Halide perovskites are hybrid materials which in recent years have attracted the attention of the scientific community for photovoltaic applications due to their impressive light absorption properties and cheap production techniques. In this scientific work, electro-optical modelling has been employed to shed more light into the properties of these peculiar materials. Equilibrium band diagrams have been obtained for methylammonium lead iodide perovskite deposited on various substrates. The Kelvin probe force microscopy measurements of these devices have been modelled to understand how the band alignment is impacted by illumination. The interaction with charge transport layers has also been considered. Other important aspects concern the study of the presence of doping by bulk and surface defects.