ScienceDaily: Photovoltaic cells directly convert sun light into electricity and hence are key technological devices to meet one of the challenges that humankind has to face in this century: a sustainable and clean production of renewable energy. Organic solar cells, using polymeric materials to capture sun light, have particularly favorable properties. They are low-cost, light-weight and flexible, and their color can be adapted by varying the material composition. Such solar cells typically consist of nanostructured...