Understanding the effects of iodine doping on the thermoelectric performance of n-type PbTe ingot materials

The superior performance of p-type PbTe has generated excitement toward discovering an n-type PbTe recipe to meet the manufacturing requirements for thermoelectric devices. PbI2 is a well-known dopant for n-type PbTe alloys fabrication. For the halogen family, the sintering process involves a common densifying strategy used to reduce the lattice thermal conductivity, which unfortunately causes strong deviations from nominal composition. Thus, to precisely determine the effects of iodine on PbTe's electrical properties, PbI2-doped ingots were fabricated and characterized in this work. We found that the ingot samples exhibited high electrical conductivity, high power factors, and low lattice thermal conductivity when x equaled 0.004 and 0.005, especially at low temperatures, which was comparable with previous reports.