Electronic structure in thin film organic semiconductors studied using soft X-ray emission and resonant inelastic X-ray scattering

The electronic structure of thin films of the organic semiconductors copper and vanadyl (VO) phthalocyanine (Pc) has been measured using resonant soft X-ray emission spectroscopy and resonant inelastic X-ray scattering. For Cu–Pc we report the observation of two discrete states near EF. This differs from published photoemission results, but is in excellent agreement with density functional calculations. For VO–Pc, the vanadyl species is shown to be highly localized. Both dipole forbidden V 3d to V 3d*, and O 2p to V 3d* charge transfer transitions are observed, and explained in a local molecular orbital model.