Trapping heat

The promise of nanotechnology again! Researchers at Northwestern University have placed nanocrystals of rock salt into lead telluride, creating a material that can harness electricity from heat-generating items such as vehicle exhaust systems, industrial processes and equipment and sun light more efficiently than scientists have seen in the past. The automotive, chemical, brick, glass and any industry that uses heat to make products could make their system more efficient with the use of this scientific breakthrough.

The material exhibits a high thermoelectric figure of merit that is expected to enable 14 percent of heat waste to electricity, a scientific first. Chemists, physicists and material scientists at Northwestern collaborated to develop the material. The results of the study are published by the journal Nature Chemistry.

The new material was obtained by dispersing nanocrystals of rock salt (SrTe) into the material lead telluride (PbTe). Past attempts at this kind of nanoscale inclusion in bulk material have improved the energy conversion efficiency of lead telluride, but the nano inclusions also increased the scattering of electrons, which reduced overall conductivity.

This is the first time nanostructures were used in lead telluride to reduce electron scattering and increase the energy conversion efficiency of the material.