Electrical and thermal transport properties of Pb-based chalcogenides: PbTe, PbSe, and PbS

Electrical and thermal transport properties of lead-based chalcogenides (PbTe, PbSe, and PbS) were studied with special emphasis on the lattice and the bipolar thermal conductivity. Both electrical resistivity and Seebeck coefficient show the transport behaviors related to the intrinsic excitation that determined by the band gap, power factors at room temperature reach 12 μW cm ^-1 K ^-2, 14 μW cm ^-1 K ^-2, and 16 μW cm ^-1 K ^-2 for PbS, PbSe and PbTe, respectively. PbTe shows the lowest total thermal conductivity, and PbS shows the highest total thermal conductivity, in which the bipolar thermal conductivity is proportional to the width of band gap, these contributions at 723 K were estimated to be 2.2%, 3.1%, and 1.1% for the PbTe, PbSe and PbS, respectively. This study demonstrates the possibility to enhance ZT value by the suppression of bipolar thermal conductivity by tuning the width of band gap, also indicates that inexpensive and earth-abundant PbSe and PbS would be promising alternative for PbTe in the thermoelectric applications.