Photoinduced Charge Separation in Donor-Acceptor Systems Sensitized by Platinum Porphyrin

Abstract

Photoinduced charge transfer is one of the important processes for the conversion of solar energy into chemical and/or electric energies. Recently, various studies including multi-step electron transfer processes have investigated. However, these systems do not always exhibit efficient, long-lived CS states. One of the most promising strategies to obtain long-lived CS states seems to be a spin control approach. Here, we report on photoinduced charge-separation of a Pt-porphyrin-viologen dyad and a triphenylamine-Pt-porphyrin-naphthalenediimide triad. In these complexes, the Pt-porphyrin moiety acts as a triplet photosensitizer. The transient absorption spectra in nano-second laser flash photolysis exhibited absorption bands assignable to the donor radical cation and the acceptor radical anion, indicating the generation of the CS states with relatively long lifetime.