Abstract
Recent, and somewhat surprising, successful n-type doping of Mg3Sb2 was the key to realizing high thermoelectric performance in this material. Herein, we use first-principles defect calculations to investigate different extrinsic n-type doping strategies for Mg3Sb2 and to reveal general chemical trends in terms of dopant solubilities and maximal achievable electron concentrations. In agreement with experiments, we find that Sb substitution is an effective doping strategy, with Se and Te doping predicted to yield up to ∼8 × 1019 cm-3 electrons. However, we also find that Mg substitution with trivalent (or higher) cations can be even more effective; in particular, the predicted highest achievable electron concentration (∼5 × 1020 cm-3) with La as an extrinsic dopant exceeds that of Se and Te doping. Interstitial doping (Li, Zn, Cu, Be) is found to be largely ineffective either due to self-compensation (Li) or high formation energy (Zn, Cu, Be).
Original language | English |
---|---|
Pages (from-to) | 13806-13815 |
Number of pages | 10 |
Journal | Journal of Materials Chemistry A |
Volume | 6 |
Issue number | 28 |
DOIs | |
State | Published - 2018 |
Externally published | Yes |
Funding
We thank G. Jeffrey Snyder for fruitful discussions. We acknowledge support from NSF DMR program, grant no. 1729594. The research was performed using computational resources sponsored by the Department of Energy's Office of Energy Efficiency and Renewable Energy and located at the NREL.