Electronic structure of thiophenes and phtalocyanines

The results of x-ray fluorescence measurements of thiophenes [regioregular poly (3-hexylthiophene (P3HT) and {α},{ω}-dihexylquaterthiophene (DH{α}4T)] and phtalocyanines [copper phtalocyanine (CuPc) and copper hexadecafluorophtalocyanine (F₁₆CuPc)] are presented. Experimental carbon, nitrogen, fluorine Kα and sulphur, copper L2,3 x-ray emission spectra are compared with ultraviolet photoemission spectroscopy spectra and deMon density-functional theory calculations of model molecules. We find that the carbon Kα emission is almost identical for P3HT and DH{α}4T. This indicates that the electronic structure of the {π} system is not affected by the presence of the side group. The ratio of emission intensities of the Cu L₂ to Cu L₃ intensities is found to be smaller by a factor of 2 for CuPc and F₁₆CuPc than it is for pure metal. This demonstrates the strong covalency in phalocyanines.