Organometal halide perovskite-based solar cells have stormed the world of photovoltaics, demonstrating power conversion efficiencies of over 20% within less than a decade of their existence. The band gap of these perovskites has been shown to be variable based on their phase, as well as the extent of compression or extension of the perovskite cage.  The understanding and control of perovskite structure is therefore key to solar cell performance.
Here, we present a systematic study on ABX3 perovskites using density functional theory, evaluating the accuracy of methodologies for band gap prediction. We demonstrate the change in electronic properties with changing lattice parameters and halogen substitutions in ABX3 perovskites. Moreover, we highlight the effects of A-X bond lengths and octahedral tilting on the electronic properties of these perovskites. By developing a systematic description of key structure-property relationships for these materials, we provide mechanistic insight and hope to contribute to future materials design principles.
 Huang, L. Y., and Lambrecht, W. R. Electronic band structure, phonons, and exciton binding energies of halide perovskites CsSnCl3, CsSnBr3, and CsSnI3. Phys. Rev. B, 88(16), 165203, 2013.