(Invited) Donor-Acceptor Systems from Triplet Photosensitizers for High Potential, Long-Lived Charge Separation

摘要

Generation of high potential, long-lived charge separated states in donor-acceptor systems are invaluable for converting light energy into either electricity or fuels. The majority of the donor-acceptor conjugates designed for this purpose are derived mainly from short-lived singlet sensitizers. In such conjugates, charge separation from the singlet excited donor or acceptor results in a short-lived charge separated state of singlet spin character. Alternatively, by utilizing high-energy triplet sensitizers one could generate long-lived charge separated states. The radical ion-pairs of triplet spin character slowly charge recombine to the ground state due to spin forbidden process. However, witnessing such a process purely from the triplet-excited state without the interference of the singlet excited state and other competing photochemical events such as excitation energy transfer has been challenging to establish.