Speaker: Anam Fatima, Université Paris-Saclay
Program Description:
Understanding the mechanism of the relaxation pathways upon photoexcitation is a decisive step for improving photoactive systems toward applications in solar energy conversion. In this context, our work provides fundamental insights into the complex photophysical processes (inter- or intramolecular electron, energy and/or proton-coupled electron transfer, vibrational cooling, etc.) in organic and inorganic photosensitizers coupled with electron acceptors or photocatalytic platforms depending on their potential applications in photovoltaics or artificial photosynthesis (Figure). On the one hand, we studied intramolecular photoinduced electron/or energy transfer processes within all organic [BODIPY]boron-dipyrromethene-[C60]fullerene- based covalently-linked donor-acceptor systems1,2. On the other hand, we investigated excited state dynamics of a new class of noble-metal-free inorganic photosensitizers (i.e., metal halide clusters) in combination with different polyoxometalates (POMs) as photocatalytic platforms3. Moreover, combining the best of the two; covalently linked organic-inorganic hybrid systems that utilize the electron affinity of the POM for catalytic purposes while using the organic residue (e.g., BODIPY) as a photosensitizer were photophysically investigated. Fast and ultrafast time-resolved spectroscopic methods, including femtosecond and nanosecond time- scale pump-probe optical transient absorption, picosecond time-scale time-correlated single photon counting, and time-resolved emission allowed the monitoring of different photoinduced processes within these complex photoactive systems in solution. The charge separation and relaxation dynamics within these donor-acceptor systems are particularly interesting for the development of artificial light-conversion devices.
Figure: Photoinduced electron and energy transfer processes within (A) all organic BODIPY- C60 based triad, (B) all inorganic metal halide cluster and POM system, (C) organic-inorganic BODIPY-POM hybrid
1 A. Fatima et al., Photochem. Photobiol. Sci., 2022, 21, 9, 1573-1584
2 A. Fatima et al., Eur. Phys. J. Spec. Top., 2022, published online
3. A.Fatima et al., Submitted to Chem. Comm, November 2022
