Thermoelectric materials, which can generate electricity from waste heat or be used as solid-state refrigerators, could play an important role in a global sustainable energy solution. Such a development involves identifying materials with a higher thermoelectric efficiency than currently available. This is a major challenge given the conflicting combination of material properties that are required.
The ability of a given material to efficiently produce thermoelectric power is related to its dimensionless figure of merit ZT=σ S2T/ κ, where the thermal conductivity κ has mainly two components: κ = κ electron + κ phonon. For good efficiency a low ratio of κ phonon / κ electron is desired.
In order to optimize the figure of merit, phonons, which are responsible for thermal conductivity must experience a high degree of scattering - lowering thermal conductivity - while electrons must experience very little scattering - maintaining electrical conductivity.
INS measurements allow to directly determine the lattice contribution to the thermal conductivity and so neutron spectroscopy is a primary source of information for studies on thermoelectric materials .
By comparing experimental studies of phonon dispersions and widths with DFT calculations, it is possible to understand the complex physics behind these class of materials to foresee their optimization.
Materials under consideration for thermoelectric device applications, where neutron techniques had a fundamental impact on the understanding of their behaviour, include inorganic clathrates, skutterudites, nanostructured semiconductors, and sodium cobaltates [2,3].
 A. Piovano Inelastic neutron scattering applied to materials for energy EPJ 104, 01006 (2015)
 D. J. Voneshen et al. Nature Materials, 12, 1028 (2013)
 M. M. Koza et al. Nature Materials 7,806 (2008)