Contrasting photodynamics between C₆₀-dithiapyrene and C ₆₀-pyrene dyads

The photodynamics of a C₆₀-dithiapyrene donor-acceptor conjugate were compared with the corresponding Cftirpyrene conjugate. The photoinduced charge separation and subsequent charge recombination processes were examined by time-resolved fluorescence measurements on the picosecond timescale and transient absorption measurements on the picosecond and microsecond timescales with detection in the visible and near-infrared regions. We have observed quite long lifetimes (i.e., up to 1.01 ns) for the photogenerated charge-separated state in a C₆₀-dithiapyrene dyad without the need for i) a long spacer between the two moieties, or ii) a gain in aromaticity in the radical ion pair.