Organic–organic and metal–organic interfaces are explored. The influence of the morphology of thin films of MEH-phenylene-vinylene oligomer (OPV5):C 60 blends on their photovoltaic characteristics is demonstrated. An interdigitating structure is considered to be favorable for efficient operation. The design of a diblock copolymer for this specific application is discussed. By means of UPS, the electronic energy levels at the interface between OPV5 and gold are assessed. Due to the formation of a dipole layer, the vacuum levels are not aligned and the barrier for charge injection is altered.