Structures and lattice dynamics of thermoelectric nanocrystals
The creation of new thermoelectric materials offers ecological solutions to a number of key issues in energy efficiency, and will make an important contribution to the low-carbon economy of the 21st century. For example, they enable the conversion of waste heat into useful power in car exhausts, and the cooling of hot spots on computer chips using solid state refrigerators.
Thermoelectrics have conflicting materials requirements, such as high electrical conductivity and low thermal conductivity. We have previously shown how rattling ions suppress the thermal conductivity in thermoelectric oxides [D.J. Voneshen et al., Nature Materials 12, 1028 (2013)]. We now wish to apply these methods to understand how nanostructuring and doping improve thermoelectric performance in simple oxides by more than one order of magnitude.
Defect structures and nanostructures will be determined by diffraction techniques at neutron facilities and synchrotrons. The lattice dynamics will be determined using inelastic neutron and x-ray scattering. First-principles density-functional calculations will be performed in order to model the experimental data and understand the effects on the parameters of thermoelectric importance: the electrical and thermal conductivity.