The work presents the effect of annealing on the change of polycrystalline α and β phases of copper and nickel phthalocyanines. We have found that this process has a great influence on the optical properties of the vapor-deposited layers. The performed measurements showed that for various forms of MPc, the values of the refractive index and the extinction coefficient increased, and consequently, so did the absorption coefficient. The AFM images taken showed that the values before and after heating are morphologically different. Raman measurements showed that the band at about 1526 cm⁻¹ (B1g symmetry) has higher intensity for the α form than for the β form. The intensity of this band is related to changing the form of phthalocyanine from α to β. Our measurements have shown that by changing the annealing temperature of the layers, we change their optical properties. As a consequence, we change their optoelectronic parameters, adjusting them to the requirements of new optoelectronic devices, such as solar cells, sensors, displays and OLEDs.

Two macrocyclic Schiff bases derived from o-phenylenediamine and 2-hydroxy-5-methylisophthalaldehyde L1 or 2-hydroxy-5-tert-butyl-1,3-benzenedicarboxaldehyde L2, respectively, were obtained and characterized by X-ray crystallography and spectroscopy (UV-vis, fluorescence and IR). X-ray crystal structure determination and DFT calculations for compounds confirmed their geometry in solution and in the solid phase. Moreover, intermolecular interactions in the crystal structure of L1 and L2 were analyzed using 3D Hirshfeld surfaces and the related 2D fingerprint plots. The 3D Hirschfeld analyses show that the most numerous interactions were found between hydrogen atoms. A considerable number of such interactions are justified by the presence of bulk tert-butyl groups in L2. The luminescence of L1 and L2 in various solvents and in the solid state was studied. In general, the quantum efficiency between 0.14 and 0.70 was noted. The increase in the quantum efficiency with the solvent polarity in the case of L1 was observed (λ_ex = 350 nm). For L2, this trend is similar, except for the chloroform. In the solid state, emission was registered at 552 nm and 561 nm (λ_ex = 350 nm) for L1 and L2, respectively. Thin layers of the studied compounds were deposited on Si(111) by the spin coating method or by thermal vapor deposition and studied by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM), spectroscopic ellipsometry and fluorescence spectroscopy. The ellipsometric analysis of thin materials obtained by thermal vapor deposition showed that the band-gap energy was 3.45 ± 0.02 eV (359 ± 2 nm) and 3.29 ± 0.02 eV (377 ± 2 nm) for L1/Si and L2/Si samples, respectively. Furthermore, the materials of the L1/Si and L2/Si exhibited broad emission. This feature can allow for using these compounds in LED diodes.