Morphology of All-Solution-Processed Bilayer Organic Solar Cells

We investigate the evolution of the vertical morphology in a solution-processed P3HT/PCBM bilayer organic solar cell using a combination of techniques, including neutron reflectometry. By correlating the device performance with the active layer morphology, we establish that the solution-processed bilayer concept is a misnomer and sequential solution processing is an elegant way to make bulk heterojunction organic solar cells with high efficiency.