Ultrafast dynamics of three novel oligomers with strong two-photon absorption properties

A comparative study of the nonlinear optical properties and ultrafast dynamics of three oligomers were carried out using femtosecond laser spectroscopic techniques. All oligomers showed intense fluorescence emission induced by a two-photon absorption process. Relaxation features with parallel and perpendicular polarization configurations were investigated in a one-color pump-probe experiment at 400 nm. Two relaxation components were assigned to the exciton migration and exciton recombination processes, respectively. Time-resolved fluorescence results showed that the electron-phonon interaction happens on the picosecond-scale, while the recombination lifetimes of the excited state are relatively long.