Electronic structure of thiophenes and phtalocyanines

The results of x-ray fluorescence measurements of thiophenes [regioregular poly (3-hexylthiophene (P3HT) and alpha,omega -dihexylquaterthiophene (DH alpha 4T)] and phtalocyanines [copper phtalocyanine (CuPc) and copper hexadecafluorophtalocyanine (F16CuPc)] are presented. Experimental carbon, nitrogen, fluorine K alpha and sulphur, copper L-2,L-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 K alpha emission is almost identical for P3HT and DH alpha 4T. This indicates that the electronic structure of the pi system is not affected by the presence of the side group. The ratio of emission intensities of the Cu L-2 to Cu L-3 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.