The unoccupied electronic structure of potassium doped copper phthalocyanine studied by near edge absorption fine structure

The unoccupied electronic structure of potassium doped copper-phthalocyanine thin films has been studied using x-ray absorption spectroscopy. The data reveal filling of the lowest unoccupied molecular orbital upon doping and related changes of the core level absorption spectra. The spectral changes can be rationalized taking into account the core level binding energies which also depend on doping.