Direct observation of intra-molecular energy migration in σ-conjugated polymer by femto-second laser flash photolysis

A direct observation of energy migration processes in σ-conjugated polymers has been firstly done to a very large extent by ultra-fast transient absorption spectroscopy in near infrared (IR) region. Especially, following new results were obtained: (1) The very broad transient absorption due to excited states in various conjugated segments immediately after 266-nm excitation; (2) The shift from the very broad absorption toward the absorption with the maximum at 0.95 eV; (3) Decrease in energetic dispersion of excited states with observation time; (4) Some excited states remain in shorter conjugated segments than the radiative segments associated with the absorption maximum at 0.95 eV.