Tuning excited-state reactivity of Iron-based photosensitizers for solar fuels formation

Due to its high abundance, low cost and low toxicity, photosensitizers based on iron have long been considered as the holy grail for photochemical applications. Unfortunately, with a few exceptions, these photosensitizers suffer from extremely short, sub-nanosecond, excited-state lifetimes that limit diffusional reactivity.

Previous work from our group has shown that this limitation can be circumvented to achieve efficient excited-state electron transfer with large cage-escape yields using green light irradiation. These results, and other related to the process of cage escape yields will be presented, with a special emphasis placed of solar fuels formation from halide oxidation.

Finally, I will present an innovative approach that used iron complexes to populate the dark state of an energy acceptor that lives for greater than 10 microseconds. This approach not only allows to improve the excited state lifetime but also leads to a 10-fold increase in cage escape yields compared to prototypical iron photosensitizers.