Fast and Ultrafast Time-Resolved Studies on Photoactive Systems for Clean Energy Applications

Wednesday, November 23, 2022 - 10:00am

SpeakerAnam 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 

Fast and Ultrafast Time-Resolved Studies on Photoactive Systems for Clean Energy Applications
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