Optical properties of soluble phthalocyanines

The optical properties of a new group of soluble phthalocyanines (Pc), containing sulpho-,amino- and sulphonamide groups are presented. The optical absorption spectrum consists of two main bands, Q and Soret ones, with maxima at about 600 700 and 350 - 400 nm, respectively, and of a broad optical window with a lower linear absorption at about 500 nm. The oxidation energies for different sulphonamide substituted phthalocyanines were determined using cyclic voltammetry. They ranged from -5.46 to -5x10 eV. Thus, the positions of the LUMO levels are in the region -3.85 to -4.27 eV. The band gap energies were determined from optical absorption spectra, and ranged from 1.69 to 1.75 eV. The thin films, after deposition by spin coating or dipping, were usually amorphous, but they could be converted into crystalline films by thermal treatment, as shown by WARS studies.