Transient absorption and time resolved fluorescence – the techniques for investigation of the excited state dynamics of organic molecules from femtoseconds to milliseconds timespan
Stanislav Stanimirov
Abstract
Unraveling Excited State Dynamics of Organic Molecules Across the Femtosecond to Millisecond Timescale.
Understanding the intricate photophysics of organic molecules hinges on the ability to probe their excited state behavior across a vast temporal landscape. This presentation will delve into two powerful laser-based spectroscopic techniques – transient absorption (TA) and time-resolved fluorescence (TRF) – and their synergistic application in elucidating excited state dynamics spanning from ultrafast femtosecond processes to slower millisecond phenomena.
We will explore the fundamental principles behind each technique, highlighting their unique capabilities and limitations in capturing different aspects of excited state evolution. TA spectroscopy, with its sensitivity to all photo-induced species, provides a comprehensive picture of population dynamics, including singlet and triplet states, as well as transient intermediates. Conversely, TRF spectroscopy offers direct insight into the radiative decay pathways and the lifetimes of emissive excited states.
Through illustrative examples, we will demonstrate how the combined use of TA and TRF can provide a holistic understanding of photophysical processes in organic molecules. This includes investigating ultrafast excited state relaxation pathways, intramolecular and intermolecular energy transfer mechanisms, photochemical reactions, and the influence of the surrounding environment on excited state lifetimes and dynamics. The presentation will also touch upon recent advancements and applications of these techniques in diverse field such as organic light emitting diodes.
Stanislav Stefanov Stanimirov is a Doctor and holds the position of Associate Professor at Sofia University “St. Kliment Ohridski”, Faculty of Chemistry and Pharmacy, Department of Organic Chemistry and Pharmacognosy. His education includes a Ph.D. from Sofia University in Organic Photochemistry, obtained in 2009. In the last five years, he has held the position of Senior Assistant until 2021 and has been an Associate Professor since 2021. His primary research areas are Organic Chemistry, Organic Photochemistry, UV-Vis-NIR Spectroscopy, and Transient Absorption, with additional research interests in Molecular Kinetics and Molecular Dynamics. He has also been involved in international collaborations and specializations, including visits to Boston College in the USA (2009), the Max Planck Institute for Polymers in Mainz, Germany (2010-2012, 2014), and the University of Swansea in the UK (2018). His research work includes 23 scientific publications, with 22 of them having an impact factor or impact rank. He has an h-index of 8, and his publications have received 206 citations.
