Ultrafast solvation and anisotropy dynamics in a tri-branched molecule based on a triphenylamine core

The steady-state spectra and the isotropic and anisotropic fluorescence dynamics of a tri-branched molecule comprising a triphenylamine core and 2,3-di(2-thienyl)acrylonitrile branches were studied in solution and solid film in the femtosecond regime. Isotropic fluorescence dynamics revealed an ultrafast decay component (ranging from 0.3 ps to 6.7 ps depending on solvent and emission wavelength) that was observed only in solution and was attributed to solvation; a slow decay component (∼1 ns), attributed to radiative population decay, was also observed. The solvation process was studied in three different solvents of different polarities and viscosities. The solvation efficiency increased with increasing solvent polarity whilst solvation time was greatest in the solvent of highest viscosity. Anisotropy dynamics showed an ultrafast decay in the fs regime indicating strong intramolecular interactions among the branches.