Ultrafast Excimer Formation and Solvent Controlled Symmetry Breaking Charge Separation in the Excitonically Coupled Subphthalocyanine Dimer

Knowledge of the factors controlling excited state dynamics in excitonically coupled dimers and higher aggregates is critical for understanding natural artificial solar energy conversion. In this work, we report ultrafast solvent polarity dependent structurally well-defined subphthalocyanine dimer, ?-OSubPc2. Stationary electronic spectra demonstrate strong exciton coupling Femtosecond transient absorption measurements reveal excimer formation from initially exciton, mediated by intramolecular structural evolution. polar solvents decays directly through symmetry breaking charge transfer to form a separated state. Charge separation occurs under control orientational relaxation.