Non-equilibrium effects in ultrafast photoinduced charge transfer kinetics

Publication date: Available online 22 November 2016 Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews Author(s): Serguei V. Feskov, Valentina A. Mikhailova, Anatoly I. Ivanov Modern laser-based spectroscopy has provided methods for detection ultrafast photochemical transformations occurring on the timescale of intramolecular and solvent reorganization. Such processes usually proceed in non-equilibrium regime, in parallel with nuclear relaxation, and often manifest strong deviations from the Kasha-Vavilov rule. In particular, they offer a possibility to control the yield of photoinduced electron transfer (ET) by using different excitation wavelengths. In the last decade the non-equilibrium charge transfer (CT) processes have attracted considerable interest from the scientific community due to their determining role in photosynthesis, dye-sensitized solar cells and various molecular electronic devices. Non-equilibrium of nuclear (intramolecular and solvent) degrees of freedom can be created by a pump pulse or by photoreaction itself at some of its stages. In this review both situations are considered and illustrated by examples in which non-equilibrium effects are pronounced. It is shown that ultrafast charge recombination in photoexcited donor-acceptor complexes and photochemical processes in donor–acceptor1–acceptor2 molecular compounds proceed predominantly in non-equilibrium (hot) regime. It is important that kinetics and product yields of...

Source: Journal of Photochemistry and Photobiology C: Photochemistry Reviews - November 21, 2016 Category: Chemistry Source Type: research