Morphology determination of functional poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene]/poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] blends as used for all‐polymer solar cells

Poly[2‐methoxy‐5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (MDMO‐PPV) blended with poly[oxa‐1,4‐phenylene‐1,2‐(1‐cyanovinylene)‐2‐methoxy,5‐(3,7‐dimethyloctyloxy)‐1,4‐phenylene‐1,2‐(2‐cyanovinylene)‐1,4‐phenylene] (PCNEPV) has been used as the active layer for an all‐polymer photovoltaic cell. The photovoltaic performance of devices is improved by a thermal treatment, which alters the morphology of the active layer. The morphology of the MDMO‐PPV/PCNEPV blend has been studied with conventional transmission electron microscopy and energy‐filtered transmission electron microscopy based on electron energy loss spectroscopy. The nitrogen of the cyano group within the PCNEPV has been be detected, and two‐dimensional nitrogen distribution maps have been acquired. Nitrogen‐rich domains have a size of approximately 20–50 nm and are homogeneously distributed over the entire film.