Porphyrin–fullerene dyad with a long linker: formation of charge transfer conformer in Langmuir–Blodgett film

A porphyrin–fullerene covalently linked dyad is studied in solutions and Langmuir–Blodgett (LB) films. The dyad is characterized by a relatively long linker. In benzonitrile, it performs a relatively slow photo-induced electron transfer (ET), kET≈5×108 s−1. Being incorporated in an LB film the dyad forms a compact conformer, which takes the smallest surface area. For this conformer the donor–acceptor separation is much shorter as compared with that in liquid phases and the molecule perform a fast photo-induced ET, kET≈8×109 s−1. The LB films were studied using time-resolved measurements of fluorescence, absorption, and Maxwell displacement charge.