Magnetic-Field-Induced Modulation of Charge-Recombination Dynamics in a Rosarin-Fullerene Complex

Charge-recombination processes are critical for photovoltaic applications and should be suppressed for efficient charge transport. Here, we report that an applied magnetic field (0-1 T) can be used control the charge-recombination dynamics in an expanded rosarin-C-60 complex. In the low magnetic field regime (<100 mT), the charge-recombination rate slows down due to hyperfine coupling, as inferred from transient absorption spectroscopic analyses. In contrast, in the high field regime, i.e., over 500 mT, the charge-recombination rate recovers and increases because the Delta g mechanism facilitates spin conversion to a triplet charge-separated state (S to T-0) that undergoes rapid charge-recombination to a localized rosarin triplet state. Therefore, we highlight the charge-recombination rate and the localized triplet state population can be modulated by the magnetic field in charge donor/acceptor non-covalent complexes.

Automated summary

The charge-recombination rate and the population of localized triplet states can be modulated by an applied magnetic field in charge donor/acceptor non-covalent complexes. In low magnetic field regime, the rate slows down due to hyperfine coupling, while in high field regime, the rate recovers and increases due to the Delta g mechanism facilitating spin conversion.