Heterostructured Approaches to Efficient Thermoelectric Materials

A key challenge for the materials chemist is the development of controllable and straightforward synthetic methodologies that will integrate multiple phases/compositions with scalar designed physical properties. The intent of this Perspective is to give a brief summary of some of the current bulk-scaled approaches that might help guide researchers in the design of optimal heterostructures in large quantity for the further improvement of thermoelectric conversion efficiency. Examples of two-phase combinations on different length scales will be discussed with a focus on the hot carrier filtering effect that results from the selective scattering of carriers with different energies. On the basis of this strategy, heterostructures fabricated by both the bottom-up solution approaches at low temperature and top-down solid-state deposition routes that show promise in improving the thermoelectric figure of merit are highlighted.