Solvent Effects on the Two-photon Absorption Cross Section of DCM Derivatives

The One-photon photo-physical properties(difference in static dipole moments, transition dipole moment, transition energy, etc.) of four DCM derivatives, which contain triphenylamine centre, were investigated in a series of organic solvents, and the solvent effects on their two-photon absorption cross-sections (delta(tpa)) were measured by means of two-photon induced fluorescence method. Steady spectra indicated that the excited states of these samples possess notable intramolecular charge transfer(ICT) character, and electron-withdrawing end groups had exerted large influences on the spectroscopic properties of these molecules, while the number of branch mainly influence the value of TPA cross-section. The differences in 5,P. of the four samples can be well fitted by two-state expression of TPA. The trends of 8 value with the increasing of solvent's dielectric constant are different by changing electron-withdrawing end groups.