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

The effects of rare-earth element impurities Ce and Pr on the electronic structure and thermoelectric properties of beta-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 beta-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. (C) 2013 Elsevier B. V. All rights reserved.