Ultrafast photoinduced processes in organic dyads

Abstract

Photoinduced ultrafast processes were studied in a variety of organic dyads. The peculiarity of photochemistry and photophysics occurring on the ultrafast timescale is that conventional rules may not apply. A multidisciplinary approach, which included a variety of UV/VIS spectroscopic methods, laser optics and computational chemistry, was used in this work. Electron transfer reactions, in particular photoinduced symmetry-breaking charge separation, which is a key step in photosynthesis, were of the main interest. Two symmetric dyads were studied and for the first time the direction of the charge flow, i.e. whether the photoexcited moiety acts as an electron donor or acceptor, was unambiguously determined. This study was extended to asymmetric dyads and to the intermolecular electron transfer reactions between the dyads and an electron donor. Additionally, the development of a four-wave mixing set-up that allows study of solvation dynamics is also presented.