Methodological Issues in First-Principle Calculations of CH₃NH₃PbI₃ Perovskite Surfaces: Quantum Confinement and Thermal Motion

Abstract

-terminated slab has in-gap surface states, which are independent of the thickness of the slab and also of the orientation of the cation on the surface. The surface states are not useful for alignments in photovoltaic devices, while they could be useful for photocatalytic reactions. The energy levels calculated for the MAI-terminated surface coincide with the widely used values to estimate the MAPI alignment with the charge transport materials, i.e., -5.4 and -3.9 eV for valence band maximum and conduction band minimum, respectively. Our study offers these slab models to provide guidelines for optimal interface engineering.