Multiple Pathways in the Triplet States Population for a Naphthalenediimide-C 60 Dyad.

The link of an antenna dye with an electron spin converter, in this case naphthalenediimide and C 60 , produces a system with a rich photophysics including the detection of more than one triplet state on the long timescale (tens of μs). Beside the use of optical spectroscopies in the ns and in the fs time scale, we used time-resolved Electron Paramagnetic Resonance (TREPR) to study the system evolution following photoexcitation. TREPR keeps track of the formation path of the triplet states through specific spin polarization patterns observed in the spectra. The flexibility of the linker and solvent polarity play a role in favouring either electron transfer or energy transfer processes.