The ultrafast dynamics and nonlinear optical properties of tribranched conjugated polymers with triphenylamine as the core

The nonlinear optical properties and the ultrafast dynamics for the polymers with the donor-acceptor structure were measured by the femtosecond laser spectroscopic techniques. Two polymers show intense two-photon absorption properties due to the unique tribranched structure. The ultrafast dynamics of the excited states were measured by two-color femtosecond pump-probe method, and the relaxation properties of the fluorescence emission state were detected by time-resolved fluorescence (TRFL) technique. We suggest that the fast decay component in the TRFL dynamics comes from the exciton migration process, and the slow decay component is caused by the recombination process of the excitons. In two-color femtosecond pump-probe and TRFL dynamics, both decay processes were accelerated when the solvent was changed from CHCl3 to DMSO, due to the fact that the dipole moment of DMSO is larger than that of CHCl3.