance of thermoelectric materials. In the present work, structures with high interface densities consisting of alternating Bi₂Te₃ and In₂Te₃ layers with varying thickness and distance have been generated by two processes. First In₂Te₃ was precipitated from a supersaturated Bi₂Te₃ matrix. Second, layered structures were generated by directional solidification of hypoeutectic and eutectic alloys, demonstrating the variability of structures with high interface densities and anisotropy that can be generated by up-to-date solidification and phase transformation techniques. The resulting microstructures have a high potential to reduce the thermal conductivity while retaining a high electric conductivity.