A framework for optimizing oxygen vacancy formation in doped perovskites

Perovskite materials are being considered for a variety of applications due to their demonstrated capacity to rapidly transport lattice oxygen. Importantly, controlling the dopant concentration in the perovskite lattice has been shown to tune the oxygen vacancy formation energy, an important descriptor for oxygen ion diffusivity. In this work, we utilize BaFe1-xInxO3-delta as a model perovskite for investigating the role that atomic-scale patterns of substitutional doping at the B site has on the formation of oxygen vacancies. Using this model material, we demonstrate a framework for evaluating the atomic-scale properties of possible dopant motifs exhibited within a doped perovskite lattice. For each relevant motif, we calculate via density functional theory the oxygen excess energy, which is a robust descriptor for evaluating the bulk oxide ion diffusion. We then formulate and solve a mathematical optimization model to identify patterns of dopant placement that yield materials with desirable properties. These results provide optimistic targets for material performance and may inform future material synthesis efforts. (C) 2019 Elsevier Ltd. All rights reserved.