The authors of this work propose a model with an adequate description of variations in the electronic properties of the structures and a complex distribution of the electron density, including the dielectric films, on the surface of the substrate. The authors determined the dependence of the ionization of the zinc phthalocyanine potential, deposited on the substrate, on the parameters. The authors varied the distances to the substrate and the dielectric constant of the material, and demonstrated that in the presence of the substrate the potential of ionization decreased by 1 eV.