Photoinduced Electron Transfer in Sexithiophene/Fullerene Derivative Blends: Evidence of Spin Correlated Radical Pairs by Transient Epr Spectroscopy.

Through photoinduced electron transfer well-designed supramolecular donor-acceptor systems have led to efficient and long lived charge-separated states suitable to study natural photosynthesis and useful for photovoltaic devices. Here, we report the first successful observation of spin-correlated radical ion pairs in sexithiophene/fullerene derivatives blends. The system allows the determination of the distance of the reaction centers, as well as of the spin relaxation and decay times that govern the pair dynamics by using Transient EPR spectroscopy.