Enhanced thermoelectric performance with participation of F-electrons in β-Zn4Sb3

Abstract

The effects of rare-earth element impurities Ce and Pr on the electronic structure and thermoelectric properties of β-Zn4Sb3 were investigated by performing self-consistent ab initio electronic structure calculations within density functional theory and solving the Boltzmann transport equations within the relaxation time approximation. The results demonstrated that these rare-earth element impurities with f orbitals could introduce giant sharp resonant peaks in the density of states (DOS) near the host valence band maximum in energy. And these deliberately engineered DOS peaks result in a sharp increase of the room-temperature Seebeck coefficient and power factor from those of impurity-free system by a factor of 100 and 22, respectively. Additionally, with the simultaneous declining of carrier thermal conductivity, a potential 5-fold increase at least with Ce doping and more than 3 times increase with Pr doping in the thermoelectric figure of merit of β-Zn4Sb3 at room temperature are achieved. The effective DOS restructuring strategy opens up new opportunities for thermoelectric power generation and waste heat recovery at large scale.