Fluidic Molecular Dynamics and Energy Relaxation Pathways in Solution-State Electronic Strong Coupling Using a...

Light-matter strong coupling (SC) has shown great potential for controlling the photophysical dynamics of molecules in recent years. Although various molecules have been used to study the laser-induced ultrafast dynamics under electronic strong coupling (ESC), nearly all measurements investigated solid molecular samples, while the impact of hybridized light-matter states on liquid phase molecular dynamics has been unexplored. Here, for the first time, we report the ultrafast dynamics of liquid-state molecules under ESC. Our transient absorption spectroscopy studies reveal the emergence of a fast decay component in liquid-state ESC, which cannot be observed in the same liquid system without a cavity. Furthermore, the depolarization kinetics is found to be accelerated, as revealed by resonant optical Kerr-effect (ROKE) spectroscopy, suggesting that energy migration occurs much faster than both the polariton lifetime and molecular rotational time constants. These findings offer critical insights into designing photochemical systems in the liquid state based on the photophysical properties of the strongly coupled molecules.