Phonon-glass electron-crystal behaviour by A site disorder in n-type thermoelectric oxides†
Phonon-glass electron-crystal (PGEC) behaviour is realised in La0.5Na0.5Ti1−xNbxO3 thermoelectric oxides. The vibrational disorder imposed by the presence of both La3+ and Na+ cations on the A site of the ABO3 perovskite oxide La0.5Na0.5TiO3 produces a phonon-glass with a thermal conductivity, κ, 80% lower than that of SrTiO3 at room temperature. Unlike other state-of-the-art thermoelectric oxides, where there is strong coupling of κ to the electronic power factor, the electronic transport of these materials can be optimised independently of the thermal transport through cation substitution at the octahedral B site. The low κ of the phonon-glass parent is retained across the La0.5Na0.5Ti1−xNbxO3 series without disrupting the electronic conductivity, affording PGEC behaviour in oxides.
- This article is part of the themed collection: 2017 Energy and Environmental Science HOT articles