Ultrafast Excited-State Dynamics of a Porphyrin–OPE Conjugate: Energy Transfer and Aggregation Effects

Understanding the ultrafast dynamics of porphyrin-based conjugates is crucial for their applications in areas such as photovoltaics, molecular electronics, and biocompatible technologies. In this study, we investigate the excited-state dynamics of a porphyrin-oligo-(phenylene ethynylene) (OPE) conjugate with β-d-glucoside termination using femtosecond transient absorption spectroscopy in both monomeric and aggregated states. Our findings reveal that in the monomeric form, rapid energy transfer (200 ps) from the OPE unit to the porphyrin core occurs. When aggregation is induced, we observe a significant shortening of the relaxation dynamics, suggesting that the new supramolecular interactions at play strongly influence the overall photophysical behavior of the system, potentially allowing for effective control of the energy transfer processes.