Steady-state excitation anisotropy, lifetimes, and time-resolved emission spectra of new 2-photon absorbing fluorene derivatives were measured in aprotic solvents at room temperature. Excitation anisotropy spectra in viscous silicon oil allowed the determination of the spectral position cf three electronic transitions S0 → S1, S0 → S 2, S0 → S3 (Si i = 1, 2, 3 are the singlet electronic states) and the angles (∼ 30°) between absorption S0 → S1 and emission S1 → S 0 dipole moments for the first electronic transition. Solvate relaxation processes in the first excited state of the investigated fluorene molecules affect the lifetimes of these states, τ1, so that experimental values of τ1 do not correspond to those calculated by Strickler and Berg theory. The influence of the molecular concentration on the fluorescence quantum yields and τ1 have been investigated.
All Science Journal Classification (ASJC) codes
- Clinical Psychology
- Social Sciences (miscellaneous)
- Sociology and Political Science
- Clinical Biochemistry
- Fluorescence lifetime
- Steady-state spectroscopy