We report on the preparation, structural characterization, and device performance of heterojunction bilayer organic solar cells (OSC) prepared via a combination of solution and vacuum processing. For a functioning OSC, the electron donor layer consisting of unsubstituted copper phthalocyanines (CuPc) is prepared via simple solution processing under ambient conditions. The unsubstituted CuPc layer is wet-deposited via spin coating and drying from a trifluoroacetic acid solution. The other layers are formed by established vacuum evaporation. The internal film structure of the OSC is characterized by atomic force microscopy. The absorption and morphology of the CuPc layer are discussed concerning the power current efficiency of the OSC. (c) 2012 Elsevier B.V. All rights reserved.