Photophysics and Applications in Plastic Solar Cells of Conjugated Polymer/Fullerene Composites

The photovoltaic applications of conjugated polymer/fullerene composites have attracted much attention from the scientific community. The photoinduced electron transfer and other related photophysical processes occurred in the composites are the central issues. Several kinds of conjugated polymers have been synthesized in our laboratory. Studies of their composites with fullerene are reviewed. We observed strong fluorescence quenching of these conjugated polymers on mixing them with C₆₀ in dilute solution. Anion radical species of C₆₀ were observed in ESR measurements as a result of photoinduced charge separation. The quenching constants vary with different conjugated polymers and thus provide a quantum measurement for the interaction between the donor and acceptor. Solar cells have been fabricated from these conjugated polymer/fullerene composites. Energy conversion efficiency up to 1.1% has been achieved.