MRI Seminar, "High thermoelectric performance in multiphase materials", Dr Sima Aminorroaya, Sheffield Hallam University
Date: Wed 2 Dec 2020, 15:00 - 16:00
Location: Online at tinyurl.com/y5oz33kf
During the last decade, great strides have been made to improve the conversion efficiency, zT, of bulk thermoelectric materials by nanostructuring to reduce the lattice thermal conductivity, to promote energy filtering and to introduce composition modulation doping. Multiphase nanostructured materials exhibit invariably higher thermoelectric efficiency than those of their constituent phases, which cannot be explained by the models that associate the physical properties of a composite to the physical properties of the individual components thereof.
We have employed advance high-resolution microscopy including HR-TEM and 3D atom probe tomography and high temperature neutron diffraction scattering techniques to correlate the chemical composition of individual phases to the transport properties of multiphase thermoelectric materials. The precipitation of secondary phases with higher concentration of dopants within the matrix act as reservoirs for dopants, minimising the diffusion distances for elements and provide the charge carrier modulated doped structure.
We also report the evolution of the microstructure at various stages of thermal aging at operating temperatures of the device. These findings can lead to further advances in designing thermally stable multiphase thermoelectric materials.