Electronic properties of potassium-doped CuPc

We have studied the electronic structure of potassium-doped copper phthalocyanine (CuPc) using photoemission spectroscopy. A detailed analysis of the core-level spectra allows us to propose possible lattice sites for the potassium ions. None of the films prepared in our studies showed a finite electronic density of states at the Fermi level ( E F ) , which is in contrast to reports in the literature. Possible reasons for this discrepancy are discussed.