Thermoelectrics is an old field. In 1823, Thomas Seebeck discovered that a voltage drop appears across a sample that has a temperature gradient. This phenomenon provided the basis for thermocouples used for measuring temperature and for thermoelectric power generators. In 1838, Heinrich Lenz placed a drop of water on the junction of metal wires made of bismuth and antimony. Passing an electric current through the junction in one direction caused the water to freeze, and reversing the current cau...

Nanocrystalline Bi2Te3 bulks were synthesized via a nanostructuring method that included steps of ball milling, cold pressing, and sintering. In the temperature range of 325–525 K, nanocrystalline Bi2Te3 bulks exhibit good thermoelectric properties with a peak ZT of 0.94. The experimental results suggest that the partially coherent boundaries allow the maintenance of low grain growth rate and low resistivity. The enhancement of ZT comes from a large reduction in the phonon thermal conducti...