New materials to generate electricity from heat

Thermoelectric materials offer ways to transform heat to electrical energy and vice versa. Here, the authors tailor the architecture of a bulk thermoelectric material, the semiconductor lead telluride, to maximize thermoelectric performance. They achieve phonon scattering on three different length scales. Atomic-scale doping, nanometer-scale endotaxial precipitation and mesoscale grain-boundary structures were introduced to the material to drastically reduce its thermal conductivity and subsequently achieve a very high thermoelectric figure of merit. These advances could aid in the design of advanced thermoelectric materials that can be used to recover waste heat.