Influence of Heat Treatment on Surface, Structural and Optical Properties of Nickel and Copper Phthalocyanines Thin Films

The work presents the effect of annealing on the change of polycrystalline alpha and beta 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 alpha form than for the beta form. The intensity of this band is related to changing the form of phthalocyanine from alpha to beta. 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.