Optical excitations in C60/PPV composites

Charge transfer (CT) and subsequent exciton dissociation are essential for organic donor/acceptor solar cells. We analyze these processes by calculating optical intrachain and CT excitations in a model donor/acceptor system. It is found that the increased electron affinity of low-gap polymers may seriously inhibit the CT efficiency. The consequences for exciton dissociation via tunneling are computed.