Electronic structure of oxide and halide perovskites

Abstract

Compounds crystallizing in the ABX3 perovskite structure are studied for a remarkable variety of technologies. Particularly for applications such as photovoltaics and photocatalysis, it is crucial to understand the key features of perovskite electronic structure and how they can be tuned by modifying the composition and crystal structure. This chapter begins with an overview of the compositional and structural diversity of perovskites. Then, density functional theory-based computational methods that have been used to study perovskite compounds are described. Next, the electronic band structures of an undistorted oxide (SrTiO3) and halide (CsPbI3) perovskite are explained in detail, merging the viewpoints of crystal wavefunctions as both linear combinations of atomic orbitals and perturbed plane waves. Finally, routes toward the tunability of perovskite electronic structure and properties are reviewed for various modifications: changes in elemental composition, various modes of geometric distortion, the application of high pressure or strain, and the formation of superstructures with reduced dimensionality. While the concepts and discussion herein are relevant to all perovskite compounds, the examples described in this chapter are mainly d0 oxide perovskite photocatalysts and halide perovskite photovoltaics.