Reduced bimolecular recombination in conjugated polymer donor/fullerene acceptor bulk heterojunction solar cells
We show significantly reduced bimolecular recombination in a novel silole-based copolymer (KP115):fullerene blend, which allows the fabrication of polymer solar cells with relatively thick active layers. This leads to improved device efficiencies and makes roll-to-roll printing much easier. The origin of the reduced recombination, however, is not known. Our recent data suggest that published models are inadequate to explain this phenomenon.