Their calculations showed that the rigid band approach was actually more accurate than the supercell method in predicting the observed properties of a popular thermoelectric - lead telluride
- doped with a small amount of sodium, potassium or thallium.
The new material, based on the common semiconductor lead telluride
, is the most efficient thermoelectric material known.
Extending their work on lead-based dots, the NREL researchers report in the March 15 Journal of the American Chemical Society that lead telluride
dots produce up to three excitons from single solar-energy photons.
To make this possible, the team dispersed nanocrystals of rock salt (SrTe) into the material lead telluride
To make the lattice, Springholz and his colleagues lay down alternating layers of lead telluride
sheets and arrays of pyramid-shaped dots of lead selenide.
Besides bismuth telluride, two other materials and their associated derivatives came to the forefront during those early research years: lead telluride
and silicon-germanium alloys.