High wide-temperature-range thermoelectric performance in n-PbSe integrated with quantum dots

Abstract

PbSe has attracted much attention due to the earth-abundant element Se and low cost. Herein, we present a peak ZT value of 1.44 and an average ZT value of approximately 1.0 in n-type PbSe achieved through Sb doping and introducing excess Cu. A high density of Cu-rich quantum dots was introduced into PbSe through introducing excess Cu, which is revealed by TEM observations. These Cu-rich quantum dots greatly strengthen phonon scattering and contribute to a decrease in the lattice thermal conductivity. Furthermore, the effective mass of the density of states in PbSe is raised by Cu-rich quantum dots, maintaining a moderate Seebeck coefficient. Sb doping and excess Cu substantially increase the carrier concentration, maintaining a high power factor throughout the entire temperature range. For thermoelectric applications at intermediate temperatures, the Pb_0.9875Sb_0.0125Cu_0.0125Se_0.99Te_0.01 material that has been reported is a great tellurium-free option. These findings provide new avenues for realizing high performance in PbSe through involving quantum dots by a phase separation strategy.